PUBLIC RELEASE DRAFT
May 2025

EPA-740-D-25-014
May 2025

Office of Chemical Safety and
Pollution Prevention

I.UA United States

Lb I	Environmental Protection Agency

Draft Environmental Release and Occupational Exposure
Assessment for Dibutyl Phthalate
(DBP)

Technical Support Document for the Draft Risk Evaluation

CASRN 84-74-2

May 2025


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27	TABLE OF CONTENTS

28	KEY ABBREVIATIONS AND ACRONYMS	14

29	SUMMARY	17

30	1 INTRODUCTION	20

31	1.1 Overview	20

32	1.2 Scope	20

33	2 COMPONENTS OF AN ENVIRONMENTAL RELEASE AND OCCUPATIONAL

34	EXPOSURE ASSESSMENT	25

35	2.1 Approach and Methodology for Process Descriptions	25

36	2.2 Approach and Methodology for Estimating Number of Facilities	26

37	2.3 Environmental Releases Approach and Methodology	26

38	2.3,1 Identifying Release Sources	27

39	2.3.2 Estimating Number of Release Days	27

40	2.3.3 Estimating Releases from Data Reported to EPA	28

41	2.3.3.1 Estimating Wastewater Discharges from TRI and DMR	30

42	2.3.3.2 Estimating Air Emissions from TRI and NEI	31

43	2.3.3.3 Estimating Land Disposals from TRI	32

44	2.3.4 Estimating Releases from Models	32

45	2.3.5 Estimating Releases Using Literature Data	33

46	2.4 Occupational Exposure Approach and Methodology	33

47	2.4.1 Identifying Worker Activities	34

48	2.4,2 Estimating Inhalation Exposures	34

49	2.4.2.1 Inhalation Monitoring Data	34

50	2.4.2.2 Inhalation Exposure Modeling	36

51	2.4.3 Estimating Dermal Exposures	37

52	2.4.3.1 Dermal Absorption Data	37

53	2.4.3.2 Flux-Limited Dermal Absorption for Liquids	38

54	2.4.3.3 Flux-Limited Dermal Absorption for Solids	38

55	2.4.3.4 Uncertainties in Dermal Absorption Estimation	40

56	2.4.4 Estimating Acute, Intermediate, and Chronic (Non-Cancer) Exposures	41

57	2.5 Consideration of Engineering Controls and Personal Protective Equipment	41

58	2.5,1 Respiratory Protection	41

59	2.5,2 Glove Protection	42

60	2.6 Evidence Integration for Environmental Releases and Occupational Exposures	43

61	2.7 Estimating Number of Workers and Occupational Non-users	44

62	2.7,1 Number of Workers and Occupational Non-users Estimation Methodology	44

63	2.7,2 Summary of Number of Workers and ONUs	47

64	3 ENVIRONMENTAL RELEASE AND OCCUPATIONAL EXPOSURE ASSESSMENTS

65	BY OES	49

66	3.1 Manufacturing	49

67	3.1.1 Process Description	49

68	3,1,2 Facility Estimates	50

69	3.1.3 Release Assessment	51

70	3.1.3.1 Environmental Release Points	51

71	3.1.3.2 Environmental Release Assessment Results	51

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3,1.4 Occupational Exposure Assessment	

3.1.4.1	W orkers Acti viti e s	

3.1.4.2	Occupational Inhalation Exposure Results	

3.1.4.3	Occupational Dermal Exposure Results	

3.1.4.4	Occupational Aggregate Exposure Results	

3.2	Import and Repackaging	

3.2.1	Process Description	

3.2.2	Facility Estimates	

3.2.3	Release Assessment	

3.2.3.1	Environmental Release Points	

3.2.3.2	Environmental Release Assessment Results	

3.2.4	Occupational Exposure Assessment	

3.2.4.1	W orkers Acti viti e s	

3.2.4.2	Occupational Inhalation Exposure Results	

3.2.4.3	Occupational Dermal Exposure Results	

3.2.4.4	Occupational Aggregate Exposure Results	

3.3	Incorporation into Formulations, Mixtures, and Reaction Products

3.3.1	Process Description	

3.3.2	Facility Estimates	

3.3.3	Release Assessment	

3.3.3.1	Environmental Release Points	

3.3.3.2	Environmental Release Assessment Results	

3.3.4	Occupational Exposure Assessment	

3.3.4.1	Worker Activities	

3.3.4.2	Occupational Inhalation Exposure Results	

3.3.4.3	Occupational Dermal Exposure Results	

3.3.4.4	Occupational Aggregate Exposure Results	

3.4	PVC Plastics Compounding	

3.4.1	Process Description	

3.4.2	Facility Estimates	

3.4.3	Release Assessment	

3.4.3.1	Environmental Release Points	

3.4.3.2	Environmental Release Assessment Results	

3.4.4	Occupational Exposure Assessment	

3.4.4.1	Worker Activities	

3.4.4.2	Occupational Inhalation Exposure Results	

3.4.4.3	Occupational Dermal Exposure Results	

3.4.4.4	Occupational Aggregate Exposure Results	

3.5	PVC Plastics Converting	

3.5.1	Process Description	

3.5.2	Facility Estimates	

3.5.3	Release Assessment	

3.5.3.1	Environmental Release Points	

3.5.3.2	Environmental Release Assessment Results	

3.5.4	Occupational Exposure Assessment	

3.5.4.1	Worker Activities	

3.5.4.2	Occupational Inhalation Exposure Results	

3.5.4.3	Occupational Dermal Exposure Results	

3.5.4.4	Occupational Aggregate Exposure Results	

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3.6	Non-PVC Material Manufacturing (Compounding and Converting)

3.6.1	Process Description	

3.6.2	Facility Estimates	

3.6.3	Release Assessment	

3.6.3.1	Environmental Release Points	

3.6.3.2	Environmental Release Assessment Results	

3.6.4	Occupational Exposure Assessment	

3.6.4.1	Worker Activities	

3.6.4.2	Occupational Inhalation Exposure Results	

3.6.4.3	Occupational Dermal Exposure Results	

3.6.4.4	Occupational Aggregate Exposure Results	

3.7	Application of Adhesives and Sealants	

3.7.1	Process Description	

3.7.2	Facility Estimates	

3.7.3	Release Assessment	

3.7.3.1	Environmental Release Points	

3.7.3.2	Environmental Release Assessment Results	

3.7.4	Occupational Exposure Assessment	

3.7.4.1	Worker Activities	

3.7.4.2	Occupational Inhalation Exposure Results	

3.7.4.3	Occupational Dermal Exposure Results	

3.7.4.4	Occupational Aggregate Exposure Results	

3.8	Application of Paints and Coatings	

3.8.1	Process Description	

3.8.2	Facility Estimates	

3.8.3	Release Assessment	

3.8.3.1	Environmental Release Points	

3.8.3.2	Environmental Release Assessment Results	

3.8.4	Occupational Exposure Assessment	

3.8.4.1	Worker Activities	

3.8.4.2	Occupational Inhalation Exposure Results	

3.8.4.3	Occupational Dermal Exposure Results	

3.8.4.4	Occupational Aggregate Exposure Results	

3.9	Industrial Process Solvent Use	

3.9.1	Process Description	

3.9.2	Facility Estimates	

3.9.3	Release Assessment	

3.9.3.1	Environmental Release Points	

3.9.3.2	Environmental Release Assessment Results	

3.9.4	Occupational Exposure Assessment	

3.9.4.1	W orkers Acti viti e s	

3.9.4.2	Occupational Inhalation Exposure Results	

3.9.4.3	Occupational Dermal Exposure Results	

3.9.4.4	Occupational Aggregate Exposure Results	

3.10	Use of Laboratory Chemicals	

3.10.1	Process Description	

3.10.2	Facility Estimates	

3.10.3	Release Assessment	

3.10.3.1 Environmental Release Points	

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3.10.3.2 Environmental Release Assessment Results	

3.10.4 Occupational Exposure Assessment	

3.10.4.1	Worker Activities	

3.10.4.2	Occupational Inhalation Exposure Results	

3.10.4.3	Occupational Dermal Exposure Results	

3.10.4.4	Occupational Aggregate Exposure Results	

3.11	Use of Lubricants and Functional Fluids	

3.11.1	Process Description	

3.11.2	Facility Estimates	

3.11.3	Release Assessment	

3.11.3.1	Environmental Release Points	

3.11.3.2	Environmental Release Assessment Results	

3.11.4	Occupational Exposure Assessment	

3.11.4.1	Worker Activities	

3.11.4.2	Occupational Inhalation Exposure Results	

3.11.4.3	Occupational Dermal Exposure Results	

3.11.4.4	Occupational Aggregate Exposure Results	

3.12	Use of Penetrants and Inspection Fluids	

3.12.1	Process Description	

3.12.2	Facility Estimates	

3.12.3	Release Assessment	

3.12.3.1	Environmental Release Points	

3.12.3.2	Environmental Release Assessment Results	

3.12.4	Occupational Exposure Assessment	

3.12.4.1	Worker Activities	

3.12.4.2	Occupational Inhalation Exposure Results	

3.12.4.3	Occupational Dermal Exposure Results	

3.12.4.4	Occupational Aggregate Exposure Results	

3.13	Fabrication or Use of Final Product or Articles	

3.13.1	Process Description	

3.13.2	Facility Estimates	

3.13.3	Release Assessment	

3.13.3.1 Environmental Release Points	

3.13.4	Occupational Exposure Assessment	

3.13.4.1	Worker Activities	

3.13.4.2	Occupational Inhalation Exposure Results	

3.13.4.3	Occupational Dermal Exposure Results	

3.13.4.4	Occupational Aggregate Exposure Results	

3.14	Recycling	

3.14.1	Process Description	

3.14.2	Facility Estimates	

3.14.3	Release Assessment	

3.14.3.1	Environmental Release Points	

3.14.3.2	Environmental Release Assessment Results	

3.14.4	Occupational Exposure Assessment	

3.14.4.1	Worker Activities	

3.14.4.2	Occupational Inhalation Exposure Results	

3.14.4.3	Occupational Dermal Exposure Results	

3.14.4.4	Occupational Aggregate Exposure Results	

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219	3.15 Waste Handling, Treatment, and Disposal	160

220	3.15.1 Process Description	160

221	3.15.2 Facility Estimates	162

222	3.15.3 Release Assessment	162

223	3.15.3.1 Environmental Release Assessment Results	162

224	3.15.4 Occupational Exposure Assessment	173

225	3.15.4.1 Worker Activities	173

226	3.15.4.2 Occupational Inhalation Exposure Results	174

227	3.15.4.3 Occupational Dermal Exposure Results	175

228	3.15.4.4 Occupational Aggregate Exposure Results	176

229	3.16 Distribution in Commerce	177

230	3.16.1 Process Description	177

231	4 WEIGHT OF SCIENTIFIC EVIDENCE CONCLUSIONS	178

232	4.1 Environmental Releases	178

233	4.2 Occupational Exposures	192

234	REFERENCES	203

235	APPENDICES	210

236	Appendix A EQUATIONS FOR CALCULATING ACUTE, INTERMEDIATE, AND

237	CHRONIC (NON-CANCER) INHALATION AND DERMAL EXPOSURES	210

238	A.l Equations for Calculating Acute, Intermediate, and Chronic (Non-Cancer) Inhalation

239	Exposure	210

240	A.2 Equations for Calculating Acute, Intermediate, and Chronic (Non-Cancer) Dermal

241	Exposures	211

242	A.3 Calculating Aggregate Exposure	211

243	A.4 Acute, Intermediate, and Chronic (Non-Cancer) Equation Inputs	212

244	A.4.1 Exposure Duration (ED)	212

245	A.4.2 Breathing Rate (BR)	212

246	A.4.3 Exposure Frequency (EF)	212

247	A.4.4 Intermediate Exposure Frequency (EF;nt)	213

248	A.4.5 Intermediate Duration (ID)	213

249	A.4.6 Working Years (WY)	213

250	A.4.7 Body Weight (BW)	215

251	Appendix B SAMPLE CALCULATIONS FOR CALCULATING ACUTE,

252	INTERMEDIATE, AND CHRONIC (NON-CANCER) OCCUPATIONAL

253	EXPOSURES	216

254	B.l Inhalation Exposures	216

255	B. 1.1 Example High-End AD, IADD, and ADD Calculations	216

256	B.l.2 Example Central Tendency AD, IADD, and ADD Calculations	216

257	B.2 Dermal Exposures	217

258	B.2.1 Example High-End AD, IADD, and ADD Calculations	217

259	B.2.2 Example Central Tendency AD, IADD, and ADD Calculations	218

260	Appendix C DERMAL EXPOSURE ASSESSMENT METHOD	219

261	C.l Dermal Dose Equation	219

262	C.l Parameters of the Dermal Dose Equation	219

263	C.2.1 Absorptive Flux	220

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C.2.1.1 Dermal Contact with Liquids or Formulations Containing DBP	

C.2.1.1 Dermal Contact with Solids or Articles Containing DBP	

C.2.2 Surface Area	

C.2.3 Absorption Time	

C.2.4 Dermal Loading	

C.2.4.1 Liquid Dermal Loading	

C.2.4.2 Solid Dermal Loading	

C.2.5 DBP Weight Fraction	

C.	2.6 G1 ove Protecti on F actors	

Appendix D MODEL APPROACHES AND PARAMETERS	

D. 1 EPA/OPPT Standard Models	

D,2 Manufacturing Model Approaches and Parameters	

D.2.1	Model Equations	

D.2.2 Model Input Parameters	

D.2.3 Number of Sites	

D.2.4 Throughput Parameters	

D.2.5 Number of Containers Per Year	

D.2.6 Operating Hours	

D.2.7 Manufactured DBP Concentration	

D.2.8 Air Speed	

D.2.9 Diameters of Opening	

D. 2.10 S aturati on Factor	

D.2.11 Container Size	

D.2.12 Sampling Loss Fraction	

D.2.13 Operating Days	

D.2.14 Process Operations Emission Factor	

D.2.15 Equipment Cleaning Loss Fraction	

D.2.16 Container Fill Rates	

D,3 Application of Adhesives and Sealants Model Approaches and Parameters

D.3.1 Model Equations	

D.3.2 Model Input Parameters	

D.3.3 Production Volume	

D.3.4 Throughput Parameters	

D.3.5 Number of Sites	

D.3.6 Number of Containers Per Year	

D.3.7 Adhesive/Sealant DBP Concentration	

D.3.8 Operating Days	

D.3.9 Container Size	

D.3.10 Small Container Residue Loss Fraction	

D.3.11 Fraction of DBP Released as Trimming Waste	

D.3.12 Container Fill Rate	

D.3.13 Equipment Cleaning Loss Fraction	

D,4 Application of Paints and Coatings Model Approaches and Parameters	

D.4.1 Model Equations	

D.4.2 Model Input Parameters	

D.4.3 Production Volume	

D.4.4 Number of Sites	

D.4.5 Throughput Parameters	

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D.4.6 Number of Containers per Year	249

D.4.7 Paint/Coating DBP Concentration	250

D.4.8 Operating Days	250

D.4.9 Container Size	250

D.4.10 Small Container Residue Loss Fraction	250

D.4.11 Sampling Loss Fraction	251

D.4.12 Transfer Efficiency Fraction	251

D.4.13 Container Unloading Rate	251

D.4.14 Equipment Cleaning Loss Fraction	251

D.4.15 Capture Efficiency for Spray Booth	252

D.4.16 Fraction of Solid Removed in Spray Mist	252

D.5 Use of Laboratory Chemicals Model Approaches and Parameters	252

D.5.1 Model Equations	252

D.5.2 Model Input Parameters	254

D.5.3 Production Volume and Throughput Parameters	257

D.5.4 Number of Sites	258

D.5.5 Number of Containers per Year	259

D.5.6 DBP Concentration in Laboratory Chemicals	259

D.5.7 Operating Days	260

D.5.8 Container Size	260

D.5.9 Container Loss Fractions	260

D.5.10 Dust Generation Loss Fraction, Dust Capture Efficiency, and Dust Control Efficiency.... 260

D.5.11 Small Container Fill Rate	261

D.5.12 Equipment Cleaning Loss Fraction	261

D,6 Use of Lubricants and Functional Fluids Model Approach and Parameters	261

D.6.1 Model Equations	262

D.6.2 Model Input Parameters	264

D.6.3 Production Volume and Throughput Parameters	266

D.6.4 Mass Fraction of DBP in Lubricant/Fluid and Product Density	267

D.6.5 Operating Days	267

D.6.6 Container Size	267

D.6.7 Loss Fractions	267

D.6.8 Percentage of Waste to Recycling	267

D.6.9 Percentage of Waste to Fuel Blending	268

D,7 Use of Penetrants and Inspection Fluids Release Model Approaches and Parameters	268

D.7.1 Model Equations	268

D.7.2 Model Input Parameters	270

D.7.3 Production Volume and Number of Sites	273

D.7.4 Throughput Parameters	273

D.7.5 Number of Containers per Year	274

D.7.6 Operating Hours	274

D.7.7 Penetrant DBP Concentration	275

D.7.8 Operating Days	275

I).7.9 AirSpeed	275

D.7.10 Saturation Factor	275

D.7.11 Container Size	276

D.7.12 Container Loss Fractions	276

D.7.13 Equipment Cleaning Loss Fraction	276

D.7.14 Container Fill Rates	276

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D.7.15 Diameters of Opening	276

D.7.16 Penetrant Used per Job	276

D.7.17 Jobs per Day	277

D.7.18 Percentage of Aerosol Released to Fugitive Air and Uncertain Media	277

D,8 Inhalation Exposure to Respirable Particulates Model Approach and Parameters	277

D.9 Inhalation Exposure Modeling for Penetrants and Inspection Fluids	278

D.9.1 Model Design Equations	279

D.9.2 Model Parameters	283

D.9.2.1 Far-Field Volume	285

D.9.2.2 Air Exchange Rate	285

D.9.2.3 Near-Field Indoor Air Speed	285

D.9.2.4 Near-Field Volume	286

D.9.2.5 Application Time	286

D.9.2.6 Averaging Time	286

D.9.2.7 DBP Product Concentration	286

D.9.2.8 Volume of Penetrant Used per Job	286

D.9.2.9 Number of Applications per Job	287

D.9.2.10 Amount of DBP Used per Application	287

D.9.2.11 Number of Jobs per Work Shift	287

Appendix E PRODUCTS CONTAINING DBP	288

Appendix F LIST OF SUPPLEMENTAL DOCUMENTS	291

LIST OF TABLES

Table 1-1. Crosswalk of Conditions of Use Listed in the Draft Risk Evaluation to Assessed Occupational

Exposure Scenarios	21

Table 2-1. Assigned Protection Factors for Respirators in OSHA Standard 29 CFR 1910.134	42

Table 2-2. Glove Protection Factors for Different Dermal Protection Strategies	43

Table 2-3. NAICS Code Crosswalk and Number of Workers and ONUs for Each OES	45

Table 2-4. Summary of Total Number of Workers and ONUs Potentially Exposed to DBP for Each OES

	47

Table 3-1. Reported Manufacturing and Import Production Volumes in the 2020 CDR	50

Table 3-2. Summary of Modeled Environmental Releases for Manufacture of DBP	51

Table 3-3. Summary of Estimated Worker Inhalation Exposures for Manufacture of DBP	53

Table 3-4. Summary of Estimated Worker Dermal Exposures for the Manufacturing of DBP	54

Table 3-5. Summary of Estimated Worker Aggregate Exposures for Manufacture of DBP	54

Table 3-6. Production Volume of DBP Repackaging Sites, 2020 CDR	56

Table 3-7. Summary of Air Releases from TRI for Repackaging	58

Table 3-8. Summary of Air Releases from NEI (2020) and NEI (2017) for Repackaging	60

Table 3-9. Summary of Land Releases from TRI for Repackaging	60

Table 3-10. Summary of Water Releases from TRI/DMR for Repackaging	60

Table 3-11. Summary of Estimated Worker Inhalation Exposures for Import and Repackaging of DBP62
Table 3-12. Summary of Estimated Worker Dermal Exposures for Import and Repackaging of DBP... 63
Table 3-13. Summary of Estimated Worker Aggregate Exposures for Import and Repackaging of DBP

	64

Table 3-14. Summary of Air Releases from TRI for Incorporation into Formulation, Mixture, or

Reaction Product	67

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Table 3-15. Summary of Air Releases from NEI (2020) for Incorporation into Formulation, Mixture, or

Reaction Product	68

Table 3-16. Summary of Air Releases from NEI (2017) for Incorporation into Formulation, Mixture, or

Reaction Product	69

Table 3-17. Summary of Land Releases from TRI for Incorporation into Formulation, Mixture, or

Reaction Product	69

Table 3-18. Summary of Water Releases from TRI for Incorporation into Formulation, Mixture, or

Reaction Product	70

Table 3-19. Summary of Estimated Worker Inhalation Exposures for Incorporation into Formulations,

Mixtures, or Reaction Products	72

Table 3-20. Summary of Estimated Worker Dermal Exposures for Incorporation into Formulations,

Mixtures, or Reaction Products	73

Table 3-21. Summary of Estimated Worker Aggregate Exposures for Incorporation into Formulations,

Mixtures, or Reaction Products	74

Table 3-22. Summary of Air Releases from TRI for PVC Plastics Compounding	77

Table 3-23. Summary of Air Releases from NEI (2020) for PVC Plastics Compounding	78

Table 3-24. Summary of Water Releases from DMR for PVC Plastics Compounding	78

Table 3-25. Summary of Estimated Worker Inhalation Exposures for Plastics Compounding	80

Table 3-26. Summary of Estimated Worker Dermal Exposures for Plastics Compounding	81

Table 3-27. Summary of Estimated Worker Aggregate Exposures for Plastics Compounding	82

Table 3-28. Summary of Air Releases from TRI for PVC Plastics Converting	85

Table 3-29. Summary of Air Releases from NEI (2020) for PVC Plastics Converting	86

Table 3-30. Summary of Air Releases from NEI (2017) for PVC Plastics Converting	86

Table 3-31. Summary of Estimated Worker Inhalation Exposures for PVC Plastics Converting	87

Table 3-32. Summary of Estimated Worker Dermal Exposures for PVC Plastics Converting	89

Table 3-33. Summary of Estimated Worker Aggregate Exposures for PVC Plastics Converting	89

Table 3-34. Summary of Air Releases from TRI for Non-PVC Plastics Manufacturing	93

Table 3-35. Summary of Air Releases from NEI (2020) for Non-PVC Plastics Manufacturing	94

Table 3-36. Summary of Air Releases from NEI (2017) for Non-PVC Plastics Manufacturing	95

Table 3-37. Summary of Land Releases from TRI for Non-PVC Plastics Manufacturing	96

Table 3-38. Summary of Water Releases from TRI for Non-PVC Plastic Manufacturing	96

Table 3-39. Summary of Estimated Worker Inhalation Exposures for Non-PVC Material Compounding

	98

Table 3-40. Summary of Estimated Worker Dermal Exposures for Non-PVC Material Compounding. 99
Table 3-41. Summary of Estimated Worker Aggregate Exposures for Non-PVC Material Compounding

	99

Table 3-42. Summary of Modeled Environmental Releases for Application of Adhesives and Sealants

	102

Table 3-43. Summary of TRI Air Release Data for Application of Paints, Coatings, Adhesives and

Sealants	102

Table 3-44. Summary of NEI (2020) for Application of Paints, Coatings, Adhesives and Sealants	103

Table 3-45. Summary of NEI (2017) for Application of Paints, Coatings, Adhesives and Sealants	106

Table 3-46. Summary of Estimated Worker Inhalation Exposures for Application of Adhesives and

Sealants	110

Table 3-47. Summary of Estimated Worker Dermal Exposures for Application of Adhesives and

Sealants	Ill

Table 3-48. Summary of Estimated Worker Aggregate Exposures for Application of Adhesives and

Sealants	112

Table 3-49. Summary of Modeled Environmental Releases for Application of Paints and Coatings.... 115

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Table 3-50. Summary of TRI Air Release Data for Application of Paints, Coatings, Adhesives and

Sealants	115

Table 3-51. Summary of NEI (2020) Air Releases for Application of Paints, Coatings, Adhesives and

Sealants	116

Table 3-52. Summary of NEI (2017) for Application of Paints, Coatings, Adhesives and Sealants	119

Table 3-53. Summary of Estimated Worker Inhalation Exposures for Application of Paints and Coatings

	122

Table 3-54. Summary of Estimated Worker Dermal Exposures for Application of Paints and Coatings

	123

Table 3-55. Summary of Estimated Worker Aggregate Exposures for Application of Paints and Coatings

	124

Table 3-56. Summary of Air Releases from TRI for Industrial Process Solvent Use	128

Table 3-57. Summary of Air Releases from NEI (2020) for Industrial Process Solvent Use	129

Table 3-58. Summary of Land Releases from TRI for Industrial Process Solvent Use (Incorporation into

Formulation, Mixture, or Reaction Product)	129

Table 3-59. Summary of Estimated Worker Inhalation Exposures for Industrial Process Solvent Use 130

Table 3-60. Summary of Estimated Worker Dermal Exposures for Industrial Process Solvent Use	131

Table 3-61. Summary of Estimated Worker Aggregate Exposures for Industrial Process Solvent Use 132

Table 3-62. Summary of Modeled Environmental Releases for Use of Laboratory Chemicals	135

Table 3-63. Summary of NEI (2020) for Use of Laboratory Chemicals	135

Table 3-64. Summary of Estimated Worker Inhalation Exposures for Use of Laboratory Chemicals .. 137

Table 3-65. Summary of Estimated Worker Dermal Exposures for Use of Laboratory Chemicals	138

Table 3-66. Summary of Estimated Worker Aggregate Exposures for Use of Laboratory Chemicals.. 139
Table 3-67. Summary of Modeled Environmental Releases for Use of Lubricants and Functional Fluids

	141

Table 3-68. Summary of Estimated Worker Inhalation Exposures for Use of Lubricants and Functional

Fluids	142

Table 3-69. Summary of Estimated Worker Dermal Exposures for Use of Lubricants and Functional

Fluids	143

Table 3-70. Summary of Estimated Worker Aggregate Exposures for Use of Lubricants and Functional

Fluids	144

Table 3-71. Summary of Modeled Environmental Releases for Use of Penetrants and Inspection Fluids

	147

Table 3-72. Summary of Estimated Worker Inhalation Exposures for Use of Penetrants and Inspection

Fluids	148

Table 3-73. Summary of Estimated Worker Dermal Exposures for Use of Penetrants and Inspection

Fluids	149

Table 3-74. Summary of Estimated Worker Aggregate Exposures for Use of Penetrants and Inspection

Fluids	150

Table 3-75. Release Activities for Fabrication/Use of Final Articles Containing DBP	151

Table 3-76. Summary of Estimated Worker Inhalation Exposures for Fabrication or Use of Final

Products or Articles	152

Table 3-77. Summary of Estimated Worker Dermal Exposures for Fabrication or Use of Final Product or

Articles	153

Table 3-78. Summary of Estimated Worker Aggregate Exposures for Fabrication or Use of Final

Product or Articles	154

Table 3-79. Production Volumes Used to Develop Recycling Estimates	156

Table 3-80. Summary of Estimated Worker Inhalation Exposures for Recycling	158

Table 3-81. Summary of Estimated Worker Dermal Exposures for Recycling	158

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Table 3-82. Summary of Estimated Worker Aggregate Exposures for Recycling	159

Table 3-83. Summary of Air Releases from TRI for Waste Handling, Treatment, and Disposal	164

Table 3-84. Summary of Air Releases from NEI (2020) for Waste Handling, Treatment, and Disposal

	165

Table 3-85. Summary of Air Releases from NEI (2017) for Waste Handling, Treatment, and Disposal

	169

Table 3-86. Summary of Land Releases from TRI for Waste Handling, Treatment, and Disposal	170

Table 3-87. Summary of Water Releases from DMR/TRI for Waste Handling, Treatment, and Disposal

	170

Table 3-88. Summary of Estimated Worker Inhalation Exposures for Disposal	175

Table 3-89. Summary of Estimated Worker Dermal Exposures for Disposal	176

Table 3-90. Summary of Estimated Worker Aggregate Exposures for Disposal	176

Table 4-1. Summary of the Data Sources Used for Environmental Releases by OES	179

Table 4-2. Summary of Assumptions, Uncertainty, and Overall Weight of Scientific Evidence

Conclusions in Release Estimates by OES	182

Table 4-3. Summary of Assumptions, Uncertainty, and Overall Confidence in Inhalation Exposure

Estimates by OES	193

LIST OF FIGURES

Figure 2-1. DBP Average Absorptive Flux vs. Absorption Time	39

Figure 3-1. Manufacturing Flow Diagram	49

Figure 3-2. Import and Repackaging Flow Diagram (U.S. EPA, 2022a)	55

Figure 3-3. Incorporation into Formulations, Mixtures, and Reaction Products Flow Diagram (U.S. EPA,

2014a)	65

Figure 3-4. PVC Plastics Compounding Flow Diagram (U.S. EPA, 2021c)	75

Figure 3-5. PVC Plastics Converting Flow Diagram (U.S. EPA, 2021d)	83

Figure 3-6. Non-PVC Material Compounding Flow Diagram (U.S. EPA, 2021c)	90

Figure 3-7. Consolidated Compounding and Converting Flow Diagram Facility Estimates	91

Figure 3-8. Application of Adhesives and Sealants Flow Diagram	100

Figure 3-9. Application of Paints and Coatings Flow Diagram	113

Figure 3-10. Industrial Process Solvent Use	126

Figure 3-11. Use of Laboratory Chemicals Flow Diagram (U.S. EPA, 2023d)	133

Figure 3-12. Use of Lubricants and Functional Fluids Flow Diagram	140

Figure 3-13. Use of Penetrants and Inspection Fluids Flow Diagram Non-Aerosol Use (OECD, 201 lc)

	145

Figure 3-14. Use of Penetrants and Inspection Fluids Flow Diagram Aerosol Use (OECD, 201 lc)	145

Figure 3-15. PVC Recycling Flow Diagram (U.S. EPA, 2021c)	155

Figure 3-16. Typical Waste Disposal Process	161

LIST OF APPENDIX TABLES

TableApx A-l. Parameter Values for Calculating Inhalation Exposure Estimates	212

Table_Apx A-2. Overview of Average Worker Tenure from U.S. Census SIPP (Age Group 50+)	215

Table_Apx A-3. Median Years of Tenure with Current Employer by Age Group	215

Table_Apx C-l. Summary of Dermal Dose Equation Values	220

Table Apx C-2. Summary of DBP Weight Fractions for Dermal Exposure Estimates	222

Table Apx C-3. Exposure Control Efficiencies and Protection Factors for Different Dermal Protection

Strategies from ECETOC TRA V3	223

Table Apx D-l. Models and Variables Applied for Release Sources in the Manufacturing OES	229

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TableApx D-2. Summary of Parameter Values and Distributions Used in the Manufacturing Models

	230

Table Apx D-3. Sites Reporting to CDR for Domestic Manufacture of DBP	232

Table Apx D-4. Sampling Loss Fraction Data from the March 2023 Methodology for Estimating

Environmental Releases from Sampling Waste	235

Table Apx D-5. Models and Variables Applied for Release Sources in the Application of Adhesives and

Sealants OES	236

Table Apx D-6. Summary of Parameter Values and Distributions Used in the Application of Adhesives

and Sealants Model	238

Table Apx D-7. CDR Reported Site Information for Use in Calculation of Use of Adhesives, Sealants,

Paints, and Coatings Production Volume	239

Table Apx D-8. Models and Variables Applied for Release Sources in the Application of Paints and

Coatings OES	243

Table Apx D-9. Summary of Parameter Values and Distributions Used in the Application of Paints and

Coatings Model	246

Table Apx D-10. Sampling Loss Fraction Data from the March 2023 Methodology for Estimating

Environmental Releases from Sampling Waste	251

TableApx D-l 1. Models and Variables Applied for Release Sources in the Use of Laboratory

Chemicals OES	253

Table Apx D-12. Summary of Parameter Values and Distributions Used in the Use of Laboratory

Chemicals Model	255

TableApx D-13. CDR Reported Site Information for Use in Calculation of Laboratory Chemicals

Production Volume	257

Table Apx D-14. Models and Variables Applied for Release Sources in the Use of Lubricants and

Functional Fluids OES	262

TableApx D-15. Summary of Parameter Values and Distributions Used in the Use of Lubricants and

Functional Fluids Model	265

Table Apx D-16. Models and Variables Applied for Release Sources in the Use of Penetrants and

Inspection Fluids OES	269

Table Apx D-17. Summary of Parameter Values and Distributions Used in the Release Estimation of

Penetrants and Inspection Fluids	271

Table Apx D-18. Summary of DBP Exposure Estimates for OESs Using the Generic Model for

Exposure to PNOR	278

Table Apx D-19. Summary of Parameter Values Used in the Near-Field/Far-Field Inhalation Exposure

Modeling of Penetrants and Inspection Fluids	284

Table_Apx E-l. Products Containing DBP	288

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590 KEY ABBREVIATIONS AND ACRONYMS

AC

Acute exposure concentration

ACGM

American Conference of Governmental Industrial Hygienists

AD

Acute retained dose

ADD

Average daily dose

AD C intermediate

Intermediate Average Daily Concentration

AIHA

American Industrial Hygiene Association

APDR

Acute potential dermal dose rate

APF

Assigned Protection Factor

AT acute

Acute Averaging Time

ATc

Averaging Time for Cancer Risk

ATi

Averaging Time for Intermediate Exposure

AWD

Annual Working Days

BLS

Bureau of Labor Statistics (U.S.)

BR

Breathing rate

BW

Body weight

CDR

Chemical Data Reporting (rule)

CEB

Chemical Engineering Branch

CEHD

Chemical Exposure Health Database

CFR

Code of Federal Regulations

CEM

Consumer Exposure Model

CPS

Current Population Survey

CPSC

Consumer Product Safety Commission (U.S.)

CT

Central tendency

DD

Dermal Daily Dose

DBP

Dicyclohexyl phthalate

DMR

Discharge Monitoring Report

ECETOC TRA

European Centre for Ecotoxicology and Toxicology of Chemicals Targeted



Risk Assessment

ED

Exposure duration

EF

Exposure frequency

EFint

Intermediate Exposure Frequency

ELG

Effluent Limitation Guidelines

EPA

Environmental Protection Agency (U.S.) (or "the Agency")

ESD

Emission scenario document

ETIMEOFF

Months When Not Working (CPS data)

G

Vapor Generation Rate

GS

Generic scenario

HAP

Hazardous Air Pollutant

HE

High-end

HVLP

High volume low pressure

IADC

Intermediate average daily concentration

IAD

Intermediate average daily dose

ID

Days for intermediate duration

IRER

Initial Review Engineering Report

LADC

Lifetime average daily concentrations

LADD

Lifetime average daily dose

LOD

Limit of detection

LT

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MW

Molecular weight of DBP

NAICS

North American Industry Classification System

NEI

National Emissions Inventory

NESHAP

National Emissions Standards of Hazardous Air Pollutants

NICNAS

National Industrial Chemicals Notification and Assessment Scheme

NIOSH

National Institute of Occupational Safety and Health

OARS

Occupational Alliance for Risk Science

OD

Operating days

OECD

Organisation for Economic Co-Operation and Development

OEL

Occupational Exposure Limit

OES

Occupational exposure scenario

OIS

Occupational Safety and Health Information System

ONU

Occupational non-users

OPPT

Office of Pollution Prevention and Toxics (EPA)

OSHA

Occupational Safety and Health Administration

OVS

OSHA Versatile Sampler

PAPR

Power air-purifying respirator

PBZ

Personal breathing zone

PEL

Permissible Exposure Limit

PF

Protection factor

POTW

Publicly owned treatment works

PPE

Personal protective equipment

PV

Production volume

RD

Release days

REL

Recommended Exposure Limits

Pproduct

Product density

PDBP

DBP density

RQ

Reportable Quantity

SDS

Safety data sheet

SIC

Standard Industrial Classification

SIPP

Survey of Income and Program Participation

SpERC

Specific Emission Release Category

SAR

Supplied-air respirator

SCBA

Self-contained breathing apparatus

SRRP

Source Reduction Research Partnership

SUSB

Statistics of U.S. Businesses

Tage

Worker Age in SIPP

TDS

Technical data sheets

TJBIND1

Employed Individual Works (SIPP Data)

TLV

Threshold Limit Value

TMAKMNYR

First Year Worked (SIPP Data)

TRI

Toxics Release Inventory

TSCA

Toxic Substances Control Act

TSD

Technical support document

TWA

Time-weighted average

U.S.

United States

Vitldbp

Molar volume of DBP

VP

DBP vapor pressure

WEEL

Workplace Environmental Exposure Level

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WWT	Wastewater treatment

WY	Working years per lifetime

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SUMMARY

This technical support document (TSD) accompanies the Toxic Substances Control Act (TSCA) Draft
Risk Evaluation for Dibutyl Phthalate (DBP) (	325b). DBP is a Toxics Release Inventory

(TRI)-reportable substance and is included on the TSCA Inventory, making it reportable under the
Chemical Data Reporting (CDR) rule. This draft assessment describes the use of reasonably available
information to estimate environmental releases of DBP and to evaluate occupational exposures. See the
Draft Risk Evaluation for DBP for a complete list of all the TSDs for DBP.

Focus of the Environmental Release and Occupational Exposure Assessment for DBP
During scoping, EPA considered the TSCA conditions of use (COUs) for DBP. The 2020 CDR
indicated 1 to 10 million pounds (lb) of DBP (CASRN 84-74-2) were manufactured or imported into the
United States in 2019 (U.S. EPA. 2020a). The largest number of reported uses of DBP was as a
plasticizer in plastics. Secondary uses for DBP are as a plasticizer/additive in adhesives, sealants, paints,
coatings, rubbers, and other applications.

Exposures to workers, consumers, general populations, and ecological species may occur from releases
of DBP to air, land, and water from industrial, commercial, and consumer uses of DBP and DBP-
containing articles. Workers and occupational non-users (ONUs) may be exposed to DBP while
handling solid and liquid formulations that contain DBP or during dust- and mist-generating activities
that may be present during most COUs. ONUs are those who may work in the vicinity of chemical-
related activities but do not handle the chemicals themselves, such as managers or inspectors. This draft
TSD provides the details of the assessment of the environmental releases and occupational exposures
from each COU of DBP.

Approach for Environmental Releases and Occupational Exposures Assessment for DBP
EPA evaluated environmental releases and occupational exposures of DBP for each occupational
exposure scenario (OES). Each OES is developed based on a set of occupational activities and
conditions such that similar occupational exposures and environmental releases are expected from the
use(s) covered under the OES. For each OES, EPA provided occupational exposure and environmental
release results, which are expected to be representative of the entire population of workers and sites for
the given OES across the United States.

EPA evaluated environmental releases of DBP to air, water, and land from the OESs associated with the
COUs assessed in the draft risk evaluation. The Agency reviewed release data from TRI (data from
2017-2022), Discharge Monitoring Reports (DMR; data from 2017-2022), and the 2017 and 2020
National Emissions Inventory (NEI) to identify relevant releases of DBP to the environment. These
sources provide site-specific release information based on measurements, mass balances, or emission
factors. In addition, EPA also considered other relevant release data to fill data gaps from other peer-
reviewed or literature sources identified through systematic review. For OESs without any release data,
the Agency used modeling approaches to assess release estimates.

EPA evaluated acute, intermediate, and chronic exposures of DBP to workers and ONUs for each OES.
The Agency used (1) inhalation monitoring data from literature sources when available; and (2)
exposure models where monitoring data were not available, or where these data were deemed
insufficient for capturing exposures within the OES. EPA also used in vitro guinea pig absorption data
along with modeling approaches to estimate dermal exposures to workers and ONUs.

Preliminary Results for Environmental Releases and Occupational Exposures to DBP

EPA evaluated environmental releases of DBP to air, water, and/or land for all OESs assessed in the

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draft risk evaluation. Detailed release results for each OES to each type of assessed media can be found
in Section 3 of this TSD. For overall releases, NEI generally provided the most release reports to air;
however, the highest release estimates were provided by TRI for releases to land and water. Where data
was not found in the available release databases, standard models were used to generate release
estimates.

EPA also evaluated inhalation and dermal exposures to worker populations, including ONUs and
females of reproductive age, for each OES. Detailed exposure results for each OES and exposure route
can be found in Section 3 of this document.

Uncertainties of this Draft Assessment

Uncertainties exist with the monitoring data and modeling approaches used to assess DBP
environmental releases and occupational exposures. One factor of uncertainty in the environmental
releases includes the accuracy of the reported releases as well as the limitations in representativeness to
all U.S. sites because TRI, DMR, and NEI may not capture all relevant sites due to reporting thresholds
and different reporting protocols. More information on the reporting requirements for each of these
databases is provided in Section 2.3.3. For modeled releases, the lack of DBP facility production volume
data adds uncertainty; in such cases, EPA used throughput estimates based on CDR reporting thresholds,
which may result in production volume estimates that are not representative of the actual production
volume of DBP in the United States. The Agency also used generic EPA models and default input
parameter values when site-specific data were not available. In addition, site-specific differences in use
practices and engineering controls for DBP exist but are largely unknown. This represents another
source of variability that EPA could not quantify in this draft assessment.

For inhalation exposures, the primary limitation of using monitoring data is the uncertainty of the
representativeness of these exposure data toward the true distribution of inhalation concentrations at a
specific facility. Because DBP has low volatility and relatively low absorption, it is possible that the
chemical remains on the surface of the skin following dermal contact until the skin is washed. Therefore,
in absence of DBP exposure duration data, for occupational dermal exposure assessment, EPA assumed
(1) a standard 8-hour workday, (2) that the chemical is contacted at least once per day, and (3) that
absorption of DBP from occupational dermal contact with materials containing DBP may extend up to 8
hours per day (	). However, if a worker uses proper personal protective equipment (PPE)

or washes their hands after contact with DBP or DBP-containing materials, dermal exposure may be
eliminated. Therefore, the assumption of an 8-hour exposure duration for DBP may lead to
overestimation of occupational dermal exposure. Also, EPA used dermal absorption data from tests
performed on guinea pigs to estimate dermal exposure from liquids. Because guinea pigs have more
permeable skin than humans (OECD. 2004c). the Agency is confident that using in vitro dermal
absorption data from guinea pigs provide an upper-bound of dermal absorption of DBP.

Environmental and Exposure Pathways Considered in this Risk Evaluation

EPA assessed environmental releases to air, water, and land to estimate exposures to the general
population and ecological species for DBP COUs. The environmental release estimates developed by the
Agency were used both to estimate the presence of DBP in the environment and biota and to evaluate
the environmental hazards. The release estimates were also used to model exposure to the general
population and ecological species where environmental monitoring data were not available.

EPA assessed risks for acute, intermediate, and chronic exposure scenarios in workers {i.e., those
directly handling DBP) and ONUs for each OES. The Agency assumed that workers and ONUs would
be individuals of both sexes (aged 16+ years, including pregnant workers) based upon occupational

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690	work permits. An objective of the assessment was to provide separate exposure level estimates for

691	workers and ONUs. Dermal exposures were considered for all workers, but only considered for ONUs

692	with potential exposure to dust or mist deposited on surfaces.

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1 INTRODUCTION

1.1	Overview

This technical document supports the TSCA Draft Risk Evaluation for Dibutyl Phthalate (DBP) (also
called "Draft Risk Evaluation for DBP") (	25b) that was conducted under the Frank R.

Lautenberg Chemical Safety for the 21st Century Act, which amended TSCA on June 22, 2016. The
new law includes statutory requirements and deadlines for actions related to conducting risk evaluations
of existing chemicals.

Under TSCA section 6(b), the U.S. Environmental Protection Agency (EPA or "the Agency") must
designate chemical substances as high-priority substances for risk evaluation or low-priority substances
for which risk evaluations are not warranted at the time, and upon designating a chemical substance as a
high-priority substance, initiate a risk evaluation on the substance. TSCA section 6(b)(4) directs EPA to
conduct risk evaluations for existing chemicals, to "determine whether a chemical substance presents an
unreasonable risk of injury to health or the environment, without consideration of costs or other nonrisk
factors, including an unreasonable risk to a potentially exposed or susceptible subpopulation identified
as relevant to the risk evaluation by the Administrator under the conditions of use."

TSCA section 6(b)(4)(D) and implementing regulations require that EPA publish the scope of the risk
evaluation to be conducted, including the hazards, exposures, conditions of use (COUs), and PESS that
the Administrator expects to consider, within 6 months after the initiation of a risk evaluation. In
addition, a draft scope is to be published pursuant to 40 CFR 702.41. In December 2019, EPA published
a list of 20 chemical substances that have been designated high priority substances for risk evaluations
CEPA-HO-Q] .19-0131) (84 FR 71924, December 30, 2019), as required by TSCA section 6(b)(2)(B),
which initiated the risk evaluation process for those chemical substances. Dibutyl phthalate (DBP) is one of
the chemicals designated as a high priority substance for risk evaluation.

DBP is a common chemical name for a chemical substance that includes the following names: dibutyl
phthalate (CASRN 84-74-2), dibutyl benzene-1,2-dicarboxylate, 1,2-benzenedicarboxylic acid, dibutyl
ester, di-n-butylorthophthalate, di-n-butyl phthalate. DBP is a low volatility liquid that is used primarily
as a plasticizer in PVC, though it is also used in the production of adhesives, sealants, paints, coatings,
rubbers, non-PVC materials, and other applications. All uses are subject to federal and state regulations
and reporting requirements. DBP is a Toxics Release Inventory (TRI)-reportable substance, included on
the TSCA Inventory, and reported under the Chemical Data Reporting (CDR) rule.

1.2	Scope

EPA assessed environmental releases and occupational exposures for conditions of use as described in
Table 2-2 of the Final Scope of the Risk Evaluation for Dibutyl Phthalate (DBP); CASRN 84-74-2 (also
called the "final scope") (	,020b). To estimate environmental releases and occupational

exposures, EPA first developed occupational exposure scenarios (OESs) related to the conditions of use
of DBP. An OES is based on a set of facts, assumptions, and inferences that describe how releases and
exposures take place within an occupational condition of use. The occurrence of releases/exposures may
be similar across multiple conditions of use, or there may be several ways in which releases/exposures
take place for a given condition of use. Table 1-1 shows mapping between the conditions of use in Table
2-2 of the Draft Risk Evaluation for Dibutyl Phthalate (DBP) (	15b) to the OESs assessed

in this draft TSD.

In general, EPA mapped OESs to COUs using professional judgment based on available data and

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information. Several of the condition of use categories and subcategories were grouped and assessed
together in a single OES due to similarities in the processes or lack of data to differentiate between
them. This grouping minimized repetitive assessments. In other cases, condition of use subcategories
were further delineated into multiple OESs based on expected differences in process equipment and
associated release/exposure potentials between facilities. EPA assessed environmental releases and
occupational exposures for the following OESs:

1.	Manufacturing

2.	Import and repackaging

3.	Incorporation into formulations, mixtures, and reaction products

4.	PVC plastics compounding

5.	PVC plastics converting

6.	Non-PVC material manufacturing (compounding and converting)

7.	Application of adhesives and sealants

8.	Application of paints and coatings

9.	Industrial process solvent use

10.	Use of laboratory chemicals

11.	Use of lubricants and functional fluids

12.	Use of penetrants and inspection fluids

13.	Fabrication or use of final product or articles

14.	Recycling

15.	Waste handling, treatment, and disposal

16.	Distribution in commerce

Table 1-1. Crosswalk of Conditions of Use Listed in the Draft Risk Evaluation to Assessed
Occupational Exposure Scenarios		

COU



Life Cycle
Stage"

Category''

Subcategory'

OES(s)rf

Manufacturing

Domestic
manufacturing

Domestic manufacturing

Manufacturing

Importing

Importing

Import and repackaging



Repackaging

Laboratory chemicals in wholesale and
retail trade; plasticizers in wholesale and
retail trade; and plastics material and resin
manufacturing

Import and repackaging



Processing as a
reactant

Intermediate in plastic manufacturing

Incorporation into
formulations, mixtures, or
reaction product

Processing

Incorporation into
formulation, mixture,

Solvents (which become part of product
formulation or mixture) in chemical

Incorporation into
formulations, mixtures, or



or reaction product

product and preparation manufacturing;
soap, cleaning compound, and toilet
preparation manufacturing; adhesive
manufacturing; and printing ink
manufacturing

reaction product

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cou



Life Cycle
Stage"

Category''

Subcategory'

OES(s)rf

Processing

Incorporation into
formulation, mixture,
or reaction product

Plasticizer in paint and coating
manufacturing; plastic material and resin
manufacturing; rubber manufacturing;
soap, cleaning compound, and toilet
preparation manufacturing; textiles,
apparel, and leather manufacturing;
printing ink manufacturing; basic organic
chemical manufacturing; and adhesive
and sealant manufacturing

Incorporation into
formulations, mixtures, or
reaction product
PVC plastics compounding;
Non-PVC material
manufacturing



Pre-catalyst manufacturing

Incorporation into
formulations, mixtures, or
reaction product



Incorporation into
articles

Plasticizer in adhesive and sealant
manufacturing; building and construction
materials manufacturing; furniture and
related product manufacturing; ceramic
powders; plastics product manufacturing;
and rubber product manufacturing

PVC plastics converting
Non-PVC material
manufacturing



Recycling

Recycling

Recycling

Distribution in

Distribution in



Distribution in commerce

Commerce

commerce







Non-incorporative
activities

Solvent, including in maleic anhydride
manufacturing technology

Industrial process solvent use



Construction, paint,
electrical, and metal
products

Adhesives and sealants

Application of adhesives and
sealants

Industrial Use

Paints and coatings

Application of paints and
coatings



Automotive articles

Fabrication or use of final
product or articles



Other uses

Lubricants and lubricant additives

Use of lubricants and





functional fluids





Propellants

Fabrication or use of final
product or articles



Automotive, fuel,

Automotive care products

Use of lubricants and



agriculture, outdoor



functional fluids



use products







Construction, paint,

Adhesives and sealants

Application of adhesives and



electrical, and metal



sealants

Commercial

products

Paints and coatings

Application of paints and

Use





coatings





Cleaning and furnishing care products

Use of lubricants and



Furnishing, cleaning,



functional fluids



treatment care

Floor coverings; construction and building

Fabrication or use of final



products

materials covering large surface areas
including stone, plaster, cement, glass and

product or articles

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cou

OES(s)rf

Life Cycle
Stage"

Category''

Subcategory'

Commercial
Use



ceramic articles; fabrics, textiles, and
apparel



Furniture and furnishings

Packaging, paper,
plastic, toys, hobby
products

Ink, toner, and colorant products

Application of paints and
coatings

Packaging (excluding food packaging),
including rubber articles; plastic articles
(hard); plastic articles (soft); other articles
with routine direct contact during normal
use, including rubber articles; plastic
articles (hard)

Fabrication or use of final
product or articles

Toys, playground, and sporting equipment

Fabrication or use of final
product or articles

Other uses

Laboratory chemicals

Use of laboratory chemicals

Automotive articles

Fabrication or use of final
product or articles

Chemiluminescent light sticks

Fabrication or use of final
product or articles

Inspection penetrant kit

Use of Penetrants and
Inspection Fluids

Lubricants and lubricant additives

Use of lubricants and
functional fluids

Disposal

Disposal

Disposal

Waste handling, treatment,
and disposal

"Life Cycle Stage Use Definitions (40 CFR ง 711.3)

-	"Industrial use" means use at a site at which one or more chemicals or mixtures are manufactured (including
imported) or processed.

-	"Commercial use" means the use of a chemical or a mixture containing a chemical (including as part of an article) in
a commercial enterprise providing saleable goods or services.

-	"Consumer use" means the use of a chemical or a mixture containing a chemical (including as part of an article, such
as furniture or clothing) when sold to or made available to consumers for their use.

-	Although EPA has identified both industrial and commercial uses here for purposes of distinguishing scenarios in
this document, the Agency interprets the authority over "any manner or method of commercial use" under TSCA
section 6(a)(5) to reach both.

b These categories of COU appear in the Life Cycle Diagram, reflect CDR codes, and broadly represent COUs of
DBP in industrial and/or commercial settings.

c These subcategories represent more specific activities within the life cycle stage and category of the COUs of DBP.
d An OES is based on a set of facts, assumptions, and inferences that describe how releases and exposures take place within
an occupational COU. The occurrence of releases/exposures may be similar across multiple conditions of use (multiple
COUs mapped to single OES), or there may be several ways in which releases/exposures take place for a given COU (single
COU mapped to multiple OESs).

764

765	The assessment of releases includes quantifying annual and daily releases of DBP to air, water, and land.

766	Releases to air include both fugitive and stack air emissions and emissions resulting from on-site waste

767	treatment equipment, such as incinerators. For the purposes of this report, releases to water include both

768	direct discharges to surface water and indirect discharges to publicly owned treatment works (POTW) or

769	non-POTW wastewater treatment (WWT) plants. EPA considers removal efficiencies of POTWs and

770	WWT plants as well as environmental fate and transport properties when evaluating risks from indirect

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discharges. Releases to land include any disposal of liquid or solid wastes containing DBP into landfills,
land treatment, surface impoundments, or other land applications. The purpose of this module is to
quantify releases; therefore, this report does not discuss downstream environmental fate and transport
factors used to estimate exposures to the general population and ecological species. The Draft Risk
Evaluation for Dibutyl Phthalate (DBP) (U.S. EPA. 2025b) describes how these factors were considered
when determining exposure and risk.

For workplace exposures, EPA considered exposures to both workers who directly handle DBP and
occupational non-users (ONUs) who do not directly handle DBP, but may be exposed to dust, vapors or
mists that enter their breathing zone while working in locations near DBP handling. EPA evaluated
inhalation and dermal exposures to both workers and ONUs. EPA has performed a quantitative
estimation on the effect of Personal Protective Equipment (PPE) on worker exposure risk estimates. The
effect of PPE on occupational risk estimates is discussed in the Draft Risk Evaluation for Dibutyl
Phthalate (DBP) (U.S.	025b) and the calculations can be found in the Draft Risk Calculator for

Occupational Exposures for Dibutyl Phthalate (DBP) (U.S. EPA. 2025a).

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2 COMPONENTS OF AN ENVIRONMENTAL RELEASE AND
OCCUPATIONAL EXPOSURE ASSESSMENT

EPA describes the assessed COUs for DBP in the Section 1.1.2 of th q Draft Risk Evaluation for Dibutyl
Phthalate (DBP) (	025b); however, some COUs differ in terms of specific DBP processes

and associated exposure/release scenarios. Therefore, Table 1-1 provides a crosswalk that maps the DBP
COUs to the more specific OESs. The environmental release and occupational exposure assessments of
each OES comprised the following components:

•	Process Description: A description of the OES, including the function of the chemical in the
scenario; physical forms and weight fractions of the chemical throughout the process; the total
production volume associated with the OES; per site throughputs/use rates of the chemical;
operating schedules; and process equipment used during the OES.

•	Facility Estimates: An estimate of the number of sites that use DBP for the given OES.

•	Environmental Release Assessment

o Environmental Release Sources: A description of the potential sources of

environmental releases in the process and their expected media of release for the OES.
o Environmental Release Assessment Results: Estimates of DBP released into each
environmental media {i.e., surface water, POTW, non POTW-WWT, fugitive air, stack
air, and each type of land disposal) for the given OES.

•	Occupational Exposure Assessment

o Worker Activities: A description of the worker activities, including an assessment of

potential worker and ONU exposure points,
o Occupational Inhalation Exposure Results: Central tendency and high-end estimates

of inhalation exposures to workers and ONUs.
o Occupational Dermal Exposure Results: Central tendency and high-end estimates of

dermal exposures to workers and ONUs.
o Aggregate Exposure Results: Aggregated central tendency and high-end estimates from
the combination of dermal and inhalation exposures.

2.1 Approach and Methodology for Process Descriptions

EPA performed a literature search to find descriptions of processes involved in each OES. Where data
were available to do so, EPA included the following information in each process description:

•	Total production volume associated with the OES;

•	Name and location of sites where the OES occurs;

•	Facility operating schedules {e.g., year-round, 5 days/week, batch process, continuous process,
multiple shifts);

•	Key process steps;

•	Physical form and weight fraction of the chemical throughout the process;

•	Information on receiving and shipping containers; and

•	Ultimate destination of chemical leaving the facility.

Where DBP-specific process descriptions were unclear or not available, EPA referenced generic process
descriptions from literature, including relevant Emission Scenario Documents (ESDs) or Generic
Scenarios (GSs). Sections 3.1 through 3.16 provide process descriptions for each OES.

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2.2	Approach and Methodology for Estimating Number of Facilities

To estimate the number of facilities within each OES, EPA used a combination of bottom-up analyses of
EPA reporting programs and top-down analyses of U.S. economic data and industry-specific data.
Generally, EPA used the following steps to develop facility estimates:

1.	Identify or "map" each facility that reported DBP in the 2020 CDR (	,020a). NEI
(U.S. EPA. 2023a\ DMR (U.S. EPA. 2024a\ and TRI databases (U.S. EPA. 2024e) to an OES.
Mapping consists of using facility reported industry sectors (typically reported as either North
American Industry Classification System (NAICS) or Standard Industrial Classification (SIC)
codes), chemical activity, and processing and use information to assign the most likely OES to
each facility.

2.	Based on the reporting thresholds and requirements of each data set, evaluate whether the data in
the reporting programs is expected to cover most or all of the facilities within the OES. If so, the
total number of facilities in the OES were assumed equal to the count of facilities mapped to the
OES from each data set. If not, EPA proceeded to Step 3.

3.	Supplement the available reporting data with U.S. economic and market data using the following
steps:

a.	Identify the NAICS codes for the industry sectors associated with the OES.

b.	Estimate total number of facilities using the U.S. Census' Statistics of US Businesses
(SUSB) data on total sites by 6-digit NAICS code.

c.	Use market penetration data to estimate the percentage of sites likely to be using DBP
instead of other chemicals.

d.	Combine the data generated in Steps 3.a. through 3.c. to produce an estimate of the
number of facilities using DBP in each 6-digit NAICS code and sum across all applicable
NAICS codes to arrive at an estimate of the total number of facilities within the OES.
Typically, it was assumed that this estimate encompassed the facilities identified in Step
1; therefore, the total number of facilities for the OES were assessed as the total
generated from the analysis.

4.	If market penetration data required for Step 3.c. are not available, EPA relied on generic industry
data from GSs, ESDs, and other literature sources on typical throughputs/use rates, operating
schedules, and the DBP production volume used within the OES to estimate the number of
facilities. In cases where EPA identified a range of operating data in the literature for an OES,
stochastic modeling was used to provide a range of estimates for the number of facilities within
the OES. The approaches, equations, and input parameters used in stochastic modeling are
described in the relevant OES sections throughout this report.

2.3	Environmental Releases Approach and Methodology

Releases to the environment were assessed using data obtained through direct measurement via
monitoring, calculations based on empirical data, and/or assumptions and models. For each OES, EPA
provided annual releases, high-end and central tendency daily releases, and the number of release days
per year for each media of release {i.e., air, water, and land).

EPA used the following hierarchy in selecting data and approaches for assessing environmental releases:

1. Monitoring and measured data:

a. Releases calculated from site- and media-specific concentration and flow rate data.

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b. Releases calculated from mass balances or emission factor methods using site-specific
measurements.

2.	Modeling approaches:

a.	Surrogate release data

b.	Fundamental modeling approaches

c.	Statistical regression modeling approaches

3.	Release limits:

a.	Company-specific limits

b.	Regulatory limits (e.g., National Emission Standards for Hazardous Air Pollutants
[NESHAPs] or effluent limitations/requirements).

EPA described the final release results as either a point estimate (i.e., a single descriptor or statistic, such
as central tendency or high-end) or a full distribution. EPA considered three general approaches for
estimating the final release result:

•	Deterministic calculations: A combination of point estimates of each input parameter (e.g., high-
end and low-end values) were used to estimate central tendency and high-end release results.
EPA documented the method and rationale for selecting parametric combinations representative
of central tendency and high-end releases in the relevant OES subsections in Section 3.

•	Probabilistic (stochastic) calculations: EPA ran Monte Carlo simulations using the statistical
distribution for each input parameter to calculate a full distribution of the final release results.
EPA selected the 50th and 95th percentiles of the resulting distribution to represent central
tendency and high-end releases, respectively.

•	Combination of deterministic and probabilistic calculations: EPA had statistical distributions for
some parameters and point estimates for the remaining parameters. For example, EPA used
Monte Carlo modeling to estimate annual throughputs and emission factors, but only had point
estimates of release frequency and production volume. In this case, EPA documented the
approach and rationale for combining point estimates with statistical distributions to estimate
central tendency and high-end results in the relevant OES subsections in Sections 3.1 through
3.16.

2.3.1	Identifying Release Sources

EPA performed a literature search to identify process operations that could potentially result in releases
of DBP to air, water, or land from each OES. For each OES, EPA identified the release sources and the
associated media of release. Where DBP-specific release sources were unclear or unavailable, EPA
referenced relevant ESDs or GSs. Sections 3.1 through 3.16 describe the release sources for each OES.

2.3.2	Estimating Number of Release Days

Unless EPA identified conflicting information, EPA assumed that the number of release days per year
for a given release source equals the number of operating days at the facility. To estimate the number of
operating days, EPA used the following hierarchy:

1. Facility-specific data: EPA used facility-specific operating days per year data, if available.
Otherwise, EPA used data for other facilities within the same OES, if possible. EPA estimated
the operating days per year using one of the following approaches:

a. If other facilities have known or estimated average daily use rates, EPA calculated the
days per year as follows: days/year = estimated annual use rate for the facility (kg/year) /
average daily use rate from facilities with available data (kg/day).

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b. If facilities with days per year data do not have known or estimated average daily use
rates, EPA used the average number of days per year from the facilities with available
data.

2.	Industry-specific data: EPA used industry-specific data from GSs, ESDs, trade publications, or
other relevant literature.

3.	Manufacture of large-production volume (PV) commodity chemicals: For the manufacture of
large-PV commodity chemicals, EPA used a value of 350 days per year. This assumes the plant
runs seven days per week and 50 weeks per year (with two weeks down for turnaround) and
always produces the chemical.

4.	Manufacture of lower-PV specialty chemicals: For the manufacture of lower-PV specialty
chemicals, it is unlikely that the plant continuously manufactures the chemical throughout the
year. Therefore, EPA used a value of 250 days per year. This assumes the plant manufactures the
chemical five days per week and 50 weeks per year (with two weeks down for turnaround).

5.	Other Chemical Plant OESs: For these OESs, EPA assumed that the facility does not always use
the chemical of interest, even if the facility operates 24/7. Therefore, EPA used a value of 300
days/year, based on the assumption that the facility operates 6 days/week and 50 weeks/year
(with two weeks for turnaround). However, in instances where the OES uses a low volume of the
chemical of interest, EPA used 250 days per year as a lower estimate based on the assumption
that the facility operates 5 days/week and 50 weeks/year (with two weeks for turnaround).

6.	POTWs: Although EPA expects POTWs to operate continuously 365 days per year, the
discharge frequency of the chemical of interest from a POTW will depend on the discharge
patterns of the chemical from upstream facilities discharging to the POTW. However, there can
be multiple upstream facilities (possibly with different OESs) discharging to the same POTW
and information on when the discharges from each facility occur (e.g., on the same day or
separate days) is typically unavailable. Since EPA could not determine the exact number of days
per year that the POTW discharges the chemical of interest, a value of 365 days per year was
assumed.

7.	All Other OESs: Regardless of the facility operating schedule, other OESs are unlikely to use the
chemical of interest every day. Therefore, EPA used a value of 250 days per year for these
OESs.

2,3.3 Estimating Releases from Data Reported to EPA	

Generally, EPA used the facility-specific release data reported in TRI, DMR, and NEI as annual releases
in each data set for each site and estimated the daily release by averaging the annual release over the
expected release days per year. EPA's approach to estimating release days per year is described in
Section 2.3.2.

Section 313 of the Emergency Planning and Community Right-to-Know Act (EPCRA) established the
TRI. TRI tracks the waste management of designated toxic chemicals from facilities within certain
industry sectors. Facilities are required to report to TRI if the facility has 10 or more full-time
employees; is included in an applicable NAICS code; and manufactures, processes, or uses the chemical
in quantities greater than a certain threshold (25,000 pounds [lb] for manufacturers and processors of
DBP and 10,000 lb for users of DBP). EPA makes the reported information publicly available through
TRI. Each facility subject to the rule must report either using a Form R or a Form A. Facilities reporting
using a Form R must report annually the volume of chemical released to the environment (i.e., surface
water, air, or land) and/or managed through recycling, energy recovery, and treatment (e.g., incineration)

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from the facility. Facilities may submit a Form A if the volume of chemical manufactured, processed, or
otherwise used does not exceed 1,000,000 pounds per year (lb/year) and the total annual reportable
releases do not exceed 500 lb/year. Facilities reporting using Form A are not required to submit annual
release and waste management volumes or use/sub-use information for the chemical. Due to reporting
limitations, some sites that manufacture, process, or use DBP may not report to TRI and are therefore
not included in EPA's assessment.

EPA included both TRI Form R and Form A submissions in the analysis of environmental releases. For
Form Rs, EPA assessed releases using the reported annual release volumes from each media. For Form
As, EPA estimated releases to each media using other approaches, where possible. Where no was
approaches were available to estimate releases from facilities reporting using Form A's, EPA assessed
releases using the 500 lb/year threshold for each release media; however, since this threshold is for total
site releases, the 500 lb/year is attributed one release media (one or the other)—not all (to avoid over
counting the releases and exceeding the total release threshold for Form A). For this draft risk
evaluation, EPA used TRI data from reporting years 2017 to 2022 to provide a basis for estimating
releases (	22d). Further details on EPA's approach to using TRI data for estimating releases

are described in Sections 2.3.3.1 through 2.3.3.3. In the assessment of releases for each OES, these
assumptions and database limitations may lead to the estimated amount of DBP that is released from the
manufacturing, processing, or use site to be under or overestimated. The methodology that sites use to
estimate releases that are reported to TRI are also typically not fully described. These points may create
some additional uncertainty in the assessment.

Under the Clean Water Act (CWA), EPA regulates the discharge of pollutants into receiving waters
through National Pollutant Discharge Elimination System (NPDES). A NPDES permit authorizes
discharging facilities to discharge pollutants to specified effluent limits. There are two types of effluent
limits: (1) technology-based, and (2) water quality-based. While the technology-based effluent limits are
uniform across the country, the quality-based effluent limits vary and are more stringent in certain areas.
NPDES permits may also contain requirements for sewage sludge management.

NPDES permits apply pollutant discharge limits to each outfall at a facility. For risk evaluation
purposes, EPA was interested only on the outfalls to surface water bodies. NPDES permits also include
internal outfalls, but they aren't included in this analysis. This is because these outfalls are internal
monitoring points within the facility wastewater collection or treatment system, so they do not represent
discharges from the facility. NPDES permits require facilities to monitor their discharges and report the
results to EPA and the state regulatory agency. Facilities report these results in DMRs. EPA makes these
reported data publicly available via EPA's Enforcement and Compliance History Online (ECHO)
system and EPA's Water Pollutant Loading Tool (Loading Tool). The Loading Tool is a web-based tool
that obtains DMR data through ECHO, presents data summaries and calculates pollutant loading (mass
of pollutant discharged). For this risk evaluation, EPA queried DMRs for all DBP point source water
discharges available for 2017 to 2022 (	)22c). DMR only includes release data from NPDES

permit holders, which affects the statistical representativeness of sites. The methodology that sites use to
estimate releases that are reported to DMR are also typically not fully described. These points may
create some additional uncertainty in the assessment. Further details on EPA's approach to using DMR
data for estimating releases are described in Section 2.3.3.1.

The NEI was established to track emissions of Criteria Air Pollutants (CAPs) and CAP precursors and
assist with National Ambient Air Quality Standard (NAAQS) compliance under the Clean Air Act
(CAA). Air emissions data for the NEI are collected at the state, local, and tribal (SLT) level. SLT air
agencies then submit these data to EPA through the Emissions Inventory System (EIS). In addition to

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CAP data, many SLT air agencies voluntarily submit data for pollutants on EPA's list of HAPs. EPA
uses the data collected from SLT air agencies, in conjunction with supplemental HAP data, to build the
NEI. EPA makes an updated NEI publicly available every three years. For this risk evaluation, EPA
used NEI data for reporting years 2017 and 2020 data to provide a basis for estimating releases (H.S.

I 23 a).

NEI emissions data are categorized into (1) point source data, (2) area or nonpoint source data, (3)
onroad mobile source data, and (4) nonroad mobile source data. EPA included all four data categories in
the assessment of environmental releases in this risk evaluation. Point sources are stationary sources of
air emissions from facilities with operating permits under Title V of the CAA, also called "major
sources." Major sources are defined as having actual or potential emissions at or above the major source
thresholds. While thresholds can vary for certain chemicals in NAAQS non-attainment areas, the default
threshold is 100 tons/year for non-HAPs, 10 tons per year for a single HAP, or 25 tons per year for any
combination of HAPs. Point source facilities include large energy and industrial sites and are reported at
the emission unit- and release point-level.

Area or nonpoint sources are stationary sources that do not qualify as major sources. The nonpoint data
are aggregated and reported at the county-level and include emissions from smaller facilities as well as
agricultural emissions, construction dust, and open burning. Industrial and commercial/institutional fuel
combustion, gasoline distribution, oil and gas production and extraction, publicly owned treatment
works, and solvent emissions may be reported in point or nonpoint source categories depending upon
source size.

Onroad mobile sources include emissions from onroad vehicles that combust liquid fuels during
operation, including passenger cars, motorcycles, trucks, and buses. The nonroad mobiles sources data
include emissions from other mobile sources that are not typically operated on public roadways, such as
locomotives, aircraft, commercial marine vessels, recreational equipment, and landscaping equipment.
Onroad and nonroad mobile data are reported in the same format as nonpoint data; however, it is not
available for every chemical. For DBP, onroad and nonroad mobile data are not available and was not
used in the air release assessment. NEI only includes release data from units subject to NESHAP with
threshold potential to emit, which affects the statistical representativeness of sites. The methodology that
sites use to estimate releases that are reported to NEI are also typically not fully described. These points
may create some additional uncertainty in the assessment. Further details on EPA's approach to using
NEI data for estimating releases are described in Section 2.3.3.2.

2.3.3.1 Estimating Wastewater Discharges from TRI and DMR

Where available, EPA used TRI and DMR data from 2017 to 2022 to estimate annual wastewater
discharges and the associated daily wastewater discharges. Reviewing data from the five-year span
allowed EPA to perform a more thorough analysis and generate medians and maximums for sites that
reported over multiple years.

Annual Wastewater Discharges

For TRI, annual discharges are reported directly by facilities. For DMR, annual discharges are
automatically calculated by the Loading Tool based on the sum of the discharges associated with each
monitoring period in DMR. Monitoring periods in DMR are set by each facility's NPDES permit and
can vary between facilities. Typical monitoring periods in DMR include monthly, bimonthly, quarterly,
semi-annual, and annual reporting. In instances where a facility reports a period's monitoring results as
below the limit of detection (LOD) (also referred to as a non-detect or ND) for a pollutant, the Loading
Tool applies a hybrid method to estimate the wastewater discharge for the period. The hybrid method

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sets the values to half of the LOD if there was at least one detected value in the facility's DMRs in a
calendar year. If all values were less than the LOD in a calendar year, the annual load is set to zero.

Average Daily Wastewater Discharges

To estimate average daily discharges, EPA used the following steps:

1.	Obtain total annual loads calculated from the Loading Tool and reported annual direct surface
water discharges and indirect discharges to POTW and non-POTW WWT in TRI.

2.	For TRI reporters using a Form A, estimate annual releases using an alternative approach (see
Sections 2.3.4 and 2.3.5) or at the threshold of 500 lb per year.

3.	Determine if any of the facilities receiving indirect discharges reported in TRI have reported
DMRs for the corresponding TRI reporting year, if so, exclude these indirect discharges from
further analysis. The associated surface water release (after any treatment at the receiving
facility) will be incorporated as part of the receiving facility's DMR.

4.	Divide the annual discharges by the number of estimated operating days (estimated as described
in Section 2.3.2).

2.3.3.2 Estimating Air Emissions from TRI and NEI

Where available, EPA used TRI data from 2017 to 2022 and NEI data from 2017 and 2020 to estimate
annual and average daily fugitive and stack air emissions. For air emissions, EPA estimated both release
patterns {i.e., days per year of release) and release durations {i.e., hours per day the release occurs).
Reviewing data from multiple years allowed EPA to perform a more thorough analysis and generate
medians and maximums for sites that reported more than once in that time span,

Annual Emissions

Facility-level annual emissions are available for TRI reporters and major sources in NEI. EPA used the
reported annual emissions directly as reported in TRI and NEI for major sources. NEI also includes
annual emissions for area sources that are aggregated at the county-level. Area source data in NEI is not
divided between sites or between stack and fugitive sources. Therefore, EPA only presented annual
emissions for each county-OES combination.

Average Daily Emissions

To estimate average daily emissions for TRI reporters and major sources in NEI, EPA used the
following steps:

1.	Obtain total annual fugitive and stack emissions for each TRI reporter and major source in NEI.

2.	For TRI reporters using a Form A, estimate annual releases using an alternative approach (see
Sections 2.3.4 and 2.3.5) or at the threshold of 500 lb per year.

3.	Divide the annual stack and fugitive emissions over the number of estimated operating days
(note: NEI data includes operating schedules for many facilities that can be used to estimate
facility-specific days per year).

4.	Estimate a release duration using facility-specific data available in NEI, models, and/or literature
sources. If no data are available, list as "unknown."

To estimate average daily emissions from area sources, EPA followed a very similar approach as
described for TRI reporters and major sources in NEI; however, area source data in NEI is not divided
between sites or between stack and fugitive sources. Area data also does not include release duration
data as the emissions are aggregated at the county-level rather than facility level. Therefore, EPA only
presented annual emissions for each county-OES combination.

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2.3.3.3 Estimating Land Disposals from TRI

Where available, EPA used TRI data from 2017 to 2022 to estimate annual and average daily land
disposal volumes. TRI includes reporting of disposal volumes for a variety of land disposal methods,
including but not limited to underground injection, RCRA Subtitle C landfills, land treatment, RCRA
Subtitle C surface impoundments, other surface impoundments, and other land disposal. EPA provided
estimates for both a total aggregated land disposal volume and disposal volumes for each disposal
method reported in TRI. Reviewing data from the 5-year span allowed the Agency to perform a more
thorough analysis and generate medians and maximums for sites that reported over multiple years.

Annual Land Disposal

Facility-level annual disposal volumes are available directly for TRI reporters. EPA used the reported
annual land disposal volumes directly as reported in TRI for each land disposal method. EPA combined
totals from all land disposal methods from each facility to estimate a total annual aggregate disposal
volume to land.

Average Daily Land Disposal

To estimate average daily disposal volumes, EPA used the following steps:

1.	Obtain total annual disposal volumes for each land disposal method for each TRI reporter.

2.	For TRI reporters using a Form A, estimate annual releases using an alternative approach (see
Sections 2.3.4 and 2.3.5) or at the threshold of 500 lb per year.

3.	Divide the annual disposal volumes for each land disposal method over the number of estimated
operating days.

4.	Combine totals from all land disposal methods from each facility to estimate a total aggregate
disposal volume to land.

2.3.4 Estimating Releases from Models

EPA utilized models to estimate environmental releases for OESs without TRI, DMR, or NEI data.
These models apply deterministic calculations, stochastic calculations, or a combination to estimate
releases. EPA used the following steps to estimate releases:

1.	Identify release sources and associated release media for each relevant process.

2.	Identify or develop model equations for estimating releases from each source.

3.	Identify model input parameter values from relevant literature sources.

4.	If a range of input values is available for an input parameter, determine the associated
distribution of input values.

5.	Calculate annual and daily release volumes for each release source using input values and model
equations.

6.	Aggregate release volumes by release media and report total releases to each media from each
facility.

For release models that utilized stochastic calculations, EPA performed a Monte Carlo simulation using
the Palisade Risk Version 8.0.0 software with 100,000 iterations and the Latin Hypercube sampling
method (Palisade. 2022). Appendix D provides detailed descriptions of the model approaches that EPA
used for each OES as well as model equations, input parameter values, and associated distributions.

For some modeled releases, the media of release is dependent on site- and process-specific practices that
are unknown. To account for this uncertainty, these release estimates may be assessed to groups of
multiple release medias based on the release point and the chemical's physical form {i.e., water,
incineration, or landfill or air, water, incineration, or landfill) to account for all possible chemical waste
endpoints.

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2,3,5 Estimating Releases Using Literature Data

Where available, EPA used data from literature sources to assist in assessing releases. Literature data for
this assessment primarily was used for information related to release modeling. When industry- or
chemical-specific emission factors are available, EPA may use these emission factors to calculate
releases for an OES or incorporate the emission factors into release models to develop a distribution of
potential releases for the OES. Sections 3.1 through 3.16 provides a detailed description of how EPA
incorporated literature data into the release estimates for each OES.

2.4 Occupational Exposure Approach and Methodology

For workplace exposures, EPA considered exposures to both workers who directly handle DBP and
ONUs who do not directly handle DBP but may be exposed to vapors, particulates, or mists that enter
their breathing zone while working in locations near DBP handling. EPA evaluated inhalation and
dermal exposures to both workers and ONUs.

EPA provided occupational exposure results representative of central tendency and high-end exposure
conditions. The central tendency is expected to represent occupational exposures in the center of the
distribution for a given COU. For risk evaluation, EPA used the 50th percentile (median), mean
(arithmetic or geometric), mode, or midpoint values of a distribution as representative of the central
tendency scenario. EPA preferred to provide the 50th percentile of the distribution. However, if the full
distribution is unknown, EPA may assume that the mean, mode, or midpoint of the distribution
represents the central tendency depending on the statistics available for the distribution.

The high-end exposure is expected to be representative of occupational exposures that occur at
probabilities above the 90th percentile, but below the highest exposure for any individual (U.S. EPA.
1992a). For risk evaluation, EPA provided high-end results at the 95th percentile. If the 95th percentile
is not reasonably available, EPA used a different percentile greater than or equal to the 90th percentile
but less than or equal to the 99.9th percentile, depending on the statistics available for the distribution. If
the full distribution is not known and the preferred statistics are not reasonably available, EPA estimated
a maximum or bounding estimate in lieu of the high-end.

For occupational exposures, EPA used measured or estimated air concentrations to calculate exposure
concentration metrics required for risk assessment, such as average daily concentration (ADC). These
calculations require additional parameter inputs, such as years of exposure, exposure duration and
exposure frequency. EPA estimated exposure concentrations from monitoring data, modeling, or
occupational exposure limits.

For the final exposure result metrics, each of the input parameters (e.g., air concentrations, working
years, exposure frequency) may be a point estimate (i.e., a single descriptor or statistic, such as central
tendency or high-end) or a full distribution. EPA considered three general approaches for estimating the
final exposure result metrics:

•	Deterministic calculations: EPA used combinations of point estimates of each parameter to
estimate a central tendency and high-end for each final exposure metric result.

•	Probabilistic (stochastic) calculations: EPA used Monte Carlo simulations using the full
distribution of each parameter to calculate a full distribution of the final exposure metric results
and selecting the 50th and 95th percentiles of this resulting distribution as the central tendency
and high-end, respectively.

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•	Combination of deterministic and probabilistic calculations: EPA had full distributions for some
parameters but point estimates of the remaining parameters. For example, the Agency used
Monte Carlo modeling to estimate exposure concentrations, but only had point estimates of
exposure duration and frequency.

Appendix A discusses the equations and input parameter values that EPA used to estimate each
exposure metric.

For each OES, EPA provided high-end and central tendency, full-shift, time-weighted average (TWA)
(typically as an 8-hour TWA) inhalation exposure concentrations as well as high-end and central
tendency acute potential dermal dose rates (APDR). EPA applied the following hierarchy in selecting
data and approaches for assessing occupational exposures:

•	Monitoring data:

a.	Personal and directly applicable to the OES

b.	Area and directly applicable to the OES

c.	Personal and potentially applicable or similar to the OES

d.	Area and potentially applicable or similar to the OES

•	Modeling approaches:

a.	Surrogate monitoring data

b.	Fundamental modeling approaches

c.	Statistical regression modeling approaches

•	Occupational exposure limits:

a.	Company-specific occupational exposure limits (OELs) (for site-specific exposure
assessments; for example, there is only one manufacturer who provides their internal
OEL to EPA, but the manufacturer does not provide monitoring data)

b.	Occupational Safety and Health Administration (OSHA) Permissible Exposure Limits
(PELs)

c.	Voluntary limits {i.e., American Conference of Governmental Industrial Hygienists
[ACGIH] Threshold Limit Values [TLV]; National Institute for Occupational Safety and
Health [NIOSH] Recommended Exposure Limits [RELs]; Occupational Alliance for Risk
Science (OARS) workplace environmental exposure level (WEELs) [formerly by
AMA])

EPA used the estimated high-end and central tendency, full-shift TWA inhalation exposure
concentrations and APDR to calculate the exposure metrics required for risk evaluation. Exposure
metrics for inhalation and dermal exposures include acute dose (AD), intermediate average daily dose
(IADD), and average daily dose (ADD). Appendix A describes the approach that EPA used to
estimating each exposure metric.

2.4.1	Identifying Worker Activities

EPA performed a literature search and reviewed data from systematic review to identify worker
activities that could potentially result in occupational exposures. Where worker activities were unclear
or not available, EPA referenced relevant ESDs or GSs. Section 3 provides worker activities for each
OES.

2.4.2	Estimating Inhalation Exposures

2.4.2.1 Inhalation Monitoring Data

To assess inhalation exposure, EPA reviewed workplace inhalation monitoring data collected by

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government agencies such as OSHA and NIOSH, monitoring data found in published literature {i.e.,
personal exposure monitoring data and area monitoring data), and monitoring data submitted via public
comments. Studies were evaluated using the strategies presented in the Application of Systematic Review
in TSCA Risk Evaluations (	21a).

EPA calculated exposures from the monitoring datasets provided in the sources discussed above, using
different methodologies depending on the size of the dataset. For datasets with six or more data points,
The Agency estimated central tendency and high-end exposures using the 50th and 95th percentile
values, respectively. For datasets with three to five data points, EPA estimated the central tendency and
high-end exposures using the 50th percentile and maximum values, respectively. For datasets with two
data points, the Agency presented the midpoint and the maximum value. Finally, EPA presented datasets
with only one data point as-is. For datasets that included exposure data reported as below the limit of
detection (LOD), EPA estimated exposure concentrations following guidance in EPA's Guidelines for
Statistical Analysis of Occupational Exposure Data (	). That report recommends using

the ^=- if the geometric standard deviation of the data is less than 3.0 and if the geometric standard

deviation is 3.0 or greater.

If the 8-hour TWA personal breathing zones (PBZ) monitoring samples were not available, area samples
were used for exposure estimates. EPA combined the exposure data from all studies applicable to a
given OES into a single dataset.

For each COU, EPA endeavors to distinguish exposures for workers and ONUs. Normally, a primary
difference between workers and ONUs is that workers may handle DBP and have direct contact with the
chemical, while ONUs are working in the general vicinity of workers but do not handle DBP and do not
have direct contact with DBP being handled by the workers. Generally, potential exposures to ONUs are
expected to be less than workers since they may not be exposed to the chemical for an entire 8-hour
workday. EPA recognizes that worker job titles and activities may vary significantly from site to site;
therefore, the Agency typically identified samples as worker samples unless it was explicitly clear from
the job title {e.g., inspectors) and the description of activities in the report that the employee was not
directly involved in the scenario. Samples from employees determined not to be directly involved in the
scenario were designated as ONU samples.

OSHA Chemical Exposure Health Data

OSHA Chemical Exposure Health Data (CEHD) is collected through industrial hygiene samples taken
by OSHA compliance officers during monitoring of worker exposures to chemical hazards. OSHA
CEHD data is obtained typically from facilities when there is suspicion about high workplace exposure
levels or potential violations. OSHA CEHD represents a reasonably available source of information to
obtain monitoring data and has received a rating of high from EPA's systematic review process. Air
sampling data records from inspections are entered into the OSHA CEHD that can be accessed online.
The database includes PBZ monitoring data, area monitoring data, bulk samples, wipe samples, and
serum samples. The collected samples are used for comparing to OSHA's PELs and STELs. OSHA's
CEHD website indicates that they do not (1) perform routine inspections at every business that uses
toxic/hazardous chemicals, (2) completely characterize all exposures for all employees every day, or (3)
always obtain a sample for an entire shift. Rather, OSHA performs targeted inspections of certain
industries based on national and regional emphasis programs, often attempts to evaluate worst case
chemical exposure scenarios, and develops "snapshots" of chemical exposures and assess their
significance {e.g., comparing measured concentrations to the regulatory limits).

EPA took the following approach to analyzing OSHA CEHD:

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1.	Downloaded monitoring data for DBP from 1992 to 2022: See Section 2.6 for evidence
integration notes on targeted years.

2.	Organized data by site: {i.e., grouped data collected at the same site together).

3.	Removed serum samples, bulk samples, wipe samples, and blanks: These data are not used in
EPA's assessment.

4.	Assigned each data point to an OES: Review NAICS codes, SIC codes, and as needed, company
information available online, to map each sample to an OES. In some instances, EPA was unable
to determine the OES from the information in the CEHD; in such cases, the Agency did not use
the data in the assessment. EPA also removed data determined to be likely for non-TSCA uses or
otherwise out of scope.

5.	Combined samples from the same worker: In some instances, OSHA inspectors will collect
multiple samples from the same worker on the same day (these are indicated by sample ID
numbers). In these cases, EPA combined results from all samples for a particular sample ID to
construct an exposure concentration based on the totality of exposures from each worker.

6.	Calculated 8-hour TWA results from combined samples: Where the total sample time was less
than 8 hours (480 minutes), but greater than 330 minutes, EPA calculated an 8-hour TWA by
assuming exposures were zero for the remainder of the shift. For any calculated 8-hour TWA
exposures that were equal to zero or non-detects, the Agency replaced this value with the LOD
divided by either two or the square root of two (see step 7). EPA did consider all samples for 8-
hour TWA that were marked "eight-hour calculation used" in the OSHA CEHD database with no
adjustment.

OSHA CEHD does not provide job titles or worker activities associated with the samples; therefore,
EPA assumed all data were collected on workers and not ONUs.

Specific details related to the use of monitoring data for each COU can be found in Sections 3.1.4
through 3.15.4.

2.4.2.2 Inhalation Exposure Modeling

Where inhalation exposures are expected for an OES but monitoring data were unavailable, EPA
utilized models (See Appendix D) to estimate inhalation exposures. These models apply deterministic
calculations, stochastic calculations, or a combination of both deterministic and stochastic calculations
to estimate inhalation exposures. EPA used the following steps to estimate exposures for each OES:

1.	Identify worker activities and potential sources of exposures from each process.

2.	Identify or develop model equations for estimating exposures from each source.

3.	Identify model input parameter values from relevant literature sources, including activity
durations associated with sources of exposures.

4.	If a range of input values is available for an input parameter, determine the associated
distribution of input values.

5.	Calculate exposure concentrations associated with each activity.

6.	Calculate full-shift TWAs based on the exposure concentration and activity duration
associated with each exposure source.

7.	Calculate exposure metrics (AD, IADD, ADD) from full-shift TWAs.

For exposure models that utilize stochastic calculations, EPA performed a Monte Carlo simulation using
the Palisade @Risk Version 8.0.0 software with 100,000 iterations and the Latin Hypercube sampling
method (Palisade. 2022). Appendix D provides detailed descriptions of the model approaches used for
each OES, model equations, and input parameter values and associated distributions.

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2,4,3 Estimating Dermal Exposures

This section summarizes the available dermal absorption data related to DBP (Section 2.4.3.1), the
interpretation of the dermal absorption data (Section 2.4.3.2), dermal absorption modeling efforts
(Section 2.4.3.3), and uncertainties associated with dermal absorption estimation (Section 2.4.3.4).
Dermal data were sufficient to characterize occupational dermal exposures to liquids or formulations
containing DBP (Section 2.4.3.1); however, dermal data were not sufficient to estimate dermal
exposures to solids or articles containing DBP. Therefore, modeling efforts described in Section 2.4.3.3
were utilized to estimate dermal exposures to solids or articles containing DBP. Dermal exposures to
vapors are not expected to be significant due to the extremely low volatility of DBP; therefore, they are
not included in the dermal exposure assessment of DBP.

2.4.3.1 Dermal Absorption Data

Dermal absorption data related to DBP were identified in scientific literature. EPA identified six studies
directly related to the dermal absorption of DBP. Of the six available studies, EPA identified one study
that was most reflective of DBP exposure from liquid products and formulation (Doan et ai. 2010). The
study received a rating of medium from EPA's systematic review process.

•	Relatively recent studies were preferred as applicable to modern dermal testing techniques and
guidelines for in vivo and in vitro dermal absorption studies {i.e., OECD Guideline 427 (OECD.
2004c) and Guideline 428 (OECD. 2004dV).

•	Studies of human skin were preferred over animal models, and when studies with human skin
were not suitable (see other criteria), animal skin studies were preferred in this order, guinea pig
over rat studies.

•	Studies of split skin thickness were preferred over studies of full thickness. Generally, studies
should provide information on dermatoming methods and ideally provide a value for thickness in
accordance with OECD guideline 428 (OECD. 2004d). which recommends a range of 400 to 800
[j,m or less than 1 mm.

•	Freshly excised (non-frozen) skin studies were preferred, if there was not a significant delay
between skin sample retrieval and assay initiation.

•	Studies using an aqueous vehicle type were preferred over neat chemical studies as there is
greater relevance to commercial product formulations and subsequent exposure and due to
greater uncertainties from neat chemical resulting in lower absorptions than formulations which
may enhance dermal absorption.

•	Studies with reported sample temperatures that represent human body temperature, in a
humidity-controlled environment were preferred.

Doan et al. ( ) conducted in vivo and in vitro experiments in female hairless guinea pigs to compare
absorption measurements using the same dose of DBP. Compared to other dermal studies, skin samples
used in this study (Doan et al.. 2010) were the most relevant and appropriate as they were exposed to a
formulation of 7 percent oil-in-water emulsion which was preferable over neat chemical. The physical
state of pure DBP is an oily liquid that is similar to an emulsion. In the in vitro experiments, skin was
excised from the animals (anatomical site of the tissue collections was not specified) and radiolabeled
DBP (1 mg/m2) was applied to a split thickness skin preparation (200 (j,m) for 24 or 72 hours.

Absorption was measured every 6 hours in a flow-through chamber. The test system was un-occluded,
and skin was washed prior to application. Though certain aspects of the experiment were not reported,
overall, the study complies with OECD guideline 428 (OECD. 2004d)). A total of 56.3 percent of the
administered dose was absorbed in the in vitro experiment; the percent total recovery was 96.3 percent
of the administered dose.

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In the in vivo experiment Q ), female hairless guinea pigs were given a single dermal application via
covered patch (3 x 3-centimeter square area; 9 cm2) of an oil-in-water emulsion containing 1 mg/cm2
DBP. The chemical was applied to the mid-scapular region of the guinea pig back, although it is unclear
if this represents 10 percent of the animal body surface. The amount of DBP absorption was measured in
the skin, urine, feces, blood, and tissues. The in vivo dermal absorption of DBP was estimated to be
approximately 62 percent of the applied dose after 24 hours. The percent total recovery was 92.9 percent
after 24 hours. Total penetration was reported to be 65.4 percent and included total systemic absorption
plus skin absorption, and recovery of materials in skin around the dosing site, which is in agreement
with the 24-hour in vitro experiment findings. The outcomes assessment method mostly agreed with
guideline OECD 427 (OECD. 2004c).

2.4.3.2	Flux-Limited Dermal Absorption for Liquids

Dermal absorption data from Doan et al. (2010) showed 56.3 percent absorption of 1 mg/cm2 of DBP
over a 24-hour period, resulting in an average absorptive flux of DBP of 2.35x 10~2 mg/cm2/h. EPA
assumed that the average absorptive flux from Doan et al. (: ) is representative of the average
absorptive flux over the period of a workday for purposes of dermal exposure estimation in occupational
settings.

The estimated steady-state fluxes of DBP presented in this section, based on the results of Doan et al.
(2010). is representative of exposures to liquid materials or formulations only. Dermal exposures to
liquids containing DBP are described in this section. Regarding dermal exposures to solids containing
DBP, there were no available data and dermal exposures to solids are modeled as described in Section
2.4.3.3.

EPA selects Doan et al. (2010) as a representative study for dermal absorption to liquids. Doan et al.
(2 ) is a relatively recent study in guinea pigs, and it uses a formulation consisting of 7 percent oil-in-
water which is preferred over studies that use neat chemicals. Two other older in vivo studies were
considered: Elsisi et al. (1989) and Janjua et al. (2008). Elsisi et al. (1989) provided data on the dermal
absorption of DBP by measuring the percentage of dose excreted in the urine and feces of rats daily over
a 7-day exposure. EPA considers more recent data (2010 vs. 1989) and study duration (24 hours vs. 7
days) from Doan et al. (2010) to be more appropriate and representative to TSCA dermal scenarios. The
third in vivo study, Janjua et al. (2008). applied cream with a 2 percent DBP formulation to the skin of
human participants daily for 5 days. This study measured the metabolite of DBP, MBP, in urine,
however this study had significant limitations including a very large inter-individual variability in
absorption values and daily variations in values for the same individual. Two additional ex vivo studies,
Scott et al. (1987) and Sugino et al. (2017) noted DBP to be more readily absorbed in rat skin versus
human skin. These ex vivo studies suggest that human skin and rat skin are not directly comparable, with
the 1987 study providing evidence of a two-magnitude greater absorption rate in rat skin compared to
human skin.

2.4.3.3	Flux-Limited Dermal Absorption for Solids

Because DBP has low volatility and relatively low absorption, the dermal absorption of DBP was
estimated based on the flux of material rather than percent absorption. For cases of dermal absorption of
DBP from a solid matrix, EPA assumes that DBP first migrates from the solid matrix to a thin layer of
moisture on the skin surface. Therefore, absorption of DBP from solid matrices is considered limited by
aqueous solubility and is estimated using an aqueous absorption model as described below.

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The first step in modeling dermal absorption through aqueous media is to estimate the steady-state
permeability coefficient, Kp (cm/h). EPA utilized the Consumer Exposure Model (CEM) (U.S. EPA.
2023b) to estimate the steady-state aqueous permeability coefficient of DBP as 0.017 cm/h. Next, EPA
relied on Equation 3.2 from the Risk Assessment Guidance for Saperfand (RAGS), Volume I: Raman
Health Evaluation Manual, (Part E: Supplemental Guidance for Dermal Risk Assessment) (U.S. EPA.
2004b) which characterizes dermal uptake (through and into skin) for aqueous organic compounds.
Specifically, Equation 3.2 from U.S. EPA (2004b). also shown in Equation 2-1 below, was used to
estimate the dermally absorbed dose (DAevent, mg/cm2) for an absorption event occurring over a defined
duration (tabs).

Equation 2-1. Dermal Absorption Dose During Absorption Event

DA

event

— 2 x FA x Kp x S^y x

16 x tiag x tai)S

71

Where:

DAevent
FA

KP

Sw

tiag
tabs

Dermally absorbed dose during absorption event tabs (mg/cm2)

Effect of stratum corneum on quantity absorbed = 0.9 (see Exhibit A-5 of

U.S. EPA (2004b)] and confirmed by Doan et al. (2010) for 0.87)

Permeability coefficient = 0.017 cm/h (calculated using CEM (U.S. EPA.

2023b))

Water solubility =11.2 mg/L (see DBP Physical and Chemical Properties
TSD)

0.105*10ฐ0056MW= 0.105*100 0056*27835 = 3.80 hours (calculated from A.4

of U.S. EPA (2004b))

Duration of absorption event (hours)

By dividing the dermally absorbed dose (DAevent) by the duration of absorption (tabs), the resulting
expression yields the average absorptive flux. Figure 2-1 illustrates the relationship between the average
absorptive flux and the absorption time.

Average Absorptive Flux vs Absorption Time for

DBP



1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30

P1

O 0.20

| 0,0

0.00

1	2	3	4	5	6

Absoiption Time (hours)
Figure 2-1. DBP Average Absorptive Flux vs. Absorption Time

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Using Equation 3.2 from the Risk Assessment Guidance for Superfund (RAGS), Volume I: Human
Health Evaluation Manual, (Part E: Supplemental Guidance for Dermal Risk Assessment) (U.S. EPA.
2004b). which characterizes dermal uptake (through and into skin) for aqueous organic compounds,
EPA estimates the flux of DBP to be 0.89 and 0.32 |ig/cm2/h at 1 and 8 hours, respectively. EPA
assumed that the flux was constant over the absorption time and estimated the average absorptive flux of
0.32 |ig/cm2/h,

2.4.3.4 Uncertainties in Dermal Absorption Estimation

As noted above in Section 2.4.3.1, EPA identified six studies directly related to the dermal absorption of
DBP; one study was determined to be most representative of DBP exposure from liquid products and
formulations (Doan et al.. ^ ). This dermal absorption study was conducted in vitro and in vivo using
female guinea pigs. There have been additional studies conducted to determine the difference in dermal
absorption between animal skin and human skin. Specifically, Scott (1987) examined the difference in
dermal absorption between rat skin and human skin for four different phthalates {i.e., DMP, DEP, DBP,
and DEHP) using in vitro dermal absorption testing. Results from the in vitro dermal absorption
experiments showed that rat skin was more permeable than human skin for all four phthalates examined.
For example, rat skin was up to 100 times more permeable than human skin for DBP, 30 times more
permeable than human skin for DEP, and rat skin was up to 4 times more permeable than human skin for
DEHP. OECD guidelines indicate that guinea pig tissue is more similar to human skin than rat tissue
(OECD. 2004c). Though there is uncertainty regarding the magnitude of difference between dermal
absorption through guinea pig skin vs. human skin for DBP, EPA is confident that the dermal absorption
data using female guinea pigs (Doan et al. 2010) provides an upper-bound of dermal absorption of DBP
based on the findings of Scott (1987).

Another source of uncertainty regarding the dermal absorption of DBP from products or formulations
stems from the varying concentrations and co-formulants that exist in products or formulations
containing DBP. For purposes of this risk evaluation, EPA assumes that the absorptive flux of 7 percent
oil-in-water formulation of DBP measured from guinea pig experiments serves as a conservative
representative estimate of the potential absorptive flux of chemical into and through the skin for dermal
contact with all liquid products or formulations, and that the modeled absorptive flux of aqueous DBP
serves as an upper-bound of potential absorptive flux of chemical into and through the skin for dermal
contact with all solid products. Dermal contact with products or formulations that have lower
concentrations of DBP may exhibit lower rates of flux since there is less material available for
absorption. Conversely, co-formulants or materials within the products or formulations may lead to
enhanced dermal absorption, even at lower concentrations. Therefore, it is uncertain whether the
products or formulations containing DBP at different concentrations than studied in Doan et al. (2010)
would result in decreased or increased dermal absorption. Additionally, it is unclear how representative
the data from Doan et al. (2010) are for neat DBP.

Lastly, EPA notes that there is uncertainty with respect to the modeling of dermal absorption of DBP
from solid matrices or articles. Because there were no available data related to the dermal absorption of
DBP from solid matrices or articles, EPA has assumed that dermal absorption of DBP from solid objects
would be limited by aqueous solubility of DBP. Therefore, to determine the maximum steady-state
aqueous flux of DBP, EPA utilized CEM (	)23b) to first estimate the steady-state aqueous

permeability coefficient of DBP. The estimation of the steady-state aqueous permeability coefficient
within CEM (	)23b) is based on quantitative structure-activity relationship (QSAR) model

presented by ten Berge (2009). which considers chemicals with log(Kow) ranging from -3.70 to 5.49 and
molecular weights ranging from 18 to 584.6. The log(Kow) and molecular weight of DBP (4.5 and
278.35 g/mol, respectively) fall within the range suggested by ten Berge (2009). Therefore, EPA is

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confident regarding the accuracy of the QSAR model used to predict the steady-state aqueous
permeability coefficient for DBP based on both parameters falling within the suggested ranges.

2.4,4 Estimating Acute, Intermediate, and Chronic (Non-Cancer) Exposures	

For each COU, the estimated exposures were used to calculate acute, intermediate, and chronic (non-
cancer) inhalation and dermal doses. These calculations require additional parameter inputs, such as
years of exposure, exposure duration and exposure frequency.

For the final exposure result metrics, each of the input parameters (e.g., air concentrations, dermal doses,
working years, exposure frequency) may be a point estimate (i.e., a single descriptor or statistic, such as
central tendency or high-end) or a full distribution. As described in Section 2.4, EPA considered three
general approaches for estimating the final exposure result metrics: deterministic calculations,
probabilistic (stochastic) calculations, and a combination of deterministic and probabilistic calculations.
Equations for these exposures can be found in Appendix A.

2.5 Consideration of Engineering Controls and Personal Protective
Equipment

This section contains general information on engineering controls and personal protective equipment.
EPA has performed a quantitative estimation on the effect of personal protective equipment (PPE) on
worker exposure. The effect of PPE on occupational risk estimates is discussed in the Draft Risk
Evaluation for DBP (	325b) and the calculations can be found in the Draft Risk Calculator

for Occupational Exposures for DBP (	25a).

Occupational Safety and Health Adminstration (OSHA) and National Institute for Occupational Safety
and Health (NIOSH) recommend employers utilize the hierarchy of controls1 to address hazardous
exposures in the workplace. The hierarchy of controls strategy outlines, in descending order of priority,
the use of elimination, substitution, engineering controls, administrative controls, and lastly PPE. The
hierarchy of controls prioritizes the most effective measures, which eliminate or substitute the harmful
chemical (e.g., use a different process, substitute with a less hazardous material), thereby preventing or
reducing exposure potential. Following elimination and substitution, the hierarchy recommends
engineering controls to isolate employees from the hazard, followed by administrative controls or
changes in work practices to reduce exposure potential (e.g., source enclosure, local exhaust ventilation
systems). Administrative controls are policies and procedures instituted and overseen by the employer to
protect worker exposures. OSHA and NIOSH recommend the use of PPE (e.g., respirators, gloves) as
the last means of control, when the other control measures cannot reduce workplace exposure to an
acceptable level.

2.5.1 Respiratory Protection

OSHA's Respiratory Protection Standard (29 CFR 1910.134) requires employers in certain industries to
address workplace hazards by implementing engineering control measures and, if these are not feasible,
providing respirators that are applicable and suitable for the purpose intended. Respirator selection
provisions are provided in section 1910.134(d) and require that appropriate respirators be selected based
on the respiratory hazard(s) to which the worker will be exposed, in addition to workplace and user
factors that affect respirator performance and reliability. Assigned protection factors (APFs) are
provided in Table 1 under section 1910.134(d)(3)(i)(A) (see below in Table 2-1) and refer to the level of
respiratory protection that a respirator or class of respirators is expected to provide to employees when

1 See https://www.osha.gov/sites/default/files/Hierarchv of Controls 02.01.23 form 508 2.pdf.

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the employer implements a respiratory protection program according to the requirements of OSHA's
Respiratory Protection Standard.

Workers are required to use respirators that meet or exceed the required level of protection listed in
Table 2-1. Based on the APF, inhalation exposures may be reduced by a factor of 5 to 10,000, if
respirators are properly worn and fitted.

Table 2-1. Assigned Protection Factors for Respirators in OSHA Standard 29 CFR 1910.134

Type of Respirator

Quarter
Mask

Half

Mask

Full

Facepiece

Helmet/
Hood

Loose-Fitting
Facepiece

1. Air-purifying respirator

5

10

50

-

-

2. Power air-purifying respirator (PAPR)

-

50

1,000

25/1,000

25

3. Supplied-air respirator (SAR) or airline respirator

• Demand mode

-

10

50

-

-

• Continuous flow mode

-

50

1,000

25/1,000

25

• Pressure-demand or other positive-
pressure mode

-

50

1,000

-

-

4. Self-contained breathing apparatus (SCBA)

• Demand mode

-

10

50

50

-

• Pressure-demand or other positive-
pressure mode {e.g., open/closed
circuit)





10,000

10,000



Source: 29 CFR 1910.134(d)(3)(i)(A)

2.5.2 Glove Protection	

Gloves are selected in industrial settings based on characteristics (permeability, durability, required task
etc). Data on the frequency of glove use {i.e., the proper use of effective gloves) in industrial settings is
very limited. An initial literature review suggests that there is unlikely to be sufficient data to justify a
specific probability distribution for effective glove use for handling of DBP specifically, for a given
industry. Instead, EPA explored the impact of effective glove use by considering different percentages
of effectiveness {e.g., 25 vs. 50% effectiveness).

Gloves only offer barrier protection until the chemical breaks through the glove material. Using a
conceptual model, Cherrie (2004) proposed a glove workplace protection factor, defined as the ratio of
estimated uptake through the hands without gloves to the estimated uptake though the hands while
wearing gloves. This protection factor is driven by flux, and thus the protection factor varies with time.
The ECETOC TRA Model v.3.2 represents the glove protection factor as a fixed, assigned value equal
to 5, 10, or 20 (Marquart et ai. 2017). Like the APR for respiratory protection, the inverse of the
protection factor is the fraction of the chemical that penetrates the glove. Table 2-2 presents glove
protection factors for different dermal protection characteristics.

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Table 2-2. Glove Protection Factors for Different Dermal Protection Strategies

Dermal Protection Characteristics

Setting

Protection
Factor (PF)

a. No gloves used, or any glove/gauntlet without permeation data
and without employee training

Industrial and

Commercial

Uses

1

b. Gloves with available permeation data indicating that the
material of construction offers good protection for the substance

5

c. Chemically resistant gloves (i.e., as b above) with "basic"
employee training

10

d. Chemically resistant gloves in combination with specific
activity training (e.g., procedure for glove removal and disposal)
for tasks where dermal exposure can be expected to occur

Industrial Uses
Only

20

Source: (Marciiiart et aL 2017)

2.6 Evidence Integration for Environmental Releases and Occupational
Exposures

Evidence integration for the environmental release and occupational exposure assessment includes
analysis, synthesis, and integration of information and data to produce estimates of environmental
releases and occupational exposures. During evidence integration, EPA considered the likely location,
duration, intensity, frequency, and quantity of releases and exposures while also considering factors that
increase or decrease the strength of evidence when analyzing and integrating the data. Key factors that
EPA considered when integrating evidence include the following:

1.	Data Quality: EPA only integrated data or information rated as high, medium, or low obtained
during the data evaluation phase of systematic review. EPA did not use data and information
rated as uninformative in exposure evidence integration. In general, EPA gave preference to
higher rankings over lower rankings; however, EPA may use lower ranked data over higher
ranked data after carefully examining and comparing specific aspects of the data. For example,
EPA may use a lower ranked data set that precisely matches the OES of interest over a higher
ranked study that does not match the OES of interest as closely.

2.	Data Hierarchy: EPA used both measured and modeled data to obtain accurate and
representative estimates (e.g., central tendency, high-end) of the environmental releases and
occupational exposures resulting directly from a specific source, medium, or product. If
available, measured release and exposure data are given preference over modeled data, with the
highest preference given to data that are both chemical-specific and directly representative of the
OES/exposure source.

EPA considered both data quality and data hierarchy when determining evidence integration strategies.
For example, the Agency may use high quality modeled data that is directly applicable to a given OES
over low quality measurement data that is not specific to the OES. The final integration of the
environmental release and occupational exposure evidence combined decisions regarding the strength of
the available information, including information on plausibility and coherence across each evidence
stream. The quality of the data sources used in the release and exposure assessments for each OES are
discussed in Section 4.

EPA evaluated environmental releases based on reported release data and evaluated occupational
exposures based on monitoring data and worker activity information from standard engineering sources
and systematic review. The Agency estimated OES-specific assessment approaches where supporting

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data existed and documented uncertainties where supporting data were only applicable for broader
assessment approaches.

2.7 Estimating Number of Workers and Occupational Non-users

This section provides a summary of the estimates for the total exposed workers and ONUs for each
OES. To prepare these estimates, EPA first identified relevant North American Industrial Classification
(NAICS) codes and Standard Occupational Classification (SOC) codes from the Bureau of Labor
Statistics (BLS) (2023). The estimation process for the total number of workers and ONUs is described
in Section 2.7.1 below. EPA also estimated the total number facilities associated with the relevant
NAICS codes based on data from the U.S. Census Bureau (2015). To estimate the average number of
potentially exposed workers and ONUs per site, the total number of workers and ONUs were divided by
the total number of facilities. The following sections provide additional details on the approach and
methodology for estimating the number of facilities using DBP and the number of potentially exposed
workers and ONUs.

2,7.1 Number of Workers and Occupational Non-users Estimation Methodology

Where available, EPA used CDR data to provide a basis to estimate the number of workers and ONUs.
EPA supplemented the available CDR data with U.S. economic data using the following method:

1.	Identify the NAICS codes for the industry sectors associated with these uses (Table 2-3 below).

2.	Estimate total employment by industry/occupation combination using the Bureau of Labor
Statistics' Occupational Employment Statistics data (BLS Data).

3.	Refine the Occupational Employment Statistics estimates where they are not sufficiently
granular by using the U.S. Census' SUSB data on total employment by 6-digit NAICS.

4.	Use market penetration data to estimate the percentage of employees likely to be using DBP
instead of other chemicals.

5.	Where market penetration data are not available, use the estimated workers/ONUs per site in the
6-digit NAICS code and multiply by the number of sites estimated from CDR, TRI, DMR and/or
NEI. In DMR data, sites report SIC codes rather than NAICS codes; therefore, EPA mapped
each reported SIC code to a NAICS code for use in this analysis.

6.	Combine the data generated in Steps 1 through 5 to produce an estimate of the number of
employees using DBP in each industry/occupation combination and sum these to arrive at a total
estimate of the number of employees with potential exposure within the OES.

Table 2-3 below contains the relevant NAICS codes and the calculated average number of workers and
ONUs identified per site for each OES.

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Table 2-3. NAICS Cod

e Crosswalk and Number of Workers and ONUs for Each OES

Occupational Exposure
Scenario (OES)

Relevant NAICS Codes

Exposed
Workers
per Site"

Exposed
ONUs per
Site"

Manufacturing

325199 - All Other Basic Organic Chemical Manufacturing

39

18

Import and repackaging

325199 - All Other Basic Organic Chemical Manufacturing
424690 - Other Chemical and Allied Products Merchant
Wholesalers

20

9

Incorporation into
formulations, mixtures,
or reaction product

325110 - Petrochemical Manufacturing

325199 - All Other Basic Organic Chemical Manufacturing

325510 - Paint and Coating Manufacturing

325520 - Adhesive Manufacturing

325920 - Explosives Manufacturing

34

15

PVC plastics
compounding

325211 - Plastics Material and Resin Manufacturing

27

12

PVC plastics converting

326100 - Plastics Product Manufacturing

18

5

Non-PVC material
manufacturing

325212 - Synthetic Rubber Manufacturing

326200 - Rubber Product Manufacturing

424690 - Other Chemical and Allied Products Merchant

Wholesalers

23

6

Recycling

562212	- Solid Waste Landfill

562213	- Solid Waste Combustors and Incinerators
562219 - Other Nonhazardous Waste Treatment and Disposal

13

7

Distribution in
commerce

Exposures not assessed

N/A

N/A

Industrial process
solvent use

325199 - All Other Basic Organic Chemical Manufacturing

39

18

Application of
adhesives and sealants

322220 - Paper Bag and Coated and Treated Paper
Manufacturing

334100 - Computer and Peripheral Equipment Manufacturing
334200 - Communications Equipment Manufacturing
334300 - Audio and Video Equipment Manufacturing
334400 - Semiconductor and Other Electronic Component
Manufacturing

334500 - Navigational, Measuring, Electromedical, and
Control Instruments

334600 - Manufacturing and Reproducing Magnetic and
Optical Media

335100 - Electric Lighting Equipment Manufacturing
335200 - Household Appliance Manufacturing
335300 - Electrical Equipment Manufacturing
335900 - Other Electrical Equipment and Component
Manufacturing

336100 - Motor Vehicle Manufacturing
336200 - Motor Vehicle Body and Trailer Manufacturing
336300 - Motor Vehicle Parts Manufacturing
336400 - Aerospace Product and Parts Manufacturing
336500 - Railroad Rolling Stock Manufacturing
336600 - Ship and Boat Building

336900 - Other Transportation Equipment Manufacturing

56

18

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Occupational Exposure
Scenario (OES)

Relevant NAICS Codes

Exposed
Workers
per Site"

Exposed
ONUs per
Site"

Application of paints
and coatings

332431 - Metal Can Manufacturing

335931 - Current-Carrying Wiring Device Manufacturing

337124 - Metal Household Furniture Manufacturing

337214	- Office Furniture (except wood) Manufacturing
337127 - Institutional Furniture Manufacturing

337215	- Showcase, Partition, Shelving, and Locker
Manufacturing

337122 - Nonupholstered Wood Household Furniture
Manufacturing

337211 - Wood Office Furniture Manufacturing
337110 - Wood Kitchen Cabinet and Countertop
Manufacturing

811120 - Automotive Body, Paint, Interior, and Glass Repair

12

6

Fabrication or use of
final product or articles

236100 - Residential Building Construction
236200 - Nonresidential Building Construction
237100 - Utility System Construction
237200 - Land Subdivision

237300 - Highway, Street, and Bridge Construction
237900 - Other Heavy and Civil Engineering Construction
337100 - Household and Institutional Furniture Manufacturing
337200 - Office Furniture (including Fixtures) Manufacturing

9

3

Use of penetrants and
inspection fluids

332100 - Forging and Stamping

332200 - Cutlery and Handtool Manufacturing

332300 - Architectural and Structural Metals Manufacturing

332400 - Boiler, Tank, and Shipping Container Manufacturing

332500 - Hardware Manufacturing

332600 - Spring and Wire Product Manufacturing

332700 - Machine Shops; Turned Product; and Screw, Nut,

and Bolt

332800 - Coating, Engraving, and Heat-Treating Metals
332900 - Other Fabricated Metal Product Manufacturing
333100 - Agriculture, Construction, and Mining Machinery
Manufacturing

333200 - Industrial Machinery Manufacturing
333300 - Commercial and Service Industry Machinery
Manufacturing

333400 - HVAC and Commercial Refrigeration Equipment
333900 - Other General Purpose Machinery Manufacturing

13

6

Use of laboratory
chemicals

541380 - Testing Laboratories
621511 - Medical Laboratories

1

9

Use of lubricants and
functional fluids

336100 - Motor Vehicle Manufacturing
336200 - Motor Vehicle Body and Trailer Manufacturing
336300 - Motor Vehicle Parts Manufacturing
336400 - Aerospace Product and Parts Manufacturing
336500 - Railroad Rolling Stock Manufacturing
336600 - Ship and Boat Building

336900 - Other Transportation Equipment Manufacturing
811100 - Automotive Repair and Maintenance

88

22

Waste handling,

562212 - Solid Waste Landfill

13

7

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Occupational Exposure
Scenario (OES)

Relevant NAICS Codes

Exposed
Workers
per Site"

Exposed
ONUs per
Site"

treatment, and disposal

562213 - Solid Waste Combustors and Incinerators
562219 - Other Nonhazardous Waste Treatment and Disposal





" For cases where multiple NAICS codes were identified for an OES, an average was calculated for the number of workers
and ONUs; this average was then applied to the OES.

1635	2.7.2 Summary of Number of Workers and ONUs

1636	Table 2-4 summarizes the number of facilities and total number of exposed workers for all OESs. For

1637	scenarios in which the results are expressed as a range, the lowend of the range is based on the 50th

1638	percentile estimate of the number of sites and the upper end of the range is based on the 95th percentile

1639	estimate of the number of sites. For some OESs, the estimated number of facilities is based on the

1640	number of reporting sites to the 2020 CDR (•. S ! ^ \ :020a), NEI (I. S ! ^ \ :023a), DMR (US„

1641	I PA, 2024a). and TRI databases (• ^ \ :024e).

1642

1643	Table 2-4. Summary of Total Number of Workers and ONUs Potentially Exposed to DBP for Each

1644	OES

Occupational

Exposure
Scenario (OES)

T otal
Exposed
Workers

Total Exposed
ONUs

Number of
Facilities

Notes

Manufacturing

195

90

5

Number of workers and ONU estimates based on the
BLS and U.S. Census Bureau data (U.S. BLS. 2023;
U.S. Census Bureau, 2015). Number of facilities
estimate based on identified sites from CDR.

Import and
repackaging

560

252

28

Number of workers and ONU estimates based on the
BLS and U.S. Census Bureau data (U.S. BLS, 2023;
U.S. Census Bureau, 2015). Number of facilities
estimate based on identified sites from CDR, TRI,
NEI, and DMR.

Incorporation into
formulations,
mixtures, and
reaction products

1,700

750

50

Number of workers and ONU estimates based on the
BLS and U.S. Census Bureau data (U.S. BLS. 2023;
U.S. Census Bureau, 2015). Number of facilities
estimate based on identified sites from CDR, TRI,
NEI, and DMR.

PVC plastics
compounding

459

204

17

Number of workers and ONU estimates based on the
BLS and U.S. Census Bureau data (U.S. BLS. 2023;
U.S. Census Bureau. 2015). Number of facilities
estimate based on identified sites from CDR, TRI,
NEI, and DMR.

PVC plastics
converting

180

50

10

Number of workers and ONU estimates based on the
BLS and U.S. Census Bureau data (U.S. BLS, 2023;
U.S. Census Bureau. 2015). Number of facilities
estimate based on identified sites from CDR, TRI,
NEI, and DMR.

Non-PVC material
manufacturing

1,196

312

52

Number of workers and ONU estimates based on the
BLS and U.S. Census Bureau data (U.S. BLS. 2023;
U.S. Census Bureau, 2015). Number of facilities
estimate based on identified sites from CDR, TRI,
NEI, and DMR.

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Occupational

Exposure
Scenario (OES)

T otal
Exposed
Workers

Total Exposed
ONUs

Number of
Facilities

Notes

Application of
adhesives and
sealants

5,264-
44,408

1,692-14,274

94-793

Number of workers and ONU estimates based on the
BLS and U.S. Census Bureau data (U.S. BLS. 2023;
U.S. Census Bureau, 2015). Number of facilities
estimated using modeled data.

Application of
paints and
coatings

2,628-
31,488

1,314-15,744

219-2,624

Number of workers and ONU estimates based on the
BLS and U.S. Census Bureau data (U.S. BLS, 2023;
U.S. Census Bureau, 2015). Number of facilities
estimated using modeled data.

Industrial process
solvent use

117

54

3

Number of workers and ONU estimates based on the
BLS and U.S. Census Bureau data (U.S. BLS. 2023;
U.S. Census Bureau. 2015). Number of facilities
estimate based on identified sites from CDR, TRI,
NEI, and DMR.

Use of laboratory
chemicals

36,873

331,857

36,873

Number of workers and ONU estimates based on the
BLS and U.S. Census Bureau data (U.S. BLS, 2023;
U.S. Census Bureau. 2015). Number of facilities
estimated using data from BLS.

Use of lubricants
and functional
fluids

293,656-
3,503,104

73,414-
875,776

3,337-
39,808

Number of workers and ONU estimates based on the
BLS and U.S. Census Bureau data (U.S. BLS. 2023;
U.S. Census Bureau. 2015). Number of facilities
estimated using modeled data.

Use of penetrants
and inspection
fluids

188,994-
270,010

87,228-
124,620

14,538-
20,770

Number of workers and ONU estimates based on the
BLS and U.S. Census Bureau data (U.S. BLS, 2023;
U.S. Census Bureau, 2015). Number of facilities
estimated using modeled data.

Fabrication or
use of final
products or
articles

N/A

Number of sites data was unavailable for this OES.
Based on the BLS and U.S. Census Bureau data (U.S.

BLS, 2023; U.S. Census Bureau, 2015).

Recycling

754

406

58

Number of workers and ONU estimates based on the
BLS and U.S. Census Bureau data (U.S. BLS, 2023;
U.S. Census Bureau. 2015). Number of facilities
estimate based on identified recycling sites (see
Section 3.14.2)

Waste handling,
treatment, and
disposal

2,951

1,589

227

Number of workers and ONU estimates based on the
BLS and U.S. Census Bureau data (U.S. BLS, 2023;
U.S. Census Bureau, 2015). Number of facilities
estimate based on identified sites from CDR, TRI,
NEI, and DMR.

1645

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3 ENVIRONMENTAL RELEASE AND OCCUPATIONAL
EXPOSURE ASSESSMENTS BY OES

3.1 Manufacturing

3.1.1 Process Description

At a typical manufacturing site, DBP is formed through the esterification of the carboxyl groups phthalic
anhydride with n-butyl alcohol in the presence of sulfuric acid as a catalyst. Similar to other phthalate
manufacturing processes, the unreacted alcohols are recovered and reused, and the DBP mixture is
purified by vacuum distillation or activated charcoal (SRC. 2001; AT SDR. 1999). According to 2020
CDR data, DBP is domestically manufactured in liquid form at concentrations at least 90 percent by
weight (	2020a). Sources indicate the purity of commercial DBP can be as high as 99.5

percent (Lee et al.. 2018; Zhu. ).

Based on manufacturing operations for similar phthalates, activities may also include filtrations and
quality control sampling of the DBP product. Additionally, manufacturing operations include equipment
cleaning/reconditioning and product transport to other areas of the manufacturing facility or offsite
shipment for downstream processing or use. No changes to chemical composition are expected to occur
during transportation (ExxonMobil. 2022a). Figure 3-1 provides an illustration of the proposed
manufacturing process based on identified process information (ExxonMobil. 2022b; SRC. 2001;
AT SDR. 1999).

1. Vented Losses
During Reaction/

Separation/Other
Process Operations

B. Exposure During	Equipment Cleaning

Equipment Cleaning

Figure 3-1. Manufacturing Flow Diagram

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3,1.2 Facility Estimates

In the 2020 CDR, one site reported a production volume for the domestic manufacturing of DBP. Dystar
LP in Reidsville, NC reported a production volume of 23,520 kg for the 2019 CDR reporting year (U.S.

20a). They had previously reported between 0 and 11,353 kg DBP manufactured between 2016
to 2018. Polymer Additives, Inc. in Bridgeport, NJ reported manufacture of DBP but indicated their PV
as CBI. An additional three sites reported their site activities as CBI; EPA assumed that these sites may
manufacture DBP. This resulted in a total of five potential DBP manufacturing sites, two with known
manufacturing activities and three sites with CBI activities.

EPA calculated the production volume for the four sites with CBI production volumes using a uniform
distribution set within the national PV range for DBP. EPA calculated the bounds of the range by taking
the total PV range reported in CDR and subtracting out the PVs that belonged to sites with known
volumes (both manufacturing and import). Then, for each bound of the PV range, EPA divided the value
by the number of sites with CBI PVs for DBP. CDR estimates a total national DBP PV of 1,000,000 to
10,000,000 lb for 2019. Based on the known PVs from importers and manufacturers, the total PV
associated with the four sites with CBI PVs is 109,546 to 5,252,403 lb/year. Based on this (and after
converting lb to kg), EPA set a uniform distribution for the PV for the four sites with CBI PVs with
lower-bound of 49,689 kg/year, and an upper-bound of 2,382,450 kg/year. EPA used the range of
production volumes as an input to the Monte Carlo modeling described in Appendix D to estimate
releases. The production volume range is not used to calculate occupational exposures for DBP. Table
3-1 shows the reported PVs in CDR.

Table 3-1. Reported Manufacturing and Import

'roduction Volumes in the 2020 <

:dr

Site Name

Location

Activity

Production
Volume (lb)

Production
Volume (kg)

Dystar LP

Reidsville, NC

Manufacture

5.2E04

2.4E04

Covalent Chemical

Raleigh, NC

Import

8.8E04

4.0E04

MAK Chemicals

Clifton, NJ

Import

1.1E05

4.8E04

GJ Chemical Co Inc

Newark, NJ

Import

1.4E05

6.3E04

Industrial Chemicals Inc

Vestavia Hills, AL

Import

4.2E05

1.9E05

EPA did not identify information from systematic review for general site throughputs; site throughput
information was estimated by dividing the site PV by the number of operating days. Based on the DBP
national aggregate PV reported in the 2020 CDR (1,000,000 to <10,000,000 lb), EPA assumed the
number of operating days was 300 days/year with 6 day/week operations and two full weeks of
downtime each operating year. CDR reporters indicated that DBP is manufactured primarily in liquid
form at a concentration of 90 to 100 percent (	20a). EPA assumed that DBP may be

packaged in drums or totes with a lower-bound and mode of 20 gallons and upper-bound of 1,000
gallons based on the ChemSTEER User Guide for the EPA/OAQPS AP-42 Loading Model (also called
"ChemSTEER User Guide" or ChemSTEER Manual") (	). The size of the container is an

input to the Monte Carlo simulation to estimate releases, but the range is not used to calculate
occupational exposures for DBP.

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3.1.3.1	Environmental Release Points

Five known sites manufacturing DBP were identified in 2020 CDR data. EPA assigned a model to
quantify potential release from each release point. EPA expects stack air releases from vented losses
during process operations. EPA expects water, incineration, or landfill releases from product sampling
and equipment cleaning. EPA expects fugitive air releases from equipment cleaning and transfer
operations from packaging manufactured DBP.

3.1.3.2	Environmental Release Assessment Results

Table 3-2 summarizes the number of release days and the annual and daily release estimates that were
modeled for each release media and scenario assessed for this OES. See Appendix D.2.2 for additional
details on model equations, and different parameters used for Monte Carlo modeling. The Monte Carlo
simulation calculated the total DBP release (by environmental media) across all release sources during
each iteration of the simulation. EPA then selected 50th percentile and 95th percentile values to estimate
the central tendency and high-end releases, respectively. The Draft Manufacturing OES Environmental
Release Modeling Results for Dibutyl Phthalate (DBP) also contains additional information about model
equations and parameters and calculation results; refer to Appendix F for a reference to this
supplemental document.

Table 3-2. Summary of Modeled Environmental Releases for Manufacture of DBP

Modeled Scenario

Environmental
Media

Annual Release
(kg/site-year)

Number of Release
Days

Daily Release''
(kg/site-day)

Central
Tendency

High-
End

Central High-
Tendency End

Central
Tendency

High-
End

23,520 kg/year
production volume
(Dystar LP)

Stack Air

0.24

0.24

300

7.8E-04

7.8E-04

Fugitive Air

9.9E-04

1.7E-03

3.3E-06

5.5E-06

Water,

Incineration, or
Landfill0

558

585

1.9

2.0

49,689-2,382,450
kg/year production
volume
(Other 4 sites)

Stack Air

3.0

5.7

300

1.0E-02

1.9E-02

Fugitive Air

7.8E-04

1.6E-03

2.6E-06

5.4E-06

Water,

Incineration, or
Landfill0

6,942

1.3E04

23

43

a When multiple environmental media are addressed together, releases may go all to one media or be split between
media depending on site-specific practices. Not enough data were provided to estimate the partitioning between
media.

b The Monte Carlo simulation calculated the total DBP release (by environmental media) across all release sources
during each iteration of the simulation. EPA then selected 50th and 95th percentile values to estimate the central
tendency and high-end releases, respectively.

3.1,4 Occupational Exposure Assessment

3.1.4.1 Workers Activities

During manufacturing, worker exposures to DBP may occur via inhalation of vapor or dermal contact
with liquid during product sampling, equipment cleaning, container cleaning, and packaging and loading
of DBP into transport containers for shipment. EPA did not identify information on engineering controls
or worker PPE used at DBP manufacturing facilities. EPA also did not seek specific information on

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safety protocols, engineering controls or standard operating procedures (SOPs) from facilities
manufacturing DBP.

ONUs include employees (e.g., supervisors, managers) who work at the manufacturing facility but do
not directly handle DBP. Generally, EPA expects ONUs to have lower inhalation and dermal exposures
than workers who handle the chemicals directly. Nevertheless, potential exposures to ONUs through
inhalation of vapors are assessed under the Manufacturing OES.

3.1.4.2 Occupational Inhalation Exposure Results

EPA identified inhalation monitoring data from three risk evaluations, however, each study only
presents a single aggregate or final data point during manufacturing of DBP. In the first source, the
Syracuse Research Corporation indicates that "following a review of six studies, the American
Chemistry Council has estimated exposure to di-n-butyl phthalate in the workplace based upon an
assumed level of 1 mg/m3 in the air during the production of phthalates." (SRC. 2001). The second
source, a risk evaluation of l,3,4,6,7,8-Hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-g-2-benzopyran
(HHCB) conducted by European Commission, Joint Research Centre (ECJRC) presented an 8-hour
TWA aggregate exposure concentration for DBP of 0.003 ppm (n = 114) for a DBP manufacturing site
(ECB. 2008). The third source, a risk evaluation of DBP also conducted by the ECJRC provides seven
separate datasets from two unnamed manufacturers. Of these datasets six did not include a sampling
method and were not used. Only one had sufficiently detailed metadata (e.g., exposure duration, sample
type) to include in this assessment; an 8-hour TWA worker exposure concentration to DBP of 0.5 mg/m3
from DBP production (ECB. 2004). With three aggregate or final concentration value from three
sources, EPA could not create a full distribution of monitoring results to estimate central tendency and
high-end exposures. To assess the high-end worker exposure to DBP during the manufacturing process,
the Agency used the maximum available value (1 mg/m3). EPA assessed the midpoint of the three
available values as the central tendency (0.5 mg/m3). All three sources of monitoring data received a
rating of medium from EPA's systematic review process.

Table 3-3 summarizes the estimated 8-hour TWA concentration, AD, IADD, and ADD for worker
exposures to DBP during manufacture. In absence of data specific to ONU exposure, EPA assumed that
worker central tendency exposure was representative of ONU exposure and used this data to generate
estimates for ONUs. The central tendency and high-end exposures use 250 days per year as the exposure
frequency, which is the expected maximum for working days. Appendix A describes the approach for
estimating AD, IADD, and ADD. The estimated exposures assume that the worker is exposed to DBP in
the form of vapors. The Draft Occupational Inhalation Exposure Monitoring Results for Dibutyl
Phthalate (DBP) contains further information on the identified inhalation exposure data and assumptions
used in the assessment, refer to Appendix F for a reference to this supplemental document.

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Table 3-3. Summary of Estimated Worker Inhalation Exposures for Manufacture of E

(BP

Modeled Scenario

Exposure Concentration Type

Central
Tendency"

High-End"

Average Adult Worker

8-hour TWA Exposure Concentration (mg/m3)

0.50

1.0

Acute dose (AD) (mg/kg-day)

6.3E-02

0.13

Intermediate Non-Cancer Exposures (IADD)
(mg/kg-day)

4.6E-02

9.2E-02

Chronic Average Daily Dose, Non-Cancer
Exposures (ADD) (mg/kg-day)

4.3E-02

8.6E-02

Female of Reproductive
Age

8-hour TWA Exposure Concentration (mg/m3)

0.50

1.0

Acute Dose (AD) (mg/kg-day)

6.9E-02

0.14

Intermediate Non-Cancer Exposures (IADD)
(mg/kg-day)

5.1E-02

0.10

Chronic Average Daily Dose, Non-Cancer
Exposures (ADD) (mg/kg-day)

4.7E-02

9.5E-02

ONU

8-hour TWA Exposure Concentration (mg/m3)

0.50

0.50

Acute Dose (AD) (mg/kg-day)

6.3E-02

6.3E-02

Intermediate Non-Cancer Exposures (IADD)
(mg/kg-day)

4.6E-02

4.6E-02

Chronic Average Daily Dose, Non-Cancer
Exposures (ADD) (mg/kg-day)

4.3E-02

4.3E-02

" EPA identified inhalation monitoring data from three sources to estimate exposures for this OES (ECB. 2008. 2004;
SRC, 2001). All three sources of monitoring data received a rating of medium from EPA's systematic review process.
With the three discrete data points, the Agency could not create a full distribution of monitoring results to estimate
central tendency and high-end exposures. To assess the high-end worker exposure to DBP during the manufacturing
process, EPA used the maximum available value (1 mg/m3). The Agency assessed the midpoint of the three available
values as the central tendency (0.5 mg/m3).

3.1.4.3 Occupational Dermal Exposure Results

EPA estimated dermal exposures for this OES using the dermal approach outlined in Section 2.4.3 and
Appendix C. The various "Exposure Concentration Types" from Table 3-4 are explained in Appendix A.
ONU dermal exposures are not assessed for this OES as there are no activities expected to expose ONUs
to DBP in liquid form. For occupational dermal exposure assessment, EPA assumed a standard 8-hour
workday and the chemical is contacted at least once per day. Because DBP has low volatility and
relatively low absorption, it is possible that the chemical remains on the surface of the skin after dermal
contact until the skin is washed. So, in absence of exposure duration data, EPA has assumed that
absorption of DBP from occupational dermal contact with materials containing DBP may extend up to 8
hours per day (	). However, if a worker uses proper PPE or washes their hands after

contact with DBP or DBP-containing materials dermal exposure may be eliminated. Therefore, the
assumption of an 8-hour exposure duration for DBP may lead to overestimation of dermal exposure.
Table 3-4 summarizes the APDR, AD, IADD, and ADD for average adult workers and female workers
of reproductive age. The Draft Occupational Dermal Exposure Modeling Results for Dibutyl Phthalate
(DBP) also contains information about model equations and parameters and contains calculation results;
refer to Appendix F for a reference to this supplemental document.

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Table 3-4. Summary of Estimated Worker Dermal Exposures for the Manufacturing of DBP

Modeled Scenario

Exposure Concentration Type

Central
Tendency

High-End

Average Adult Worker

Dose Rate (APDR, mg/day)

100

201

Acute (AD, mg/kg-day)

1.3

2.5

Intermediate (IADD, mg/kg-day)

0.92

1.8

Chronic, Non-Cancer (ADD, mg/kg-day)

0.86

1.7

Female of Reproductive Age

Dose Rate (APDR, mg/day)

84

167

Acute (AD, mg/kg-day)

1.2

2.3

Intermediate (IADD, mg/kg-day)

0.85

1.7

Chronic, Non-Cancer (ADD, mg/kg-day)

0.79

1.6

Note: For high-end estimates, EPA assumed the exposure surface area was equivalent to mean values for two-hand
surface areas (i.e., 1.070 cm2 for male workers and 890 cm2 for female workers) (U.S. EPA, 2011). For central
tendency estimates, EPA assumed the exposure surface area was equivalent to only a single hand (or one side of two
hands) and used half the mean values for two-hand surface areas (i.e., 535 cm2 for male workers and 445 cm2for
female workers).

3.1.4.4 Occupational Aggregate Exposure Results

Inhalation and dermal exposure estimates were aggregated based on the approach described in Appendix
A.3 to arrive at the aggregate worker and ONU exposure estimates in the table below. The assumption
behind this approach is that an individual worker could be exposed by both the inhalation and dermal
routes, and the aggregate exposure is the sum of these exposures.

Table 3-5. Summary of Estimated Worker Aggregate Exposures for Manufacture of E

(BP

Modeled Scenario

Exposure Concentration Type
(mg/kg-day)

Central Tendency

High-End

Average Adult Worker

Acute (AD, mg/kg-day)

1.3

2.6

Intermediate (IADD, mg/kg-day)

0.97

1.9

Chronic, Non-Cancer (ADD, mg/kg-day)

0.90

1.8

Female of Reproductive Age

Acute (AD, mg/kg-day)

1.2

2.4

Intermediate (IADD, mg/kg-day)

0.90

1.8

Chronic, Non-Cancer (ADD, mg/kg-day)

0.84

1.7

ONU

Acute (AD, mg/kg-day)

6.3E-02

6.3E-02

Intermediate (IADD, mg/kg-day)

4.6E-02

4.6E-02

Chronic, Non-Cancer (ADD, mg/kg-day)

4.3E-02

4.3E-02

Note: A worker could be exposed by both the inhalation and dermal routes, and the aggregate exposure is the sum of
these exposures.

3.2 Import and Repackaging

3.2.1 Process Description

DBP may be imported into the United States in bulk via water, air, land, and intermodal shipments
(Tomer and Kane. 2015). These shipments take the form of oceangoing chemical tankers, railcars, tank
trucks, and intermodal tank containers. Chemicals may be repackaged by wholesalers for resale, for
example, repackaging bulk packaging into drums or bottles. The type and size of container will vary
depending on customer requirement.

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Based on the Chemical Repackaging Generic Scenario, import and repackaging sites unload the import
containers and transfer DBP into smaller containers (drums or bottles) for downstream processing, use
within the facility, or offsite use. Operations may include quality control sampling of DBP product and
equipment cleaning. Some import facilities may only serve as storage and distribution locations, and
repackaging/sampling may not occur at all import facilities. No changes to chemical composition occur
during repackaging (U.S. EPA. 2022a).

According to the 2020 CDR, DBP is shipped in liquid form. One facility reported DBP was imported at
a concentration of 1 to 30 percent, one facility reported DBP concentrations of 60 to 90 percent and nine
facilities reported DBP concentrations were at least 90 percent (	20a). Sources indicate the

purity of neat commercial DBP is 99.5 percent (Lee et al.. 2018; Zhu. 2015). Figure 3-2 provides an
illustration of the import and repackaging process.

Cleaning Releases	3- import Container

Residue Losses

Figure 3-2. Import and Repackaging Flow Diagram (U.S. EPA. 2022a)

3.2.2 Facility Estimates	

In the 2020 CDR, 10 sites reported import of DBP and are listed in the table below. Two sites reported
both manufacturing and import activities - Covalent Chemical and BAE Systems; one site withheld their
site activity - Shrieve Chemical Company, LLC, and two sites claimed CBI for their site name, location,
and activity. In the NEI (\ ^ \ :023a). DMR (U.S. EPA. 2024a). and TRI (\ ^ \ 2024e) data
that EPA analyzed, EPA identified that an additional 15 sites may repackage DBP based on site names
and their reported NAICS and SIC codes. EPA identified two reports from NEI air release data
indicating 365 operating days. TRI/DMR did not report operating days; therefore, EPA assumed 260
days/year of operation based on the Repackaging GS Revised Draft, as discussed in Section 2.3.2 (U.S.
22a). Table 3-6 presents the production volume of DBP repackaging sites.

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Table 3-6. Production Volume of DBP Repackaging Sites, 2020 CDR

DBP Repackaging Site, Site Location

2019 Reported Import Production Volume
(kg/year)

Lanxess Corporation, Pittsburgh, PA

0

Univar Solutions USA Inc., Redmond, WA

0

MAK Chemicals, Clifton, NJ

105,884

GJ Chemical Co Inc., Newark, NJ

139,618

Industrial Chemicals Inc., Vestavia Hills, AL

422,757

Allchem Industries Industrial Chemicals Group,
Inc., Gainesville, FL

0

Sika Corp, Lyndhurst, NJ

0

The Sherwin-Williams Company, Cleveland, OH

CBI

Huntsman Corporation - The Woodlands
Corporate Site, Montgomery, TX

CBI

Greenchem, West Palm Beach, FL

CBI

Covalent Chemical, Raleigh, NC

88,184

BAE Systems, Radford, VA

0

Shrieve Chemical Company LLC, Spring, TX

CBI

CBI

CBI

CBI

CBI

EPA evaluated the production volumes for sites that reported this information as CBI by subtracting
known production volumes for other manufacturing and import sites from the total DBP production
volume reported to the 2020 CDR. EPA considered production volumes for both import and
manufacturing sites because the annual DBP production volume in the CDR includes both domestic
manufacture and repackaging. The 2020 CDR reported a range of national production volume for DBP;
therefore, the Agency provided the import and repackaging production volume as a range. EPA split the
remaining production volume range evenly across all sites that reported this information as CBI. The
calculated production volume range for the sites with CBI or withheld production volumes resulted in
12,423 to 595,613 kg/site-year.

3.2.3 Release Assessment

3.2.3.1 Environmental Release Points

Based on TRI, DMR and NEI data, repackaging releases may go to fugitive air, stack air, surface water,
POTWs, and landfills (U.S. EPA. 2024a. e, 2023a). Additional releases may occur from transfers of
wastes to off-site treatment facilities (assessed in the Waste handling, treatment, and disposal OES).
Fugitive air releases may occur during sampling, equipment cleaning, and container loading. Stack air
releases may occur from vented losses during process operations. Releases to surface water, POTWs, or
landfills may occur from equipment cleaning wastes, process wastes, and sampling wastes. Surface
water releases may occur from container cleaning. Additional fugitive air releases may occur during
leakage of pipes, flanges, and other equipment used for transport.

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3.2.3.2 Environmental Release Assessment Results

Table 3-7 presents fugitive and stack air releases per year and per day for DBP Repackaging based on
the 2017 to 2022 TRI database years along with the number of release days per year, with medians and
maxima presented from across the 6-year reporting range. Table 3-8 presents fugitive and stack air
releases per year and per day based on the 2020 NEI database along with the number of release days per
year. Table 3-9 presents land releases per year based on the 2017 to 2022 TRI database along with the
number of release days per year. Table 3-10 presents water releases per year and per day based on the
2017 to 2022 TRI database along with the number of release days per year, with medians and maxima
presented from across the 6-year reporting range. Some sites qualified to report their releases under TRI
form A because the amount of the chemical manufactured, processed, or used were below 1,000,000 lb
and the total reportable release did not exceed 500 lb (227 kg). The Draft Summary of Results for
Identified Environmental Releases to Air for Dibutyl Phthalate (DBP), Draft Summary of Results for
Identified Environmental Releases to Landfor Dibutyl Phthalate (DBP), and Draft Summary of Results
for Identified Environmental Releases to Water for Dibutyl Phthalate (DBP) contain additional
information about these identified releases and their original sources; refer to Appendix F for a reference
to these supplemental documents.

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1861 Table 3-7. Summary of Air Releases from TRI for Re

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)ackaging

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual Stack
Air Release
(kg/year)

Median
Annual
Fugitive Air
Release
(kg/year)

Median
Annual Stack
Air Release
(kg/year)

Annual
Release Days
(days/year)

Maximum

Daily
Fugitive Air
Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

Median Daily
Fugitive Air
Release
(kg/day)

Median Daily
Stack Air
Release
(kg/day)

Superior
Industrial
Solutions Inc.

227

227

0

0

260

0.87

0.87

3.4E-03

0

Doremus
Terminal LLC

1.4

0

0.68

0

260

5.2E-03

0

0

0

Univar

Solutions-

Doraville

113

4.5E-05

2.5

0

260

0.44

1.7E-07

6.7E-10

0

Harwick
Standard
Distribution
Corp

0.45

0

0.45

0

260

1.7E-03

0

0

0

Greenchem

Industries

LLC

0

0

0

0

260

0

0

0

0

Superior
Industrial
Solutions Inc.

227

227

227

227

260

0.87

0.87

3.4E-03

0.87

Wego

Chemical

Group

0

0

0

0

260

0

0

0

0

The Dow
Chemical Co
- Louisiana
Operations

0

0

0

0

260

0

0

0

0

Barton
Solvents Inc
Council
Bluffs

0

0

0

0

260

0

0

0

0

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Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual Stack
Air Release
(kg/year)

Median
Annual
Fugitive Air
Release
(kg/year)

Median
Annual Stack
Air Release
(kg/year)

Annual
Release Days
(days/year)

Maximum

Daily
Fugitive Air
Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

Median Daily
Fugitive Air
Release
(kg/day)

Median Daily
Stack Air
Release
(kg/day)

SolvChem
Inc. -
Pearland
Facility

0

0

0

0

260

0

0

0

0

1862

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1863 Table 3-8. Summary of Air Releases from NEI (2020) and NEI (2017) for Repackaging

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual
Stack Air
Release
(kg/year)

Annual
Release Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

Tanker Terminal Bayport (2020)

35

0

364

9.5E-02

0

Univar Solutions USA, Inc.
(1677130036)(2020)

8.2

0

365

2.2E-02

0

Galena Park Terminal (2017)

113

0

365

0.31

0

Conroe Plant(2017)

N/A

0

365

N/A

0

Table 3-9. Summary of Land Releases from TRI for Repackaging

Site Identity

Median Annual
Release (kg/year)

Maximum Annual
Release (kg/year)

Annual Release
Days (days/year)

Harwick Standard Distribution Corp

56

873

260

US Navy NSWC Crane Div
Installation Activity - Installation

1.2E04

3.7E04

260

Table 3-10. Summary of Water Releases from TRI/DMR for Repackaging

Site Identity

Source- Discharge
Type

Median
Annual
Discharge
(kg/year)

Median Daily
Discharge
(kg/day)

Maximum
Annual
Discharge
(kg/year)

Maximum

Daily
Discharge
(kg/day)

Annual
Release Days
(days/year)

GreenChem
Industries LLC

TRI Form A -
Direct

227

0.87

227

0.87

260

GreenChem
Industries LLC

TRI Form A -
Transfer to POTW

227

0.87

227

0.87

260

GreenChem
Industries LLC

TRI Form A -
Transfer to Non-
POTW

227

0.87

227

0.87

260

IMTT-BC

DMR

1.1E-02

4.0E-05

1.1E-02

4.0E-05

260

Superior Industrial
Solutions Inc.

TRI Form A -
Direct

227

0.87

227

0.87

260

Superior Industrial
Solutions Inc.

TRI Form A -
Direct

227

0.87

227

0.87

260

Univar Solutions -
Doraville

TRI Form A -
Direct

227

0.87

227

0.87

260

Superior Industrial
Solutions Inc.

TRI Form A -
Transfer to POTW

227

0.87

227

0.87

260

Superior Industrial
Solutions Inc.

TRI Form A -
Transfer to POTW

227

0.87

227

0.87

260

Univar Solutions-
Doraville

TRI Form A -
Transfer to POTW

227

0.87

227

0.87

260

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Site Identity

Source- Discharge
Type

Median
Annual
Discharge
(kg/year)

Median Daily
Discharge
(kg/day)

Maximum
Annual
Discharge
(kg/year)

Maximum

Daily
Discharge
(kg/day)

Annual
Release Days
(days/year)

Superior Industrial
Solutions Inc.

TRI Form A -
Transfer to Non-
POTW

227

0.87

227

0.87

260

Superior Industrial
Solutions Inc.

TRI Form A -
Transfer to Non-
POTW

227

0.87

227

0.87

260

Univar Solutions -
Doraville

TRI Form A -
Transfer to Non-
POTW

227

0.87

227

0.87

260

3,2,4 Occupational Exposure Assessment

3.2.4.1	Workers Activities

During import and repackaging, worker exposures to DBP occur when transferring DBP from the import
vessels into smaller containers. Worker exposures also occur via inhalation of vapor or dermal contact
with liquid when cleaning import vessels, loading and unloading DBP, sampling, and cleaning
equipment. EPA did not find any information on the extent to which engineering controls and worker
PPE are used at facilities that repackage DBP from import vessels into smaller containers.

ONUs include employees (e.g., supervisors, managers) that work at the import site where repackaging
occurs but do not directly handle DBP. Therefore, EPA expects ONUs to have lower inhalation
exposures and dermal exposures than workers. Nevertheless, potential exposures to ONUs through
inhalation of vapors is assessed under the Import and Repackaging OES.

3.2.4.2	Occupational Inhalation Exposure Results

EPA did not identify inhalation monitoring data for import and repackaging from systematic review of
literature sources. DBP is imported as a liquid, per CDR, and EPA assessed worker inhalation exposures
to DBP vapor during the unloading and loading processes. EPA used DBP manufacturing monitoring
data to estimate inhalation exposures. EPA identified inhalation monitoring data from three risk
evaluations, however, each study only presents a single aggregate or final data point during
manufacturing of DBP. In the first source, the Syracuse Research Corporation indicates that "following
a review of six studies, the American Chemistry Council has estimated exposure to di-n-butyl phthalate
in the workplace based upon an assumed level of 1 mg/m3 in the air during the production of
phthalates." (SRC. 2001). The second source, a risk evaluation of l,3,4,6,7,8-Hexahydro-4,6,6,7,8,8-
hexamethylcyclopenta-g-2-benzopyran (HHCB) conducted by European Commission, Joint Research
Centre (ECJRC) presented an 8-hour TWA aggregate exposure concentration for DBP of 0.003 ppm (n
= 114) for a DBP manufacturing site (ECB. 2008). The third source, a risk evaluation of DBP also
conducted by the ECJRC provides seven separate datasets from two unnamed manufacturers. Of these
datasets, six did not include a sampling method and were not used. Only one had sufficiently detailed
metadata (e.g., exposure duration, sample type) to include in this assessment; an 8-hour TWA worker
exposure concentration to DBP of 0.5 mg/m3 from DBP production (ECB. 2004). With three aggregate
or final concentration value from three sources, EPA could not create a full distribution of monitoring
results to estimate central tendency and high-end exposures. To assess the high-end worker exposure to
DBP during the manufacturing process, the Agency used the maximum available value (1 mg/m3). EPA
assessed the midpoint of the three available values as the central tendency (0.5 mg/m3). All three sources

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of monitoring data received a rating of medium from EPA's systematic review process. In absence of
data specific to ONU exposure, the Agency assumed that worker central tendency exposure was
representative of ONU exposure and used this data to generate estimates for ONUs. EPA assessed the
exposure frequency as 250 days/year for both high-end and central tendency exposures based on the
expected operating days for the OES and accounting for off days for workers.

Table 3-11 summarizes the estimated 8-hour TWA concentration, AD, IADD, and ADD for worker
exposures to DBP during import and repackaging. Appendix A describes the approach for estimating
AD, IADD, and ADD. The estimated exposures assume that the worker is exposed to DBP in the form
of vapor. Because DBP is imported as a liquid as opposed to solid, inhalation exposures to vapor is more
likely than dust. The Draft Occupational Inhalation Exposure Monitoring Results for Dibutyl Phthalate
(DBP) contains further information on the identified inhalation exposure data and assumptions used in
the assessment, refer to Appendix F for a reference to this supplemental document.

Table 3-11. Summary of Estimated Worker Inhalation Exposures for Import and Repackaging of

DBP

Modeled Scenario

Exposure Concentration Type

Central
Tendency"

High-End"

Average Adult Worker

8-hour TWA Exposure Concentration
(mg/m3)

0.50

1.0

Acute Dose (AD) (mg/kg-day)

6.3E-02

0.13

Intermediate Non-Cancer Exposures
(IADD) (mg/kg-day)

4.6E-02

9.2E-02

Chronic Average Daily Dose, Non-Cancer
Exposures (ADD) (mg/kg-day)

4.3E-02

8.6E-02

Female of Reproductive Age

8-hour TWA Exposure Concentration
(mg/m3)

0.50

1.0

Acute Dose (AD) (mg/kg-day)

6.9E-02

0.14

Intermediate Non-Cancer Exposures
(IADD) (mg/kg-day)

5.1E-02

0.10

Chronic Average Daily Dose, Non-Cancer
Exposures (ADD) (mg/kg-day)

4.7E-02

9.5E-02

ONU

8-hour TWA Exposure Concentration
(mg/m3)

0.50

0.50

Acute Dose (AD) (mg/kg-day)

6.3E-02

6.3E-02

Intermediate Non-Cancer Exposures
(IADD) (mg/kg-day)

4.6E-02

4.6E-02

Chronic Average Daily Dose, Non-Cancer
Exposures (ADD) (mg/kg-day)

4.3E-02

4.3E-02

a EPA identified surrogate inhalation monitoring data from three sources to estimate exposures for this OES (ECB.
2008. 2004; SRC, 2001). All three sources of monitoring data received a rating of medium from EPA's systematic
review process. With the three discrete data points, EPA could not create a full distribution of monitoring results to
estimate central tendency and high-end exposures. To assess the high-end worker exposure to DBP during the
manufacturing process, the Agency used the maximum available value (1 mg/m3). EPA assessed the midpoint of the
three available values as the central tendency (0.5 mg/m3).

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3.2.4.3 Occupational Dermal Exposure Results

EPA estimated dermal exposures for this OES using the dermal approach outlined in Section 2.4.3 and
Appendix C. The various "Exposure Concentration Types" from Table 3-12 are explained in Appendix
A. ONU dermal exposures are not assessed for this OES as there are no activities expected to expose
ONUs to DBP in liquid form. For occupational dermal exposure assessment, EPA assumed a standard 8-
hour workday and the chemical is contacted at least once per day. Because DBP has low volatility and
relatively low absorption, it is possible that the chemical remains on the surface of the skin after dermal
contact until the skin is washed. So, in absence of exposure duration data, EPA has assumed that
absorption of DBP from occupational dermal contact with materials containing DBP may extend up to 8
hours per day (	). However, if a worker uses proper personal protective equipment (PPE)

or washes their hands after contact with DBP or DBP-containing materials dermal exposure may be
eliminated. Therefore, the assumption of an 8-hour exposure duration for DBP may lead to
overestimation of dermal exposure. Table 3-12 summarizes the APDR, AD, IADD, and ADD for
average adult workers and female workers. The Draft Occupational Dermal Exposure Modeling Results
for Dibutyl Phthalate (DBP) also contains information about model equations and parameters and
contains calculation results; refer to 4.2Appendix F for a reference to this supplemental document.

Table 3-12. Summary of Estimated Worker Dermal Exposures for Import and Repackaging of

DBP

Modeled Scenario

Exposure Concentration Type

Central
Tendency

High-End

Average Adult Worker

Dose Rate (APDR, mg/day)

100

201

Acute (AD, mg/kg-day)

1.3

2.5

Intermediate (IADD, mg/kg-day)

0.92

1.8

Chronic, Non-Cancer (ADD, mg/kg-day)

0.86

1.7

Female of
Reproductive Age

Dose Rate (APDR, mg/day)

84

167

Acute (AD, mg/kg-day)

1.2

2.3

Intermediate (IADD, mg/kg-day)

0.85

1.7

Chronic, Non-Cancer (ADD, mg/kg-day)

0.79

1.6

Note: For high-end estimates, EPA assumed the exposure surface area was equivalent to mean values for two-hand
surface areas (i.e., 1.070 cm2 for male workers and 890 cm2 for female workers) (U.S. EPA, 2011). For central
tendency estimates, EPA assumed the exposure surface area was equivalent to only a single hand (or one side of two
hands) and used half the mean values for two-hand surface areas (i.e., 535 cm2 for male workers and 445 cm2 for
female workers).

3.2.4.4 Occupational Aggregate Exposure Results

Inhalation and dermal exposure estimates were aggregated based on the approach described in Appendix
A to arrive at the aggregate worker and ONU exposure estimates in the table below. The assumption
behind this approach is that an individual worker could be exposed by both the inhalation and dermal
routes, and the aggregate exposure is the sum of these exposures.

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Table 3-13. Summary of Estimated Worker Aggregate Exposures for Import and Repackaging of

DBP

Modeled Scenario

Exposure Concentration Type
(mg/kg-day)

Central
Tendency

High-End

Average Adult Worker

Acute (AD, mg/kg-day)

1.3

2.6

Intermediate (IADD, mg/kg-day)

0.97

1.9

Chronic, Non-Cancer (ADD, mg/kg-day)

0.90

1.8

Female of Reproductive Age

Acute (AD, mg/kg-day)

1.2

2.5

Intermediate (IADD, mg/kg-day)

0.90

1.8

Chronic, Non-Cancer (ADD, mg/kg-day)

0.84

1.7

ONU

Acute (AD, mg/kg-day)

6.3E-02

6.3E-02

Intermediate (IADD, mg/kg-day)

4.6E-02

4.6E-02

Chronic, Non-Cancer (ADD, mg/kg-day)

4.3E-02

4.3E-02

Note: A worker could be exposed by both the inhalation and dermal routes, and the aggregate exposure is the
sum of these exposures.

3.3 Incorporation into Formulations, Mixtures, and Reaction Products

3.3.1 Process Description

"Incorporation into formulations, mixtures, and reaction products" refers to the process of mixing or
blending of several raw materials to obtain a single product or preparation. Exact process operations
involved in the incorporation of DBP into a chemical formulation, mixture, or reaction product are
dependent on the specific manufacturing process or processes involved. EPA expects that each
individual formulation process is small; therefore, EPA assessed releases and exposures for the
incorporation of DBP into a chemical formulation, mixture, or reaction product as a group rather than
individually. Companies reported to the 2020 CDR that DBP is used as a plasticizer in the manufacture
of paints and coatings, soap, cleaning compounds, and toilet preparation manufacturing (NLM. 2024;

020a). DBP is also used in the formulation ink, toner, and colorant products, as a functional
fluid in printing activities, and as a solvent in other chemical manufacturing (	:0a). The

concentration of DBP in the formulation varies widely depending on the type of formulation (e.g., paint,
adhesive, dye, ink).

DBP-specific formulation processes were not identified; however, the Agency identified several ESDs
published by the OECD and Generic Scenarios published by EPA that provide general process
descriptions for these types of products. The manufacture of coatings involves four steps. The
formulation of coatings and inks typically involves dispersion, milling, finishing and filling into final
packages (	). Modern processes can combine the final steps by creating intermediate

formulations during the first two steps. The intermediates are then dispensed directly into the shipping
containers for the final blending in order to produce the end-product (1, c. < ^ \ _ 0l0).

Waterborne coatings are produced with the same approach, using water as one of the liquid ingredients
(I	1010). Adhesive formulation involves mixing volatile and non-volatile chemical

components together in sealed, unsealed, or heated processes (OECD. 2009a). Sealed processes are most
common for adhesive formulation because many adhesives are designed to set or react when exposed to
ambient conditions (OECD. 2009a). The manufacturing process for radiation curable coating products is
similar to adhesive formulation, with volatile and non-volatile chemical components being mixed in an
open or sealed batch process, with the photoinitiator being added last. The high cost of radiation curable

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raw materials has led to the use of practices to reduce container residues, such as heating containers to
reduce viscosity (OECD. 2010).

DBP has been identified in quantities ranging from 0.1 to 75 percent in adhesives, sealants, paints, and
coatings. In addition, two CDR entries reported a concentration of at least 90 percent DBP in the
formulation of adhesives, sealants and inks (U.S. EPA. 2020a). Figure 3-3 provides an illustration of the
incorporation into formulations, mixtures, and reaction products process.

1. Transfer Operation
Losses from Unloading
DBP

4. Vented Losses During
Dispersion and

Blending/Process

9. Filter Waste Losses
10. Open Surface

11. Transfer Operation Losses
During loading of Product

8. Exposure During
Container Cleaning

7. Equipment
Cleaning Releases
8. Open Surface
Losses During
Equipment Cleaning

D. Exposure During
Equipment Cleaning

Figure 3-3. Incorporation into Formulations, Mixtures, and Reaction Products Flow Diagram
(U.S. EPA. 2014a)

3.3.2	Facility Estimates

In the NEI (	; , ), DMR ( u;-. ),'and TRI ( s r	) data that

EPA analyzed, EPA identified 50 sites that may have used DBP in incorporative activities based on site
names and their reported NAICS and SIC codes. Due to the lack of data on the annual PV of DBP in
incorporation into formulation, mixture, or reaction products, EPA does not present annual or daily site
throughputs. The ESD on Formulation of Radiation Curable Coatings, Inks and Adhesives estimates 250
operating days/year and an annual production rate of 130,000 kg formulation/site-year (I	).

EPA identified operating days ranging from 250 to 365 days with an average of 252 days through NEI
air release data. TRI/DMR data did not report operating days; therefore, EPA assumed 250 days/year of
operation as discussed in Section 2.3.2.

3.3.3	Release Assessment

3.3.3.1 Environmental Release Points

Based on TRI and NEI data, Incorporation into formulation, mixture, or reaction product releases may
go to stack air, fugitive air, surface water, POTW, and landfill (	24e. 2023a. 2019).

Additional releases may occur from transfers of waste to off-site treatment facilities (assessed in the
Waste handling, treatment, and disposal OES). Stack air releases may occur from vented losses during
mixing, vented during transfer, and vented losses during process operations. POTW, incineration, or

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landfill releases may occur from container residue, sampling wastes, equipment cleaning wastes, and
off-specification wastes. Incineration or landfill releases may occur from filter waste. Additional fugitive
air releases may occur during leakage from pipes, flanges, and accessories used for transport (OECD.
2010. 2009aY

3.3.3.2 Environmental Release Assessment Results

Table 3-14 summarizes the fugitive and stack air releases per year and per day for incorporation into
formulation, mixture, or reaction product based on the 2017 to 2022 TRI database reporting years along
with the number of release days per year, with medians and maxima presented from across the 6-year
reporting range. Table 3-15 presents fugitive and stack air releases per year and per day based on the
2020 NEI database along with the number of release days per year. Table 3-16 presents fugitive and
stack air releases per year and per day based on the 2017 NEI database along with the number of release
days per year. Table 3-17 presents land releases per year based on reports from TRI. Table 3-18 presents
water releases per year and per day based on the 2017 to 2022 TRI database along with the number of
release days per year, with medians and maxima presented from across the 6-year reporting range. Some
sites qualified to report their releases under TRI form A because the amount of the chemical
manufactured, processed, or used were below 1,000,000 lb and the total reportable release did not
exceed 500 lb (227 kg). The Draft Summary of Results for Identified Environmental Releases to Air for
Dibutyl Phthalate (DBF), Draft Summary of Results for Identified Environmental Releases to Landfor
Dibutyl Phthalate (DBF), and Draft Summary of Results for Identified Environmental Releases to Water
for Dibutyl Phthalate (DBP) contain additional information about these identified releases and their
original sources; refer to Appendix F for a reference to these supplemental documents.

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Table 3-14. Summary of Air

Releases from TRI for Incorporation into Formulation, Mixture, or Reaction Prot

uct

Site Identity

Maximum
Annual
Fugitive
Air Release
(kg/year)

Maximum
Annual
Stack Air
Release
(kg/year)

Median
Annual
Fugitive
Air Release
(kg/year)

Median
Annual
Stack Air
Release
(kg/year)

Annual
Release
Days
(days/year)

Maximum

Daily
Fugitive
Air Release
(kg/year)

Maximum
Daily Stack
Air Release
(kg/day)

Median
Daily
Fugitive
Air Release
(kg/day)

Median
Daily
Stack Air
Release
(kg/day)

Penn Color Inc.

227

227

0

0

250

0.91

0.91

0

0

St. Marks Powder Inc.

0

0

0

0

250

0

0

0

0

Century Industrial Coatings Inc.

41

787

0

0

250

0.17

3.2

0

0

Lanxess Corp-Baytown

182

0.91

109

0.91

250

0.73

3.6E-03

0.43

3.6E-03

Arkema Inc.

0

0

0

0

250

0

0

0

0

Grace-Pasadena Catalyst Site

298

224

224

0.45

250

1.2

0.89

0.89

1.8E-03

Prime Resins Inc.

0

0

0

0

250

0

0

0

0

Sika Corp-Marion Operations

0

0

0

0

250

0

0

0

0

GAF

227

227

0

0

250

0.91

0.91

0

0

Polycoat Products LLC

227

227

0

0

250

0.91

0.91

0

0

Henkel Us Operations Corp

227

227

0

0

250

0.91

0.91

0

0

Amvac Chemical Co

227

227

0

0

250

0.91

0.91

0

0

Lanco Manufacturing Corp

6.1

5.4E-04

4.9

3.8E-04

250

2.4E-02

2.1E-06

1.9E-02

1.5E-06

The Sierra Co LLC

199

0

199

0

250

0.79

0

0.79

0

Essential Industries Inc

227

227

227

227

250

0.91

0.91

0.91

0.91

Buckeye International Inc.

227

227

113

113

250

0.91

0.91

0.45

0.45

National Chemical Laboratories
Inc

0

0

0

0

250

0

0

0

0

Evonik Corp

0

0

0

0

250

0

0

0

0

2027

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2028 Table 3-15. Summary of Air Releases from NEI (2020) for Incorporation into Formulation,

Mixture, or Reaction Prot

uct

Site Identity

Maximum
Annual Fugitive
Air Release
(kg/year)

Maximum
Annual Stack
Air Release
(kg/year)

Annual
Release
Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum
Daily Stack Air
Release
(kg/day)

Owens Corning Roofing and
Asphalt, LLC

N/A

0

250

N/A

0

Tamko Building Products
LLC

3.6E-03

0

250

1.5E-05

0

Frazee Industries

11

N/A

250

4.5E-02

N/A

General Polymer, Inc.

0.91

N/A

250

3.6E-03

N/A

Marcus Paint Company

0

N/A

250

0

N/A

Crane Div Naval Surface
Warfare CtrNSW

100

0

250

0.40

0

Tamko Building Products
LLC Rangeline Plant

N/A

0

250

N/A

0

True Value Manufacturing
Co

N/A

8.7

250

N/A

3.5E-02

Covestro Industrial Park
Baytown

12

N/A

365

3.2E-02

N/A

Plasti-Dip International

N/A

19

250

N/A

7.5E-02

Owens Corning -
Minneapolis Plant

N/A

0

250

N/A

0

T1 Edwards Inc

2.0E-06

N/A

250

7.8E-09

N/A

Forest County Highway
Dept

N/A

0

250

N/A

0

Sierra Corp

33

0

250

0.13

0

Ceramic Industrial Coatings

4.4

0

250

1.8E-02

0

Certainteed LLC

N/A

0

250

N/A

0

3M Alexandria

N/A

0

250

N/A

0

Gaf Materials Corp

N/A

0

250

N/A

0

Palmer Paving Corp

0

N/A

250

0

N/A

Akron Paint and Varnish
(1677010028)

5.4

N/A

260

2.1E-02

N/A

Lanco Mfg Corp

4.9

0

250

1.9E-02

0

Tnemec Company

N/A

0

250

N/A

0

Tnemec Company Inc North
Kansas City

N/A

0

250

N/A

0

Akzonobel Aerospace
Coating

N/A

7.3

250

N/A

2.9E-02

Itw Phila

Resins/Montgomery

0.91

0

250

3.6E-03

0

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Site Identity

Maximum
Annual Fugitive
Air Release
(kg/year)

Maximum
Annual Stack
Air Release
(kg/year)

Annual
Release
Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum
Daily Stack Air
Release
(kg/day)

Certainteed Corporation

0.20

0

250

8.1E-04

0

Glenn O Hawbaker
Inc/Dubois Pit 4

N/A

0

181

N/A

0

Stark Pavement Corp - Ultra
135-85577-00-Na

N/A

0

250

N/A

0

2030

2031

2032	Table 3-16. Summary of Air Releases from NEI (2017) for Incorporation into Formulation,

Mixture, or Reaction Product

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual Stack
Air Release
(kg/year)

Annual
Release
Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/year)

Maximum
Daily Stack Air
Release
(kg/year)

CertainTeed Corp

N/A

0

250

N/A

0

Trumbull Asphalt

N/A

0

250

N/A

0

Kop-Coat, Inc.

34

N/A

250

0.14

N/A

Bradley Laboratories

N/A

1.5

250

N/A

5.8E-03

Century Industrial Coatings Inc

5.0

0

250

2.0E-02

0

2034

2035

2036	Table 3-17. Summary of Land Releases from TRI for Incorporation into Formulation, Mixture, or

2037	Reaction Product

Site Identity

Median Annual
Release (kg/year)

Maximum Annual
Release (kg/year)

Annual Release
Days (days/year)

St. Marks Powder Inc.

510

723

250

Rubicon LLC

2,629

1.0E04

250

Century Industrial Coatings Inc.

2.7

552

250

2038

2039

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2040	Table 3-18. Summary of Water Releases from TRI for Incorporation into Formulation, Mixture,

2041	or Reaction Product

Site Identity

Source- Discharge
Type

Median
Annual
Discharge
(kg/year)

Median
Daily
Discharge
(kg/day)

Maximum
Annual
Discharge
(kg/year)

Maximum

Daily
Discharge
(kg/day)

Annual
Release
Days
(days/year)

Amvac Chemical Co

TRI Form A - Direct

227

0.91

227

0.91

250

Amvac Chemical Co

TRI Form A - Transfer
toPOTW

227

0.91

227

0.91

250

Amvac Chemical Co

TRI Form A - Transfer
to Non-POTW

227

0.91

227

0.91

250

Arkema Inc.

TRI Form A - Transfer
toPOTW

227

0.91

227

0.91

250

Arkema Inc.

TRI Form A - Transfer
to Non-POTW

227

0.91

227

0.91

250

Buckeye
International Inc.

TRI Form A - Direct

227

0.91

227

0.91

250

Essential Industries
Inc

TRI Form A - Direct

227

0.91

227

0.91

250

GAF

TRI Form A - Direct

227

0.91

227

0.91

250

Buckeye
International Inc.

TRI Form A - Transfer
toPOTW

227

0.91

227

0.91

250

Essential Industries
Inc

TRI Form A - Transfer
toPOTW

227

0.91

227

0.91

250

GAF

TRI Form A - Transfer
toPOTW

227

0.91

227

0.91

250

Buckeye
International Inc.

TRI Form A - Transfer
to Non-POTW

227

0.91

227

0.91

250

Essential Industries
Inc

TRI Form A - Transfer
to Non-POTW

227

0.91

227

0.91

250

GAF

TRI Form A - Transfer
to Non-POTW

227

0.91

227

0.91

250

Grace -Pasadena
Catalyst Site

TRI Form R - Transfer
toPOTW

1,743

7.0

3,630

15

250

Henkel Us
Operations Corp

TRI Form A - Direct

227

0.91

227

0.91

250

Henkel Us
Operations Corp

TRI Form A - Transfer
toPOTW

227

0.91

227

0.91

250

Henkel US
Operations Corp

TRI Form A - Transfer
to Non-POTW

227

0.91

227

0.91

250

National Chemical
Laboratories Inc

TRI Form R - Transfer
toPOTW

2.3

2.3

9.1E-03

9.1E-03

250

Penn Color Inc.

TRI Form A - Direct

227

0.91

227

0.91

250

Polycoat Products
LLC

TRI Form A - Direct

227

0.91

227

0.91

250

Sika Corp-Marion
Operations

TRI Form A - Direct

227

0.91

227

0.91

250

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2043

2044

2045

2046

2047

2048

2049

2050

2051

2052

2053

2054

2055

2056

2057

2058

2059

2060

2061

2062

2063

2064

2065

2066

2067

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PUBLIC RELEASE DRAFT
May 2025

Site Identity

Source- Discharge
Type

Median
Annual
Discharge
(kg/year)

Median
Daily
Discharge
(kg/day)

Maximum
Annual
Discharge
(kg/year)

Maximum

Daily
Discharge
(kg/day)

Annual
Release
Days
(days/year)

Penn Color Inc.

TRI Form A - Transfer
toPOTW

227

0.91

227

0.91

250

Polycoat Products
LLC

TRI Form A - Transfer
toPOTW

227

0.91

227

0.91

250

Sika Corp-Marion
Operations

TRI Form A - Transfer
toPOTW

227

0.91

227

0.91

250

Penn Color Inc.

TRI Form A - Transfer
to Non-POTW

227

0.91

227

0.91

250

Polycoat Products
LLC

TRI Form A - Transfer
to Non-POTW

227

0.91

227

0.91

250

Sika Corp-Marion
Operations

TRI Form A - Transfer
to Non-POTW

227

0.91

227

0.91

250

3,3,4 Occupational Exposure Assessment

3.3.4.1	Worker Activities

During the formulation of products containing DBP, workers are potentially exposed to DBP via
inhalation or dermal contact with vapors and liquids when unloading DBP, packaging final products,
cleaning transport containers, product sampling, equipment cleaning, and during filter media change out
(I	ฃ014a). EPA did not identify information on engineering controls or workers PPE used at

other formulation sites.

For this OES, ONUs may include supervisors, managers, and other employees that work in the
formulation area but do not directly contact DBP that is received or processed onsite or handle the
formulated product.

3.3.4.2	Occupational Inhalation Exposure Results

EPA did not identify inhalation monitoring data for incorporation into formulations, mixtures, and
reaction products from systematic review of literature sources. DBP is imported and manufactured as a
liquid, per CDR, and EPA assessed worker inhalation exposures to DBP vapor during the unloading and
loading processes. EPA used DBP manufacturing monitoring data to estimate inhalation exposures. EPA
identified inhalation monitoring data from three risk evaluations, however, each study only presents a
single aggregate or final data point during manufacturing of DBP. In the first source, the Syracuse
Research Corporation indicates that "following a review of six studies, the American Chemistry Council
has estimated exposure to di-n-butyl phthalate in the workplace based upon an assumed level of 1 mg/m3
in the air during the production of phthalates." (SRC. 2001). The second source, a risk evaluation of
l,3,4,6,7,8-Hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-g-2-benzopyran (HHCB) conducted by
European Commission, Joint Research Centre (ECJRC) presented an 8-hour TWA aggregate exposure
concentration for DBP of 0.003 ppm (N=l 14) for a DBP manufacturing site (ECB. 2008). The third
source, a risk evaluation of DBP also conducted by the ECJRC provides seven separate datasets from
two unnamed manufacturers. Of these datasets six did not include a sampling method and were not used.
Only one had sufficiently detailed metadata (e.g., exposure duration, sample type) to include in this
assessment; an 8-hour TWA worker exposure concentration to DBP of 0.5 mg/m3 from DBP production
(ECB. 2004). With three aggregate or final concentration value from three sources, EPA could not create

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2072

2073

2074

2075

2076

2077

2078

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2080

2081

2082

2083

2084

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2086

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a full distribution of monitoring results to estimate central tendency and high-end exposures. To assess
the high-end worker exposure to DBP during the manufacturing process, the Agency used the maximum
available value (1 mg/m3). EPA assessed the midpoint of the three available values as the central
tendency (0.5 mg/m3). All three sources of monitoring data received a rating of medium from EPA's
systematic review process. In absence of data specific to ONU exposure, the Agency assumed that
worker central tendency exposure was representative of ONU exposure and used this data to generate
estimates for ONUs. EPA assessed the exposure frequency as 250 days/year for both high-end and
central tendency exposures based on the expected operating days for the OES and accounting for off
days for workers.

Table 3-19 summarizes the estimated 8-hour TWA concentration, AD, IADD, and ADD for worker
exposures to DBP during the incorporation into formulations, mixtures, or reaction products. Appendix
A describes the approach for estimating AD, IADD, and ADD. The estimated exposures assume that the
worker is exposed to DBP in the form of vapor. The Draft Occupational Inhalation Exposure
Monitoring Results for Dibutyl Phthalate (DBP) contains further information on the identified inhalation
exposure data and assumptions used in the assessment, refer to Appendix F for a reference to this
supplemental document.

Table 3-19. Summary of Estimated Worker Inhalation Exposures for Incorporation into
Formulations, Mixtures, or Reaction Products	

Modeled Scenario

Exposure Concentration Type

Central
Tendency"

High-End"

Average Adult Worker

8-hour TWA Exposure Concentration (mg/m3)

0.50

1.0

Acute Dose (AD) (mg/kg-day)

6.3E-02

0.13

Intermediate Non-Cancer Exposures (IADD)
(mg/kg-day)

4.6E-02

9.2E-02

Chronic Average Daily Dose, Non-Cancer
Exposures (ADD) (mg/kg-day)

4.3E-02

8.6E-02

Female of Reproductive
Age

8-hour TWA Exposure Concentration (mg/m3)

0.50

1.0

Acute Dose (AD) (mg/kg-day)

6.9E-02

0.14

Intermediate Non-Cancer Exposures (IADD)
(mg/kg-day)

5.1E-02

0.10

Chronic Average Daily Dose, Non-Cancer
Exposures (ADD) (mg/kg-day)

4.7E-02

9.5E-02

ONU

8-hour TWA Exposure Concentration (mg/m3)

0.50

0.50

Acute Dose (AD) (mg/kg-day)

6.3E-02

6.3E-02

Intermediate Non-Cancer Exposures (IADD)
(mg/kg-day)

4.6E-02

4.6E-02

Chronic Average Daily Dose, Non-Cancer
Exposures (ADD) (mg/kg-day)

4.3E-02

4.3E-02

a EPA identified surrogate inhalation monitoring data from three sources to estimate exposures for this OES (ECB.
2008. 2004; SRC, 2001). All three sources of monitoring data received a rating of medium from EPA's systematic
review process. With the three discrete data points, EPA could not create a full distribution of monitoring results to
estimate central tendency and high-end exposures. To assess the high-end worker exposure to DBP during the
manufacturing process, the Agency used the maximum available value (1 mg/m3). EPA assessed the midpoint of the
three available values as the central tendency (0.5 mg/m3).

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2092

2093

2094

2095

2096

2097

2098

2099

2100

2101

2102

2103

2104

2105

2106

2107

2108

2109

2110

2111

2112

2113

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2115

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3.3.4.3 Occupational Dermal Exposure Results

EPA estimated dermal exposures for this OES using the dermal approach outlined in Section 2.4.3 and
Appendix C. The various "Exposure Concentration Types" from Table 3-20 are explained in Appendix
A. ONU dermal exposures are not assessed for this OES as there are no activities expected to expose
ONUs to DBP in liquid form. For occupational dermal exposure assessment, EPA assumed a standard 8-
hour workday and the chemical is contacted at least once per day. Because DBP has low volatility and
relatively low absorption, it is possible that the chemical remains on the surface of the skin after dermal
contact until the skin is washed. So, in absence of exposure duration data, EPA has assumed that
absorption of DBP from occupational dermal contact with materials containing DBP may extend up to 8
hours per day (	). However, if a worker uses proper personal protective equipment (PPE)

or washes their hands after contact with DBP or DBP-containing materials dermal exposure may be
eliminated. Therefore, the assumption of an 8-hour exposure duration for DBP may lead to
overestimation of dermal exposure. Table 3-20 summarizes the APDR, AD, IADD, and ADD for
average adult workers and female workers of reproductive age. The Draft Occupational Dermal
Exposure Modeling Results for Dibutyl Phthalate (DBP) also contains information about model
equations and parameters and contains calculation results; refer to Appendix F for a reference to this
supplemental document.

Table 3-20. Summary of Estimated Worker Dermal Exposures for Incorporation into
Formulations, Mixtures, or Reaction Products	

Modeled Scenario

Exposure Concentration Type

Central
Tendency

High-End

Average Adult Worker

Dose Rate (APDR, mg/day)

100

201

Acute (AD, mg/kg-day)

1.3

2.5

Intermediate (IADD, mg/kg-day)

0.92

1.8

Chronic, Non-Cancer (ADD, mg/kg-day)

0.86

1.7

Female of
Reproductive Age

Dose Rate (APDR, mg/day)

84

167

Acute (AD, mg/kg-day)

1.2

2.3

Intermediate (IADD, mg/kg-day)

0.85

1.7

Chronic, Non-Cancer (ADD, mg/kg-day)

0.79

1.6

Note: For high-end estimates, EPA assumed the exposure surface area was equivalent to mean values for two-hand
surface areas (i.e., 1.070 cm2 for male workers and 890 cm2 for female workers) (U.S. EPA, 2011). For central
tendency estimates, EPA assumed the exposure surface area was equivalent to only a single hand (or one side of two
hands) and used half the mean values for two-hand surface areas (i.e., 535 cm2 for male workers and 445 cm2 for
female workers).

3.3.4.4 Occupational Aggregate Exposure Results

Inhalation and dermal exposure estimates were aggregated based on the approach described in Appendix
A.3 to arrive at the aggregate worker and ONU exposure estimates in the table below. The assumption
behind this approach is that an individual worker could be exposed by both the inhalation and dermal
routes, and the aggregate exposure is the sum of these exposures.

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2118

2119

2120

2121

2122

2123

2124

2125

2126

2127

2128

2129

2130

2131

2132

2133

2134

2135

2136

2137

2138

2139

2140

2141

2142

2143

2144

2145

2146

2147

2148

2149

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Table 3-21. Summary of Estimated Worker Aggregate Exposures for Incorporation into
Formulations, Mixtures, or Reaction Products	

Modeled Scenario

Exposure Concentration Type
(mg/kg-day)

Central
Tendency

High-End

Average Adult Worker

Acute (AD, mg/kg-day)

1.3

2.6

Intermediate (IADD, mg/kg-day)

0.97

1.9

Chronic, Non-Cancer (ADD, mg/kg-day)

0.90

1.8

Female of Reproductive Age

Acute (AD, mg/kg-day)

1.2

2.5

Intermediate (IADD, mg/kg-day)

0.90

1.8

Chronic, Non-Cancer (ADD, mg/kg-day)

0.84

1.7

ONU

Acute (AD, mg/kg-day)

6.3E-02

6.3E-02

Intermediate (IADD, mg/kg-day)

4.6E-02

4.6E-02

Chronic, Non-Cancer (ADD, mg/kg-day)

4.3E-02

4.3E-02

Note: A worker could be exposed by both the inhalation and dermal routes, and the aggregate exposure is the sum of
these exposures.

3.4 PVC Plastics Compounding

3.4.1 Process Description

PVC plastics compounding involves mixing the polymer with the plasticizer and other chemicals such as
fillers and heat stabilizers (U.S. EPA-HQ-OPPT-218-0435-0021; EPA-HQ-OPPT-218-0435-22). The
plasticizer needs to be absorbed into the particle to impart flexibility to the polymer. The 2020 CDR
reports use of DBP as a plasticizer in plastic product manufacturing (see Appendix E for EPA-identified,
DBP-containing products for this OES) (	2020a). CPSC found that DBP is present in the

manufacturing of various plastics, typically as a catalyst, carrier, or accelerant (	:>€. 2015b).

According to the ESD on Plastic Additives, plasticizers are typically handled in bulk and processed into
PVC through dry blending or plastisol blending (OECD. 2009b). Dry blending is used to make polymer
blends for extrusion, injection molding, and calendaring. It involves mixing all ingredients with a high-
speed rotating agitator that heats the material by friction to a maximum of 100 to 120 ฐC. Plastisol
blending is used to make plastisol, which is a suspension of polymer particles in liquid plasticizer that
can be poured into molds and heated to form the plastic. Plastisol blending involves stirring of
ingredients at ambient temperature (OECD. 2009b).

Companies that reported the use of DBP as a plasticizer in plastic products in 2020 CDR report the use
of DBP in liquid form. Most companies report using concentrations of at least 90 percent DBP in the
plasticizers. However, one company reported the use of liquid DBP in concentrations of less than one
percent, and one company reported concentrations of 60 to 90 percent DBP. (U.S. EPA. 2020a). The
concentration of DBP in compounded plastic resins is unknown. Sources indicate that plasticizers are
typically used at concentrations of 30 to 50 percent of the plastic material (OECD. 2009b). but may be
up to 70 percent (Vainiotalo and Pfafi )). In final consumer products, the concentration of DBP is
typically claimed CBI, but one report (UBE America Inc.) indicates DBP is at least 90 percent in
consumer plastic product (	2020a). One literature source found that DBP identified in

polypropylene is expected to be present at concentrations below 0.2 percent but could be as high as 2.7
percent (	). EPA assessed releases of DBP assuming 45 percent by mass as the highest

expected DBP concentration based on the Generic Scenario for the Use of Additives in Plastic
Compounding (	2021c).

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2150

2151

2152

2153

2154

2155

2156

2157

2158

2159

2160

2161

2162

2163

2164

2165

2166

2167

2168

2169

2170

2171

2172

2173

2174

2175

2176

2177

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Figure 3-4 provides an illustration of the plastic compounding process (	)21c).

1. Transfer Operation	6. Releases During

B. Exposure During	4. Equipment

Container Cleaning	Cleaning Losses

Figure 3-4. PVC Plastics Compounding Flow Diagram (U.S. EPA. 2021c)

3.4.2	Facility Estimates

In the Nh7U!s~EPA7202":'si. :01< % DMRTuITepX^

EPA analyzed, EPA identified that 16 sites may have used DBP in plastic compounding based on site
names and their reported NAICS and SIC codes. Due to the lack of data on the annual PV of DBP used
in plastic compounding, EPA did not present annual or daily site throughputs. EPA identified one site
that submitted NEI air release data that included an estimate of 364 operating days. TRI/DMR datasets
do not report operating days; therefore, EPA assumed 246 days/year of operation per the Revised Plastic
Compounding GS as discussed in Section 2.3.2 (U.S. EPA. 2021c).

3.4.3	Release Assessment

3.4.3.1 Environmental Release Points

Based on TRI, NEI, and DMR data, plastic compounding releases may go to fugitive air, stack air,
surface water, POTW, and landfill and additional releases may occur from transfers of wastes to off-site
treatment facilities (assessed in the Waste handling, treatment, and disposal OES) (	024a. e,

2023a. 2019). Fugitive air, POTW, incineration, or landfill releases may occur from loading plastic
masterbatch and unloading plastic additives. Fugitive or stack air releases may occur from
blending/compounding operations. Surface water or POTW releases may occur from direct contact
cooling. POTW, incineration, or landfill releases may occur from container residues and equipment
cleaning. Additional fugitive air releases may occur during leakage of pipes, flanges, and accessories
used for transport.

Sites may utilize air capture technology, in which case releases to incineration or landfill may occur
from dust during product loading and the remaining uncontrolled dust would be released to stack air.
Releases to fugitive air, POTW, incineration, or landfill may occur from dust during product loading in
cases where air capture technology is not utilized.

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3.4.3.2 Environmental Release Assessment Results

Table 3-22 presents fugitive and stack air releases per year and per day for the PVC plastics
compounding OES based on the 2017 to 2022 TRI database years along with the number of release days
per year, with medians and maxima presented from across the six-year reporting range. Table 3-23
presents fugitive and stack air releases per year and per day based on 2020 NEI database along with the
number of release days per year. Table 3-24 presents water releases per year and per day based on the
2017 to 2022 DMR database along with the number of release days per year, with medians and maxima
presented from across the 6-year reporting range. The Draft Summary of Results for Identified
Environmental Releases to Air for Dibutyl Phthalate (DBP), Draft Summary of Results for Identified
Environmental Releases to Landfor Dibutyl Phthalate (DBP), and Draft Summary of Results for
Identified Environmental Releases to Water for Dibutyl Phthalate (DBP) contain additional information
about these identified releases and their original sources; refer to Appendix F for a reference to these
supplemental documents.

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Table 3-22. Summary of Air Re

eases from r

"RI for PVC Plastics Compounding

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual
Stack Air
Release
(kg/year)

Median
Annual
Fugitive Air
Release
(kg/year)

Median
Annual
Stack Air
Release
(kg/year)

Annual
Release
Days
(days/
year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

Median Daily
Fugitive Air
Release
(kg/day)

Median
Daily Stack
Air Release
(kg/day)

ITW Performance
Polymers

1.4

13

1.4

10

246

5.5E-03

5.3E-02

5.5E-03

4.2E-02

2194

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2195 Table 3-23. Summary of Air Releases from NEI (2020) for PVC Plastics Compounding

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual Stack
Air Release
(kg/year)

Annual
Release Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

Axiall LLC - Plaquemine Facility

6.8

N/A

364

1.9E-02

N/A

2196

2197	No data was reported for land releases for the PVC plastics compounding OES. EPA assessed data for

2198	Non-PVC material manufacturing as a surrogate (Table 3-37).

2199

2200	Table 3-24. Summary of Water Releases from DMR for PVC Plastics Compounding 	

Site Identity

Source-
Discharge
Type

Median
Annual
Discharge
(kg/year)

Median Daily
Discharge
(kg/day)

Maximum

Annual
Discharge
(kg/year)

Maximum

Daily
Discharge
(kg/day)

Annual
Release Days
(days/year)

AMCOL Health
& Beauty
Solutions Inc.

DMR- Direct
Discharges

2.1E-03

8.6E-06

2.1E-03

8.6E-06

246

Braskem
American Inc-
LaPorte Site

DMR- Direct
Discharges

5.6E-02

2.3E-04

0.28

1.1E-03

246

Chemours
Company FC
LLC

DMR- Direct
Discharges

106

0.43

106

0.43

246

DDP Specialty
Electronic
Materials US
LLC

DMR- Direct
Discharges

0.12

4.7E-04

0.21

8.3E-04

246

Equistar
Chemicals LP

DMR- Direct
Discharges

0.30

1.2E-03

0.30

1.2E-03

246

Equistar
Chemicals LP-
Lake Charles
Polymers Site

DMR- Direct
Discharges

0.66

2.7E-03

0.66

2.7E-03

246

Metton
America La
Porte Plant

DMR- Direct
Discharges

1.9E-02

7.8E-05

2.8E-02

1.2E-04

246

Neal Plant

DMR- Direct
Discharges

4.1E-02

1.7E-04

6.9E-02

2.8E-04

246

Nova

Chemicals

Incorporated

DMR- Direct
Discharges

0.26

1.0E-03

0.26

1.0E-03

246

Owensboro

Specialty

Polymers

DMR- Direct
Discharges

3.3E-02

1.3E-04

3.3E-02

1.3E-04

246

Rohm & Haas
Bristol Facility

DMR- Direct
Discharges

0.63

2.5E-03

0.63

2.5E-03

246

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Site Identity

Source-
Discharge
Type

Median
Annual
Discharge
(kg/year)

Median Daily
Discharge
(kg/day)

Maximum

Annual
Discharge
(kg/year)

Maximum

Daily
Discharge
(kg/day)

Annual
Release Days
(days/year)

Shintech Inc

DMR- Direct
Discharges

8.3

3.4E-02

8.3

3.4E-02

246

Styrolution
America LLC

DMR- Direct
Discharges

0.33

1.3E-03

0.33

1.3E-03

246

Total

Petrochemicals
& Refining
USA Inc

DMR- Direct
Discharges

0.64

2.6E-03

1.1

4.4E-03

246

3.4.4 Occupational Exposure Assessment

3.4.4.1	Worker Activities

Workers are potentially exposed to DBP during the compounding process via inhalation of vapor and
dust or dermal contact with dust during unloading and loading, equipment cleaning, and transport
container cleaning (U.S. EPA. 2021c). EPA did not identify information on engineering controls or
worker PPE used at plastics compounding sites.

For this OES, ONUs may include supervisors, managers, and other employees that work in the
compounding area but do not directly contact DBP that is received or processed onsite or handle the
compounded plastic product. ONUs are potentially exposed via inhalation to vapors and inhalation and
dermal exposures to airborne and settled dust while in the working area.

3.4.4.2	Occupational Inhalation Exposure Results

EPA did not identify chemical-specific or OES-specific inhalation monitoring data for DBP from
systematic review, however, EPA utilized surrogate vapor inhalation monitoring data from PVC plastics
converting to assess worker inhalation exposure to DBP vapors. The data are from a risk evaluation
completed by the ECJRC, which included four data points compiled from two sources (ECB. 2004). The
ECJRC risk evaluation received a rating of medium from EPA's systematic review process. All data are
from unnamed facilities, with two datapoints from a facility using PVC in the manufacturing of cables
(thermodegradation of PVC) and the other two datapoints summarizing a dataset listed only as from the
"polymer industry." With the four discrete data points, EPA could not create a full distribution of
monitoring results to estimate central tendency and high-end exposures. To assess the high-end worker
exposure to DBP during the converting process, EPA used the maximum available value (0.75 mg/m3).
EPA assessed the average of the four available values as the central tendency (0.24 mg/m3).

In addition to vapor exposure, EPA expects worker inhalation exposures to DBP via exposure to
particulates of plastic materials during the compounding process. To estimate worker and ONU
inhalation exposure, EPA used the Generic Model for Central Tendency and High-End Inhalation
Exposure to Total and Respirable Particulates Not Otherwise Regulated (also called "PNOR Model")
(I	ฃ02lb). Model approaches and parameters are described in Appendix D. EPA used a subset

of the model data that came from facilities with the NAICS code starting with 326 - Plastics and Rubber
Manufacturing to estimate plastic particulate concentrations in the air. For this OES, EPA identified 45
percent by mass as the highest expected DBP concentration based on the Generic Scenario for the Use

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of Additives in Plastic Compounding (	s21c). The estimated exposures assume that DBP is

present in particulates at this fixed concentration throughout the working shift.

The PNOR Model (U.S. EPA. 2021b) estimates an 8-hour TWA for particulate concentrations by
assuming exposures outside the sample duration are zero. The model does not determine exposures
during individual worker activities. In absence of data specific to ONU exposure, EPA assumed that
worker central tendency exposure was representative of ONU exposure and used this data to generate
estimates for ONUs. EPA used the number of operating days estimated in the release assessment for this
OES to estimate exposure frequency, which is the expected maximum number of working days. EPA
assessed the exposure frequency as 250 days/year for both high-end and central tendency exposures
based on the expected operating days for the OES and accounting for off days for workers.

Table 3-25 summarizes the estimated 8-hour TWA concentration, AD, IADD, and ADD for worker and
ONU exposures to DBP during the plastics compounding process. Appendix A describes the approach
for estimating AD, IADD, and ADD. The estimated exposures assume that the worker is exposed to
DBP primarily in the form of particulates, but also accounts for other potential inhalation exposure
routes, such as from the inhalation of vapors. Based on the low vapor pressure of DBP, exposure to
vapors is not expected to be a major contribution to exposures. The Draft Occupational Inhalation
Exposure Monitoring Results for Dibutyl Phthalate (DBP) contains further information on the identified
inhalation exposure data, information on the PNOR Model parameters used, and assumptions used in the
assessment, refer to Appendix F for a reference to this supplemental document.

Table 3-25. Summary of Estimated Worker Inhalation Exposures for Plastics Compounding

Modeled Scenario

Exposure Concentration Type

Central
Tendency"

High-End"



8-hour TWA Exposure Concentration (mg/m3)

0.34

2.9



Acute Dose (AD) (mg/kg-day)

4.3E-02

0.36

Average Adult Worker

Intermediate Non-Cancer Exposures (IADD)
(mg/kg-day)

3.1E-02

0.26



Chronic Average Daily Dose, Non-Cancer
Exposures (ADD) (mg/kg-day)

2.9E-02

0.25



8-hour TWA Exposure Concentration (mg/m3)

0.34

2.9



Acute Dose (AD) (mg/kg-day)

4.7E-02

0.40

Female of Reproductive
Age

Intermediate Non-Cancer Exposures (IADD)
(mg/kg-day)

3.5E-02

0.29



Chronic Average Daily Dose, Non-Cancer
Exposures (ADD) (mg/kg-day)

3.2E-02

0.27



8-hour TWA Exposure Concentration (mg/m3)

0.34

0.34



Acute Dose (AD) (mg/kg-day)

4.3E-02

4.3E-02

ONU

Intermediate Non-Cancer Exposures (IADD)
(mg/kg-day)

3.1E-02

3.1E-02



Chronic Average Daily Dose, Non-Cancer

2.9E-02

2.9E-02



Exposures (ADD) (mg/kg-day)





a EPA utilized surrogate vapor inhalation monitoring data from PVC plastics converting to assess worker inhalation
exposure to DBP vapors. The data is from a risk evaluation completed by the ECJRC, which included four data points
compiled from two sources (ECB. 2004). The ECJRC risk evaluation received a ratine of medium from EPA's

systematic review process. To assess the high-end worker exposure to DBP, EPA used the maximum available value
(0.75 mg/m3). EPA assessed the average of the four available values as the central tendency (0.24 mg/m3). EPA used

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Modeled Scenario

Exposure Concentration Type

Central
Tendency"

High-End"

the PNOR Model to estimate exposures to dust. For the PNOR Model, EPA multiplied the concentration of DBP with
the central tendency and HE estimates of the relevant NAICS code from the PNOR Model to calculate the central
tendency and HE estimates for this OES.

3.4.4.3 Occupational Dermal Exposure Results

EPA estimated dermal exposures for this OES using the dermal approach outlined in Section 2.4.3 and
Appendix C. The various "Exposure Concentration Types" from Table 3-26 are explained in Appendix
A. Since there may be dust deposited on surfaces from this OES, dermal exposures to ONUs from
contact with dust on surfaces were assessed. In the absence of data specific to ONU exposure, EPA
assumed that worker central tendency exposure was representative of ONU exposure and used this data
to generate an estimate of exposure. For occupational dermal exposure assessment, EPA assumed a
standard 8-hour workday and the chemical is contacted at least once per day. Because DBP has low
volatility and relatively low absorption, it is possible that the chemical remains on the surface of the skin
after dermal contact until the skin is washed. So, in absence of exposure duration data, EPA has assumed
that absorption of DBP from occupational dermal contact with materials containing DBP may extend up
to 8 hours per day (	). However, if a worker uses proper personal protective equipment

(PPE) or washes their hands after contact with DBP or DBP-containing materials dermal exposure may
be eliminated. Therefore, the assumption of an 8-hour exposure duration for DBP may lead to
overestimation of dermal exposure. Table 3-26 summarizes the APDR, AD, IADD, and ADD for
average adult workers, female workers of reproductive age, and ONUs. The Draft Occupational Dermal
Exposure Modeling Results for Dibutyl Phthalate (DBP) also contains information about model
equations and parameters and contains calculation results; refer to Appendix F for a reference to this
supplemental document.

Table 3-26. Summary of Estimated Worker Dermal Exposures for Plastics Compounding

Modeled Scenario

Exposure Concentration Type

Central Tendency

High-End



Dose Rate (APDR, mg/day)

102

204

Average Adult Worker

Acute (AD, mg/kg-day)

1.3

2.5

Intermediate (IADD, mg/kg-day)

0.93

1.9



Chronic, Non-Cancer (ADD, mg/kg-day)

0.87

1.7



Dose Rate (APDR, mg/day)

85

169

Female of

Acute (AD, mg/kg-day)

1.2

2.3

Reproductive Age

Intermediate (IADD, mg/kg-day)

0.86

1.7



Chronic, Non-Cancer (ADD, mg/kg-day)

0.80

1.6



Dose Rate (APDR, mg/day)

1.4

1.4



Acute Dose (AD) (mg/kg/day)

1.7E-02

1.7E-02

ONU

Intermediate Average Daily Dose, Non-Cancer
Exposures (IADD) (mg/m3)

1.2E-02

1.2E-02



Chronic Average Daily Dose, Non-Cancer
Exposures (ADD) (mg/kg/day)

1.2E-02

1.2E-02

Note: For high-end estimates, EPA assumed the exposure surface area was equivalent to mean values for two-hand
surface areas (i.e., 1.070 cm2 for male workers and 890 cm2 for female workers) (U.S. EPA, 2011). For central

tendency estimates, EPA assumed the exposure surface area was equivalent to only a single hand (or one side of two
hands) and used half the mean values for two-hand surface areas (i.e., 535 cm2 for male workers and 445 cm2for

female workers).







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3.4.4.4 Occupational Aggregate Exposure Results

Inhalation and dermal exposure estimates were aggregated based on the approach described in Appendix
A.3 to arrive at the aggregate worker and ONU exposure estimates in the table below. The assumption
behind this approach is that an individual worker could be exposed by both the inhalation and dermal
routes, and the aggregate exposure is the sum of these exposures.

Table 3-27. Summary of Estimated Worker Aggregate Exposures for Plastics Compounding

Modeled Scenario

Exposure Concentration Type (mg/kg-day)

Central
Tendency

High-End

Average Adult Worker

Acute (AD, mg/kg-day)

1.3

2.9

Intermediate (IADD, mg/kg-day)

0.96

2.1

Chronic, Non-Cancer (ADD, mg/kg-day)

0.90

2.0

Female of Reproductive Age

Acute (AD, mg/kg-day)

1.2

2.7

Intermediate (IADD, mg/kg-day)

0.89

2.0

Chronic, Non-Cancer (ADD, mg/kg-day)

0.83

1.9

ONU

Acute (AD, mg/kg-day)

6.0E-02

6.0E-02

Intermediate (IADD, mg/kg-day)

4.4E-02

4.4E-02

Chronic, Non-Cancer (ADD, mg/kg-day)

4.1E-02

4.1E-02

Note: A worker could be exposed by both the inhalation and dermal routes, and the aggregate exposure is the sum of
these exposures.

3.5 PVC Plastics Converting

3,5.1 Process Description

DBP is used as a plasticizer in plastics (see Appendix E for EPA-identified DBP-containing products for
this OES). EPA expects that DBP in compounded resins will arrive at a typical converting site as a solid
in containers of different sizes(	34a). After the compounding process described in 3.4.1,

compounded plastic resins are converted into solid plastic articles. According to the ESD on Plastic
Additives, compounded resin can be converted into final products through many processes, including
closed processes such as extrusion, injection molding, compression molding, extrusion blow molding,
partially open processes such as film extrusion, and open processes including, calendaring,
thermoforming, and fiber reinforced plastic fabrication ("OECD. 2009b). Vapor (fume) elimination
equipment is commonly used during these processes (OECD. 2009b).

During extrusion, heated plastic resin is forced through a die and then quenched to form products such
as pipe, profiles, sheets, and wire coating. Injection molding involves heated plastic resin which is
injected into a cold mold where the plastic takes the shape of the mold as it solidifies. Compression
molding is the main process used for thermosetting materials. This process is performed by inserting
prepared compound into a mold which is closed and maintained under pressure during a heating cycle.
In extrusion blow molding, an extruder delivers a tubular extrudate between two halves of a mold joined
around the hot extrudate before air is blown through, forcing the polymer to meld against the sides of the
mold. The high-speed process is used to manufacture packaging bottles and containers (	39b).

During film extrusion, a film is cooled by travelling upwards over a vertical bubble of air before being
taken up onto reels or extruded through a slit die and immediately quenched. In calendaring, heated
plastic resin is fed onto rolls that compress the material into a thin layer to form sheets and films. With
thermoforming, a plastic sheet is locked in a frame and heated to the forming temperature then brought

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into contact with a mold of the desired shape. The sheet may be drawn onto the form using vacuum or
applied pressure. If the sheets are extruded on site rather than being brought in, the process may be
continuous. Fiber reinforced plastic fabrication involves unsaturated polyester resins and reinforcements
cured at ambient temperatures or with small amounts of heat. This process may fabricate large shapes by
using hand lay up or spray techniques to deposit resin and reinforcements onto a mold for curing.
Filament winding may also be used to deposit resin and reinforcements onto a rotating mandrel before
being introduced to an oven for heating (OECD. 2009b).

In some cases, after converting into the desired shape, the plastic product may undergo subsequent
trimming to remove excess material (I	)9b). Other finishing operations, such as paint, coating,

and bonding may occur (these are covered under other COUs). Plasticizers are not chemically bound to
the polymer and are able to migrate to the surface (OECD. 2009b).

The concentration of DBP in compounded plastic resins is unknown. Sources indicate that plasticizers
are typically used at concentrations of 20 to 40 percent of the plastic material (Chao et al.. 2015; Xu et
ai. 2010). but may be up to 60 percent (Gaudin et al.. 2011; Gaudin et al.. 2008). EPA did not identify
other sources with information on DBP concentration in plastic products.

Figure 3-5 provides an illustration of the plastic converting process (U.S. EPA.. 2004a).

3. Vapor Emissions
During Converting
4. Particulate Emissions
1. Dust Generated During	During Converting

Unloading Plastic Additives	5. Direct Contact	7. Solid Waste from

6. Equipment
Cleaning Losses

Figure 3-5. PVC Plastics Converting Flow Diagram ('U.S. EPA. 202 I d)

3,5,2 Facility Estimates

In the ^(iIsTePATIE^

EPA analyzed, EPA identified 8 sites that have possibly used DBP in PVC plastics converting based on
site names and their reported NAICS and SIC codes. Two CDR reporters indicated the use of DBP for

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Plastics Product Manufacturing in the 2020 CDR. EPA identified operating days ranging from 253 to
260 with an average of 256 days through NEI air release data. TRI/DMR (U.S. EPA. 2024a) datasets did
not report operating days; therefore, EPA used 253 days/year of operation according to the Revised
Plastic Converting GS as discussed in Section 2.3.2 (	).

The ESD on Plastic Additives estimates 341 to 3,990 metric tons of flexible PVC produced per site per
year (341,000 to 3,990,000 kg/site-year) (QE ป09b). This production range is not used to estimate
releases because of the availability of environmental release data reported by facilities for this OES. A
typical number of production days during a year is 148 to 264 days (	014b). Assuming a

concentration of DBP in the plastic of 30 to 45 percent (see PVC plastics compounding section) and 264
days/year, this results in a use rate of 388 to 12,131 kg/site-day and 102,300 to 1,795,500 kg/site-year.

3.5.3 Release Assessment

3.5.3.1	Environmental Release Points

EPA assigned release points based on NE1/TR1 data for air releases ('	ฆฆ, , '')•

There was no identified data for water and land releases for this OES, so these releases were assessed
using data for Non-PVC Material Manufacturing (Table 3-37 and Table 3-38). Potential sites might not
have reported water and land releases because the releases from the facilities might have been below the
threshold required to report to the databases.

EPA assessed potential release points based on the 2021 Use of Additives in Plastics Converting Draft
Generic Scenario (	). Releases of dust to stack air, fugitive air, wastewater, incineration,

or landfill are expected while unloading plastic additives. EPA expects converting operations to release
vapor emissions to fugitive or stack air and particulate emissions to fugitive air, wastewater,
incineration, or landfill. EPA expects releases to wastewater, incineration, or landfill from container
residues and equipment cleaning. EPA expects releases to wastewater from direct contact cooling and
incineration and landfill releases from solid waste trimming.

Converting sites may utilize air capture technology. If a site uses air capture technology, EPA expects
dust releases from unloading plastic additives during transfer operations to be controlled and released to
disposal facilities for incineration or landfill. The site would release the remaining uncontrolled dust to
stack air. If the site does not use air control technology, EPA expects plastic unloading releases to
fugitive air, water, incineration, or landfill as described above.

3.5.3.2	Environmental Release Assessment Results

Table 3-28 presents fugitive and stack air releases per year and per day for plastic converting based on
the 2017 to 2022 TRI database years along with the number of release days per year, with medians and
maxima presented from across the 6-year reporting range. Table 3-29 presents fugitive and stack air
releases per year and per day based on 2020 NEI database along with the number of release days per
year. Table 3-30 presents fugitive and stack air releases per year and per day based on 2017 NEI
database along with the number of release days per year. The Draft Summary of Results for Identified
Environmental Releases to Air for Dibutyl Phthalate (DBP), Draft Summary of Results for Identified
Environmental Releases to Landfor Dibutyl Phthalate (DBP), and Draft Summary of Results for
Identified Environmental Releases to Water for Dibutyl Phthalate (DBP) contain additional information
about these identified releases and their original sources; refer to Appendix F for a reference to these
supplemental documents.

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2381 Table 3-28. Summary of Air Releases from TRI for PVC Plastics Converting

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual Stack
Air Release
(kg/year)

Median
Annual
Fugitive Air
Release
(kg/year)

Median
Annual
Stack Air
Release
(kg/year)

Annual
Release Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

Median
Daily
Fugitive
Air Release
(kg/day)

Median
Daily Stack
Air Release
(kg/day)

Premold
Corp

0.45

0

0.45

0

253

1.8E-03

0

1.8E-03

0

2382

Page 85 of 291


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2383

2384

2385

2386

2387

2388

2389

2390

2391

2392

2393

2394

2395

2396

2397

2398

2399

2400

2401

2402

2403

2404

2405

2406

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PUBLIC RELEASE DRAFT
May 2025

Table 3-29. Summary of Air

Releases from NEI (2020) for PVC Plastics Converting

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual
Stack Air
Release
(kg/year)

Annual
Release
Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum
Daily Stack Air
Release
(kg/day)

Armstrong Flooring Inc

N/A

53

253

N/A

0.21

Polyurethane Molding Ind, Inc.

2.2

N/A

253

8.6E-03

N/A

Ampac Flex LLC

N/A

58

253

N/A

0.23

Real Fleet Solutions, LLC

0

N/A

260

0

N/A

Graham Packaging LC LP Plant
0176

0.15

N/A

260

5.8E-04

N/A

Table 3-30. Summary of Air

Releases from NEI (2017) for PVC Plastics Converting

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual
Stack Air
Release
(kg/year)

Annual
Release
Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum
Daily Stack Air
Release
(kg/day)

Novolex Shields, LLC

0

0

253

0

0

Formed Fiber Technologies,
LLC - Auburn

3.4E-02

N/A

253

1.4E-04

N/A

No water release or land release data was identified for the PVC plastics converting OES. EPA assessed
water release data for this OES using the PVC plastics compounding OES as a surrogate (Table 3-24).
EPA assessed land release data for this OES using the Non-PVC material manufacturing OES as a
surrogate (Table 3-37).

3,5,4 Occupational Exposure Assessment

3.5.4.1	Worker Activities

Worker exposures to DBP during the converting process occur via inhalation to vapors generated from
materials and elevated temperatures and inhalation of dust or dermal contact with dust during unloading
and loading, transport container cleaning, equipment cleaning, and trimming of excess plastic (U.S.
E 2Id). EPA did not identify information on engineering controls or worker PPE used at DBP-
containing PVC plastics converting sites.

ONUs include supervisors, managers, and other employees that work in the PVC converting area but do
directly contact the DBP-containing PVC material that is received or handle the finished product or
article. ONUs are potentially exposed to airborne and settled dust via inhalation and dermal routes while
in the working area.

3.5.4.2	Occupational Inhalation Exposure Results

EPA identified vapor inhalation monitoring data from a risk evaluation completed by the ECJRC, which
included four data points compiled from two sources (	04). The ECJRC risk evaluation received

a rating of medium from EPA's systematic review process. All data is from unnamed facilities, with two
datapoints from a facility using PVC in the manufacturing of cables and the other two datapoints

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2409

2410

2411

2412

2413

2414

2415

2416

2417

2418

2419

2420

2421

2422

2423

2424

2425

2426

2427

2428

2429

2430

2431

2432

2433

2434

2435

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PUBLIC RELEASE DRAFT
May 2025

summarizing a dataset listed only as from the "polymer industry." With the four discrete data points,
EPA could not create a full distribution of monitoring results to estimate central tendency and high-end
exposures. To assess the high-end worker exposure to DBP during the converting process, EPA used the
maximum available value (0.75 mg/m3). EPA assessed the average of the four available values as the
central tendency (0.24 mg/m3).

EPA also expects worker inhalation exposures to DBP via exposure to particulates of plastic materials
during the compounding process in addition to DBP unloading and loading tasks, container cleaning,
and equipment cleaning. To estimate worker and ONU inhalation exposure, EPA used the PNOR Model
(	2021b). Model approaches and parameters are described in Appendix D. EPA used a subset

of the model data that came from facilities with the NAICS code starting with 326 - Plastics and Rubber
Manufacturing to estimate plastic particulate concentrations in the air. For this OES, EPA identified 45
percent by mass as the highest expected DBP concentration based on the Generic Scenario for the Use
of Additives in Plastic Compounding (	)21c). The estimated exposures assume that DBP is

present in particulates at this fixed concentration throughout the working shift.

The PNOR Model (	21b) estimates an 8-hour TWA for particulate concentrations by

assuming exposures outside the sample duration are zero. The model does not determine exposures
during individual worker activities. In absence of data specific to ONU exposure, EPA assumed that
worker central tendency exposure was representative of ONU exposure and used this data to generate
estimates for ONUs. EPA assessed the exposure frequency as 250 days/year for both high-end and
central tendency exposures based on the expected operating days for the OES and accounting for off
days for workers.

Table 3-31 summarizes the estimated 8-hour TWA concentration, AD, IADD, and ADD for worker
exposures to DBP during PVC plastics converting. Appendix A describes the approach for estimating
AD, IADD, and ADD. The estimated exposures assume that the worker is exposed to DBP primarily in
the form of particulates, but also accounts for other potential inhalation exposure routes, such as from
the inhalation of vapors. Based on the low vapor pressure of DBP, exposure to vapors is not expected to
be a major contribution to exposures. The Draft Occupational Inhalation Exposure Monitoring Results
for Dibutyl Phthalate (DBP) contains further information on the identified inhalation exposure data,
information on the PNOR Model parameters used, and assumptions used in the assessment, refer to
Appendix F for a reference to this supplemental document.

Table 3-31. Summary of Estimated Worker Inhalation Exposures for PVC Plastics Converting

Modeled
Scenario

Exposure Concentration Type

Central
Tendency"

High-End"

Average Adult
Worker

8-hour TWA Exposure Concentration(mg/m3)

0.34

2.9

Acute Dose (AD) (mg/kg-day)

4.3E-02

0.36

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

3.1E-02

0.26

Chronic Average Daily Dose, Non-Cancer Exposures (ADD)
(mg/kg-day)

2.9E-02

0.25

Female of

Reproductive

Age

8-hour TWA Exposure Concentration(mg/m3)

0.34

2.9

Acute Dose (AD) (mg/kg-day)

4.7E-02

0.40

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

3.5E-02

0.29

Chronic Average Daily Dose, Non-Cancer Exposures (ADD)
(mg/kg-day)

3.2E-02

0.27

ONU

8-hour TWA Exposure Concentration(mg/m3)

0.34

0.34

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2444

2445

2446

2447

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2449

2450

2451

2452

2453

2454

2455

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2457

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PUBLIC RELEASE DRAFT
May 2025

Modeled
Scenario

Exposure Concentration Type

Central
Tendency"

High-End"



Acute Dose (AD) (mg/kg-day)

4.3E-02

4.3E-02



Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

3.1E-02

3.1E-02



Chronic Average Daily Dose, Non-Cancer Exposures (ADD)
(mg/kg-day)

2.9E-02

2.9E-02

a EPA utilized vapor inhalation monitoring data to assess worker inhalation exposure to DBP vapors. The data is
from a risk evaluation completed bv the ECJRC. which included four data points compiled from two sources CECB,
2004). The ECJRC risk evaluation received a ratine of medium from EPA's systematic review process. To assess the
high-end worker exposure to DBP, EPA used the maximum available value (0.75 mg/m3). EPA assessed the average
of the four available values as the central tendency (0.24 mg/m3). EPA used the PNOR Model to estimate exposures
to dust. For the PNOR Model, EPA multiplied the concentration of DBP with the central tendency and HE estimates
of the relevant NAICS code from the PNOR Model to calculate the central tendency and HE estimates for this OES.

3.5.4.3

Occupational Dermal Exposure Results





EPA estimated dermal exposures for this OES using the dermal approach outlined in Section 2.4.3 and
Appendix C. The various "Exposure Concentration Types" from Table 3-32 are explained in Appendix
A. Since there may be dust deposited on surfaces from this OES, dermal exposures to ONUs from
contact with dust on surfaces were assessed. In the absence of data specific to ONU exposure, EPA
assumed that worker central tendency exposure was representative of ONU exposure. For occupational
dermal exposure assessment, EPA assumed a standard 8-hour workday and the chemical is contacted at
least once per day. Because DBP has low volatility and relatively low absorption, it is possible that the
chemical remains on the surface of the skin after dermal contact until the skin is washed. So, in absence
of exposure duration data, EPA has assumed that absorption of DBP from occupational dermal contact
with materials containing DBP may extend up to 8 hours per day (	). However, if a

worker uses proper personal protective equipment (PPE) or washes their hands after contact with DBP
or DBP-containing materials dermal exposure may be eliminated. Therefore, the assumption of an 8-
hour exposure duration for DBP may lead to overestimation of dermal exposure. Table 3-32 summarizes
the APDR, AD, IADD, and ADD for average adult workers, female workers of reproductive age, and
ONUs. The Draft Occupational Dermal Exposure Modeling Results for Dibutyl Phthalate (DBP) also
contains information about model equations and parameters and contains calculation results; refer to
Appendix F for a reference to this supplemental document.

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2463 Table 3-32. Summary of Estimated Worker Dermal Exposures for PVC Plastics Converting

Modeled Scenario

Exposure Concentration Type

Central Tendency

High-End



Dose Rate (APDR, mg/day)

1.4

2.7

Average Adult Worker

Acute (AD, mg/kg-day)

1.7E-02

3.4E-02

Intermediate (IADD, mg/kg-day)

1.2E-02

2.5E-02



Chronic, Non-Cancer (ADD, mg/kg-day)

1.2E-02

2.3E-02



Dose Rate (APDR, mg/day)

1.1

2.3

Female of Reproductive

Acute (AD, mg/kg-day)

1.6E-02

3.1E-02

Age

Intermediate (IADD, mg/kg-day)

1.1E-02

2.3E-02



Chronic, Non-Cancer (ADD, mg/kg-day)

1.1E-02

2.1E-02



Dose Rate (APDR, mg/day)

1.4

1.4



Acute Dose (AD) (mg/kg/day)

1.7E-02

1.7E-02

ONU

Intermediate Average Daily Dose, Non-Cancer
Exposures (IADD) (mg/m3)

1.2E-02

1.2E-02



Chronic Average Daily Dose, Non-Cancer

1.2E-02

1.2E-02



Exposures (ADD) (mg/kg/day)





Note: For high-end estimates, EPA assumed the exposure surface area was equivalent to mean values for two-hand

surface areas (i.e., 1.070 cm2 for male workers and 890 cm2 for female workers) (U.S. EPA, 2011). For central

tendency estimates, EPA assumed the exposure surface area was equivalent to only a single hand (or one side of two
hands) and used half the mean values for two-hand surface areas (i.e., 535 cm2 for male workers and 445 cm2for

female workers).







2464	3.5.4.4 Occupational Aggregate Exposure Results

2465	Inhalation and dermal exposure estimates were aggregated based on the approach described in Appendix

2466	A.3 to arrive at the aggregate worker and ONU exposure estimates in the table below. The assumption

2467	behind this approach is that an individual worker could be exposed by both the inhalation and dermal

2468	routes, and the aggregate exposure is the sum of these exposures.

2469

Table 3-33. Summary of Estimated Worker Aggregate Exposures for PVC Plastics

Converting

Modeled Scenario

Exposure Concentration Type (mg/kg-
day)

Central
Tendency

High-End

Average Adult Worker

Acute (AD, mg/kg-day)

6.0E-02

0.39

Intermediate (IADD, mg/kg-day)

4.4E-02

0.29

Chronic, Non-Cancer (ADD, mg/kg-day)

4.1E-02

0.27

Female of Reproductive Age

Acute (AD, mg/kg-day)

6.3E-02

0.43

Intermediate (IADD, mg/kg-day)

4.6E-02

0.31

Chronic, Non-Cancer (ADD, mg/kg-day)

4.3E-02

0.29

ONU

Acute (AD, mg/kg-day)

6.0E-02

6.0E-02

Intermediate (IADD, mg/kg-day)

4.4E-02

4.4E-02

Chronic, Non-Cancer (ADD, mg/kg-day)

4.1E-02

4.1E-02

Note: A worker could be exposed by both the inhalation and dermal routes, and the aggregate exposure is the sum of
these exposures.

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2471

2472

2473

2474

2475

2476

2477

2478

2479

2480

2481

2482

2483

2484

2485

2486

2487

2488

2489

2490

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PUBLIC RELEASE DRAFT
May 2025

3.6 Non-PVC Material Manufacturing (Compounding and Converting)

3,6.1 Process Description

2020 CDR reporters indicate DBP use in non-PVC polymers, such as rubber or non-PVC resins and as
an intermediate in rubber product manufacturing (	320a). EPA identified three product safety

data sheets (SDSs) for resins used for casting plastic products, all three contained DBP concentrations
between 1 to 5 percent (BIB Enterprises. 2021. 2 , ) (see Appendix E for EPA-identified, DBP-
containing products for this OES).

EPA expects that a typical non-PVC material compounding site operates similar to a plastic
compounding site. Typical compounding sites receive and unload DBP and transfer it into mixing
vessels to produce a compounded resin masterbatch. Following completion of the masterbatch, sites
transfer the solid resin to extruders that shape and size the plastic and package the final product for
shipment to downstream conversion sites after cooling (U.S. EPA. 2021c). Figure 3-6 provides an
illustration of the plastic compounding process (•, c. < i1 \	c IG. 2020b; OEt U „oQ4a).

1. Transfer Operation	6. Releases During

B. Exposure During	4. Equipment

Container Cleaning	Cleaning Losses

Figure 3-6. Non-PVC Material Compounding Flow Diagram (U.S. EPA. 2021c)

Note that some materials, such as rubbers, may be formulated via a consolidated compounding and
converting operation, as described in the SpERC Fact Sheet on Rubber Production and Processing.
Figure 3-7 provides an illustration of the rubber formulation process (ESIG. 2020b; OECD. 2004a).
However, the rate of consolidated operations for non-PVC materials is unknown; therefore, EPA
assessed all formulations as separate compounding and converting steps. Figure 3-7 provides an
illustration of the consolidated process.

Page 90 of 291


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2495

2496

2497

2498

2499

2500

2501

2502

2503

2504

2505

2506

2507

2508

2509

2510

2511

2512

2513

2514

2515

2516

2517

2518

PUBLIC RELEASE DRAFT
May 2025

3. Vapor Emissions
During
Blending/Compounding

1, Transfer Operation	Direct Contact	g. Releases During Loading

B. Exposure During	5, Equipment

Container Cleaning	Cleaning tosses

Figure 3-7. Consolidated Compounding and Converting Flow Diagram Facility Estimates

3.6.2	Facility Estimates

In the MhTUITePAT^OZ^^

EPA analyzed, EPA identified that 54 sites may have released DBP from manufacturing non-PVC
materials based on site names and their reported NAICS and SIC codes. No sites were reported under
CDR. Due to the lack of data on the annual PV of DBP in non-PVC material manufacturing, EPA did
not present annual or daily site throughputs. EPA identified information on operating days in the NEI air
release data. Operating days ranged from 20 to 365 days per year, with an average of 298 days.
TRI/DMR (U.S. EPA. 2024a) datasets do not report operating days; therefore, EPA assumed 250
days/year of operation as discussed in Section 2.3.2.

3.6.3	Release Assessment

3.6.3.1 Environmental Release Points

EPA analyzed releases based on NEI/TRI data (	ij , /'• \ , /'• j ). EPA expects blending

and compounding operations to release vapor emissions to fugitive or stack air. EPA expects releases to
water, incineration, or landfill from container residues and equipment cleaning wastes. EPA expects
releases to water from direct contact cooling. Releases to fugitive air, water, incineration, or landfill are
expected during transfer operations and while loading plastic additives.

Sites may utilize air capture technology. If a site uses air capture technology, EPA expects dust releases
from product loading to be controlled and released to disposal facilities for incineration or landfill. EPA
expects the remaining uncontrolled dust to be released to stack air. If the site does not use air control
technology, EPA expects releases to fugitive air, wastewater, incineration, or landfill as described above.

Page 91 of 291


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2519

2520

2521

2522

2523

2524

2525

2526

2527

2528

2529

2530

2531

2532

2533

2534

PUBLIC RELEASE DRAFT
May 2025

3.6.3.2 Environmental Release Assessment Results

Table 3-34 presents fugitive and stack air releases per year and per day for non-PVC material
manufacturing based on the 2017 to 2022 TRI database years along with the number of release days per
year, with medians and maxima presented from across the 6-year reporting range. Table 3-35 presents
fugitive and stack air releases per year and per day based on 2020 NEI database along with the number
of release days per year. Table 3-36 presents fugitive and stack air releases per year and per day based
on 2017 NEI database along with the number of release days per year. Table 3-37 presents land releases
per year based on the TRI database along with the number of release days per year. Table 3-38 presents
water releases per year and per day based on the 2017 to 2022 TRI database along with the number of
release days per year, with medians and maxima presented from across the 6-year reporting range. The
Draft Summary of Results for Identified Environmental Releases to Air for Dibutyl Phthalate (DBF),
Draft Summary of Results for Identified Environmental Releases to Landfor Dibutyl Phthalate (DBF),
and Draft Summary of Results for Identified Environmental Releases to Water for Dibutyl Phthalate
(DBF) contain additional information about these identified releases and their original sources; refer to
Appendix F for a reference to these supplemental documents.

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Table 3-34. Summary of Air I

Releases from r

RI for Non-

'VC Plastics Manufacturing

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual Stack
Air Release
(kg/year)

Median
Annual
Fugitive Air
Release
(kg/year)

Median
Annual
Stack Air
Release
(kg/year)

Annual
Release Days
(days/
year)

Maximum

Daily
Fugitive Air
Release
(kg/year)

Maximum
Daily Stack
Air Release
(kg/day)

Median Daily
Fugitive Air
Release
(kg/day)

Median
Daily Stack
Air Release
(kg/day)

Danfoss-
Mountain Home

2.3

5.4

0

3.8

250

9.1E-03

2.2E-02

0

1.5E-02

Belt Concepts of
America Inc

0

34

0

30

250

0

0.14

0

0.12

Danfoss Power
Solutions II
LLC

59

5.4

27

4.7

250

0.23

2.2E-02

0.11

1.9E-02

Parker Hannifin

0.95

2.9E-04

0.48

1.5E-04

250

3.8E-03

1.2E-06

1.9E-03

5.8E-07

2536

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Table 3-35. Summary of Air

Releases from NEI (2020)

'or Non-PV<

2 Plastics Manufacturing

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual
Stack Air
Release
(kg/year)

Annual
Release
Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum
Daily Stack Air
Release
(kg/day)

BFGoodrich Tire Co

21

8.8E-03

287

7.2E-02

3.1E-05

The Cooper Tire Company

174

0

322

0.54

0

Goodyear Tire & Rubber
Company

N/A

0

321

N/A

0

Boston Weatherhead

N/A

2.8

287

N/A

9.7E-03

Michelin Na US5/US7
Lexington

N/A

3.5

343

N/A

1.0E-02

Michelin: Anderson US 8

N/A

1.4E-05

302

N/A

4.5E-08

Michelin NaUS3 Spartanburg

N/A

7.8E-02

300

N/A

2.6E-04

Bridgestone Americas Tire
Operations, LLC - Warren
Plant

N/A

171

287

N/A

0.59

Michelin Na US 1 Greenville

6.2E-02

64

283

2.2E-04

0.23

Bridgestone Americas Tire
Operations, LLC - Lavergne

27

N/A

287

9.4E-02

N/A

Henniges Automotive Sealing
Systems Na Danny Scott Drive

1.1

N/A

287

3.8E-03

N/A

Contitech USA Inc

N/A

0

365

0

0

Cooper Tire and Rubber
Company, Clarksdale

1.3

28

287

4.4E-03

9.9E-02

Michelin Tire Corporation

16

0

287

5.7E-02

0

Goodyear Lawton

144

0

336

0.43

0

Timken SMO LLC Springfield

1.0

4.3

287

3.6E-03

1.5E-02

The Goodyear Tire & Rubber
Company

2.3

0

287

7.8E-03

0

Saint-Gobain SGPPL

9.1E-02

N/A

287

3.2E-04

N/A

Oliver Rubber Company, LLC

1.8E-02

359

343

5.3E-05

1.05

Dana Sealing Products, LLC

0.11

N/A

287

3.7E-04

N/A

Fulflex Inc

5.9

N/A

287

2.1E-02

N/A

The Cooper Tire Company

90

2.5

287

0.31

8.8E-03

Goodyear Tire & Rubber

26

4.5

350

7.3E-02

1.3E-02

Bridgestone-Bandag, LLC

N/A

79

364

0

0.22

The Goodyear Tire & Rubber
Company

0.16

8.1E-06

364

4.4E-04

2.2E-08

Bridgestone Americas Tire
Operations, LLC

27

1.4

250

0.11

5.8E-03

Michelin Na US2 Sandy
Springs

N/A

2.2E-02

262

N/A

8.6E-05

Michelin Aircraft Tire
Company

N/A

0

364

N/A

0

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Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual
Stack Air
Release
(kg/year)

Annual
Release
Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum
Daily Stack Air
Release
(kg/day)

Goodyear Dunlop Tires North
America Ltd

8.0

344

287

2.8E-02

1.20

Belt Concepts of America Inc.

N/A

54

287

N/A

0.19

Brannon Tire

3.5E-04

N/A

260

1.4E-06

N/A

Industrial Rubber Applicators

N/A

0

287

N/A

0

Continental Tire the Americas
LLC

N/A

177

365

N/A

0.48

Michelin North America Inc
US10

N/A

5.7

335

N/A

1.7E-02

Giti Tire Manufacturing Co
USA Ltd

4.0

N/A

329

1.2E-02

N/A

Yokohama Tire Manufacturing
Mississippi

1.6

N/A

287

5.7E-03

N/A

Les Schwab Production Center

2.2

0

287

7.8E-03

0

Superior Tire Service, Inc.

N/A

0

287

N/A

0

Ultimate Rb, Inc.

N/A

0

287

N/A

0

2538

2539

2540	Table 3-36. Summary of Air Releases from NEI (2017) for Non-PVC Plastics Manufacturing



Maximum

Maximum

Annual
Release
Days
(days/year)

Maximum

Maximum
Daily Stack
Air Release
(kg/day)

Site Identity

Annual
Fugitive Air
Release
(kg/year)

Annual
Stack Air
Release
(kg/year)

Daily
Fugitive Air
Release
(kg/day)

Fluid Routing Systems, Inc.

1.4

N/A

154

9.4E-03

N/A

Eaton Aeroquip Inc

N/A

0

287

N/A

0

Michelin Na US5 & US7 Lexington

N/A

0.22

328

N/A

6.6E-04

Michelin Na US8 Starr Facility

N/A

0.10

287

N/A

3.5E-04

Titan Tire Corporation of Union City

1.2E-02

N/A

287

4.2E-05

N/A

Cooper Tire and Rubber Company
Clarksdale

1.5

0

329

4.7E-03

0

Snider Tire, Inc.

N/A

27

260

N/A

0.10

Parrish Tire Company

1.1E-02

3.2

255

4.3E-05

1.3E-02

Airboss Rubber Compounding (NC)
Inc.

N/A

0

250

N/A

0

Bridgestone Aircraft Tire (USA), Inc.

0.38

9.0

250

1.5E-03

3.6E-02

Patch Rubber Company

0.23

0

250

9.1E-04

0

Industrial Rubber Applicators Inc

N/A

53

287

N/A

0.18

Snider Tire, Inc. Dba Snider Fleet Sol

N/A

0

260

N/A

0

Cooper Standard - Woodland Church
Road

5.4E-02

N/A

364

1.5E-04

N/A

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Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual
Stack Air
Release
(kg/year)

Annual
Release
Days
(days/year)

Maximum

Daily
Fugitive Air
Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

Giti Tire Manufacturing USA

1.3

N/A

287

4.5E-03

N/A

Table 3-37. Summary of Lant

Releases from TRI for Non-PVC Plastics Manufacturing

Site Identity

Median Annual
Release (kg/year)

Maximum Annual
Release (kg/year)

Annual Release Days
(days/year)

Danfoss Power Solutions II LLC

491

566

250

Parker Hannifin

2.3

2.3

250

Danfoss-Mountain Home

2.7

2.7

250

Table 3-38. Summary of Water Releases from TRI for Non-PVC Plastic JV

Site Identity

Source-
Discharge Type

Median
Annual
Discharge
(kg/year)

Median
Daily
Discharge
(kg/day)

Maximum
Annual
Discharge
(kg/year)

Maximum

Daily
Discharge
(kg/day)

Annual
Release Days
(days/year)

Danfoss-Mountain
Home

TRI Form R

4.5E-03

1.8E-05

4.5E-03

1.8E-05

250

Danfoss-Mountain
Home

TRI Form R-
Transfer to POTW

4.5E-03

1.8E-05

4.5E-03

1.8E-05

250

anufacturing

3.6.4 Occupational Exposure Assessment

3.6.4.1 Worker Activities

Worker exposures during the compounding and converting process may occur via inhalation of vapors
formed during operations that occur at elevated temperatures or inhalation or dermal contact with dust
during unloading and loading, equipment cleaning, and transport container cleaning (	21c).

EPA did not identify site-specific information on engineering controls or worker PPE used at DBP-
containing non-PVC plastics compounding sites.

ONUs may include supervisors, managers, and other employees that work in the formulation area but do
not directly contact DBP that is received or processed onsite or handle compounded product. ONUs are
potentially exposed via inhalation and dermal routes to airborne and settled dust while in the working
area.

3.6.4.2 Occupational Inhalation Exposure Results

EPA did not identify chemical- or OES-specific inhalation monitoring data for DBP from systematic
review, however, EPA utilized surrogate vapor inhalation monitoring data from PVC plastics converting
to assess worker inhalation exposure to DBP vapors. The data is from a risk evaluation completed by the
ECJRC, which included four data points compiled from two sources (ECB. 2004). The ECJRC risk
evaluation received a rating of medium from EPA's systematic review process. All data is from
unnamed facilities, with two datapoints from a facility using PVC in the manufacturing of cables and the
other two datapoints summarizing a dataset listed only as from the "polymer industry". With the four

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discrete data points, EPA could not create a full distribution of monitoring results to estimate central
tendency and high-end exposures. To assess the high-end worker exposure to DBP during the converting
process, the Agency used the maximum available value (0.75 mg/m3). EPA assessed the average of the
four available values as the central tendency (0.24 mg/m3).

In addition to vapor exposure, EPA expects worker inhalation exposures to DBP via exposure to
particulates of non-PVC materials during the compounding and converting processes. Additionally,
exposures to DBP are expected during unloading and loading tasks, container cleaning, and equipment
cleaning. To estimate worker and ONU inhalation exposure, EPA used the PNOR Model (
2i ). Model approaches and parameters are described in Appendix D. The Agency used a subset of
the model data that came from facilities with NAICS codes starting with 326 - Plastics and Rubber
Manufacturing to estimate DBP-containing, non-PVC material particulate concentrations in the air. For
this OES, EPA selected 20 percent by mass as the highest expected DBP concentration based on the
Emission Scenario Document on Additives in Rubber Industry ("OECD. 2004a)to estimate the
concentration of DBP present in particulate formed at the compounding and converting site. The
estimated exposures assume that DBP is present in particulates at this fixed concentration throughout the
working shift.

The PNOR Model (U.S. EPA. 2021b) estimates an 8-hour TWA for particulate concentrations by
assuming exposures outside the sample duration are zero. The model does not determine exposures
during individual worker activities. In absence of data specific to ONU exposure, EPA assumed that
worker central tendency exposure was representative of ONU exposure and used this data to generate
estimates for ONUs. EPA assessed the exposure frequency as 250 days/year for both high-end and
central tendency exposures based on the expected operating days for the OES and accounting for off
days for workers.

Table 3-39 summarizes the estimated 8-hour TWA concentration, AD, IADD, and ADD for worker
exposures to DBP during non-PVC material compounding. Appendix A describes the approach for
estimating AD, IADD, and ADD. The estimated exposures assume that the worker is exposed to DBP
primarily in the form of particulates, but also accounts for other potential inhalation exposure routes,
such as from the inhalation of vapors. Based on the low vapor pressure of DBP, exposure to vapors is
not expected to be a major contribution to exposures. The Draft Occupational Inhalation Exposure
Monitoring Results for Dibutyl Phthalate (DBP) contains further information on the identified inhalation
exposure data, information on the PNOR Model parameters used, and assumptions used in the
assessment, refer to Appendix F for a reference to this supplemental document.

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Table 3-39. Summary of Estimated Worker Inhalation Exposures for Non-PVC Material
Compounding 		

Modeled Scenario

Exposure Concentration Type

Central
Tendency"

High-
End"



8-hour TWA Exposure Concentration (mg/m3)

100

201

Average Adult
Worker

Acute Dose (AD) (mg/kg-day)

3.6E-02

0.21

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

2.6E-02

0.15

Chronic Average Daily Dose, Non-Cancer Exposures
(ADD) (mg/kg-day)

2.4E-02

0.14



8-hour TWA Exposure Concentration (mg/m3)

84

167

Female of
Reproductive Age

Acute Dose (AD) (mg/kg-day)

3.9E-02

0.23

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

2.9E-02

0.17

Chronic Average Daily Dose, Non-Cancer Exposures
(ADD) (mg/kg-day)

2.7E-02

0.16



8-hour TWA Exposure Concentration (mg/m3)

1.5

1.5



Acute Dose (AD) (mg/kg-day)

3.6E-02

3.6E-02

ONU

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

2.6E-02

2.6E-02



Chronic Average Daily Dose, Non-Cancer Exposures
(ADD) (mg/kg-day)

2.4E-02

2.4E-02

a EPA utilized surrogate vapor inhalation monitoring data from PVC plastics converting to assess worker inhalation
exposure to DBP vapors. The data is from a risk evaluation completed by the ECJRC, which included four data points
compiled from two sources (ECB. 2004). The ECJRC risk evaluation received a rating of medium from EPA's

systematic review process. To assess the high-end worker exposure to DBP, EPA used the maximum available value
(0.75 mg/m3). EPA assessed the average of the four available values as the central tendency (0.24 mg/m3). EPA used
the PNOR Model to estimate exposures to dust. For the PNOR Model, EPA multiplied the concentration of DBP with

the central tendency and HE estimates of the relevant NAICS code from the PNOR Model to calculate the central

tendency and HE estimates for this OES.





3.6.4.3 Occupational Dermal Exposure Results

EPA estimated dermal exposures for this OES using the dermal approach outlined in Section 2.4.3 and
Appendix C. The various "Exposure Concentration Types" from Table 3-40 are explained in Appendix
A. Since there may be dust deposited on surfaces from this OES, dermal exposures to ONUs from
contact with dust on surfaces were assessed. In the absence of data specific to ONU exposure, EPA
assumed that worker central tendency exposure was representative of ONU exposure. For occupational
dermal exposure assessment, EPA assumed a standard 8-hour workday and the chemical is contacted at
least once per day. Because DBP has low volatility and relatively low absorption, it is possible that the
chemical remains on the surface of the skin after dermal contact until the skin is washed. Therefore, in
absence of exposure duration data, EPA has assumed that absorption of DBP from occupational dermal
contact with materials containing DBP may extend up to 8 hours per day (	). However, if

a worker uses proper PPE or washes their hands after contact with DBP or DBP-containing materials
dermal exposure may be eliminated. Therefore, the assumption of an 8-hour exposure duration for DBP
may lead to overestimation of dermal exposure. Table 3-40 summarizes the APDR, AD, IADD, and
ADD for average adult workers, female workers of reproductive age, and ONUs. The Draft
Occupational Dermal Exposure Modeling Results for Dibutyl Phthalate (DBP) also contains
information about model equations and parameters and contains calculation results; refer to Appendix F
for a reference to this supplemental document.

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2624	Table 3-40. Summary of Estimated Worker Dermal Exposures for Non-PVC Material

2625	Compounding			

Modeled Scenario

Exposure Concentration Type

Central Tendency

High-End



Dose Rate (APDR, mg/day)

102

204

Average Adult Worker

Acute (AD, mg/kg-day)

1.3

2.5

Intermediate (IADD, mg/kg-day)

0.93

1.9



Chronic, Non-Cancer (ADD, mg/kg-day)

0.87

1.7



Dose Rate (APDR, mg/day)

85

169

Female of Reproductive

Acute (AD, mg/kg-day)

1.2

2.3

Age

Intermediate (IADD, mg/kg-day)

0.86

1.7



Chronic, Non-Cancer (ADD, mg/kg-day)

0.80

1.6



8-hour TWA Exposure Concentration (mg/m3)

1.4

1.4



Acute Dose (AD) (mg/kg/day)

1.7E-02

1.7E-02

ONU

Intermediate Average Daily Dose, Non-Cancer
Exposures (IADD) (mg/m3)

1.2E-02

1.2E-02



Chronic Average Daily Dose, Non-Cancer

1.2E-02

1.2E-02



Exposures (ADD) (mg/kg/day)





Note: For high-end estimates, EPA assumed the exposure surface area was equivalent to mean values for two-hand
surface areas {i.e., 1.070 cm2 for male workers and 890 cm2 for female workers) (U.S. EPA, 2011). For central

tendency estimates, EPA assumed the exposure surface area was equivalent to only a single hand (or one side of two
hands) and used half the mean values for two-hand surface areas (i.e.. 535 cm2 for male workers and 445 cm2for

female workers).







2626	3.6.4.4 Occupational Aggregate Exposure Results

2627	Inhalation and dermal exposure estimates were aggregated based on the approach described in Appendix

2628	A.3 to arrive at the aggregate worker and ONU exposure estimates in the table below. The assumption

2629	behind this approach is that an individual worker could be exposed by both the inhalation and dermal

2630	routes, and the aggregate exposure is the sum of these exposures.

2631

2632	Table 3-41. Summary of Estimated Worker Aggregate Exposures for Non-PVC Material

2633	Compounding				

Modeled Scenario

Exposure Concentration Type
(mg/kg-day)

Central
Tendency

High-End

Average Adult Worker

Acute (AD, mg/kg-day)

1.3

2.8

Intermediate (IADD, mg/kg-day)

0.96

2.0

Chronic, Non-Cancer (ADD, mg/kg-day)

0.90

1.9

Female of Reproductive Age

Acute (AD, mg/kg-day)

1.2

2.6

Intermediate (IADD, mg/kg-day)

0.89

1.9

Chronic, Non-Cancer (ADD, mg/kg-day)

0.83

1.8

ONU

Acute (AD, mg/kg-day)

5.3E-02

5.3E-02

Intermediate (IADD, mg/kg-day)

3.9E-02

3.9E-02

Chronic, Non-Cancer (ADD, mg/kg-day)

1.9E-02

1.9E-02

Note: A worker could be exposed by both the inhalation and dermal routes, and the aggregate exposure is the sum of
these exposures.

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3.7 Application of Adhesives and Sealants

3,7.1 Process Description

DBP is used as an additive in adhesive and sealant products for industrial and commercial use, including
floor sealants and adhesive and sealant chemicals used in construction (	)20b). One industry

commenter provided descriptions of their DBP use in pedigreed adhesives used in testing test articles
and human-rated spaceflight hardware (U.S. EPA-HQ-OPPT-2018-0503-0035). DBP is expected to
arrive on site as an additive in liquid adhesive or sealant formulations. All identified products are in
liquid form, and the application site receives the final formulation as a single-component
adhesive/sealant product. The liquid product arrives at the site in containers ranging in size from 5 to 20
gallons and at concentrations of 0.1 to 75 percent DBP (see Appendix E for EPA identified-DBP-
containing products for this OES). The size of the container is an input to the Monte Carlo simulation to
estimate releases but is not used to calculate occupational exposures for DBP. The application site
directly transfers the liquid product to the application equipment to apply it as the final adhesive/sealant
to the substrate (OE	).

Application methods for the final adhesive/sealant include spray, roll, dip, curtain, bead, roll, and
syringe application. Application may occur over the course of an 8-hour workday at a given site,
accounting for drying or curing times and additional coats where necessary. The site may trim excess
adhesive/sealant from the applied substrate area. Figure 3-8 provides an illustration of the process of
applying adhesives and sealants (OECD. 2015).

A. Exposure During
Container Cleaning

4, Eci'i
Clean

ipment
Releases

5, Open Sv.rface
Lcssei cluing
Equipment C.eaning

Figure 3-8. Application of Adhesives and Sealants Flow Diagram

3.7.2 Facility Estimates

EPA estimated the total DBP production volume for adhesive and sealant products using a uniform
distribution with a lower-bound of 99,157 kg/year and an upper-bound of 2,140,323 kg/year. This range
is based on DBP CDR data of site production volumes, national aggregate production volumes, and
percentages of the production volumes going to various industrial sectors (	20a).

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There were two reporters that reported to CDR for use of DBP in adhesive/sealant or paint/coating
products: G.J. Chemical Co, Inc. in Somerset, New Jersey, who reported a volume of 139,618 lb; and
MAK Chemicals in Clifton, NJ, who reported a use volume of 105,884 lb of DBP. This equates to a
total known use volume of 245,502 lb of DBP; however, there is still a large portion of the aggregate PV
range for DBP that is not attached to a known use. A breakdown of the known production volume
information is provided in Table Apx D-7.

Due to uncertainty in the expected use of DBP, EPA assumes that the remaining PV with unknown use
is split between the use of adhesives and sealants and paint and coating products. Subtracting the PV
with known uses that are not associated with adhesives/sealants/paints/coatings from the aggregate
national PV range equates to a range of 99,157 to 2,140,323 kg for this OES (see Section D.3.3). EPA
used the range of production volumes as an input to the Monte Carlo modeling described in Appendix D
to estimate releases. The production volume range is not used to calculate occupational exposures for
DBP.

EPA did not identify site- or chemical-specific adhesive and sealant application operating data {i.e.,
facility use rates). However, the 2015 ESD on the Use of Adhesives estimated an adhesive use rate of
1,500 to 141,498 kg/site-year. Based on DBP concentration in the liquid adhesive product of 0.1 to 75
percent, EPA estimated a DBP use rate of 1.5 to 106,124 kg/site-year. Additionally, the ESD estimated
the number of operating days as 50 to 365 days/year while NEI reporters indicated an average of 269
release days per year (U.S. EPA. 2019; OECD. 20151 EPA identified 166 entries in the 2017 and 2020
NEI databases for air releases from sites that were assumed to use adhesive/sealant or paint/coating
products that contained DBP; however, the product type used between these two groups was uncertain
and, due to reporting thresholds, this estimate may not represent all adhesive application sites (U.S.
E 23a, 2019). EPA identified 1 entry in the TRI database for air releases from sites that were
assumed to use adhesive/sealant or paint/coating products that contained DBP; however, the product
type used between these two groups was uncertain and, due to reporting thresholds, this estimate may
not represent all adhesive application sites (I; S 1 T \ 2024a). Due to these uncertainties, EPA
estimated the total number of application sites that use DBP-containing adhesives and sealants using a
Monte Carlo model (see Appendix D.3 for details). The 50th to 95th percentile range of the number of
sites was 94 to 793 based on the production volume and site throughput estimates.

3.7.3 Release Assessment

3.7.3.1	Environmental Release Points

EPA assigned release points based on the 2015 ESD on the Use of Adhesives (OECD. 2015) and based
on NEI (2020), NEI (2017), TRI data (	24e, 2023a. 2019). The ESD identified models to

quantify releases from each release point for water and land releases. EPA expects releases to water,
incineration, or landfill from equipment cleaning waste and releases to incineration or landfill from
adhesive component container residue and trimming wastes. EPA expects releases to water, air,
incineration, or landfill from process releases during adhesive application.

3.7.3.2	Environmental Release Assessment Results

Table 3-42 summarizes the number of release days and the annual and daily release estimates that were
modeled for each release media and scenario assessed for this OES. Table 3-43 presents fugitive and
stack air releases per year based on the TRI database along with the number of release days per year.
Table 3-44 presents fugitive and stack air releases per year and per day based on 2020 NEI database
along with the number of release days per year. Table 3-45 presents fugitive and stack air releases per
year and per day based on 2017 NEI database along with the number of release days per year. EPA used

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NEI data for air emissions data, so modeled air emissions are not presented. See Appendix D.3.2 for
additional details on model equations, and different parameters used for Monte Carlo modeling. The
Monte Carlo simulation calculated the total DBP release (by environmental media) across all release
sources during each iteration of the simulation. EPA then selected 50th and 95th percentile values to
estimate the central tendency and high-end releases. The Draft Application ofAdhesives and Sealants
OES Environmental Release Modeling Results for Dibutyl Phthalate (DBP) contains additional
information about model equations and parameters and contains calculation results. The Draft Summary
of Results for Identified Environmental Releases to Air for Dibutyl Phthalate (DBP) contains additional
information about identified air releases and their original sources, refer to Appendix F for a reference to
these supplemental documents.

Table 3-42. Summary of Modeled Environmental Releases for Application of Adhesives and
Sealants

Modeled
Scenario

Environmental
Media

Annual Release
(kg/site-year)

Number of Release
Days

Daily Release
(kg/site-day)

Central
Tendency

High-
End

Central
Tendency

High-
End

Central
Tendency

High-End

99,157-

2,140,323

kg/year

production

volume

Fugitive Air

NEI/TRI data

232

325

NEI/ TRI Data

Water, Incineration,
or LandfilF

209

860

0.97

4.5

Incineration or
Landfill0

291

1,357

1.4

7.1

a When multiple environmental media are addressed together, releases may go all to one media, or be split between
media depending on site-specific practices. Not enough data was provided to estimate the partitioning between media.
h The Monte Carlo simulation calculated the total DBP release (by environmental media) across all release sources
during each iteration of the simulation. EPA then selected 50th and 95th percentile values to estimate the central
tendency and high-end releases, respectively.

Table 3-43. Summary of TRI Air Release Data for Application of Paints, Coatings, Adhesives and
Sealants

Site Identity

Maximum
Annual Fugitive
Air Release
(kg/year)

Maximum
Annual Stack
Air Release
(kg/year)

Annual
Release Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum Daily

Stack Air
Release (kg/day)

Heytex- USA

0

0

250

0

0

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2726 Table 3-44. Summary of NEI (2020) for Application of Paints, Coatings, Adhesives and Sealants

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual
Stack Air
Release
(kg/year)

Annual
Release Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum
Daily Stack Air
Release
(kg/day)

Sikorsky Aircraft Corporation

N/A

9.8E-03

250

N/A

3.9E-05

Electric Boat Corp

0

36

250

0

0.14

FCA US LLC

N/A

67

250

N/A

0.27

Knud Nielsen (WAF)

64

N/A

250

0.25

N/A

Vulcraft Inc

N/A

0

250

N/A

0

George C Marshall Space
Flight Center

N/A

118

250

N/A

0.47

Tiffin Motor Homes Inc

290

N/A

250

1.16

N/A

Anacapa Boatyard

0.79

N/A

260

3.0E-03

N/A

Applied Aerospace Str Corp

N/A

0

260

N/A

0

Marine Group Boat Works
LLC

5.0

N/A

190

2.6E-02

N/A

Fellowes Inc

N/A

61

250

N/A

0.25

Britt Industries

N/A

1.0E-02

250

N/A

4.2E-05

Textron Aviation -
Independence

5.7

N/A

200

2.8E-02

N/A

Talaria Co., LLC

7.7

N/A

250

3.1E-02

N/A

Safe Harbor New England
Boatworks Inc.

1.5

N/A

250

6.1E-03

N/A

Gibson Guitar Custom Shop

N/A

13

250

N/A

5.0E-02

Crestwood Inc.

N/A

0

250

N/A

0

BAE Systems SDSR

1.0

N/A

250

4.2E-03

N/A

Ventura Harbor Boatyard Inc.

49

N/A

312

0.16

N/A

Ritz Craft Corp/Mifflinburg
PLT

36

N/A

191

0.19

N/A

US Department of Energy
Office of Science, Oak Ridge
National Laboratory

N/A

0

250

N/A

0

Watco Transloading LLC

N/A

6.9

250

N/A

2.7E-02

Lockheed Martin Aeronautics
Company

3.0

N/A

350

8.7E-03

N/A

Hearne Maintenance Facility

122

N/A

365

0.33

N/A

North American Lighting Inc.

N/A

5.4

250

N/A

2.2E-02

Hallmark Cards - Lawrence

15

N/A

364

4.2E-02

N/A

Trinity Industries Plant 19

N/A

0

250

N/A

0

Gibson USA

N/A

10

250

N/A

4.0E-02

USAF Shaw Air Force Base

N/A

0

250

N/A

0

Thermo King Corporation

N/A

0.78

250

N/A

3.1E-03

Page 103 of 291


-------
PUBLIC RELEASE DRAFT
May 2025

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual
Stack Air
Release
(kg/year)

Annual
Release Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum
Daily Stack Air
Release
(kg/day)

The Boeing Company St.
Louis

1.22

N/A

250

4.9E-03

N/A

Vulcraft - Division of Nucor
Corporation- Steel Products
Manufacturing

3.0

N/A

250

1.2E-02

N/A

Progress Rail Service -
Electric Fuels Corp

N/A

2.8

250

N/A

1.1E-02

Textron Aviation - West
Campus

N/A

0

364

N/A

0

Textron Aviation - Pawnee
Campus

0.91

N/A

312

2.9E-03

N/A

Fort Hood

9.1E-02

N/A

260

3.5E-04

N/A

Island Park Fabrication Plant

9.1E-02

0

111

8.2E-04

0

US Air Force Plant 4

18

N/A

250

7.1E-02

N/A

Embraer Aircraft Maint
Services, Inc

N/A

1.9E-05

250

N/A

7.8E-08

Barber Cabinet Co Inc

N/A

59

250

N/A

0.24

Portsmouth Naval Shipyard -
Kittery

N/A

0

250

N/A

0

Wastequip Manufacturing Co

N/A

0

250

N/A

0

Quality Painting & Metal
Finishing Inc

N/A

0

250

N/A

0

Commercial Plastics Mora
LLC

1.38

0

250

5.5E-03

0

HATCO

N/A

0

200

N/A

0

Raytheon Technologies

1.8E-02

N/A

250

7.3E-05

N/A

Electric Boat Corporation

0.66

N/A

250

2.6E-03

N/A

Chief Agri Industrial
Products

1.8E-03

0

200

9.1E-06

0

Boeing Company St. Charles

N/A

3.2E-04

250

N/A

1.3E-06

Marvin Windows and Doors

N/A

0

250

N/A

0

Modern Design LLC

N/A

0

250

N/A

0

Progress Rail Service -
DeCoursey Car Shop

N/A

0

250

N/A

0

Caterpillar INC

0.36

N/A

250

1.5E-03

N/A

Kurz Transfer Products, LP

0

126

364

0

0.35

Northrop Grumman Systems
Corp. - BWI

0

5.6

260

0

2.1E-02

Bernhardt Furniture Company
- Plants 3&7

0

0.16

250

0

6.5E-04

Fleet Readiness Center East

0.57

60

364

1.6E-03

0.16

Page 104 of 291


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PUBLIC RELEASE DRAFT
May 2025

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual
Stack Air
Release
(kg/year)

Annual
Release Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum
Daily Stack Air
Release
(kg/day)

Kirtland Air Force Base

7.3E-02

N/A

364

2.0E-04

N/A

Maintenance Engineering
Center

0.45

0

365

1.2E-03

0

Textron Aviation - East
Campus

1.1

N/A

300

3.6E-03

N/A

3M Hutchinson

N/A

0

250

N/A

0

Swaim, Inc.

N/A

4.4E-06

250

N/A

1.7E-08

Hickory Chair, LLC

N/A

0

250

N/A

0

Ethan Allen Inc (Orleans Div)

N/A

0

250

N/A

0

Woodgrain Millwork Inc. -
Fruitland

N/A

0

250

N/A

0

Huntington Ingalls Inc,
Ingalls Shipbuilding

80

N/A

250

0.32

N/A

Eudys Cabinet
Manufacturing, Inc.

62

0

250

0.25

0

Tektronix, Inc.

1.6

N/A

250

6.5E-03

N/A

Marine Corps Air Station -
Cherry Point

6.3E-03

33

364

1.7E-05

9.1E-02

PLASTIC FILM PLANT

1.81

0

365

5.0E-03

0

Spirit AeroSystems - Wichita

18

N/A

364

5.0E-02

N/A

Lockheed Martin Aeronautics
Company

N/A

4.5

312

N/A

1.4E-02

Cobham Advanced
Electronics Solutions Inc.

8.7E-05

N/A

270

3.2E-07

N/A

Nashville Custom
Woodwork, Inc.

N/A

2.7

250

N/A

1.1E-02

Apex Engineering - Wichita
(W 2nd)

N/A

18

260

N/A

6.7E-02

Lewistown Cabinet
Ctr/Milroy

N/A

3.0E-09

232

N/A

1.3E-11

University of Iowa

N/A

0

250

N/A

0

United Airlines IAH Airport

0.64

N/A

260

2.4E-03

N/A

Cabinotch, Inc.

N/A

64

250

N/A

0.25

Alstom Power Inc

N/A

60

250

N/A

0.24

Central Sandblasting
Company

N/A

0

250

N/A

0

SHM LMC LLC

9.2

N/A

364

2.5E-02

N/A

Nautical Structures
Industries, Inc.

N/A

9.3

312

N/A

3.0E-02

Amcor Pharmaceutical
Packaging USA Inc

N/A

0

250

N/A

0

Page 105 of 291


-------
PUBLIC RELEASE DRAFT
May 2025

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual
Stack Air
Release
(kg/year)

Annual
Release Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum
Daily Stack Air
Release
(kg/day)

HME Inc.

N/A

0

280

N/A

0

Marine Corps Logistics Base

1409

N/A

365

3.86

N/A

Schenck Process - Sabetha

19

N/A

258

7.4E-02

N/A

P C Auto Body

0.79

N/A

260

3.0E-03

N/A

Freight Car America

N/A

0

250

N/A

0

The New York Blower
Company

N/A

0

250

N/A

0

Eminence Speaker LLC

46

N/A

250

0.18

N/A

C & L Aerospace Holdings,
LLC

N/A

0.72

250

N/A

2.9E-03

Teknicote

1.9

N/A

250

7.4E-03

N/A

The Boeing Company

0.38

N/A

365

1.1E-03

N/A

Premier Marine LLC

N/A

0

250

N/A

0

Curry Supply
Co/Hollidaysburg

N/A

0

365

N/A

0

Phillips Diversified
Manufacturing (PDM) Inc

N/A

266

250

N/A

1.1

Kalitta Air, LLC

0.68

N/A

250

2.7E-03

N/A

Davis Tool, Inc.

N/A

0

250

N/A

0

2727

2728

2729	Table 3-45. Summary of NEI (2017) for Application of Paints, Coatings, Adhesives and Sealants

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual Stack
Air Release
(kg/year)

Annual
Release
Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum
Daily Stack Air
Release
(kg/day)

Ventura Harbor Marina &
Yacht Yard

0.77

N/A

250

3.1E-03

N/A

Bellport Anacapa Marine
Services

58

N/A

40

1.44

N/A

Naval Base Ventura County

1.1

N/A

250

4.2E-03

N/A

Eagle Wings Industries Inc

N/A

1.55

250

N/A

6.2E-03

Electronic Data Systems
North Island

5.96

N/A

250

2.4E-02

N/A

FIC America Corp

N/A

0

250

N/A

0

CE Niehoff & Co

N/A

13

250

N/A

5.2E-02

U.S. Postal Service- Mail
Facility

6.9

N/A

250

2.8E-02

N/A

Us Airways Maintenance
Base/Pgh

N/A

0

250

N/A

0

Page 106 of 291


-------
PUBLIC RELEASE DRAFT
May 2025

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual Stack
Air Release
(kg/year)

Annual
Release
Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum
Daily Stack Air
Release
(kg/day)

El Paso Division

N/A

0

250

N/A

0

New England Boatworks
Inc.

0.91

N/A

250

3.6E-03

N/A

American Shipyard LLC.

8.3

N/A

250

3.3E-02

N/A

Knapheide Manufacturing
Co

N/A

6.6

250

N/A

2.6E-02

Bae Systems San Diego
Ship Repair Inc

1.8

N/A

250

7.4E-03

N/A

Bill Stasek Chevrolet Inc

N/A

1.6

250

N/A

6.5E-03

GBW Railcar Services LLC

N/A

34

250

N/A

0.14

Lockheed Martin
Aeronautics Company
Palmdale

1.2

N/A

350

3.5E-03

N/A

West Refinery

2.7

N/A

250

1.1E-02

N/A

TTX Company

N/A

7.3E-03

208

N/A

3.5E-05

American Ntn Bearing Mfg
Corp

N/A

0.16

250

N/A

6.6E-04

Stripmasters Of Illinois

N/A

3.5

250

N/A

1.4E-02

Modern Welding Company
Of Kentucky Inc -
Elizabethtown

N/A

0

250

N/A

0

Union Pacific Railroad Co
Desoto Car Shop

N/A

0

250

N/A

0

DFW Maintenance Facility

0.36

N/A

365

9.9E-04

N/A

United Parcel Service,
Worldport

2.2

7.6E-03

250

8.9E-03

3.0E-05

Progress Rail Raceland
Corp

N/A

0

250

N/A

0

Institutional Casework, Inc

N/A

0

250

N/A

0

Wastequip Manufacturing
Co LLC

N/A

0.67

250

N/A

2.7E-03

Litho Technical Services

N/A

18

250

N/A

7.1E-02

Delta Air Lines Inc -
Mpls/Saint Paul

N/A

58

250

N/A

0.23

Construction
Materials/CMI Coatings
Group Dba Industrial
Painting Specialists

0.15

13

250

5.9E-04

5.1E-02

Crystal Cabinet Works Inc

0.11

106

250

4.3E-04

0.43

3m - Alexandria

N/A

0

250

N/A

0

Johnston Tombigbee
Furniture Company, Co

N/A

0

250

N/A

0

Page 107 of 291


-------
PUBLIC RELEASE DRAFT
May 2025

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual Stack
Air Release
(kg/year)

Annual
Release
Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum
Daily Stack Air
Release
(kg/day)

Knu LLC

N/A

0

250

N/A

0

Structural Steel Services
Inc, Plants 1

N/A

0

250

N/A

0

Harden Furniture Inc

N/A

0

250

N/A

0

General Motors LLC
Wentzville Center

N/A

0

250

N/A

0

Ford Motor Co

N/A

10

250

N/A

4.2E-02

Commercial Property LLC
- Carolina Heritage
Cabinetry Pit. 2

N/A

41

250

N/A

0.16

Caldwell Tanks

N/A

38

250

N/A

0.15

L & J G Stickley Inc

14

N/A

250

5.5E-02

N/A

Ethan Allen Operations,
Inc. - Pine Valley Division

N/A

0

250

N/A

0

Pompanoosuc Mills Corp

N/A

0

250

N/A

0

Hamilton Square Lenoir
Casegoods Plant

N/A

0

250

N/A

0

Panels, Services &
Components, Inc.

22

N/A

208

0.11

N/A

Fort Drum - U.S. Military

N/A

617

250

N/A

2.5

Haeco Airframe Services,
LLC

7.2

0

364

2.0E-02

0

May-Craft Fiberglass
Products, Inc.

N/A

13

364

N/A

3.5E-02

Structural Coatings Inc. -
Clayton

N/A

0

312

N/A

0

Rockwell Collins, Inc.

N/A

0

365

N/A

0

Manchester Wood Inc

N/A

0

250

N/A

0

Wabash National Corp

N/A

0

250

N/A

0

Lexington Furniture
Industries - Plant No. 15

N/A

38

250

N/A

0.15

Spear USA

N/A

2.8E-02

250

N/A

1.1E-04

Knapheide Truck
Equipment Co

N/A

199

250

N/A

0.80

Piedmont Composites and
Tooling, LLC

N/A

0

200

N/A

0

UPM Raflatac Inc Dixon 11

N/A

0

250

N/A

0

Phills Custom Cabinets

N/A

3.6E-04

250

N/A

1.5E-06

Kellex Corporation, Inc. -
Morganton Facility

N/A

0

250

N/A

0

CRP LMC Prop Co., LLC

3.1

N/A

364

8.5E-03

N/A

Page 108 of 291


-------
2730

2731

2732

2733

2734

2735

2736

2737

2738

2739

2740

2741

2742

2743

2744

2745

2746

2747

2748

2749

2750

2751

2752

2753

2754

2755

2756

2757

2758

2759

2760

2761

2762

PUBLIC RELEASE DRAFT
May 2025

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual Stack
Air Release
(kg/year)

Annual
Release
Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum
Daily Stack Air
Release
(kg/day)

Ornamental Products, LLC

N/A

0

250

N/A

0

Leggett & Piatt, Inc. -
Metal Bed Rail

2233

N/A

260

8.59

N/A

Century Furniture - Plant
No. 2

N/A

0

250

N/A

0

Mickelson Body Shop

N/A

32

250

N/A

0.13

Premier Marine Inc

N/A

0

250

N/A

0

3,7,4 Occupational Exposure Assessment

3.7.4.1	Worker Activities

During the use of adhesives and sealants containing DBP, worker inhalation exposures to DBP may
occur while unloading, applying, and mixing any liquid component of the adhesive or sealant, such as a
liquid catalyst or 1-part adhesive. Worker dermal exposures to DBP in adhesives and sealants may occur
while unloading, mixing, applying, curing or drying, container cleaning, and application equipment
cleaning ("OECD. 2015). EPA did not identify information on engineering controls or worker PPE used
at DBP-containing adhesive and sealant sites.

ONUs include supervisors, managers, and other employees that work in the application area but do not
directly contact adhesives or sealants or handle or apply products. ONUs are potentially exposed via
inhalation to vapors while in the working area.

3.7.4.2	Occupational Inhalation Exposure Results

EPA identified 19 monitoring samples in NIOSH's HHE database (NIOSH. 1977). The source received
a rating of medium from EPA's systematic review process. Six of the samples were PBZ samples, and
the remaining 13 samples were area samples taken at various locations around an acrylic furniture
manufacturing site. The site uses 2-part adhesives where the part B component is 96.5 percent DBP.
Two of the area samples recorded values at the limit of detection, and the remaining 17 samples were
below the limit of detection. All samples were collected on AA cellulose membrane filters with 0.8|i
average pore size and a pump flow rate of 1 LPM. The detection limit was 0.01 mg/m3 by gas
chromatography. With all samples at or below the LOD, EPA assessed inhalation exposures as a range
from 0 to the LOD. EPA estimated the high-end exposure as equal to the LOD and the central tendency
as the midpoint {i.e., half the LOD).

In absence of data specific to ONU exposure, EPA assumed that worker central tendency exposure was
representative of ONU exposure and used this data to generate estimates for ONUs. EPA assessed the
exposure frequency as 250 days/year for both high-end and central tendency exposures based on the
expected operating days for the OES and accounting for off days for workers.

Table 3-46 summarizes the estimated 8-hour TWA concentration, AD, IADD, and ADD for worker
exposures to DBP during the use of adhesives and sealants. Appendix A describes the approach for
estimating AD, IADD, and ADD. The Draft Occupational Inhalation Exposure Monitoring Results for

Page 109 of 291


-------
2763

2764

2765

2766

2767

2768

2769

2770

2771

2772

2773

2774

2775

2776

2777

2778

2779

2780

2781

2782

2783

2784

2785

PUBLIC RELEASE DRAFT
May 2025

Dibutyl Phthalate (DBP) contains further information on the identified inhalation exposure data and
assumptions used in the assessment, refer to Appendix F for a reference to this supplemental document.

Table 3-46. Summary of Estimated Worker Inhalation Exposures for Application of Adhesives
and Sealants

Modeled Scenario

Exposure Concentration Type

Central
Tendency"

High-End"

Average Adult Worker

8-hour TWA Exposure Concentration (mg/m3)

5.0E-02

0.10

Acute Dose (AD) (mg/kg-day)

6.3E-03

1.3E-02

Intermediate Non-Cancer Exposures (IADD)
(mg/kg-day)

4.6E-03

9.2E-03

Chronic Average Daily Dose, Non-Cancer
Exposures (ADD) (mg/kg-day)

4.0E-03

8.6E-03

Female of Reproductive
Age

8-hour TWA Exposure Concentration (mg/m3)

5.0E-02

0.10

Acute Dose (AD) (mg/kg-day)

6.9E-03

1.4E-02

Intermediate Non-Cancer Exposures (IADD)
(mg/kg-day)

5.1E-03

1.0E-02

Chronic Average Daily Dose, Non-Cancer
Exposures (ADD) (mg/kg-day)

4.4E-03

9.5E-03

ONU

8-hour TWA Exposure Concentration (mg/m3)

5.0E-02

5.0E-02

Acute Dose (AD) (mg/kg-day)

6.3E-03

6.3E-03

Intermediate Non-Cancer Exposures (IADD)
(mg/kg-day)

4.6E-03

4.6E-03

Chronic Average Daily Dose, Non-Cancer
Exposures (ADD) (mg/kg-day)

4.0E-03

4.3E-03

a EPA used monitoring data for adhesive application as described by 19 monitoring samples in NIOSH's HHE
database CNIOSH, 1977). which received a ratine of medium from EPA's systematic review process. The Agency
estimated the high-end exposure as equal to the LOD and the central tendency as the midpoint (i.e., half the LOD).

3.7.4.3 Occupational Dermal Exposure Results

EPA estimated dermal exposures for this OES using the dermal approach outlined in Section 2.4.3 and
Appendix C. The various "Exposure Concentration Types" from Table 3-47 are explained in Appendix
A. Because there may be mist deposited on surfaces from this OES, dermal exposures to ONUs from
contact with mist on surfaces were assessed. In the absence of data specific to ONU exposure, EPA
assumed that worker central tendency exposure was representative of ONU exposure. For occupational
dermal exposure assessment, EPA assumed a standard 8-hour workday and the chemical is contacted at
least once per day. Because DBP has low volatility and relatively low absorption, it is possible that the
chemical remains on the surface of the skin after dermal contact until the skin is washed. So, in absence
of exposure duration data, EPA has assumed that absorption of DBP from occupational dermal contact
with materials containing DBP may extend up to 8 hours per day (	). However, if a

worker uses proper PPE or washes their hands after contact with DBP or DBP-containing materials
dermal exposure may be eliminated. Therefore, the assumption of an 8-hour exposure duration for DBP
may lead to overestimation of dermal exposure. Table 3-47 summarizes the APDR, AD, IADD, and
ADD for average adult workers, female workers of reproductive age, and ONUs. The Draft
Occupational Dermal Exposure Modeling Results for Dibutyl Phthalate (DBP) also contains
information about model equations and parameters and contains calculation results; refer to Appendix F
for a reference to this supplemental document.

Page 110 of 291


-------
PUBLIC RELEASE DRAFT
May 2025

2786

2787	Table 3-47. Summary of Estimated Worker Dermal Exposures for Application of Adhesives and

2788	Sealants

Modeled Scenario

Exposure Concentration Type

Central Tendency

High-End

Average Adult Worker

Dose Rate (APDR, mg/day)

100

201

Acute (AD, mg/kg-day)

1.3

2.5

Intermediate (IADD, mg/kg-day)

0.92

1.8

Chronic, Non-Cancer (ADD, mg/kg-day)

0.80

1.7

Female of Reproductive Age

Dose Rate (APDR, mg/day)

84

167

Acute (AD, mg/kg-day)

1.2

2.3

Intermediate (IADD, mg/kg-day)

0.85

1.7

Chronic, Non-Cancer (ADD, mg/kg-day)

0.73

1.6

ONU

8-hour TWA Exposure Concentration
(mg/m3)

100

100

Acute (AD, mg/kg-day)

1.3

1.3

Intermediate (IADD, mg/kg-day)

0.92

0.92

Chronic, Non-Cancer (ADD, mg/kg-day)

0.80

0.86

Note: For high-end estimates, EPA assumed the exposure surface area was equivalent to mean values for two-hand
surface areas {i.e., 1.070 cm2 for male workers and 890 cm2 for female workers) (U.S. EPA, 2011). For central
tendency estimates, EPA assumed the exposure surface area was equivalent to only a single hand (or one side of
two hands) and used half the mean values for two-hand surface areas (i.e., 535 cm2 for male workers and 445 cm2
for female workers).

2789

2790	3.7.4.4 Occupational Aggregate Exposure Results

2791	Inhalation and dermal exposure estimates were aggregated based on the approach described in Appendix

2792	A.3 to arrive at the aggregate worker and ONU exposure estimates in the table below. The assumption

2793	behind this approach is that an individual worker could be exposed by both the inhalation and dermal

2794	routes, and the aggregate exposure is the sum of these exposures.

2795

Page 111 of 291


-------
2796

2797

2798

2799

2800

2801

2802

2803

2804

2805

2806

2807

2808

2809

2810

2811

2812

2813

2814

2815

2816

2817

2818

2819

2820

2821

2822

2823

2824

PUBLIC RELEASE DRAFT
May 2025

Table 3-48. Summary of Estimated Worker Aggregate Exposures for Application of Adhesives
and Sealants

Modeled Scenario

Exposure Concentration Type (mg/kg-
day)

Central
Tendency

High-End

Average Adult Worker

Acute (AD, mg/kg-day)

1.3

2.5

Intermediate (IADD, mg/kg-day)

0.92

1.9

Chronic, Non-Cancer (ADD, mg/kg-day)

0.80

1.7

Female of Reproductive
Age

Acute (AD, mg/kg-day)

1.2

2.3

Intermediate (IADD, mg/kg-day)

0.85

1.7

Chronic, Non-Cancer (ADD, mg/kg-day)

0.74

1.6

ONU

Acute (AD, mg/kg-day)

1.3

1.3

Intermediate (IADD, mg/kg-day)

0.92

0.92

Chronic, Non-Cancer (ADD, mg/kg-day)

0.80

0.86

Note: A worker could be exposed by both the inhalation and dermal routes, and the aggregate exposure is the sum of
these exposures.

3.8 Application of Paints and Coatings

3,8,1 Process Description

EPA identified the use of DBP in paint and coating products for industrial and commercial use,
including floor coatings, polyvinyl acetate coatings, lacquers, varnishes, and paints and coatings used in
the building and construction industry (	320a). Liquid paint and coating products containing

DBP may arrive at end use sites in containers ranging in size from 5 to 20 gallons and at concentrations
ranging from 0.1 to 10 percent DBP (see Appendix E for EPA identified DBP-containing products for
this OES). The size of the container is an input to the Monte Carlo simulation to estimate releases but is
not used to calculate occupational exposures for DBP. For these products, the application site receives
the final formulation as a single-component paint/coating product.

The application site directly transfers the liquid product to the application equipment to apply the
coating to the substrate (OECD. 2015). The application procedure depends on the type of paint or
coating formulation and the type of substrate. Typically, the formulation is loaded into the application
reservoir or apparatus and applied to the substrate via brush, spray, roll, dip, curtain, or syringe or bead
application (OE<	). Application may be manual or automated. Manual spray equipment includes

air (e.g., low volume/high pressure), air-assisted, and airless spray systems (OECD. 201 I j, 2009c; U.S.

34d). End use sites may utilize spray booth capture technologies when performing spray
applications (OECD. 201 la). DBP will remain in the dried/cured coating as an additive following
application to the substrate. The drying/curing process may be promoted through the use of heat or
radiation (radiation can include ultraviolet (UV) and electron beam radiation) (OECD. 2010).

EPA assumes that use sites perform coating activities using spray application methods, as this is
expected to generate the highest release and exposure estimates. Applications may occur over the course
of a worker's 8-hour workday at a given site and may include multiple coats and time for drying or
curing (OECD. i ). Figure 3-9 provides an illustration of the spray application of paints and
coatings (OH 1ป :0l Li. b. :009c: I * n \ _pQ4d).

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1. Transfer Operation
Losses from Unloading

2. Open Surface Losses
to Air During Raw
Material Sampling
5. Process Releases
During Operation
8. Raw Material QA/QC

B. Exposure During
Container Cleaning

6. Equipment
Cleaning
7. Open Surface
Losses to Air During
Equipment Cleaning

Figure 3-9. Application of Paints and Coatings Flow Diagram
3.8.2 Facility Estimates

EPA estimated the total DBP production volume for paint and coating products using a uniform
distribution with a lower-bound of 99,157 kg/year and an upper-bound of 2,140,323 kg/year. This range
is based on DBP CDR data of site production volumes, national aggregate production volumes, and
percentages of the production volumes going to various industrial sectors (U.S. EPA. 2020a).

There were two reporters that reported to CDR for use of DBP in adhesive/sealant or paint/coating
products: G.J. Chemical Co, Inc. in Somerset, NJ, who reported a volume of 139,618 lb and MAK
Chemicals in Clifton, NJ, who reported a use volume of 105,884 lb of DBP. This equates to a total
known use volume of 245,502 lb of DBP; however, there is still a large portion of the aggregate PV
range for DBP that is not attached to a known use. A breakdown of the known production volume
information is provided in Table Apx D-7.

Due to uncertainty in the expected use of DBP, EPA assumes that the remaining PV with unknown use
is split between the use of adhesives and sealants and paint and coating products. Subtracting the PV
with known uses that are not associated with adhesives/sealants/paints/coatings from the aggregate
national PV range equates to a range of 99,157 to 2,140,323 kg for this OES (see Section D.4.3). EPA
used the range of production volumes as an input to the Monte Carlo modeling described in Appendix D
to estimate releases. The production volume range is not used to calculate occupational exposures for
DBP.

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EPA did not identify site- or chemical-specific paint and coating use operating data (e.g., facility use
rates). EPA based the facility use rate on the 2011 ESD on Radiation Curable Coatings, Inks and
Adhesives, the 2011 ESD on Coating Application via Spray-Painting in the Automotive Finishing
Industry, the 2004 GS on Spray Coatings in the Furniture Industry, and the European Council of the
Paint, Printing Ink, and Artist's Colours Industry (CEPE) SpERC Factsheet for Industrial Application of
Coatings and Inks by Spraying. The ESDs, GS, and SpERC estimated coating use rates of 946 to
446,600 kg/site-year. Based on a DBP concentration in liquid paints and coatings of 0.1 to 10 percent,
EPA estimated a DBP use rate of 0.95 to 44,660 kg/site-year. Additionally, the ESDs, GS, and SpERC
estimated the number of operating days as 225 to 300 days/year with 8 hour/day operations, while NEI
reporters indicated an average of 269 release days per year (ESIG. 2020a;

201 I j, b; 1 c< i i1 \ J004c). EPA identified 166 entries in the 2017 and 2020 NEI databases for air
releases from sites that were assumed to use adhesive/sealant or paint/coating products that contained
DBP; however, the product type used between these two groups was uncertain (U.S. EPA. 2019). EPA
identified 1 entry in the TRI database for air releases from sites that were assumed to use
adhesive/sealant or paint/coating products that contained DBP; however, the product type used between
these two groups was uncertain and, due to reporting thresholds, this estimate may not represent all
adhesive application sites (U.S. EPA. 2024a). Due to this uncertainty, EPA estimated the total number of
application sites that use DBP-containing paints and coatings using a Monte Carlo model (see Appendix
D.4 for details). The 50th to 95th percentile range of the number of sites was 219 to 2,660.

3.8.3 Release Assessment

3.8.3.1	Environmental Release Points

EPA assigned release points based on the 2011 ESD on Radiation Curable Coatings, Inks and Adhesives
(C	) and NEI (2020) and NEI (2017) data (	Ja,: ). The ESD identified

models to quantify releases from each release point for water, incineration, and landfill and NEI data for
air releases. EPA expects stack air releases from process releases during operation and fugitive air
releases from transfer operations, raw material sampling, container cleaning, and equipment cleaning.
EPA expects water, incineration, or landfill releases from container residue losses and sampling.
Releases to incineration or landfill are expected from equipment cleaning and process releases in
addition to fugitive air, water, incineration, or landfill releases from process releases during operation.

EPA modeled two scenarios, one where application sites use overspray control technologies and one
where no controls are used. Sites may utilize overspray control technology to prevent additional air
releases during spray application. If a site uses overspray control technology, EPA expects stack air
releases of approximately 10 percent of process related operational losses. EPA expects the site to
release the remaining 90 percent of operational losses to water, landfill, or incineration (OE<	).

If the site does not use control technology, EPA expects the site to release all process related operational
losses to fugitive air, water, incineration, or landfill in unknown percentages.

3.8.3.2	Environmental Release Assessment Results

Table 3-49 summarizes the number of release days and the annual and daily release estimates that were
modeled for each release media and scenario assessed for this OES. Table 3-50 presents fugitive and
stack air releases per year based on the TRI database along with the number of release days per year.
Table 3-51 presents fugitive and stack air releases per year and per day based on 2020 NEI database
along with the number of release days per year. Table 3-52 presents fugitive and stack air releases per
year and per day based on 2017 NEI database along with the number of release days per year. See
Appendix D.4.2 for additional details on model equations, and different parameters used for Monte
Carlo modeling. The Monte Carlo simulation calculated the total DBP release (by environmental media)

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across all release sources during each iteration of the simulation. EPA then selected 50th and 95th
percentile values to estimate the central tendency and high-end releases, respectively. The Draft
Application of Paints and Coatings OES Environmental Release Modeling Results for Dibutyl Phthalate
(DBP) contains additional information about model equations and parameters and contains calculation
results. The Draft Summary of Results for Identified Environmental Releases to Air for Dibutyl
Phthalate (DBP) contains additional information about identified air releases and their original sources,
refer to Appendix F for a reference to these supplemental documents.

Table 3-49. Summary of Modeled Environmental Releases for Application of Paints and Coatings

Modeled Scenario

Environmental

Annual Release
(kg/site-year)

Number of Release
Days

Daily Release6
(kg/site-day)

Media

Central
Tendency

High-
End

Central
Tendency

High-
End

Central
Tendency

High-
End



Fugitive Air

NEI/TRI data





NEI/ TRI Data



Stack Air

NEI/TRI data





NEI/TRI data

99,157-2,140,323
kg/year production

Water,

Incineration, or
Landfill17

72

206

257

287

0.28

0.80

volume (No Spray
Control)

Incineration or
Landfill17

92

368

0.36

1.4



Unknown (air,
water,

incineration, or
landfill)17

1,957

8,655





7.6

34



Fugitive Air

NEI/TRI data





NEI/TRI data

99,157-2,140,323
kg/year production
volume (Spray
Control)

Stack Air

NEI/TRI data





NEI/TRI data

Water,

Incineration, or
Landfill17

72

206

257

287

0.28

0.80

Incineration or
Landfill17

1,858

8,170





7.2

32

11 When multiple environmental media are addressed together, releases may go all to one media, or be split between
media depending on site-specific practices. Not enough data was provided to estimate the partitioning between
media.

h The Monte Carlo simulation calculated the total DBP release (by environmental media) across all release sources
during each iteration of the simulation. EPA then selected 50th and 95th percentile values to estimate the central
tendency and high-end releases, respectively.

Table 3-50. Summary of TRI Air Release Data for Application of Paints, Coatings, Adhesives and
Sealants

Site Identity

Maximum
Annual Fugitive
Air Release
(kg/year)

Maximum
Annual Stack
Air Release
(kg/year)

Annual
Release

Days
(days/yea
r)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum Daily

Stack Air
Release (kg/day)

Heytex- USA

0

0

250

0

0

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2907

2908	Table 3-51. Summary of NEI (2020) Air Releases for Application of Paints, Coatings, Adhesives

2909	and Sealants

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual
Stack Air
Release
(kg/year)

Annual
Release Days
(days/year)

Maximum

Daily
Fugitive Air
Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

Sikorsky Aircraft Corporation

N/A

9.8E-03

250

N/A

3.9E-05

Electric Boat Corp

0

36

250

0

0.14

FCA US LLC

N/A

67

250

N/A

0.27

Knud Nielsen (WAF)

64

N/A

250

0.25

N/A

Vulcraft Inc

N/A

0

250

N/A

0

George C Marshall Space Flight
Center

N/A

118

250

N/A

0.47

Tiffin Motor Homes Inc

290

N/A

250

1.16

N/A

Anacapa Boatyard

0.79

N/A

260

3.0E-03

N/A

Applied Aerospace Str Corp

N/A

0

260

N/A

0

Marine Group Boat Works LLC

5.0

N/A

190

2.6E-02

N/A

Fellowes Inc

N/A

61

250

N/A

0.25

Britt Industries

N/A

1.0E-02

250

N/A

4.2E-05

Textron Aviation - Independence

5.7

N/A

200

2.8E-02

N/A

Talaria Co., LLC

7.7

N/A

250

3.1E-02

N/A

Safe Harbor New England
Boatworks Inc.

1.5

N/A

250

6.1E-03

N/A

Gibson Guitar Custom Shop

N/A

13

250

N/A

5.0E-02

Crestwood Inc.

N/A

0

250

N/A

0

BAE Systems SDSR

1.0

N/A

250

4.2E-03

N/A

Ventura Harbor Boatyard Inc.

49

N/A

312

0.16

N/A

Ritz Craft Corp/Mifflinburg PLT

36

N/A

191

0.19

N/A

US Department of Energy Office
of Science, Oak Ridge National
Laboratory

N/A

0

250

N/A

0

Watco Transloading LLC

N/A

6.9

250

N/A

2.7E-02

Lockheed Martin Aeronautics
Company

3.0

N/A

350

8.7E-03

N/A

Hearne Maintenance Facility

122

N/A

365

0.33

N/A

North American Lighting Inc.

N/A

5.4

250

N/A

2.2E-02

Hallmark Cards - Lawrence

15

N/A

364

4.2E-02

N/A

Trinity Industries Plant 19

N/A

0

250

N/A

0

Gibson USA

N/A

10

250

N/A

4.0E-02

USAF Shaw Air Force Base

N/A

0

250

N/A

0

Thermo King Corporation

N/A

0.78

250

N/A

3.1E-03

The Boeing Company St. Louis

1.2

N/A

250

4.9E-03

N/A

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Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual
Stack Air
Release
(kg/year)

Annual
Release Days
(days/year)

Maximum

Daily
Fugitive Air
Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

Vulcraft - Division of Nucor
Corporation- Steel Products
Manufacturing

3.0

N/A

250

1.2E-02

N/A

Progress Rail Service - Electric
Fuels Corp

N/A

2.8

250

N/A

1.1E-02

Textron Aviation - West Campus

N/A

0

364

N/A

0

Textron Aviation - Pawnee
Campus

0.91

N/A

312

2.9E-03

N/A

Fort Hood

9.1E-02

N/A

260

3.5E-04

N/A

Island Park Fabrication Plant

9.1E-02

0

111

8.2E-04

0

US Air Force Plant 4

18

N/A

250

7.1E-02

N/A

Embraer Aircraft Maint Services,
Inc

N/A

1.9E-05

250

N/A

7.8E-08

Barber Cabinet Co Inc

N/A

59

250

N/A

0.24

Portsmouth Naval Shipyard -
Kittery

N/A

0

250

N/A

0

Wastequip Manufacturing Co

N/A

0

250

N/A

0

Quality Painting & Metal
Finishing Inc

N/A

0

250

N/A

0

Commercial Plastics Mora LLC

1.38

0

250

5.5E-03

0

HATCO

N/A

0

200

N/A

0

Raytheon Technologies

1.8E-02

N/A

250

7.3E-05

N/A

Electric Boat Corporation

0.66

N/A

250

2.6E-03

N/A

Chief Agri Industrial Products

1.8E-03

0

200

9.1E-06

0

Boeing Company St. Charles

N/A

3.2E-04

250

N/A

1.3E-06

Marvin Windows and Doors

N/A

0

250

N/A

0

Modern Design LLC

N/A

0

250

N/A

0

Progress Rail Service -
DeCoursey Car Shop

N/A

0

250

N/A

0

Caterpillar INC

0.36

N/A

250

1.5E-03

N/A

Kurz Transfer Products, LP

0

126

364

0

0.35

Northrop Grumman Systems
Corp. - BWI

0

5.6

260

0

2.1E-02

Bernhardt Furniture Company -
Plants 3&7

0

0.16

250

0

6.5E-04

Fleet Readiness Center East

0.57

60

364

1.6E-03

0.16

Kirtland Air Force Base

7.3E-02

N/A

364

2.0E-04

N/A

Maintenance Engineering Center

0.45

0

365

1.2E-03

0

Textron Aviation - East Campus

1.1

N/A

300

3.6E-03

N/A

3M Hutchinson

N/A

0

250

N/A

0

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Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual
Stack Air
Release
(kg/year)

Annual
Release Days
(days/year)

Maximum

Daily
Fugitive Air
Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

Swaim, Inc.

N/A

4.4E-06

250

N/A

1.7E-08

Hickory Chair, LLC

N/A

0

250

N/A

0

Ethan Allen Inc (Orleans Div )

N/A

0

250

N/A

0

Woodgrain Millwork Inc. -
Fruitland

N/A

0

250

N/A

0

Huntington Ingalls Inc, Ingalls
Shipbuil

80

N/A

250

0.32

N/A

Eudys Cabinet Manufacturing,
Inc.

62

0

250

0.25

0

Tektronix, Inc.

1.6

N/A

250

6.5E-03

N/A

Marine Corps Air Station -
Cherry Point

6.3E-03

33

364

1.7E-05

9.1E-02

Plastic Film Plant

1.8

0

365

5.0E-03

0

Spirit AeroSystems - Wichita

18

N/A

364

5.0E-02

N/A

Lockheed Martin Aeronautics
Company

N/A

4.5

312

N/A

1.4E-02

Cobham Advanced Electronics
Solutions Inc.

8.7E-05

N/A

270

3.2E-07

N/A

Nashville Custom Woodwork,
Inc.

N/A

2.7

250

N/A

1.1E-02

Apex Engineering - Wichita (W
2nd)

N/A

18

260

N/A

6.7E-02

Lewistown Cabinet Ctr/Milroy

N/A

3.0E-09

232

N/A

1.3E-11

University of Iowa

N/A

0

250

N/A

0

United Airlines IAH Airport

0.64

N/A

260

2.4E-03

N/A

Cabinotch, Inc.

N/A

64

250

N/A

0.25

Alstom Power Inc

N/A

60

250

N/A

0.24

Central Sandblasting Company

N/A

0

250

N/A

0

SHM LMC LLC

9.2

N/A

364

2.5E-02

N/A

Nautical Structures Industries,
Inc.

N/A

9.3

312

N/A

3.0E-02

Amcor Pharmaceutical Packaging
USA Inc

N/A

0

250

N/A

0

HME Inc.

N/A

0

280

N/A

0

Marine Corps Logistics Base

1409

N/A

365

3.9

N/A

Schenck Process - Sabetha

19

N/A

258

7.4E-02

N/A

P C Auto Body

0.79

N/A

260

3.0E-03

N/A

Freight Car America

N/A

0

250

N/A

0

The New York Blower Company

N/A

0

250

N/A

0

Eminence Speaker LLC

46

N/A

250

0.18

N/A

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Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual
Stack Air
Release
(kg/year)

Annual
Release Days
(days/year)

Maximum

Daily
Fugitive Air
Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

C & L Aerospace Holdings, LLC

N/A

0.72

250

N/A

2.9E-03

Teknicote

1.9

N/A

250

7.4E-03

N/A

The Boeing Company

0.38

N/A

365

1.1E-03

N/A

Premier Marine LLC

N/A

0

250

N/A

0

Curry Supply Co/Hollidaysburg

N/A

0

365

N/A

0

Phillips Diversified
Manufacturing (PDM) Inc

N/A

266

250

N/A

1.06

Kalitta Air, LLC

0.68

N/A

250

2.7E-03

N/A

Davis Tool, Inc.

N/A

0

250

N/A

0

2910

2911

Table 3-52. Summary of >

EI (2017) for Ap

plication of Paints, Coatings, Adhesives and Sealants

Site Identity

Maximum
Annual Fugitive
Air Release
(kg/year)

Maximum
Annual Stack
Air Release
(kg/year)

Annual
Release
Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

Ventura Harbor Marina &
Yacht Yard

0.77

N/A

250

3.1E-03

N/A

Bellport Anacapa Marine
Services

58

N/A

40

1.4

N/A

Naval Base Ventura County

1.1

N/A

250

4.2E-03

N/A

Eagle Wings Industries Inc

N/A

1.55

250

N/A

6.2E-03

Electronic Data Systems
North Island

6.0

N/A

250

2.4E-02

N/A

FIC America Corp

N/A

0

250

N/A

0

CE Niehoff & Co

N/A

13

250

N/A

5.2E-02

U.S. Postal Service- Mail
Facility

6.9

N/A

250

2.8E-02

N/A

Us Airways Maintenance
Base/Pgh

N/A

0

250

N/A

0

EL PASO DIVISION

N/A

0

250

N/A

0

New England Boatworks
Inc.

0.91

N/A

250

3.6E-03

N/A

American Shipyard LLC.

8.3

N/A

250

3.3E-02

N/A

Knapheide Manufacturing
Co

N/A

6.6

250

N/A

2.6E-02

Bae Systems San Diego Ship
Repair Inc

1.8

N/A

250

7.4E-03

N/A

Bill Stasek Chevrolet Inc

N/A

1.6

250

N/A

6.5E-03

GBW Railcar Services LLC

N/A

34

250

N/A

0.14

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Site Identity

Maximum
Annual Fugitive
Air Release
(kg/year)

Maxim um
Annual Stack
Air Release
(kg/year)

Annual
Release
Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

Lockheed Martin
Aeronautics Company
Palmdale

1.2

N/A

350

3.5E-03

N/A

West Refinery

2.7

N/A

250

1.1E-02

N/A

TTX Company

N/A

7.3E-03

208

N/A

3.5E-05

American NTN Bearing Mfg
Corp

N/A

0.16

250

N/A

6.6E-04

Stripmasters of Illinois

N/A

3.5

250

N/A

1.4E-02

Modern Welding Company
of Kentucky Inc -
Elizabethtown

N/A

0

250

N/A

0

Union Pacific Railroad Co
Desoto Car Shop

N/A

0

250

N/A

0

DFW Maintenance Facility

0.36

N/A

365

9.9E-04

N/A

United Parcel Service,
WorldPort

2.2

7.6E-03

250

8.9E-03

3.0E-05

Progress Rail Raceland Corp

N/A

0

250

N/A

0

Institutional Casework, Inc

N/A

0

250

N/A

0

Wastequip Manufacturing
Co LLC

N/A

0.67

250

N/A

2.7E-03

Litho Technical Services

N/A

18

250

N/A

7.1E-02

Delta Air Lines Inc -
Mpls/Saint Paul

N/A

58

250

N/A

0.23

Construction Materials/CMI
Coatings Group dba
Industrial Painting
Specialists

0.15

13

250

5.9E-04

5.1E-02

Crystal Cabinet Works Inc

0.11

106

250

4.3E-04

0.43

3M - Alexandria

N/A

0

250

N/A

0

Johnston Tombigbee
Furniture Company, Co

N/A

0

250

N/A

0

Knu LLC

N/A

0

250

N/A

0

Structural Steel Services Inc,
Plants 1

N/A

0

250

N/A

0

Harden Furniture Inc

N/A

0

250

N/A

0

General Motors LLC
Wentzville Center

N/A

0

250

N/A

0

Ford Motor Co

N/A

10

250

N/A

4.2E-02

Commercial Property LLC -
Carolina Heritage Cabinetry
Pit. 2

N/A

41

250

N/A

0.16

Caldwell Tanks

N/A

38

250

N/A

0.15

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Site Identity

Maximum
Annual Fugitive
Air Release
(kg/year)

Maxim um
Annual Stack
Air Release
(kg/year)

Annual
Release
Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

L & J G Stickley Inc

14

N/A

250

5.5E-02

N/A

Ethan Allen Operations, Inc.
- Pine Valley Division

N/A

0

250

N/A

0

Pompanoosuc Mills Corp

N/A

0

250

N/A

0

Hamilton Square Lenoir
Casegoods Plant

N/A

0

250

N/A

0

Panels, Services &
Components, Inc.

22

N/A

208

0.11

N/A

Fort Drum - US Military

N/A

617

250

N/A

2.47

HAECO Airframe Services,
LLC

7.2

0

364

2.0E-02

0

May-Craft Fiberglass
Products, Inc.

N/A

13

364

N/A

3.5E-02

Structural Coatings Inc. -
Clayton

N/A

0

312

N/A

0

Rockwell Collins, Inc.

N/A

0

365

N/A

0

Manchester Wood Inc

N/A

0

250

N/A

0

Wabash National Corp

N/A

0

250

N/A

0

Lexington Furniture
Industries - Plant No. 15

N/A

38

250

N/A

0.15

SPEAR USA

N/A

2.8E-02

250

N/A

1.1E-04

Knapheide Truck Equipment
Co

N/A

199

250

N/A

0.80

Piedmont Composites and
Tooling, LLC

N/A

0

200

N/A

0

UPM Raflatac Inc Dixon IL

N/A

0

250

N/A

0

Phills Custom Cabinets

N/A

3.6E-04

250

N/A

1.5E-06

Kellex Corporation, Inc. -
Morganton Facility

N/A

0

250

N/A

0

CRP LMC PROP CO., LLC

3.1

N/A

364

8.5E-03

N/A

Ornamental Products, LLC

N/A

0

250

N/A

0

Leggett & Piatt, Inc. - Metal
Bed Rail

2233

N/A

260

8.59

N/A

Century Furniture - Plant
No. 2

N/A

0

250

N/A

0

Mickelson Body Shop

N/A

32

250

N/A

0.13

Premier Marine Inc

N/A

0

250

N/A

0

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3,8,4 Occupational Exposure Assessment

3.8.4.1	Worker Activities

During the use of DBP-containing paints and coatings, workers are potentially exposed to DBP mist
from overspray inhalation during spray coating. Workers may be exposed via inhalation of vapors or
dermal contact to liquids containing DBP during product unloading into application equipment, brush
and trowel applications, raw material sampling, and container and equipment cleaning (OEC	).

EPA did not find information on the extent to which engineering controls and worker PPE are used at
facilities that use DBP-containing paints and coatings.

For this OES, ONUs would include supervisors, managers, and other employees that do not directly
handle paint or coating equipment but may be present in the application area. ONUs are potentially
exposed through the inhalation of mist or vapor and dermal contact with surfaces where mist has been
deposited.

3.8.4.2	Occupational Inhalation Exposure Results

EPA identified two full-shift PBZ monitoring samples in OSHA's CEHD from two different inspections
one from 201 1 of a fabric coating mill and one from a janitorial services company (OSHA. 1 ). The
OSHA CEHD database received a rating of high from EPA's systematic review process. The Agency
additionally found 12 8-hour TWA monitoring samples during systematic review completed by Rohm
and Haas Co. (Rohm and Haas. 1990). The study received a rating of low from EPA's systematic review
process. With a total of 14 data points, EPA characterized the data by taking the 95th percentile and the
50th percentile of the combined dataset to represent the high-end and central tendency. There was no
ONU-specific exposure data and EPA assumed that worker central tendency exposure is representative
of ONU exposure. Therefore, worker central tendency exposure values from spray application were
assumed representative of ONU inhalation exposure to the same.

Table 3-53 summarizes the estimated 8-hour TWA concentration, AD, IADD, and ADD for worker
exposures to DBP from unloading and mixing the solid DBP-containing component of a paint and
coating and the spray application of liquid paints and coatings. The high-end exposures use 250 days per
year as the exposure frequency since the 95th percentile of operating days in the release assessment
exceeded 250 days per year, which is the expected maximum for working days. The central tendency
exposures use 232 days per year as the exposure frequency based on the 50th percentile of operating
days from the release assessment. Appendix A describes the approach for estimating AD, IADD, and
ADD. The dataset is expected to characterize all potential exposure routes, including any dust, mist, and
vapor exposures. The Draft Occupational Inhalation Exposure Monitoring Results for Dibutyl Phthalate
(DBP) contains further information on the identified inhalation exposure data and assumptions used in
the assessment, refer to Appendix F for a reference to this supplemental document.

Table 3-53. Summary of Estimated Worker Inhalation Exposures for Application of Paints and
Coatings 			

Modeled
Scenario

Exposure Concentration Type

Central
Tendency"

High-
End"

Average

Adult

Worker

8-hour TWA Exposure Concentration (mg/m3)

0.83

5.2

Acute Dose (AD) (mg/kg-day)

0.10

0.66

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

7.6E-02

0.48

Chronic Average Daily Dose, Non-Cancer Exposures (ADD) (mg/kg-
day)

7.1E-02

0.45

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Modeled
Scenario

Exposure Concentration Type

Central
Tendency"

High-
End"

Female of

Reproductive

Age

8-hour TWA Exposure Concentration (mg/m3)

0.83

5.2

Acute Dose (AD) (mg/kg-day)

0.11

0.72

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

8.4E-02

0.53

Chronic Average Daily Dose, Non-Cancer Exposures (ADD) (mg/kg-
day)

7.8E-02

0.50

ONU

8-hour TWA Exposure Concentration (mg/m3)

0.83

0.83

Acute Dose (AD) (mg/kg-day)

0.10

0.10

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

7.6E-02

7.6E-02

Chronic Average Daily Dose, Non-Cancer Exposures (ADD) (mg/kg-
day)

7.1E-02

7.1E-02

a EPA identified two full-shift PBZ monitoring samples in OSHA's Chemical Exposure Health Data database
COSH A, 2019). The study received a ratine of high from EPA's systematic review process. The Agency additionally
found 12 8-hour TWA monitoring samples during systematic review completed bv Rohm and Haas Co CRohm and
Haas, 1990). The study received a rating of low from EPA's systematic review process. With a total of 14 data
points, EPA characterized the data by taking the 95th percentile and the 50th percentile of the combined dataset to
represent the high-end and central tendency.

3.8.4.3 Occupational Dermal Exposure Results

EPA estimated dermal exposures for this OES using the dermal approach outlined in Section 2.4.3 and
Appendix C. The various "Exposure Concentration Types" from Table 3-54 are explained in Appendix
A. Since there may be mist deposited on surfaces from this OES, dermal exposures to ONUs from
contact with mist on surfaces were assessed. In the absence of data specific to ONU exposure, EPA
assumed that worker central tendency exposure was representative of ONU exposure. For occupational
dermal exposure assessment, EPA assumed a standard 8-hour workday and the chemical is contacted at
least once per day. Because DBP has low volatility and relatively low absorption, it is possible that the
chemical remains on the surface of the skin after dermal contact until the skin is washed. So, in absence
of exposure duration data, EPA has assumed that absorption of DBP from occupational dermal contact
with materials containing DBP may extend up to 8 hours per day (	). However, if a

worker uses proper personal protective equipment (PPE) or washes their hands after contact with DBP
or DBP-containing materials dermal exposure may be eliminated. Therefore, the assumption of an 8-
hour exposure duration for DBP may lead to overestimation of dermal exposure. Table 3-54 summarizes
the APDR, AD, IADD, and ADD for average adult workers, female workers of reproductive age, and
ONUs. The Draft Occupational Dermal Exposure Modeling Results for Dibutyl Phthalate (DBP) also
contains information about model equations and parameters and contains calculation results; refer to
Appendix F for a reference to this supplemental document.

Table 3-54. Summary of Estimated Worker Dermal Exposures for Application of Paints and
Coatings				

Modeled Scenario

Exposure Concentration Type

Central
Tendency

High-
End

Average Adult Worker

Dose Rate (APDR, mg/day)

100

201

Acute (AD, mg/kg-day)

1.3

2.5

Intermediate (IADD, mg/kg-day)

0.92

1.8

Chronic, Non-Cancer (ADD, mg/kg-day)

0.86

1.7



Dose Rate (APDR, mg/day)

84

167

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Modeled Scenario

Exposure Concentration Type

Central
Tendency

High-
End

Female of Reproductive
Age

Acute (AD, mg/kg-day)

1.2

2.3

Intermediate (IADD, mg/kg-day)

0.85

1.7

Chronic, Non-Cancer (ADD, mg/kg-day)

0.79

1.6

ONU

Dose Rate (APDR, mg/day)

75

75

Acute Dose (AD) (mg/kg/day)

0.94

0.94

Intermediate Average Daily Dose, Non-Cancer
Exposures (IADD) (mg/m3)

0.69

0.69

Chronic Average Daily Dose, Non-Cancer Exposures
(ADD) (mg/kg/day)

0.64

0.64

Note: For high-end estimates, EPA assumed the exposure surface area was equivalent to mean values for two-hand
surface areas (i.e., 1.070 cm2 for male workers and 890 cm2 for female workers) (U.S. EPA, 2011). For central
tendency estimates, EPA assumed the exposure surface area was equivalent to only a single hand (or one side of two
hands) and used half the mean values for two-hand surface areas (i.e., 535 cm2 for male workers and 445 cm2for
female workers).

3.8.4.4 Occupational Aggregate Exposure Results

Inhalation and dermal exposure estimates were aggregated based on the approach described in Appendix
A.3 to arrive at the aggregate worker and ONU exposure estimates in the table below. The assumption
behind this approach is that an individual worker could be exposed by both the inhalation and dermal
routes, and the aggregate exposure is the sum of these exposures.

Table 3-55. Summary of Estimated Worker Aggregate Exposures for Application of Paints and
Coatings				

Modeled Scenario

Exposure Concentration Type (mg/kg-
day)

Central
Tendency

High-End

Average Adult Worker

Acute (AD, mg/kg-day)

1.4

3.2

Intermediate (IADD, mg/kg-day)

1.0

2.3

Chronic, Non-Cancer (ADD, mg/kg-day)

0.93

2.2

Female of Reproductive Age

Acute (AD, mg/kg-day)

1.3

3.0

Intermediate (IADD, mg/kg-day)

0.93

2.2

Chronic, Non-Cancer (ADD, mg/kg-day)

0.87

2.1

ONU

Acute (AD, mg/kg-day)

1.0

1.0

Intermediate (IADD, mg/kg-day)

0.76

0.76

Chronic, Non-Cancer (ADD, mg/kg-day)

0.71

0.71

Note: A worker could be exposed by both the inhalation and dermal routes, and the aggregate exposure is the sum of
these exposures.

3.9 Industrial Process Solvent Use

3.9.1 Process Description

In 2015, Huntsman International LLC reported their industrial use of DBP as a solvent in their maleic
anhydride manufacturing technology. DBP acts as a processing agent and does not itself participate in
the reactions that lead to the formation of maleic anhydride, it is also incorporated into the maleic
anhydride product (Huntsman. 2015).

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2991

2992

2993

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2995

2996

2997

2998

2999

3000

3001

3002

3003

3004

3005

3006

3007

3008

3009

3010

3011

3012

3013

3014

3015

3016

3017

3018

3019

3020

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3022

3023

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3025

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PUBLIC RELEASE DRAFT
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Huntsman International LLC uses DBP as an absorption solvent in the manufacture of maleic anhydride
at two facilities in the U.S.: Pensacola, FL and Geismar, LA. The total production of maleic anhydride
across both sites accounts for 47 percent of the maleic anhydride capacity in North America. Dibutyl
phthalate is supplied to the sites via intermodal containers, each with a capacity of 45,000 lb. Two
containers per month are typically supplied and unloaded at the Pensacola facility while one container
per month is typically unloaded at the Geismar facility. The content of the container is sampled before
unloading and a lab analysis is performed to verify the container content (Huntsman. 2015).

Dibutyl phthalate is unloaded by pressuring the container with nitrogen from a top vent line. Unloading
is either accomplished using a dip tube or by attaching a flexible hose to a valve on the container and
piping it out. The Pensacola operation has an unloading pump to assist with the movement of DBP while
the Geismar operation relies on the pressure from the nitrogen pad. In both instances, the intermodal
container chassis is tilted so that all of the DBP contents are removed from the container and unloaded
into on-site storage tanks. The piping is blown free and clear with nitrogen before the hoses are
disconnected. All the container openings are confirmed to be wrench tight and all caps are secured
before the container is released. Empty intermodal containers are returned to the supplier for cleaning
and disposal of residues (Huntsman. 2015).

To manufacture maleic anhydride, normal butane vapor is mixed with compressed air and is fed to a
multiple tube reactor which contains a solid vanadium pyrophosphate catalyst. In the presence of the
catalyst, normal butane is converted to maleic anhydride by reacting with the oxygen present in the air.
While most of the normal butane is reacted to form maleic anhydride, some residual normal butane
remains in the product gas from the reactor. This reaction is highly exothermic and produces high
pressure steam as a significant byproduct of the process (Huntsman. 2015).

The hot product gas from the reactor is cooled and then fed to an absorber column with DBP which is
used to absorb maleic anhydride from the reactor product gas. This is achieved by feeding DBP solvent
from the top of the absorber while reactor product gas containing maleic anhydride is simultaneously fed
from the bottom. The DBP-maleic anhydride solvent mixture from the bottom of the absorber is routed
to a stripping column where the maleic anhydride is recovered from the DBP solvent. A portion of the
stripped DBP solvent is fed to a solvent treater to remove undesirable impurities from the circulating
solvent. The treated DBP solvent, along with the remainder of the DBP from the bottom of the stripping
column, is recycled back to the top of the absorber (Huntsman. 2015).

The aqueous waste stream from the solvent treater, which contains the DBP decomposition product
phthalic acid, is disposed of by deep well injection. Crude maleic anhydride from the stripping column is
further purified in a refining column. When the product gas exits the top of the absorber, essentially all
of the maleic anhydride has been absorbed from the product gas. Undesirable components of the product
gas, such as water, are not absorbed and exit the absorber at the top. The product gas, from which
essentially all of the maleic anhydride has been absorbed, is then routed to an incinerator or boiler.
Unreacted butane and other components are incinerated to produce additional energy in the form of
steam (Huntsman. 2015).

Figure 3-10 provides an overview of the industrial solvent use process.

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C. Exposure During	Cleaning Releases

Container Cleaning	6- Open Surface

Losses During
Equipment Cleaning

Figure 3-10. Industrial Process Solvent Use

3.9.2	Facility Estimates

In the NEI (	; , ), DMR ( s r	),'and TRI ( il;; ) data that

EPA analyzed, EPA identified that two sites reported releases of DBP from its use as an industrial
solvent in maleic anhydride production, while one additional site reported this use in CDR with their PV
reported as CBI. Huntsman International, LLC operates two maleic anhydride manufacturing sites and
estimated that one 45,000 lb container of DBP was used at one of their sites per month, while the other
site would use two containers per month. Throughput and use rates from other processing sites are
unknown. In the NEI air release data, two sites reported 250 operating days per year. TRI/DMR (U.S.

Ma, e) datasets do not report operating days; therefore, EPA assumed 250 days/year of
operation as discussed in Section 2.3.2.

3.9.3	Release Assessment

3.9.3.1	Environmental Release Points

Based on TRI and NEI data, industrial process solvent use releases may go to stack air, fugitive air and
additional releases may occur from transfers of wastes to off-site treatment facilities (assessed in the
Waste handling, treatment, and disposal OES) (\ v < < \ jL 2023a. 201 * ). EPA assumed that there
are no releases to water for this OES in general. Land releases were assessed using data for the
Incorporation into formulation, mixture, or reaction product OES.

3.9.3.2	Environmental Release Assessment Results

Table 3-56 presents fugitive and stack air releases per year and per day based on 2017 to 2022 TRI
database along with the number of release days per year, with medians and maxima presented from
aacross the 6-year reporting range. Table 3-57 presents fugitive and stack air releases per year and per
day based on 2020 NEI database along with the number of release days per year. Table 3-58 presents
land releases per year based on the TRI database along with the number of release days per year based

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3058	on surrogate data from the Incorporation into formulation, mixture, or reaction product OES. EPA

3059	assumed that there may be potential land releases from industrial process solvent use, but releases from

3060	facilities may not include releases to land. No data was reported for water releases for the Industrial

3061	process solvent use OES. Based on the identified process details and description of the use of DBP, EPA

3062	assumed that there are no releases to water for this use. The Draft Summary of Results for Identified

3063	Environmental Releases to Air for Dibutyl Phthalate (DBP) and Draft Summary of Results for Identified

3064	Environmental Releases to Landfor Dibutyl Phthalate (DBP) contain additional information about these

3065	identified releases and their original sources; refer to Appendix F for a reference to these supplemental

3066	documents.

3067

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Table 3-56. Summary ol

'Air Releases from TRI for Industria

Process Solvent Use

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual Stack
Air Release
(kg/year)

Median
Annual
Fugitive Air
Release
(kg/year)

Median
Annual
Stack Air
Release
(kg/year)

Annual
Release
Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

Median
Daily
Fugitive Air
Release
(kg/day)

Median
Daily Stack
Air Release
(kg/day)

Ascend Performance
Materials Operations LLC

180

122

180

74

250

1.6

1.1

0.30

0.66

3069

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3073

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3075

3076

3077

3078

3079

3080

3081

3082

3083

3084

3085

3086

3087

3088

3089

3090

3091

3092

3093

3094

3095

3096

3097

3098

3099

3100

3101

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Table 3-57. Summary of Air Releases from NEI (2020) for Industrial Process Solvent Use

Site Identity

Maxim um

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual Stack
Air Release
(kg/year)

Annual
Release
Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

Ascend Performance Materials
Operations

180

192

250

0.72

0.77

Lanxess Corp Baytown

182

0

250

0.73

0

Table 3-58. Summary of Land Releases from TRI for Industrial Process Solvent Use
Incorporation into Formulation, Mixture, or Reaction Product)		

Site Identity

Median Annual
Release (kg/year)

Maximum Annual
Release (kg/year)

Annual Release
Days (days/year)

St. Marks Powder Inc.

510

723

250

Rubicon LLC

2,629

1.0E04

250

Century Industrial Coatings Inc.

2.7

552

250

3.9.4 Occupational Exposure Assessment

3.9.4.1	Workers Activities

During industrial process solvent use, worker exposures to DBP occur when transferring DBP from
transport containers into process vessels. Worker exposures also occur via inhalation of vapor or dermal
contact with liquid when cleaning transport containers, loading and unloading DBP, sampling, and
cleaning equipment. EPA did not find any information on the extent to which engineering controls and
worker PPE are used at facilities that use DBP in industrial process solvents.

ONUs include employees (e.g., supervisors, managers) that work at the import site where repackaging
occurs but do not directly handle DBP. Therefore, EPA expects ONUs to have lower inhalation
exposures and dermal exposures than workers.

3.9.4.2	Occupational Inhalation Exposure Results

EPA did not identify inhalation monitoring data for use of industrial solvents from systematic review of
literature sources. DBP is imported and manufactured as a liquid, per CDR, and EPA assessed worker
inhalation exposures to DBP vapor during the unloading and loading processes. EPA used DBP
manufacturing monitoring data to estimate inhalation exposures. EPA identified inhalation monitoring
data from three risk evaluations, however, each study only presents a single aggregate or final data point
during manufacturing of DBP. In the first source, the Syracuse Research Corporation indicates that
"following a review of six studies, the American Chemistry Council has estimated exposure to di-n-
butyl phthalate in the workplace based upon an assumed level of 1 mg/m3 in the air during the
production of phthalates." (SRC. 2001). The second source, a risk evaluation of 1,3,4,6,7,8-Hexahydro-
4,6,6,7,8,8-hexamethylcyclopenta-g-2-benzopyran (HHCB) conducted by European Commission, Joint
Research Centre (ECJRC) presented an 8-hour TWA aggregate exposure concentration for DBP of
0.003 ppm (n = 114) for a DBP manufacturing site (ECB. 2008). The third source, a risk evaluation of
DBP also conducted by the ECJRC provides seven separate datasets from two unnamed manufacturers.
Of these datasets six did not include a sampling method and were not used. Only one had sufficiently
detailed metadata (e.g., exposure duration, sample type) to include in this assessment; an 8-hour TWA

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3103

3104

3105

3106

3107

3108

3109

3110

3111

3112

3113

3114

3115

3116

3117

3118

3119

3120

3121

3122

3123

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worker exposure concentration to DBP of 0.5 mg/m3 from DBP production (ECB. 2004). With three
aggregate or final concentration value from three sources, EPA could not create a full distribution of
monitoring results to estimate central tendency and high-end exposures. To assess the high-end worker
exposure to DBP during the manufacturing process, EPA used the maximum available value (1 mg/m3).
The Agency assessed the midpoint of the three available values as the central tendency (0.5 mg/m3). All
three sources of monitoring data received a rating of medium from EPA's systematic review process.

Table 3-3 summarizes the estimated 8-hour TWA concentration, AD, IADD, and ADD for worker
exposures to DBP during manufacture. In absence of data specific to ONU exposure, EPA assumed that
worker central tendency exposure was representative of ONU exposure and used this data to generate
estimates for ONUs. The central tendency and high-end exposures use 250 days per year as the exposure
frequency, which is the expected maximum for working days. Appendix A describes the approach for
estimating AD, IADD, and ADD. The Draft Occupational Inhalation Exposure Monitoring Results for
Dibutyl Phthalate (DBP) contains further information on the identified inhalation exposure data and
assumptions used in the assessment, refer to Appendix F for a reference to this supplemental document.

Table 3-59. Summary of Estimated Worker Inhalation Exposures for Industrial Process Solvent
Use

Modeled Scenario

Exposure Concentration Type

Central
Tendency"

High-End"

Average Adult
Worker

8-hour TWA Exposure Concentration (mg/m3)

0.50

1.0

Acute Dose (AD) (mg/kg-day)

6.3E-02

0.13

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

4.6E-02

9.2E-02

Chronic Average Daily Dose, Non-Cancer Exposures
(ADD) (mg/kg-day)

4.3E-02

8.6E-02

Female of
Reproductive Age

8-hour TWA Exposure Concentration (mg/m3)

0.50

1.0

Acute Dose (AD) (mg/kg-day)

6.9E-02

0.14

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

5.1E-02

0.10

Chronic Average Daily Dose, Non-Cancer Exposures
(ADD) (mg/kg-day)

4.7E-02

9.5E-02

ONU

8-hour TWA Exposure Concentration (mg/m3)

0.50

0.50

Acute Dose (AD) (mg/kg-day)

6.3E-02

6.3E-02

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

4.6E-02

4.6E-02

Chronic Average Daily Dose, Non-Cancer Exposures
(ADD) (mg/kg-day)

4.3E-02

4.3E-02

a EPA identified surrogate inhalation monitoring data from three sources to estimate exposures for this OES (ECB,
2008. 2004; SRC, 2001). All three sources of monitoring data received a rating of medium from EPA's systematic
review process. With the three discrete data points, EPA could not create a full distribution of monitoring results to
estimate central tendency and high-end exposures. To assess the high-end worker exposure to DBP during the
manufacturing process, EPA used the maximum available value (1 mg/m3). EPA assessed the midpoint of the three
available values as the central tendency (0.5 mg/m3).

3.9.4.3 Occupational Dermal Exposure Results

EPA estimated dermal exposures for this OES using the dermal approach outlined in Section 2.4.3 and
Appendix C. The various "Exposure Concentration Types" from Table 3-60 are explained in Appendix
A. ONU dermal exposures are not assessed for this OES as there are no activities expected to expose
ONUs to DBP liquid. For occupational dermal exposure assessment, EPA assumed a standard 8-hour
workday and the chemical is contacted at least once per day. Because DBP has low volatility and

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relatively low absorption, it is possible that the chemical remains on the surface of the skin after dermal
contact until the skin is washed. So, in absence of exposure duration data, EPA has assumed that
absorption of DBP from occupational dermal contact with materials containing DBP may extend up to 8
hours per day (	). However, if a worker uses proper PPE or washes their hands after

contact with DBP or DBP-containing materials dermal exposure may be eliminated. Therefore, the
assumption of an 8-hour exposure duration for DBP may lead to overestimation of dermal exposure.
Table 3-60 summarizes the APDR, AD, IADD, and ADD for average adult workers, female workers,
and ONUs. The Draft Occupational Dermal Exposure Modeling Results for Dibutyl Phthalate (DBP)
also contains information about model equations and parameters and contains calculation results; refer
to Appendix F for a reference to this supplemental document.

Table 3-60. Summary of Estimated Worker Dermal Exposures for Industrial Process Solvent Use

Modeled Scenario

Exposure Concentration Type

Central Tendency

High-End



Dose Rate (APDR, mg/day)

100

201

Average Adult Worker

Acute (AD, mg/kg-day)

1.3

2.5

Intermediate (IADD, mg/kg-day)

0.92

1.8



Chronic, Non-Cancer (ADD, mg/kg-day)

0.86

1.7



Dose Rate (APDR, mg/day)

84

167

Female of

Acute (AD, mg/kg-day)

1.2

2.3

Reproductive Age

Intermediate (IADD, mg/kg-day)

0.85

1.7



Chronic, Non-Cancer (ADD, mg/kg-day)

0.79

1.6

Note: For high-end estimates, EPA assumed the exposure surface area was equivalent to mean values for two-hand
surface areas (i.e., 1.070 cm2 for male workers and 890 cm2 for female workers) (U.S. EPA, 2011). For central

tendency estimates, EPA assumed the exposure surface area was equivalent to only a single hand (or one side of two
hands) and used half the mean values for two-hand surface areas (i.e., 535 cm2 for male workers and 445 cm2 for

female workers).







3.9.4.4 Occupational Aggregate Exposure Results

Inhalation and dermal exposure estimates were aggregated based on the approach described in Appendix
A to arrive at the aggregate worker and ONU exposure estimates in Table 3-61 below. The assumption
behind this approach is that an individual worker could be exposed by both the inhalation and dermal
routes, and the aggregate exposure is the sum of these exposures.

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Table 3-61. Summary of Estimated Worker Aggregate Exposures for Industrial Process Solvent
Use

Modeled Scenario

Exposure Concentration Type (mg/kg-
day)

Central
Tendency

High-End

Average Adult Worker

Acute (AD, mg/kg-day)

1.3

2.6

Intermediate (IADD, mg/kg-day)

0.97

1.9

Chronic, Non-Cancer (ADD, mg/kg-day)

0.90

1.8

Female of Reproductive Age

Acute (AD, mg/kg-day)

1.2

2.5

Intermediate (IADD, mg/kg-day)

0.90

1.8

Chronic, Non-Cancer (ADD, mg/kg-day)

0.84

1.7

ONU

Acute (AD, mg/kg-day)

6.3E-02

6.3E-02

Intermediate (IADD, mg/kg-day)

4.6E-02

4.6E-02

Chronic, Non-Cancer (ADD, mg/kg-day)

4.3E-02

4.3E-02

Note: A worker could be exposed by both the inhalation and dermal routes, and the aggregate exposure is the sum of
these exposures.

3.10 Use of Laboratory Chemicals

3,10,1 Process Description

Multiple products identified in the Use Report for DBP confirm that DBP is used as a laboratory
chemical (see Appendix E for EPA identified DBP-containing products for this OES). One industry
commenter reported the use of DBP in laboratory use including such applications as analytical
standards, research, equipment calibration, sample preparation and as a component of a variety of other
common off the shelf materials, including anti-seize compound (U.S. EPA-HQ-OPPT-2018-0503-0035).
EPA identified relevant SDS that indicate laboratory chemicals containing DBP in a concentration of 0.1
to 10 percent for liquid products or concentrations from 0.3 to 20 percent for solids.

EPA did not identify DBP-specific laboratory procedures. Based on the 2023 GS on Laboratory
Chemicals, EPA expects laboratory chemicals containing DBP to arrive at end use sites in 1-gallon
bottles for liquid chemicals or in 1 kg containers for solids based on a 1 L container and a density of 1
kg/L (	23d). The size of the container is an input to the Monte Carlo simulation to estimate

releases but is not used to calculate occupational exposures for DBP. EPA expects the end use site to
transfer the chemical to labware and lab equipment for analyses. After analysis, laboratory sites clean
containers, labware, and lab equipment and dispose of laboratory waste and unreacted DBP-containing
laboratory chemicals. Figure 3-1 1 provides an illustration of the use of laboratory chemicals (U.S. EPA.
2023d)-

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1.	Transport Container

Transfer Releases
(Liquids only)

2.	Transport Container

Transfer Dust Releases	7. Laboratory Analyses	8. Lab Waste Disposal

(Solids only)	Releases (Liquids Only)	Releases

T	~

B. Exposure During	5. Labware

Container Cleaning	Equipment Cleaning

6, Labware
Equipment Cleaning
Releases to Air
(Liquids Only)

Figure 3-11. Use of Laboratory Chemicals Flow Diagram (U.S. EPA, 2023d)

3.10.2 Facility Estimates	

No sites reported to CDR for use of DBP in laboratory chemicals. EPA estimated the total production
volume (PV) for all sites of 215,415 lb/year (97,710 kg/year) that was estimated based on the reporting
requirements for CDR. The threshold for CDR reporters requires a site to report processing and use for a
chemical if the usage exceeds 5 percent of its reported PV or if the use exceeds 25,000 lb per year. For
the 12 sites that reported to CDR for the manufacture or import of DBP, EPA assumed that each site
used DBP for laboratory chemicals in volumes up to the reporting threshold limit of 5 percent of their
reported PV. If 5 percent of each site's reported PV exceeds the 25,000 lb reporting limit, EPA assumed
the site used only 25,000 lb annually as an upper-bound. If the site reported a PV that was CBI, EPA
assumed the maximum PV contribution of 25,000 lb. The CDR sites and their PV contributions to this
OES are shown in Table Apx D-13.

EPA did not identify site- or chemical-specific operating data for laboratory use of DBP (i.e., facility
throughput). For solid products, the 2023 GS on The Use of Laboratory Chemicals provides an
estimated throughput of 0.33 kg/site-day for solid laboratory chemicals (U.S. EPA. 2023d). Based on the
concentration of DBP in the laboratory chemical of 0.3 to 20 percent, EPA estimated a daily facility use
rate using Monte Carlo modeling, resulting in a 50th to 95th percentile range of 1.2><10"2 to 5.3xlO"2
kg/site-day. For liquid products, the 2023 GS provided an estimated throughput of 0.5 to 4,000 mL/site-
day for liquid laboratory chemicals (U.S. EPA. 2023 d). Based on the concentration of DBP in liquid
laboratory chemicals of 0.1 to 10 percent, (see Appendix E for EPA identified DBP-containing products
for this OES) and the DBP density of 1.0 kg/L, EPA estimated a daily facility use rate of laboratory
chemicals using Monte Carlo modeling, resulting in a 50th to 95th percentile range of 4.8x 10~2 to 0.22

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kg/site-day. Additionally, the GS estimated the number of operating days as 174 to 260 days/year, with
8 to 12 hours/day operations (II	2023d). This range of operating days was used for the modeled

releases, while the two NEI sites both reported 365 release days per year.

Two laboratories reported air releases in the 2020 NEI; however, there were no other reported releases
from laboratories, and it is unlikely that only two laboratories in the United States use products that
contain DBP. Therefore, EPA estimated the total number of sites that use DBP-containing laboratory
chemicals using a Monte Carlo model (see Appendix D for details). Both the 50th and 95th percentile
results for the number of sites were the bounding estimate of 36,873 for the liquid use case. For the solid
use case, the 50th to 95th percentile range of the number of sites was 1,978 to 25,643.

3,10,3 Release Assessment

3.10.3.1	Environmental Release Points

EPA assigned release points based on the 2023 GS on the Use of Laboratory Chemicals (

2023d) and based on NEI and TRI data (\ ^ \ 2024e. 2023a. :01 <"). In the solid laboratory
chemical use case, EPA expects sites to release dust emissions from transferring powders containing
DBP to stack or fugitive air, water, incineration, or landfill. In both liquid and solid use cases, EPA
expects water, incineration, or landfill releases from container cleaning wastes, labware equipment
cleaning wastes, and laboratory waste disposal.

3.10.3.2	Environmental Release Assessment Results

Table 3-62 summarizes the number of release days and the annual and daily release estimates that were
modeled for each release media and scenario assessed for this OES. Table 3-63 presents fugitive and
stack air releases per year and per day based on 2020 NEI database along with the number of release
days per year. The GS identified models to quantify releases from each release point for water,
incineration and landfill, and NEI data provided air emissions data, so modeled air emissions are not
presented. Laboratory sites may use a combination of solid and liquid laboratory chemicals, but for
release modeling, EPA assumed each site used either the liquid or solid form (not both) of the DBP-
containing laboratory chemical. See Appendix D.5.2 for additional details on model equations and
parameters. The Draft Use of Laboratory Chemicals OES Environmental Release Modeling Results for
Dibutyl Phthalate (DBP) contains additional information about model equations and parameters and
contains calculation results. The Draft Summary of Results for Identified Environmental Releases to Air
for Dibutyl Phthalate (DBP) contains additional information about identified air releases and their
original sources, refer to Appendix F for a reference to these supplemental documents.

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3224 Table 3-62. Summary of Modeled Environmental Releases for Use of Laboratory Chemicals

Modeled
Scenario

Environmental
Media

Annual Release
(kg/site-year)

Number of Release
Days

Daily Release
(kg/site-day)''

Central
Tendency

High-
End

Central High-
Tendency End

Central
Tendency

High-
End

97,710 kg/year
production volume

Liquid Laboratory
Chemicals

Fugitive Air

NEI data

365

NEI data

Water, Incineration, or
Landfilla

17

80

4.8E-02

0.22

97,710 kg/year
production volume

Solid Laboratory
Chemicals

Fugitive Air

NEI data

365

NEI data

Unknown Media (Air,
Water, Incineration, or
Landfill)a

1.5E-02

0.11

4.0E-05

2.9E-04

Water, Incineration, or
Landfilla

4.3

19

1.2E-02

5.2E-02

Incineration or
Landfilla

1.9E-02

0.13

5.3E-05

3.5E-04

a When multiple environmental media are addressed together, releases may go all to one media, or be split between
media depending on site-specific practices. Not enough data was provided to estimate the partitioning between
media.

''For the modeling releases, the Monte Carlo simulation calculated the total DBP release (by environmental media)
across all release sources during each iteration of the simulation. EPA then selected 50th and 95th percentile values
to estimate the central tendency and high-end releases, respectively.

3225

3226

Table 3-63. Summary of NEI (2020) for Use of Laboratory Chemica

s

Site Identity

Maximum
Annual Fugitive
Air Release
(kg/year)

Maximum
Annual Stack
Air Release
(kg/year)

Annual
Release
Days
(days/year)

Maximum
Daily Fugitive
Air Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

University of California
Merced

1.2E-02

N/A

364

3.4E-05

N/A

Los Alamos National
Laboratory

2.7

N/A

365

7.5E-03

N/A

3228

3229	3,10,4 Occupational Exposure Assessment

3230	3.10.4.1 Worker Activities

3231	Worker exposures to DBP may occur through the inhalation of solid powders while unloading and

3232	transferring laboratory chemicals and during laboratory analysis. Dermal exposure to liquid and solid

3233	chemicals may occur during laboratory chemical unloading, container cleaning, labware equipment

3234	cleaning, laboratory analysis, and disposal of laboratory wastes (	2023d). EPA did not find

3235	information on the extent to which laboratories that use DBP-containing chemicals also use engineering

3236	controls and worker PPE.

3237

3238	ONUs include supervisors, managers, and other employees that do not directly handle the laboratory

3239	chemical or laboratory equipment but may be present in the laboratory or analysis area. ONUs are

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potentially exposed through the inhalation route while in the laboratory area from airborne dust and
through the dermal route from contact with surfaces where dust has been deposited.

3.10.4.2 Occupational Inhalation Exposure Results

EPA did not identify inhalation monitoring data for the use of laboratory chemicals during systematic
review. DBP is present in solid and liquid laboratory chemicals. EPA assessed potential for worker and
ONU inhalation to dust from solid laboratory chemicals and vapor from liquid laboratory chemicals. No
vapor inhalation exposure data was found, and EPA used data from the adhesives and sealants OES as a
surrogate data source due to the expected similarity in usage and concentrations. Assumption has been
made that laboratory workers use the chemicals on the benchtop similar to the usage of adhesives. The
adhesives and sealant data consists of 19 monitoring samples in a NIOSH HHE (NIQSB ), which
received a rating of medium from EPA's systematic review process. Six of the samples were PBZ
samples, and the remaining 13 samples were area samples taken at various locations around an acrylic
furniture manufacturing site. With all samples at or below the LOD, EPA assessed inhalation exposures
as a range from zero to the LOD. EPA estimated the high-end exposure as equal to the LOD and the
central tendency as the midpoint {i.e., half the LOD).

To estimate worker and ONU inhalation exposure to dust for the use of solid laboratory chemicals, EPA
used the PNOR Model (	21b). Model approaches and parameters are detailed in Appendix

D. EPA used a subset of the model data that came from facilities with the NAICS code starting with 54
- Professional, Scientific, and Technical Services - to estimate DBP-containing particulate
concentrations in the air. EPA used the highest expected concentration of DBP to estimate the
concentration of DBP in particulates. For the Use of laboratory chemicals OES, the highest expected
concentration of DBP is 20 percent by mass based on identified lab-grade chemicals. The estimated
exposures assume that DBP is present in particulates at this fixed concentration throughout the working
shift.

The Generic Model for Central Tendency and High-End Inhalation Exposure to Total and Respirable
Particulates Not Otherwise Regulated (PNOR)(I	2021b) estimates an 8-hour TWA for

particulate concentrations by assuming exposures outside the sample duration are zero. The model does
not determine exposures during individual worker activities. For both vapor and dust exposures EPA
used the number of operating days estimated in the release assessment for this OES to estimate exposure
frequency, which is the expected maximum number of working days. EPA assessed the exposure
frequency as 250 days/year for both high-end and central tendency exposures based on the expected
operating days for the OES and accounting for off days for workers. In absence of data specific to ONU
exposure, EPA assumed that worker central tendency exposure is representative of ONU exposure and
were used to generate estimates for ONUs.

Table 3-64 summarizes the estimated 8-hour TWA concentration, AD, IADD, and ADD for worker
exposures to DBP during the use of solid laboratory chemicals. Appendix A describes the approach for
estimating AD, IADD, and ADD. The estimated exposures assume that the worker is exposed to DBP in
the form of particulates or vapors. The Draft Occupational Inhalation Exposure Monitoring Results for
Dibutyl Phthalate (DBP) contains further information on the identified inhalation exposure data,
information on the PNOR Model parameters used, and assumptions used in the assessment; refer to
Appendix F for a reference to this supplemental document.

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3285	Table 3-64. Summary of Estimated Worker Inhalation Exposures for Use of Laboratory

3286	Chemicals

Modeled Scenario

Exposure Concentration Type

Central
Tendency"

High-
End"

Average Adult Worker
- Solids

8-hour TWA Exposure Concentration (mg/m3)

3.8E-02

0.54

Acute Dose (AD) (mg/kg-day)

4.8E-03

6.8E-02

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

3.5E-03

5.0E-02

Chronic Average Daily Dose, Non-Cancer Exposures
(ADD) (mg/kg-day)

3.3E-03

4.6E-02

Female of Reproductive
Age - Solids

8-hour TWA Exposure Concentration (mg/m3)

3.8E-02

0.54

Acute Dose (AD) (mg/kg-day)

5.2E-03

7.5E-02

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

3.8E-03

5.5E-02

Chronic Average Daily Dose, Non-Cancer Exposures
(ADD) (mg/kg-day)

3.6E-03

5.1E-02

ONU - Solids

8-hour TWA Exposure Concentration (mg/m3)

3.8E-02

3.8E-02

Acute Dose (AD) (mg/kg-day)

4.8E-03

4.8E-03

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

3.5E-03

3.5E-03

Chronic Average Daily Dose, Non-Cancer Exposures
(ADD) (mg/kg-day)

3.3E-03

3.3E-03

Average Adult Worker
- Liquids

8-hour TWA Exposure Concentration (mg/m3)

5.0E-02

0.10

Acute Dose (AD) (mg/kg-day)

6.3E-03

1.3E-02

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

4.6E-03

9.2E-03

Chronic Average Daily Dose, Non-Cancer Exposures
(ADD) (mg/kg-day)

4.3E-03

8.6E-03

Female of Reproductive
Age - Liquids

8-hour TWA Exposure Concentration (mg/m3)

5.0E-02

0.10

Acute Dose (AD) (mg/kg-day)

6.9E-03

1.4E-02

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

5.1E-03

1.0E-02

Chronic Average Daily Dose, Non-Cancer Exposures
(ADD) (mg/kg-day)

4.7E-03

9.5E-03

ONU - Liquids

8-hour TWA Exposure Concentration (mg/m3)

5.0E-02

5.0E-02

Acute Dose (AD) (mg/kg-day)

6.3E-03

6.3E-03

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

4.6E-03

4.6E-03

Chronic Average Daily Dose, Non-Cancer Exposures
(ADD) (mg/kg-day)

4.3E-03

4.3E-03

a EPA used surrogate monitoring data for adhesive application as described by 19 monitoring samples in NIOSH's
HHE database CNIOS ). which received a ratine of medium from EPA's systematic review process. The
Agency estimated the high-end exposure as equal to the LOD and the central tendency as the midpoint (i.e., half the
LOD). For the PNOR Model, EPA multiplied the concentration of DBP with the central tendency and HE estimates of
the relevant NAICS code from the PNOR Model to calculate the central tendency and HE estimates for this OES.

3287	3.10.4.3 Occupational Dermal Exposure Results

3288	EPA estimated dermal exposures for this OES using the dermal approach outlined in Section 2.4.3 and

3289	Appendix C. The various "Exposure Concentration Types" from Table 3-65 are explained in Appendix

3290	A. For solid laboratory chemicals, since there may be dust deposited on surfaces from this OES, dermal

3291	exposures to ONUs from contact with dust on surfaces were assessed. In the absence of data specific to

3292	ONU exposure, EPA assumed that worker central tendency exposure was representative of ONU

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exposure. For occupational dermal exposure assessment, EPA assumed a standard 8-hour workday and
the chemical is contacted at least once per day. Because DBP has low volatility and relatively low
absorption, it is possible that the chemical remains on the surface of the skin after dermal contact until
the skin is washed. So, in absence of exposure duration data, EPA has assumed that absorption of DBP
from occupational dermal contact with materials containing DBP may extend up to 8 hours per day
(	). However, if a worker uses proper personal protective equipment (PPE) or washes

their hands after contact with DBP or DBP-containing materials dermal exposure may be eliminated.
Therefore, the assumption of an 8-hour exposure duration for DBP may lead to overestimation of dermal
exposure. Table 3-65 summarizes the APDR, the AD, the IADD, and the ADD for average adult
workers, female workers of reproductive age, and ONUs. The Draft Occupational Dermal Exposure
Modeling Results for Dibutyl Phthalate (DBP) also contains information about model equations and
parameters and contains calculation results; refer to Appendix F for a reference to this supplemental
document.

Table 3-65. Summary of Estimated Worker Dermal Exposures for Use of Laboratory Chemicals

Modeled Scenario

Exposure Concentration Type

Central
Tendency

High-
End

Average Adult Worker - Solid

Dose Rate (APDR, mg/day)

1.4

2.7

Acute (AD, mg/kg-day)

1.7E-02

3.4E-02

Intermediate (IADD, mg/kg-day)

1.2E-02

2.5E-02

Chronic, Non-Cancer (ADD, mg/kg-day)

1.2E-02

2.3E-02

Female of Reproductive Age - Solid

Dose Rate (APDR, mg/day)

1.1

2.3

Acute (AD, mg/kg-day)

1.7E-02

3.1E-02

Intermediate (IADD, mg/kg-day)

1.1E-02

2.3E-02

Chronic, Non-Cancer (ADD, mg/kg-day)

1.1E-02

2.1E-02

ONU - Solid

Dose Rate (APDR, mg/day)

1.4

1.4

Acute (AD, mg/kg-day)

1.9E-02

1.9E-02

Intermediate (IADD, mg/kg-day)

1.4E-02

1.4E-02

Chronic, Non-Cancer (ADD, mg/kg-day)

1.3E-02

1.3E-02

Average Adult Worker - Liquid

Dose Rate (APDR, mg/day)

75

201

Acute (AD, mg/kg-day)

0.94

2.5

Intermediate (IADD, mg/kg-day)

0.69

1.8

Chronic, Non-Cancer (ADD, mg/kg-day)

0.64

1.7

Female of Reproductive Age - Liquid

Dose Rate (APDR, mg/day)

62

167

Acute (AD, mg/kg-day)

0.86

2.3

Intermediate (IADD, mg/kg-day)

0.63

1.7

Chronic, Non-Cancer (ADD, mg/kg-day)

0.59

1.6

Note: For high-end estimates, EPA assumed the exposure surface area was equivalent to mean values for two-hand
surface areas (i.e., 1.070 cm2 for male workers and 890 cm2 for female workers) (U.S. EPA, 2011). For central
tendency estimates, EPA assumed the exposure surface area was equivalent to only a single hand (or one side of two
hands) and used half the mean values for two-hand surface areas (i.e., 535 cm2 for male workers and 445 cm2for
female workers).

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3.10.4.4 Occupational Aggregate Exposure Results

Inhalation and dermal exposure estimates were aggregated based on the approach described in Appendix
A.3 to arrive at the aggregate worker and ONU exposure estimates in the table below. The assumption
behind this approach is that an individual worker could be exposed by both the inhalation and dermal
routes, and the aggregate exposure is the sum of these exposures.

Table 3-66. Summary of Estimated Worker Aggregate Exposures for Use of Laboratory
Chemicals

Worker Population

Exposure Concentration Type

Central Tendency

High-End

Average Adult Worker - Solid

Acute (AD, mg/kg-day)

2.2E-02

0.10

Intermediate (IADD, mg/kg-day)

1.6E-02

7.4E-02

Chronic, Non-Cancer (ADD, mg/kg-day)

1.5E-02

6.9E-02

Female of Reproductive Age -
Solid

Acute (AD, mg/kg-day)

2.1E-02

0.11

Intermediate (IADD, mg/kg-day)

1.5E-02

7.8E-02

Chronic, Non-Cancer (ADD, mg/kg-day)

1.4E-02

7.2E-02

ONU - Solid

Acute (AD, mg/kg-day)

2.2E-02

2.2E-02

Intermediate (IADD, mg/kg-day)

1.6E-02

1.6E-02

Chronic, Non-Cancer (ADD, mg/kg-day)

1.5E-02

1.5E-02

Average Adult Worker -
Liquid

Acute (AD, mg/kg-day)

0.94

2.5

Intermediate (IADD, mg/kg-day)

0.69

1.9

Chronic, Non-Cancer (ADD, mg/kg-day)

0.65

1.7

Female of Reproductive Age -
Liquid

Acute (AD, mg/kg-day)

0.87

2.3

Intermediate (IADD, mg/kg-day)

0.64

1.7

Chronic, Non-Cancer (ADD, mg/kg-day)

0.59

1.6

ONU - Liquid

Acute (AD, mg/kg-day)

6.3E-03

6.3E-03

Intermediate (IADD, mg/kg-day)

4.6E-03

4.6E-03

Chronic, Non-Cancer (ADD, mg/kg-day)

4.3E-03

4.3E-03

Note: A worker could be exposed by both the inhalation and dermal routes, and the aggregate exposure is the sum of
these exposures.

3.11 Use of Lubricants and Functional Fluids

3.11.1 Process Description	

DBP is used as a functional fluid for processes in printing and related support activities and is also used
as a lubricant such as textile fiber lubricant in industrial processes (see Appendix E for EPA identified
DBP-containing products for this OES). A typical end use site unloads the lubricant/functional fluid
when ready for changeout (OECD. 2004b). Sites incorporate the product into the system with a
frequency ranging from once every 3 months to once every 5 years. After changeout, sites clean the

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transport containers and equipment and dispose of used fluid. Figure 3-12 provides an illustration of the
expected use of lubricants and functional fluids process (OECD. 2004b).

1. Transport Container	3, Releases During	5. Disposal Releases

B. Exposure During	4. Equipment

Container Cleaning	Cleaning Releases

Figure 3-12. Use of Lubricants and Functional Fluids Flow Diagram

3,11,2 Facility Estimates

No sites reported to CDR for use of DBP in lubricants or functional fluids. EPA estimated the total
production volume (PV) for all sites assuming a static value of 215,415 lb/year (97,710 kg/year) that
was estimated based on the reporting requirements for CDR. The threshold for CDR reporters requires a
site to report processing and use for a chemical if the usage exceeds 5 percent of its reported PV or if the
use exceeds 25,000 lb per year. For the 12 sites that reported to CDR for the manufacture or import of
DBP, EPA assumed that each site used DBP for lubricants or functional fluids in volumes up to the
reporting threshold limit of 5 percent of their reported PV. If 5 percent of each site's reported PV
exceeds the 25,000 lb reporting limit, EPA assumed the site used only 25,000 lb annually as an upper-
bound. If the site reported a PV that was CBI, EPA assumed the maximum PV contribution of 25,000 lb.
The CDR sites and their PV contributions to this OES are shown in Table Apx D-13.

EPA did not identify site- or DBP-specific lubricant and functional fluid use operating data (e.g., facility
use rates, operating days). However, based on the 2004 ESD on Lubricants and Lubricant Additives,
EPA assumed a product throughput equivalent to one container per lubricant/functional fluid changeout
(OECD. 2004bY

The ESD provides an estimate of 1 to 4 changeouts per year for different types of lubricant/functional
fluids, and EPA assumed each changeout occurs over the course of 1 day. Based on this relationship, the
EPA assessed 1 to 4 operating days per year. Based on this operating day distribution, the 50th and 95th
percentile range of the resulting DBP use rate was 14 to 47 kg/site-year. EPA did not identify any
estimates of the number of sites that may use lubricants/functional fluids containing DBP. Therefore,
EPA estimated the total number of sites that use DBP-containing lubricants/functional fluids using a

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Monte Carlo model (see Appendix D.6 for details). The 50th to 95th percentile range of the number of
sites was 3,337 to 39,808 sites.

3,11,3 Release Assessment

3.11.3.1	Environmental Release Points

EPA assigned release points based on the 2004 ESD on Lubricants and Lubricant Additives (OECD.
2004b). EPA assigned models to quantify releases from each release point. EPA expects releases to
wastewater or landfill during the use of equipment. Releases to wastewater, landfill, recycling, and
incineration during the changeout of lubricants and functional fluids are expected.

3.11.3.2	Environmental Release Assessment Results

Table 3-67 summarizes the number of release days and the annual and daily release estimates that were
modeled for each release media and scenario assessed for this OES. See Appendix D.6.2 for additional
details on model equations and, and different parameters used for used for Monte Carlo modeling. The
Monte Carlo simulation calculated the total DBP release (by environmental media) across all release
sources during each iteration of the simulation. EPA then selected 50th and 95th percentile values to
estimate the central tendency and high-end releases, respectively. The Draft Use of Lubricants and
Functional Fluids OES Environmental Release Modeling Results for Dibutyl Phthalate (DBP) also
contains additional information about model equations and parameters and contains calculation results;
refer to Appendix F for a reference to this supplemental document.

Table 3-67. Summary of Modeled Environmental Releases for Use of Lubricants and Functional
Fluids





Annual Release

Number of Release

Daily Release"

Modeled

Environmental

(kg/site-year)

Days

(kg/site-day)

Scenario

Media

Central
Tendency

High-End

Central
Tendency

High-End

Central
Tendency

High-End



Land

6.4

35





3.0

13

97,710 kg/year

Water

15

74





6.8

26

production

Recycling

0.22

1.7

2

4

0.11

0.62

volume

Fuel Blending
(Incineration)

5.0

37





2.3

14

a The Monte Carlo simulation calculated the total DBP release (by environmental media)

across all release sources

during each iteration of the simulation. EPA then selected 50th and 95th percentile values to estimate the central

tendency and high-end releases, respectively.











3.11.4 Occupational Exposure Assessment

3.11.4.1 Worker Activities

Workers are potentially exposed to DBP from lubricant and functional fluid use when unloading
lubricants and functional fluids from transport containers, during changeout and removal of used
lubricants and functional fluids, and during any associated equipment or container cleaning activities.
Workers may be exposed via inhalation of DBP vapors or dermal contact with liquids containing DBP.
EPA did not identify chemical-specific information for engineering controls and worker PPE used at
facilities that perform changeouts of lubricants or functional fluids.

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ONUs include supervisors, managers, and other employees that may be in the area when changeouts
occur but do not perform changeout tasks. ONUs are potentially exposed via inhalation but have no
expected dermal exposure.

3.11.4.2 Occupational Inhalation Exposure Results

EPA did not identify inhalation monitoring data for use of lubricants and functional fluids during
systematic review of literature sources. However, EPA estimated inhalation exposures for this OES
using monitoring data for DBP exposures during the application of adhesives and sealants. EPA expects
that inhalation exposures during the application of adhesives and sealants are similar to inhalation
exposures expected during use of lubricants and functional fluids and serve as reasonable surrogate.

EPA used surrogate monitoring data for adhesive application as described by 19 monitoring samples in
NIOSH's HHE database (NIOSH. 1977). which received a rating of medium from EPA's systematic
review process. Six of the samples were PBZ samples, and the remaining 13 samples were area samples
taken at various locations around an acrylic furniture manufacturing site. The site uses 2-part adhesives
where the part B component is 96.5 percent DBP. EPA assessed inhalation exposures as a range from 0
to the LOD. EPA estimated the high-end exposure as equal to the LOD and the central tendency as the
midpoint (i.e., half the LOD).

Table 3-68 summarizes the estimated 8-hour TWA concentration, AD, IADD, and ADD for worker
exposures to DBP during use of lubricants and functional fluids. The high-end exposures use 4 days per
year as the exposure frequency based on the 95th percentile of operating days from the release
assessment. The central tendency exposures use two days per year as the exposure frequency based on
the 50th percentile of operating days from the release assessment. In absence of data specific to ONU
exposure, EPA assumed that worker central tendency exposure was representative of ONU exposure and
used this data to generate estimates for ONUs. Appendix A describes the approach for estimating AD,
IADD, and ADD. The Draft Occupational Inhalation Exposure Monitoring Results for Dibutyl
Phthalate (DBP) contains further information on the identified inhalation exposure data and assumptions
used in the assessment, refer to Appendix F for a reference to this supplemental document.

Table 3-68. Summary of Estimated Worker Inhalation Exposures for Use of Lubricants and
Functional Fluids

Modeled
Scenario

Exposure Concentration Type

Central
Tendency"

High-
End"

Average Adult
Worker

8-hour TWA Exposure Concentration (mg/m3)

5.0E-02

0.10

Acute Dose (AD) (mg/kg-day)

6.3E-03

1.3E-02

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

4.2E-04

1.7E-03

Chronic Average Daily Dose, Non-Cancer Exposures (ADD) (mg/kg-
day)

3.4E-05

1.4E-04

Female of

Reproductive

Age

8-hour TWA Exposure Concentration (mg/m3)

5.0E-02

0.10

Acute Dose (AD) (mg/kg-day)

6.9E-03

1.4E-02

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

4.6E-04

1.8E-03

Chronic Average Daily Dose, Non-Cancer Exposures (ADD) (mg/kg-
day)

3.8E-05

1.5E-04

ONU

8-hour TWA Exposure Concentration (mg/m3)

5.0E-02

5.0E-02

Acute Dose (AD) (mg/kg-day)

6.3E-03

6.3E-03

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

4.2E-04

8.3E-04

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Modeled
Scenario

Exposure Concentration Type

Central
Tendency"

High-
End"



Chronic Average Daily Dose, Non-Cancer Exposures (ADD) (mg/kg-
day)

3.4E-05

6.8E-05

a EPA used surrogate monitoring data for adhesive application as described by 19 monitoring samples in NIOSH's
HHE database CNIOS ). which received a ratine of medium from EPA's systematic review process. The
Agency estimated the high-end exposure as equal to the LOD and the central tendency as the midpoint (i.e., half the
LOD).

3.11.4.3 Occupational Dermal Exposure Results

EPA estimated dermal exposures for this OES using the dermal approach outlined in Section 2.4.3 and
Appendix C. For occupational dermal exposure assessment, EPA assumed a standard 8-hour workday
and the chemical is contacted at least once per day. Because DBP has low volatility and relatively low
absorption, it is possible that the chemical remains on the surface of the skin after dermal contact until
the skin is washed. So, in absence of exposure duration data, EPA has assumed that absorption of DBP
from occupational dermal contact with materials containing DBP may extend up to 8 hours per day
(	). However, if a worker uses proper PPE or washes their hands after contact with DBP

or DBP-containing materials dermal exposure may be eliminated. Therefore, the assumption of an 8-
hour exposure duration for DBP may lead to overestimation of dermal exposure. The various "Exposure
Concentration Types" from Table 3-69 are explained in Appendix A. Table 3-69 summarizes the APD),
AD, the IADD, and the ADD for both average adult workers and female workers of reproductive age.
Because there is no dust or mist expected to be deposited on surfaces from this OES, dermal exposures
to ONUs from contact with surfaces were not assessed. Dermal exposure parameters are described in
Appendix C. The Draft Occupational Dermal Exposure Modeling Results for Dibutyl Phthalate (DBP)
also contains information about model equations and parameters and contains calculation results; refer
to Appendix F for a reference to this supplemental document.

Table 3-69. Summary of Estimated Worker Dermal Exposures for Use of Lubricants and
Functional Fluids

Worker Population

Exposure Concentration Type

Central
Tendency

High-End

Average Adult Worker

Dose Rate (APDR, mg/day)

56

169

Acute (AD, mg/kg-day)

0.70

2.1

Intermediate (IADD, mg/kg-day)

4.7E-02

0.28

Chronic, Non-Cancer (ADD, mg/kg-day)

3.8E-03

2.3E-02

Female of
Reproductive Age

Dose Rate (APDR, mg/day)

47

140

Acute (AD, mg/kg-day)

0.65

1.9

Intermediate (IADD, mg/kg-day)

4.3E-02

0.26

Chronic, Non-Cancer (ADD, mg/kg-day)

3.5E-03

2.1E-02

Note: For high-end estimates, EPA assumed the exposure surface area was equivalent to mean values for two-hand
surface areas (i.e., 1.070 cm2 for male workers and 890 cm2 for female workers) (U.S. EPA, 2011). For central
tendency estimates, EPA assumed the exposure surface area was equivalent to only a single hand (or one side of two
hands) and used half the mean values for two-hand surface areas (i.e., 535 cm2 for male workers and 445 cm2 for
female workers).

3.11.4.4 Occupational Aggregate Exposure Results

Inhalation and dermal exposure estimates were aggregated based on the approach described in Appendix
A.3 to arrive at the aggregate worker and ONU exposure estimates in the table below. The assumption

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behind this approach is that an individual worker could be exposed by both the inhalation and dermal
routes, and the aggregate exposure is the sum of these exposures.

Table 3-70. Summary of Estimated Worker Aggregate Exposures for Use of Lubricants and
Functional Fluids

Modeled Scenario

Exposure Concentration Type (mg/kg-
day)

Central
Tendency

High-End

Average Adult Worker

Acute (AD, mg/kg-day)

0.71

2.1

Intermediate (IADD, mg/kg-day)

4.7E-02

0.28

Chronic, Non-Cancer (ADD, mg/kg-day)

3.9E-03

2.3E-02

Female of Reproductive Age

Intermediate (IADD, mg/kg-day)

0.65

1.9

Chronic, Non-Cancer (ADD, mg/kg-day)

4.3E-02

0.26

Chronic, Cancer (LADD, mg/kg-day)

3.6E-03

2.1E-02

ONU

Acute (AD, mg/kg-day)

6.3E-03

6.3E-03

Chronic, Non-Cancer (ADD, mg/kg-day)

4.2E-04

8.3E-04

Chronic, Cancer (LADD, mg/kg-day)

3.4E-05

6.8E-05

Note: A worker could be exposed by both the inhalation and dermal routes, and the aggregate exposure is the sum of
these exposures.

3.12 Use of Penetrants and Inspection Fluids

3.12,1 Process Description	

One comment from industry identified the commercial use of DBP in inspection penetrant kits;
however, EPA was unable to identify any penetrants or inspection fluid products that contained DBP
(U.S. EPA-HQ-OPPT-2018-0503-0036). According to the ESD on metalworking fluids, concentrations
of additives can range from less than one percent to less than 80 percent (ซ	). EPA assessed

aerosol-based penetrants and non-aerosol penetrants as separate processes with unique release points.
EPA expects that sites receive aerosol penetrants in 0.082-gallon containers based on a 10.5-oz aerosol
product can and non-aerosol penetrants in bottles, cans, or drums, ranging in size from 0.082 to 55
gallons, with the maximum container size based on the ESD default for drums and the minimum based
on a 10.5-oz aerosol product can (	). The size of the container is an input to the Monte

Carlo simulation to estimate releases but is not used to calculate occupational exposures.

The site transfers the non-aerosol penetrant from transport containers into process vessels and applies
the product using brushing and/or immersion. EPA expects that non-aerosol penetrant application occurs
over the course of an 8-hour workday A typical site that uses aerosol penetrants receives cans of
penetrant and an operator sprays the aerosol penetrant and disposes of the used aerosol can. EPA expects
the operator to apply the aerosol in non-steady, instantaneous bursts at the start of each job, and allow
the penetrant to remain on the surface as it reveals defects before eventually wiping it away. EPA
expects that the penetrant product is self-contained and does not require transfer or cleaning from
shipping containers or application equipment for this OES. Figure 3-13 and Figure 3-14 provide
illustrations of the use of inspection fluids or penetrants for the non-aerosol and aerosol use cases
respectively ("OECD. 2011c).

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1, Transport Container
Transfer Releases

7. Disposal Releases

B. Exposure During
Container Cleaning

3464

3465

3466

4. Equipment Cleaning
5. Open Surface Losses to
Air During Equipment
Cleaning

Figure 3-13. Use of Penetrants and Inspection Fluids Flow Diagram Non-Aerosol Use (OECD.
2 )

6. Aerosol
Application Releases







2, Container Residue

Container

Losses "*

Cleaning











Receive
Penetrant at Site
in Spray Cans

	~

Aerosol
Application



Disposal of Used
Penetrant







+

D. Exposure During
Application



3467

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B. Exposure During
Container Cleaning

Figure 3-14. Use of Penetrants and Inspection Fluids Flow Diagram Aerosol Use ( IIP. 2011c)

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3.12.2	Facility Estimates

No sites reported to CDR for use of DBP in penetrants or inspection fluids. EPA estimated the total
production volume (PV) for all sites assuming a static value of 215,415 lb/year (97,710 kg/year) that
was estimated based on the reporting requirements for CDR. The threshold for CDR reporters requires a
site to report processing and use for a chemical if the usage exceeds 5 percent of its reported PV or if the
use exceeds 25,000 lb per year. For the 12 sites that reported to CDR for the manufacture or import of
DBP, EPA assumed that each site used DBP for penetrants or inspection fluids in volumes up to the
reporting threshold limit of 5 percent of their reported PV. If 5 percent of each site's reported PV
exceeds the 25,000 lb reporting limit, EPA assumed the site used only 25,000 lb annually as an upper-
bound. If the site reported a PV that was CBI, EPA assumed the maximum PV contribution of 25,000 lb.
The CDR sites and their PV contributions to this OES are show in Table Apx D-13.

EPA did not identify site- or DBP-specific inspection fluid/penetrant site operating data {i.e., batch size
or number of batches per year) from systematic review; therefore, EPA assessed the daily DBP facility
throughput of 1.81><10~2to 3,62/ 10 2 kg/site-day based on a penetrant product throughput of eight 10.5-
oz cans per day (1 can of product per hour), and a concentration of DBP in inspection fluid/penetrant
products of 10 to 20 percent based on the concentration of DINP in penetrants (Appendix F of the
Environmental Release and Occupational Exposure Assessment for Diisononyl Phthalate (DINP) (U.S.
E 24b). EPA assessed the number of operating days using the 2011 ESD on the Use of
Metalworking Fluids, which cites general averages for facilities with a range of 246 to 249 operating
days/year of 8 hour/day, 5 days/week operations up to the operating days for the given site throughput
scenario (OECD. 2011c). EPA assessed the total number of sites that use DBP-containing inspection
fluids/penetrants using a Monte Carlo model that considered the total production volume for this OES
and the annual DBP facility throughput of 0.027 to 0.035 kg/site-year. The 50th to 95th percentile range
of the number of sites was 14,538 to 20,770 (non-aerosol run) and 14,541 to 20,767 (aerosol run).

3.12.3	Release Assessment

3.12.3.1	Environmental Release Points

EPA assigned release points based on the 2011 ESD on the Use of Metalworking Fluids (OECD.
2011c). EPA assigned models to quantify releases from each release point and suspected fugitive air
release. For the aerosol penetrant use case, EPA expects releases to wastewater, incineration, or landfill
from container residue losses and aerosol application processes. EPA also expects fugitive air releases
from aerosol application. For the non-aerosol penetrant use case, EPA expects releases to fugitive air
from unloading penetrant containers, container cleaning, and equipment cleaning. EPA expects
wastewater, incineration, or landfill releases from container residue losses, equipment cleaning, and
disposal of used penetrant.

3.12.3.2	Environmental Release Assessment Results

Table 3-71 summarizes the number of release days and the annual and daily release estimates that were
modeled for each release media and scenario assessed for this OES. See Appendix D.7.2 for additional
details on model equations, and different parameters used for used for Monte Carlo modeling. The
Monte Carlo simulation calculated the total DBP release (by environmental media) across all release
sources during each iteration of the simulation. EPA then selected 50th percentile and 95th percentile
values to estimate the central tendency and high-end releases, respectively. The Draft Use of Penetrants
OES Environmental Release Modeling Results for Dibutyl Phthalate (DBP) also contains additional
information about model equations and parameters and contains calculation results; refer to Appendix F
for a reference to this supplemental document.

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Table 3-71. Summary of Modeled Environmental Releases for Use of Penetrants and Inspection
Fluids

Modeled Scenario

Environmental
Media

Annual Release
(kg/site-year)

Number of Release
Days

Daily Release''
(kg/site-day)

Central
Tendency

High-End

Central
Tendency

High-
End

Central
Tendency

High-
End

97,710 kg/year
production volume
Aerosol Based

Fugitive Air

0.99

1.3

247

249

4.0E-03

5.2E-03

Wastewater,
Incineration, or
Landfill0

5.7

7.4

2.3E-02

3.0E-02

97,710 kg/year
production volume
Non-Aerosol Based

Fugitive Air

1.6E-05

3.0E-05

247

249

6.4E-08

1.2E-07

Wastewater,
Incineration, or
Landfill0

6.7

8.7

2.7E-02

3.5E-02

a When multiple environmental media are addressed together, releases may go all to one media, or be split between
media depending on site-specific practices. Not enough data was provided to estimate the partitioning between
media.

b The Monte Carlo simulation calculated the total DBP release (by environmental media) across all release sources
during each iteration of the simulation. EPA then selected 50th and 95th percentile values to estimate the central
tendency and high-end releases, respectively.

3.12.4 Occupational Exposure Assessment

3.12.4.1	Worker Activities

Worker exposures during the use of penetrant and inspection fluids may occur via dermal contact with
liquids when applying the product to substrate from the container for non-aerosol application and
inhalation and dermal contact when applying via aerosol application. Worker exposures may also occur
via vapor inhalation and dermal contact with liquids during aerosol application, equipment cleaning,
container cleaning, and disposal of used penetrants (OE	). EPA did not identify chemical-

specific information on the use of engineering controls and worker PPE used at facilities that use DBP-
containing penetrants and inspection fluids.

ONUs include supervisors, managers, and other employees that are in the application area but do not
directly use or contact penetrants. ONU exposure may occur via inhalation while the ONU is present in
the application area. Also, dermal exposures from contact with surfaces where mist has been deposited
were assessed for ONUs.

3.12.4.2	Occupational Inhalation Exposure Results

EPA did not identify inhalation monitoring data for the use of penetrants and inspection fluids during
systematic review of literature sources. However, through review of the literature and consideration of
existing EPA/OPPT exposure models, EPA identified the Brake Servicing Near-Field/Far-Field
Inhalation Exposure Model as an appropriate approach for estimating occupational exposures to DBP-
containing aerosols. The model is based on a near-field/far-field approach (	309), where aerosol

application in the near-field generates a mist of droplets and indoor air movements lead to the
convection of droplets between the near-field and far-field. The model assumes workers are exposed to
DBP droplets in the near-field, while ONUs are exposed in the far-field.

Penetrant/inspection fluid application generates a mist of droplets in the near-field, resulting in worker
exposures. The DBP exposure concentration is directly proportional to the amount of penetrant applied

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by the worker standing in the near-field zone {i.e., the working zone). The ventilation rate for the near-
field zone determines the rate of DBP dissipation into the far-field {i.e., the facility space surrounding
the near-field), resulting in occupational bystander exposures to DBP. The ventilation rate of the
surroundings determines the rate of DBP dissipation from the surrounding space into the outside air.

Table 3-72 summarizes the estimated 8-hour TWA concentration, AD, IADD, and ADD for worker
exposures to DBP during the use of penetrants and inspection fluids. The high-end exposures use 249
days per year as the exposure frequency based on the 95th percentile of operating days from the release
assessment. The central tendency exposures use 247 days per year as the exposure frequency based on
the 50th percentile of operating days from the release assessment. Appendix A describes the approach
for estimating AD, IADD, and ADD. The Draft Use of Penetrants OES Occupational Inhalation
Exposure Modeling Results for Dibutyl Phthalate (DBP) also contains information about model
equations and parameters and contains calculation results; refer to Appendix F for a reference to this
supplemental document.

Table 3-72. Summary of Estimated Worker Inhalation Exposures for Use of Penetrants and

Inspection F

uids

Modeled
Scenario

Exposure Concentration Type

Central
Tendency"

High-
End"

Average

Adult

Worker

8-hour TWA Exposure Concentration (mg/m3)

1.5

5.6

Acute Dose (AD) (mg/kg-day)

0.19

0.70

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

0.14

0.51

Chronic Average Daily Dose, Non-Cancer Exposures (ADD) (mg/kg-day)

0.13

0.48

Female of

Reproductive

Age

8-hour TWA Exposure Concentration (mg/m3)

1.5

5.6

Acute Dose (AD) (mg/kg-day)

0.21

0.77

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

0.15

0.56

Chronic Average Daily Dose, Non-Cancer Exposures (ADD) (mg/kg-day)

0.14

0.53



8-hour TWA Exposure Concentration (mg/m3)

5.1E-02

0.38

ONU

Acute Dose (AD) (mg/kg-day)

6.4E-03

4.7E-02

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

4.7E-03

3.5E-02



Chronic Average Daily Dose, Non-Cancer Exposures (ADD) (mg/kg-day)

4.3E-03

3.2E-02

a From monte carlo modeling, EPA selected the 95th percentile value to represent high-end exposure level and the
50th percentile value to represent the central tendency exposure level.

3.12.4.3 Occupational Dermal Exposure Results

EPA estimated dermal exposures for this OES using the methodology outlined in Appendix C. For
occupational dermal exposure assessment, EPA assumed a standard 8-hour workday and the chemical is
contacted at least once per day. Because DBP has low volatility and relatively low absorption, it is
possible that the chemical remains on the surface of the skin after dermal contact until the skin is
washed. So, in absence of exposure duration data, EPA has assumed that absorption of DBP from
occupational dermal contact with materials containing DBP may extend up to 8 hours per day (U.S.
E	). However, if a worker uses proper personal protective equipment (PPE) or washes their

hands after contact with DBP or DBP-containing materials dermal exposure may be eliminated.
Therefore, the assumption of an 8-hour exposure duration for DBP may lead to overestimation of dermal
exposure. The various "Exposure Concentration Types" from Table 3-73 are explained in Appendix A.
Since there may be mist deposited on surfaces from this OES, dermal exposures to ONUs from contact

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with mist on surfaces were assessed. In the absence of data specific to ONU exposure, EPA assumed
that worker central tendency exposure was representative of ONU exposure.

Table 3-73 summarizes the APDR, the AD, the IADD, and the ADD for average adult workers, female
workers of reproductive age, and ONUs. Dermal exposure parameters are described in Appendix C. The
Draft Occupational Dermal Exposure Modeling Results for Dibutyl Phthalate (DBP) also contains
information about model equations and parameters and contains calculation results; refer to Appendix F
for a reference to this supplemental document.

Table 3-73. Summary of Estimated Worker Dermal Exposures for Use of Penetrants and
Inspection Fluids 		

Worker Population

Exposure Concentration Type

Central
Tendency

High-End



Dose Rate (APDR, mg/day)

100

201

Average Adult

Acute (AD, mg/kg-day)

1.3

2.5

Worker

Intermediate (IADD, mg/kg-day)

0.92

1.8



Chronic, Non-Cancer (ADD, mg/kg-day)

0.85

1.7



Dose Rate (APDR, mg/day)

84

167

Female of

Acute (AD, mg/kg-day)

1.2

2.3

Reproductive Age

Intermediate (IADD, mg/kg-day)

0.85

1.7



Chronic, Non-Cancer (ADD, mg/kg-day)

0.78

1.6



8-hour TWA Exposure Concentration (mg/m3)

100

100



Acute Dose (AD) (mg/kg/day)

1.3

1.3

ONU

Intermediate Average Daily Dose, Non-Cancer Exposures
(IADD) (mg/m3)

0.92

0.92



Chronic Average Daily Dose, Non-Cancer Exposures
(ADD) (mg/kg/day)

0.85

0.86

Note: For high-end estimates, EPA assumed the exposure surface area was equivalent to mean values for two-hand
surface areas (i.e., 1.070 cm2 for male workers and 890 cm2 for female workers) (U.S. EPA, 2011). For central
tendency estimates, EPA assumed the exposure surface area was equivalent to only a single hand (or one side of two
hands) and used half the mean values for two-hand surface areas (i.e., 535 cm2 for male workers and 445 cm2for
female workers).

3.12.4.4

Occupational Aggregate Exposure Results





Inhalation and dermal exposure estimates were aggregated based on the approach described in Appendix
A.3 to arrive at the aggregate worker and ONU exposure estimates in the table below. The assumption
behind this approach is that an individual worker could be exposed by both the inhalation and dermal
routes, and the aggregate exposure is the sum of these exposures.

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Table 3-74. Summary of Estimated Worker Aggregate Exposures for Use of Penetrants and
Inspection Fluids				

Modeled Scenario

Exposure Concentration Type (mg/kg-
day)

Central
Tendency

High-End

Average Adult Worker

Acute (AD, mg/kg-day)

1.4

3.2

Intermediate (IADD, mg/kg-day)

1.1

2.4

Chronic, Non-Cancer (ADD, mg/kg-day)

0.98

2.2

Female of Reproductive
Age

Acute (AD, mg/kg-day)

1.4

3.1

Intermediate (IADD, mg/kg-day)

1.0

2.3

Chronic, Non-Cancer (ADD, mg/kg-day)

0.92

2.1

ONU

Acute (AD, mg/kg-day)

1.3

1.3

Intermediate (IADD, mg/kg-day)

0.93

0.96

Chronic, Non-Cancer (ADD, mg/kg-day)

0.85

0.89

Note: A worker could be exposed by both the inhalation and dermal routes, and the aggregate exposure is the sum of these
exposures.

3.13 Fabrication or Use of Final Product or Articles

3.13.1	Process Description

EPA anticipates that DBP may be present in a wide array of final articles that are used both
commercially and industrially. DBP is used in products such as building and construction materials,
flooring materials, furniture, and furnishings CNLM. 2024; U.S. EPA. 2020a). Use cases may include
melting articles containing DBP and drilling, cutting, grinding, or otherwise shaping articles containing
DBP. EPA did not identify any specific product data to support these uses and the only source that
indicated these potential uses was the 2020 CDR report (	'20a). Per the above discussion,

EPA assumed that most products used in this OES are plastics. As a result, EPA used the DBP
concentration from the plastic compounding/converting OESs to represent this OES, with DBP at a
concentration ranging from 30 to 45 percent (	21c).

3.13.2	Facility Estimates

EPA did not identify representative site- or chemical-specific operating data for this OES {i.e., facility
throughput, number of sites, total production volume, operating days, product concentration), as DBP-
containing article use occurs at many disparate industrial and commercial sites, with different operating
conditions. Due to a lack of readily available information for this OES, the number of industrial or
commercial use sites is unquantifiable and unknown. Total production volume for this OES is also
unquantifiable, and EPA assumed that each end use site utilizes a small number of finished articles
containing DBP. EPA assumed the number of operating days was 250 days/year with 5 day/week
operations and two full weeks of downtime per operating year.

3.13.3	Release Assessment

3.13.3.1 Environmental Release Points

EPA did not quantitatively assess environmental releases for this OES due to the lack of process-specific
and DBP-specific data; however, EPA expects releases from this OES to be small and disperse in
comparison to other upstream OES. EPA also expects DBP to be present in small amounts and
predominantly remain in the final article, limiting the potential for release. Table 3-75 describes the

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expected fabrication and use activities that may potentially generate releases. All releases are non-
quantifiable due to a lack of process- and product- specific data.

Table 3-75. Release Activities for

7abrication/Use of Final Articles Containing DBP

Release Point

Release Behavior

Release Media

Cutting, Grinding, Shaping, Drilling,
Abrading, and Similar Activities

Dust Generation

Fugitive or Stack Air, Water,
Incineration, or Landfill

Heating/Plastic Welding Activities

Vapor Generation

Fugitive or Stack Air

3.13.4 Occupational Exposure Assessment

3.13.4.1	Worker Activities

During fabrication and final use of products or articles, worker exposures to DBP may occur via dermal
contact while handling and shaping articles containing DBP additives. Worker exposures may also occur
via vapor or particulate inhalation during activities such as cutting, grinding, shaping, drilling, and/or
abrasive actions that generate particulates from the product. EPA did not identify chemical-specific
information on engineering controls and worker PPE used at final product or article formulation or use
sites.

ONUs include supervisors, managers, and other employees that may be present in manufacturing or use
areas but do not directly handle DBP-containing materials or articles. ONU inhalation exposures may
occur when ONUs are present in the manufacturing area during dust generating activities. EPA also
assessed dermal exposures from contact with surfaces where dust has been deposited for ONUs.

3.13.4.2	Occupational Inhalation Exposure Results

EPA identified one sample result from a facility melting, shaping, and joining plastics and two
inhalation exposure data points from the machine and manual welding of plastic roofing materials that
describes worker exposure to vapor (ECB. 2004; Rudel et al. 2001). Both sources received a rating of
medium from EPA's systematic review process. With the three discrete data points, EPA could not
create a full distribution of monitoring results to estimate central tendency and high-end exposures. To
assess the high-end worker exposure to DBP during the fabrication process, EPA used the maximum
available value (0.03 mg/m3). EPA assessed the median of the three available values as the central
tendency (0.01 mg/m3).

EPA expects the primary exposure route, however, to be from particulates generated during activities
such as cutting, grinding, drilling, and other abrasive actions. Therefore, EPA estimated worker
inhalation exposures during fabrication or use of final products or articles using the PNOR Model as
well (	21b). Model approaches and parameters are described in Appendix D.8.

In the model, EPA used a subset of the PNOR Model (U.S. EPA. 2 ) data for facilities with NAICS
codes starting with 337 - Furniture and Related Product Manufacturing to estimate final product
particulate concentrations in the air. Particulate exposures across end-use industries may occur during
trimming, cutting, and/or abrasive actions on the DBP-containing product. EPA used the highest
expected concentration of DBP in final products to estimate the concentration of DBP in the particulates.
For this OES, EPA identified 45 percent by mass as the highest expected DBP concentration based on
the estimated plasticizer concentrations in relevant products given by the Use of Additives in Plastic
Compounding Generic Scenario (	2021c). The estimated exposures assume that DBP is

present in particulates at this fixed concentration throughout the working shift.

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The PNOR Model (	2021b) estimates an 8-hour TWA concentration for particulate by

assuming exposures outside the sample duration are zero. The model does not determine exposures
during individual worker activities.

Table 3-76 summarizes the estimated 8-hour TWA concentration, AD, IADD, and ADD for worker
exposure to DBP during fabrication or use of final products or articles. The high-end and central
tendency exposures use 250 days per year as the exposure frequency since the 95th and 50th percentiles
of operating days in the release assessment exceeded 250 days per year, which is the expected maximum
number of working days. Appendix A describes the approach for estimating AD, IADD, and ADD. The
Draft Occupational Inhalation Exposure Monitoring Results for Dibutyl Phthalate (DBP) contains
further information on the identified inhalation exposure data, information on the PNOR Model
parameters used, and assumptions used in the assessment; refer to Appendix F for a reference to this
supplemental document.

Table 3-76. Summary of Estimated Worker Inhalation Exposures for Fabrication or Use of Final
Products or Articles

Modeled
Scenario

Exposure Concentration Type

Central
Tendency"

High-End"

Average
Adult Worker

8-hour TWA Exposure Concentration (mg/m3)

0.10

0.84

Acute Dose (AD) (mg/kg-day)

1.3E-02

0.11

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

9.2E-03

7.7E-02

Chronic Average Daily Dose, Non-Cancer Exposures (ADD)
(mg/kg-day)

8.6E-03

7.2E-02

Female of

Reproductive

Age

8-hour TWA Exposure Concentration (mg/m3)

0.10

0.84

Acute Dose (AD) (mg/kg-day)

1.4E-02

0.12

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

1.0E-02

8.5E-02

Chronic Average Daily Dose, Non-Cancer Exposures (ADD)
(mg/kg-day)

9.5E-03

7.9E-02

ONU

8-hour TWA Exposure Concentration (mg/m3)

0.10

0.10

Acute Dose (AD) (mg/kg-day)

1.3E-02

1.3E-02

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

9.2E-03

9.2E-03

Chronic Average Daily Dose, Non-Cancer Exposures (ADD)
(mg/kg-day)

8.6E-03

8.6E-03

a For the monitoring data, with the three discrete data points, EPA could not create a full distribution of monitoring
results to estimate central tendency and high-end exposures (ECB. 2004; Rude I et aL 2001). To assess the high-end
worker exposure to DBP during the fabrication process, EPA used the maximum available value (0.03 mg/m3). EPA
assessed the median of the three available values as the central tendency (0.01 mg/m3). Both sources received a rating
of medium from EPA's systematic review process. To calculate dust exposure using the PNOR Model, EPA assumed
concentration of DBP in fabrication products is equal to estimated DBP concentrations in flexible PVC to estimate
the concentration of DBP. EPA multiplied the concentration of DBP with the central tendency and HE estimates of
the relevant NAICS code from the PNOR Model to calculate the central tendency and HE estimates for this OES.

3.13.4.3 Occupational Dermal Exposure Results

EPA estimated dermal exposures for this OES using the dermal approach outlined in Section 2.4.3 and
Appendix C. For occupational dermal exposure assessment, EPA assumed a standard 8-hour workday.
For occupational dermal exposure assessment, EPA assumed a standard 8-hour workday and the
chemical is contacted at least once per day. Because DBP has low volatility and relatively low
absorption, it is possible that the chemical remains on the surface of the skin after dermal contact until

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the skin is washed. So, in absence of exposure duration data, EPA has assumed that absorption of DBP
from occupational dermal contact with materials containing DBP may extend up to 8 hours per day
(I	[). However, if a worker uses proper PPE or washes their hands after contact with DBP

or DBP-containing materials dermal exposure may be eliminated. Therefore, the assumption of an 8-
hour exposure duration for DBP may lead to overestimation of dermal exposure. The various "Exposure
Concentration Types" from Table 3-77 are explained in Appendix A. Since there may be dust deposited
on surfaces from this OES, dermal exposures to ONUs from contact with dust on surfaces were
assessed. In the absence of data specific to ONU exposure, EPA assumed that worker central tendency
exposure was representative of ONU exposure. Table 3-77 summarizes the APDR, AD, IADD, and
ADD for average adult workers, female workers of reproductive age, and ONUs. The Draft
Occupational Dermal Exposure Modeling Results for Dibutyl Phthalate (DBP) also contains
information about model equations and parameters and contains calculation results; refer to Appendix F
for a reference to this supplemental document.

Table 3-77. Summary of Estimated Worker Dermal Exposures for Fabrication or Use of Final

Product or Artie

es

Modeled
Scenario

Exposure Concentration Type

Central
Tendency

High-End



Dose Rate (APDR, mg/day)

1.4

2.7

Average Adult

Acute (AD, mg/kg-day)

1.7E-02

3.4E-02

Worker

Intermediate (IADD, mg/kg-day)

1.2E-02

2.5E-02



Chronic, Non-Cancer (ADD, mg/kg-day)

1.2E-02

2.3E-02

Female of

Reproductive

Age

Dose Rate (APDR, mg/day)

1.1

2.3

Acute (AD, mg/kg-day)

1.6E-02

3.1E-02

Intermediate (IADD, mg/kg-day)

1.1E-02

2.3E-02

Chronic, Non-Cancer (ADD, mg/kg-day)

1.1E-02

2.1E-02



Dose Rate (APDR, mg/day)

1.4

1.4



Acute Dose (AD) (mg/kg/day)

1.7E-02

1.7E-02

ONU

Intermediate Average Daily Dose, Non-Cancer Exposures (IADD)
(mg/m3)

1.2E-02

1.2E-02



Chronic Average Daily Dose, Non-Cancer Exposures (ADD)
(mg/kg/day)

1.2E-02

1.2E-02

Note: For high-end estimates, EPA assumed the exposure surface area was equivalent to mean values for two-hand
surface areas (i.e., 1.070 cm2 for male workers and 890 cm2 for female workers) (U.S. EPA, 2011). For central
tendency estimates, EPA assumed the exposure surface area was equivalent to only a single hand (or one side of two
hands) and used half the mean values for two-hand surface areas (i.e., 535 cm2 for male workers and 445 cm2 for
female workers).

3.13.4.4 Occupational Aggregate Exposure Results

Inhalation and dermal exposure estimates were aggregated based on the approach described in Appendix
A.3 to arrive at the aggregate worker and ONU exposure estimates in the table below. The assumption
behind this approach is that an individual worker could be exposed by both the inhalation and dermal
routes, and the aggregate exposure is the sum of these exposures.

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Table 3-78. Summary of Estimated Worker Aggregate Exposures for Fabrication or Use of Final
Product or Articles

Modeled Scenario

Exposure Concentration Type (mg/kg-day)

Central
Tendency

High-End

Average Adult Worker

Acute (AD, mg/kg-day)

2.9E-02

0.14

Intermediate (IADD, mg/kg-day)

2.2E-02

0.10

Chronic, Non-Cancer (ADD, mg/kg-day)

2.0E-02

0.10

Female of Reproductive Age

Acute (AD, mg/kg-day)

2.9E-02

0.15

Intermediate (IADD, mg/kg-day)

2.2E-02

0.11

Chronic, Non-Cancer (ADD, mg/kg-day)

2.0E-02

0.10

ONU

Acute (AD, mg/kg-day)

2.9E-02

2.9E-02

Intermediate (IADD, mg/kg-day)

2.2E-02

2.2E-02

Chronic, Non-Cancer (ADD, mg/kg-day)

2.0E-02

2.0E-02

Note: A worker could be exposed by both the inhalation and dermal routes, and the aggregate exposure is the sum of
these exposures.

3.14 Recycling

3.14,1 Process Description

In the 2020 CDR, 13 facilities reported that DBP was not recycled (' ! r '":)20a). EPA did not
identify information regarding the recycling of products containing DBP but assumed that DBP is
primarily recycled industrially in the form of DBP-containing PVC/plastic waste streams. EPA did not
identify additional information on PVC/plastic recycling from systematic review. While
chemical/feedstock recycling is possible, EPA did not identify any market share data indicating
chemical/feedstock recycling processes for DBP-containing waste streams.

The Association of Plastic Recyclers reports that recycled PVC arrives at a typical recycling site tightly
baled as crushed finished articles ranging from 240 to 453 kg (APR. 2023). The bales are unloaded into
process vessels, where PVC is grinded and separated from non-PVC fractions using electrostatic
separation, washing/floatation, or air/jet separation. Following cooling of grinded PVC, the site transfers
the product to feedstock storage for use in the plastics compounding or converting lines or loaded into
containers for shipment to downstream use sites. Figure 3-15 provides an illustration of the PVC
recycling process (	).

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B. Exposure During	5. Equipment

Container Cleaning	Cleaning Losses

Figure 3-15. PVC Recycling Flow Diagram (U.S. EPA. 2021c)

3,14,2 Facility Estimates

ENF Recycling (ENF Plastic. 2024) estimated a total of 228 plastics recyclers operating in the United
States, of which 58 accept PVC wastes for recycling. It is unclear if the total number of sites includes
some or all circular recycling sites, which are facilities where new PVC can be manufactured from both
recycled and virgin materials. Such sites would be identified primarily by the manufactured product;
however, EPA developed site parameters and release estimates for the PVC plastics compounding OES
based on generic values specified in the 2021 Generic Scenario on Plastics Compounding, which
incorporates all PVC material streams whether from recycled or virgin production (1 c. ซ ^ \ JO J I.*).

EPA was unable to quantify the volume of DBP-containing PVC that is recycled. EPA based volume
estimates on data for PVC waste that contained the phthalates Diisononyl Phthalate (DINP) and
Diisodecyl Phthalate (DIDP), and scaled these estimates based on overall production volumes for these
chemicals in plastic products. The Quantification and Evaluation of Plastic Waste in the United States
estimated that of the 699 kilotons of PVC waste managed in 2019, three percent was recycled or
20,970,000 kg of PVC (Milbrandt et al.. 2022).

The 2010 technical report on the Evaluation of New Scientific Evidence Concerning DINP and DIDP
estimated the fraction of DIDP-containing and DINP-containing PVC used in the overall PVC market as
9.78 percent and 18.3 percent, respectively (ECHA. ). As a result, EPA calculated the use rate of
recycled PVC plastics containing DBP as 9.78 percent of the yearly recycled production volume of PVC
or 2,050,866 kg/year. For DINP the use rate was calculated as 18.3 percent of the yearly recycled
production volume of PVC or 3,846,801 kg/year. EPA related the DINP and DIDP information to the
production volume of DBP used in plastic products to develop scaling factors for recyclable PVC
volumes (see Table 3-79).

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Table 3-79. Production Volumes Used to Develop Recycling Estimates

Chemical

Production Volume of Plastic Products
(kg/year)

Source

DBP

18,543-222,659

See Section 3.4.2

DINP

64,568,873-473,505,075

( 2025c)

DIDP

43,859,857-434,749,009

( 2024d)

EPA divided the PV range for DBP by the PV ranges of the other two phthalates to develop scaling
factors:

•	Low-end scaling factor with DINP data: 18,543 kg/year -h 473,505,075 kg/year = 3.92x 10~5

•	High-end scaling factor with DINP data: 222,659 kg/year -h 64,568,873 kg/year = 3.45x 10~3

•	Low-end scaling factor with DIDP data: 18,543 kg/year -h 434,749,009 kg/year = 4.27x 10~5

•	High-end scaling factor with DIDP data: 222,659 kg/year -h 43,859,857 kg/year = 5.08x 10~3

EPA then multiplied these scaling factors by the market percentages of the two phthalates in order to
estimate a proportional market percentage range for DBP:

•	DINP: 0.183 x (3.92x10-5 to 3.45xl0~3) = 7.05xl0~6 to 6.2xl0~4

•	DIDP: 0.098 x (4.27xl0~5 to 5.13xl0~3) = 4.18xl0~6 to 5.02xl0~4

•	Overall range of scaling factors: 4.18 x 10~6 to 6.2 x 10 4

Based on the 2021 Generic Scenario on Plastics Compounding, EPA estimated that the mass fraction of
DBP used as a plasticizer in plastics was 30 to 45 percent (	2021c). EPA multiplied the

estimated overall PVC waste volume estimate of 20,970,000 kg PVC by the estimated PVC market
share for DBP and the fraction of DBP assumed to be used in plastic products. This resulted in a range
of 26.3 to 5,857 kg of DBP recycled per year. The GS estimated the total number of operating days of
148 to 264 days/year, with 24 hour/day, 7 day/week {i.e., multiple shifts) operations for the given site
throughput scenario (U.S. EPA. 2021c).

3.14.3 Release Assessment

3.14.3.1	Environmental Release Points

No NEI, DMR or TRI data was mapped to this OES. EPA assigned release points for the Recycling OES
based on data from the PVC plastics compounding/converting OES for air releases, the Non-PVC
material manufacturing OES for land releases, and the PVC plastics compounding OES for water
releases. Based on identified details on the recycling process and assumptions from the PVC plastics
compounding process, releases to fugitive air, surface water, incineration or landfill may occur from
storage or loading of recycled plastic and general recycling processing {\ v H \ 4V I. Water,
incineration, or landfill releases may occur from container residue losses and equipment cleaning.

Surface water releases may occur from direct contact cooling water. Stack air releases may occur from
loading recycled plastics into storage and transport containers. Additional fugitive air releases may occur
during leakage of pipes, flanges, and accessories used for transport. Due to lack of specific process
information at recycling sites, EPA assumed that these sites don't utilize air pollution capture and
control technologies.

3.14.3.2	Environmental Release Assessment Results

Table 3-22, Table 3-23, Table 3-28, Table 3-29, and Table 3-30 provide the air release data from PVC
compounding/converting to be applied to the Recycling OES. Table 3-37 provides the land release data

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from Non-PVC material manufacturing to be applied to the Recycling OES. Table 3-24 provides the
water release data from PVC plastics compounding to be applied to the Recycling OES.

3,14.4 Occupational Exposure Assessment

3.14.4.1	Worker Activities

At PVC recycling sites, worker exposures from dermal contact with solids and inhalation of dust may
occur during unloading of bailed PVC, loading of PVC onto compounding or converting lines, loading
PVC into transport containers, processing recycled PVC, and equipment cleaning (	004a).

EPA did not identify information on engineering controls or workers PPE used at recycling sites.

ONUs include supervisors, managers, and other employees that work in the processing area but do not
directly handle DBP-containing PVC. ONUs are potentially exposed through the inhalation route while
in the working area. EPA also assessed dermal exposures from contact with surfaces where dust has
been deposited for ONUs.

3.14.4.2	Occupational Inhalation Exposure Results

EPA did not identify inhalation monitoring data to assess exposures to DBP during recycling processes.
Based on the presence of DBP as an additive in plastics (U.S. CPSC. 2015a). EPA assessed worker
inhalation exposures to DBP as exposure to particulates of recycled plastic materials. Therefore, EPA
estimated worker inhalation exposures during recycling using the PNOR Model (	21b).

Model approaches and parameters are described in Appendix D.8.

In the model, EPA used a subset of the PNOR Model (U.S. EPA. 2021b) data for facilities with the
NAICS code starting with 56 - Administrative and Support and Waste Management and Remediation
Services to estimate plastic particulate concentrations in the air. EPA used the highest expected
concentration of DBP in recyclable plastic products to estimate the concentration of DBP present in
particulates. For this OES, EPA identified 45 percent by mass as the highest expected DBP
concentration based on the estimated plasticizer concentrations in flexible PVC given by the 2021
Generic Scenario on Plastic Compounding (	2021c). The estimated exposures assume that

DBP is present in particulates of the plastic at this fixed concentration throughout the working shift.

The PNOR Model (U.S. EPA. 2021b) estimates an 8-hour TWA for particulate concentrations by
assuming exposures outside the sample duration are zero. The model does not determine exposures
during individual worker activities. In absence of data specific to ONU exposure, EPA assumed that
worker central tendency exposure was representative of ONU exposure and used this data to generate
estimates for ONUs. EPA used the number of operating days estimated in the release assessment for this
OES to estimate exposure frequency. The high-end and central tendency exposures use 250 days per
year as the exposure frequency since the 95th and 50th percentiles of operating days in the release
assessment exceeded 250 days per year, which is the expected maximum number of working days.

Table 3-80 summarizes the estimated 8-hour TWA concentration, AD, IADD, and ADD for worker
exposures to DBP during recycling. Appendix A describes the approach for estimating AD, IADD, and
ADD. The estimated exposures assume that the worker is exposed to DBP in the form of plastic
particulates and does not account for other potential inhalation exposure routes, such as from the
inhalation of vapors, which EPA expects to be de minimis. The Draft Occupational Inhalation Exposure
Monitoring Results for Dibutyl Phthalate (DBP) contains further information on the identified inhalation
exposure data, information on the PNOR Model parameters used, and assumptions used in the
assessment; refer to Appendix F for a reference to this supplemental document.

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Table 3-80. Summary of Estimated Worker Inhalation Exposures for Recycling

Modeled Scenario

Exposure Concentration Type

Central
Tendency"

High-End"

Average Adult Worker

8-hour TWA Exposure Concentration (mg/m3)

0.11

1.6

Acute Dose (AD) (mg/kg-day)

1.4E-02

0.20

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

9.9E-03

0.14

Chronic Average Daily Dose, Non-Cancer Exposures (ADD)
(mg/kg-day)

9.2E-03

0.13

Female of
Reproductive Age

8-hour TWA Exposure Concentration (mg/m3)

0.11

1.6

Acute Dose (AD) (mg/kg-day)

1.5E-02

0.22

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

1.1E-02

0.16

Chronic Average Daily Dose, Non-Cancer Exposures (ADD)
(mg/kg-day)

1.0E-02

0.15

ONU

8-hour TWA Exposure Concentration (mg/m3)

0.11

0.11

Acute Dose (AD) (mg/kg-day)

1.4E-02

1.4E-02

Intermediate Non-Cancer Exposures (IADD) (mg/kg-day)

9.9E-03

9.9E-03

Chronic Average Daily Dose, Non-Cancer Exposures (ADD)
(mg/kg-day)

9.2E-03

9.2E-03

aTo calculate dust exposure using the PNOR Model, EPA assumed concentration of DBP in recycling products is
equal to estimated DBP concentrations in flexible PVC to estimate the concentration of DBP. EPA multiplied the
concentration of DBP with the central tendency and HE estimates of the relevant NAICS code from the PNOR Model
to calculate the central tendency and HE estimates for this OES.

3.14.4.3 Occupational Dermal Exposure Results

EPA estimated dermal exposures for this OES using the dermal approach outlined in Section 2.4.3 and
Appendix C. For occupational dermal exposure assessment, EPA assumed a standard 8-hour workday
and the chemical is contacted at least once per day. Because DBP has low volatility and relatively low
absorption, it is possible that the chemical remains on the surface of the skin after dermal contact until
the skin is washed. So, in absence of exposure duration data, EPA has assumed that absorption of DBP
from occupational dermal contact with materials containing DBP may extend up to 8 hours per day
(	). However, if a worker uses proper PPE or washes their hands after contact with DBP

or DBP-containing materials dermal exposure may be eliminated Therefore, the assumption of an 8-hour
exposure duration for DBP may lead to overestimation of dermal exposure. The various "Exposure
Concentration Types" from Table 3-81 are explained in Appendix A. Since there may be dust deposited
on surfaces from this OES, EPA assessed dermal exposures to ONUs from contact with dust on surfaces.
In the absence of data specific to ONU exposure, EPA assumed that worker central tendency exposure
was representative of ONU exposure. Table 3-81 summarizes the APDR, AD, IADD, and ADD for
average adult workers, female workers of reproductive age, and ONUs. The Draft Occupational Dermal
Exposure Modeling Results for Dibutyl Phthalate (DBP) also contains information about model
equations and parameters and contains calculation results; refer to Appendix F for a reference to this
supplemental document.

Table 3-81. Summary of Estimated Worker Dermal Exposures for Recycling

Modeled
Scenario

Exposure Concentration Type

Central
Tendency

High-End



Dose Rate (APDR, mg/day)

1.4

2.7

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Modeled
Scenario

Exposure Concentration Type

Central
Tendency

High-End

Average Adult
Worker

Acute (AD, mg/kg-day)

1.7E-02

3.4E-02

Intermediate (IADD, mg/kg-day)

1.2E-02

2.5E-02

Chronic, Non-Cancer (ADD, mg/kg-day)

1.2E-02

2.3E-02

Female of
Reproductive Age

Dose Rate (APDR, mg/day)

1.1

2.3

Acute (AD, mg/kg-day)

1.6E-02

3.1E-02

Intermediate (IADD, mg/kg-day)

1.1E-02

2.3E-02

Chronic, Non-Cancer (ADD, mg/kg-day)

1.1E-02

2.1E-02

ONU

8-hour TWA Exposure Concentration (mg/m3)

1.4

1.4

Acute Dose (AD) (mg/kg/day)

1.7E-02

1.7E-02

Intermediate Average Daily Dose, Non-Cancer Exposures
(IADD) (mg/m3)

1.2E-02

1.2E-02

Chronic Average Daily Dose, Non-Cancer Exposures (ADD)
(mg/kg/day)

1.2E-02

1.2E-02

Note: For high-end estimates, EPA assumed the exposure surface area was equivalent to mean values for two-hand
surface areas {i.e., 1.070 cm2 for male workers and 890 cm2 for female workers) (U.S. EPA, 2011). For central
tendency estimates, EPA assumed the exposure surface area was equivalent to only a single hand (or one side of two
hands) and used half the mean values for two-hand surface areas (i.e.. 535 cm2 for male workers and 445 cm2for
female workers).

3851	3.14.4.4 Occupational Aggregate Exposure Results

3852	Inhalation and dermal exposure estimates were aggregated based on the approach described in Appendix

3853	A.3 to arrive at the aggregate worker and ONU exposure estimates in the table below. The assumption

3854	behind this approach is that an individual worker could be exposed by both the inhalation and dermal

3855	routes, and the aggregate exposure is the sum of these exposures.

3856

3857	Table 3-82. Summary of Estimated Worker Aggregate Exposures for Recycling		

Modeled Scenario

Exposure Concentration Type (mg/kg-day)

Central
Tendency

High-End

Average Adult Worker

Acute (AD, mg/kg-day)

3.0E-02

0.23

Intermediate (IADD, mg/kg-day)

2.2E-02

0.17

Chronic, Non-Cancer (ADD, mg/kg-day)

2.1E-02

0.16

Female of Reproductive
Age

Acute (AD, mg/kg-day)

3.0E-02

0.25

Intermediate (IADD, mg/kg-day)

2.2E-02

0.18

Chronic, Non-Cancer (ADD, mg/kg-day)

2.1E-02

0.17

ONU

Acute (AD, mg/kg-day)

3.0E-02

3.0E-02

Intermediate (IADD, mg/kg-day)

2.2E-02

2.2E-02

Chronic, Non-Cancer (ADD, mg/kg-day)

2.1E-02

2.1E-02

Note: A worker could be exposed by both the inhalation and dermal routes, and the aggregate exposure is the sum of
these exposures.

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3.15 Waste Handling, Treatment, and Disposal

3,15,1 Process Description

Each of the conditions of use of DBP may generate waste streams of the chemical that are collected and
transported to third-party sites for disposal, treatment, or recycling. These waste streams may include the
following:

Wastewater

DBP may be contained in wastewater discharged to POTW or other, non-public treatment works for
treatment. Industrial wastewater containing DBP discharged to a POTW may be subject to EPA or
authorized NPDES state pretreatment programs. An assessment of wastewater discharges to POTWs and
non-public treatment works of DBP is included in each of the condition of use assessed in Sections 3.1
through 3.14.

Solid Wastes

Solid wastes are defined under RCRA as any material that is discarded by being abandoned; inherently
waste-like; a discarded military munition; or recycled in certain ways (certain instances of the generation
and legitimate reclamation of secondary materials are exempted as solid wastes under RCRA). Solid
wastes may subsequently meet RCRA's definition of hazardous waste by either being listed as a waste at
40 CFR งง 261.30 to 261.35 or by meeting waste-like characteristics defined at 40 CFR งง 261.20 to
261.24. Solid wastes that are hazardous wastes are regulated under the more stringent requirements of
Subtitle C of RCRA, whereas non-hazardous solid wastes are regulated under the less stringent
requirements of Subtitle D of RCRA. DBP is not listed as a toxic chemical as specified in Subtitle C of
RCRA and is not subject to hazardous waste regulations. However, solid wastes containing DBP may
require regulation if the waste leaches constituents, specified in the toxicity characteristic leaching
procedure (TLCP), in excess of regulatory limits. These constituents could include toxins, such as lead
and cadmium, which are used as stabilizers in PVC. An assessment of solid waste discharges of DBP is
included in each of the condition of use assessed in Sections 3.1 through 3.14.

EPA expects off-site transfers of DBP and DBP-containing wastes to land disposal, wastewater
treatment, incineration, and recycling facilities, based on industry supplied data and published EPA and
OECD emission documentation, such as Generic Scenarios and Emission Scenario Documents. Off-site
transfers are incinerated, sent to land disposal, sent to wastewater treatment, recycled off-site, or sent to
other or unknown off-site disposal/treatment (see Figure 3-16).

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Recycling

Hazardous Waste
Generation

Hazardous Waste
Transportation

*

Treatment

ฆฆ

Disposal

Figure 3-16. Typical Waste Disposal Process

Source: (U.S. EPA. 2017) (https://\\\\\\ .cpa.go\7h\\/lcarn-basics-hazardous-\\astc)

Municipal Waste Incineration

Municipal waste combustors (MWCs) that recover energy are generally located at large facilities and
comprised of an enclosed tipping floor and a deep waste storage pit. Typical large MWCs may range in
capacity from 250 to over 1,000 tons per day. At facilities of this scale, waste materials are not generally
handled directly by workers. Trucks may dump the waste directly into the pit, or waste may be tipped to
the floor and later pushed into the pit by a worker operating a front-end loader. A large grapple from an
overhead crane is used to grab waste from the pit and drop it into a hopper, where hydraulic rams feed
the material continuously into the combustion unit at a controlled rate. The crane operator also uses the
grapple to mix the waste within the pit, in order to provide a fuel consistent in composition and heating
value, and to pick out hazardous or problematic waste.

Facilities burning refuse-derived fuel (RDF) conduct on-site sorting, shredding, and inspection of the
waste prior to incineration to recover recyclables and remove hazardous waste or other unwanted
materials. Sorting is usually an automated process that uses mechanical separation methods, such as
trommel screens, disk screens, and magnetic separators. Once processed, the waste material may be
transferred to a storage pit, or it may be conveyed directly to the hopper for combustion.

Tipping floor operations may generate dust. Air from the enclosed tipping floor, however, is
continuously drawn into the combustion unit via one or more forced air fans to serve as the primary
combustion air and minimize odors. Dust and lint present in the air are typically captured in filters or
other cleaning devices to prevent the clogging of steam coils, which are used to heat the combustion air
and help dry higher-moisture inputs ( vilto and Stultz. 1992).

Municipal Waste Landfill

Municipal solid waste landfills are discrete areas of land or excavated sites that receive household
wastes and other types of non-hazardous wastes {e.g., industrial and commercial solid wastes).

Standards and requirements for municipal waste landfills include location restrictions, composite liner

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requirements, leachate collection and removal systems, operating practices, groundwater monitoring
requirements, corrective action provisions, and closure-and post-closure care requirements that include
financial assurance. Non-hazardous solid wastes are regulated under RCRA Subtitle D, but states may
impose more stringent requirements.

Municipal solid wastes may be first unloaded at waste transfer stations for temporary storage, prior to
being transported to the landfill or other treatment or disposal facilities.

Hazardous Waste Landfill

Hazardous waste landfills are excavated or engineered sites specifically designed for the final disposal
of non-liquid hazardous wastes. Design standards for these landfills require double liners, double
leachate collection and removal systems, leak detection systems, runoff and wind dispersal controls, and
construction quality assurance programs.2 There are also requirements for closure and post-closure, such
as the addition of a final cover over the landfill and continued monitoring and maintenance. These
standards and requirements are designed to prevent contamination of groundwater and nearby surface
water resources. Hazardous waste landfills are regulated under 40 CFR 264/265, Subpart N.

3.15.2	Facility Estimates	

In the NEI (	, ), DMR ( s r	), and TRI ( il;; ) data that

EPA analyzed, EPA identified eight sites that may have used DBP in PVC plastics converting, based on
site names and their reported NAICS and SIC codes. Two CDR reporters indicated the use of DBP for
Plastics Product Manufacturing in the 2020 CDR. EPA identified operating days ranging from 2-365
with an average of 307 days in the NEI air release data. TRI/DMR (U.S. EPA. 2024a. e) datasets did not
report operating days; therefore, EPA used 253 days/year of operation, based on the Revised Plastic
Converting GS as discussed in Section 2.3.2 (	).

The ESD on Plastic Additives estimates 341 to 3,990 metric tons of flexible PVC produced per site per
year (341,000 to 3,990,000 kg/site-year) (QE >09b). A typical number of production days during a
year is 148 to 264 days (	)). Assuming a concentration of DBP in the plastic of 30 to 45

percent (see above) and 264 production days/year, the use rate of DBP is 388 to 12,131 kg/site-day and
102,300 to 1,795,500 kg/site-year.

3.15.3	Release Assessment

3.15.3.1 Environmental Release Assessment Results

EPA assessed environmental releases for this OES based on NEI, TRI, and DMR data. Based this data,
waste handling, treatment, and disposal releases may go to fugitive air, stack air, surface water, POTW,
landfill, and additional releases may occur from transfers of wastes from off-site treatment facilities

(	>024a. e, 2023a. 2019.).

Table 3-83 presents fugitive and stack air releases per year and per day based on information in the 2017
to 2022 TRI databases, along with the number of release days per year and medians and maxima from
across the 6-year reporting range. Table 3-84 presents fugitive and stack air releases per year and per
day, based on information in the 2020 NEI database, along with the number of release days per year.
Table 3-85 presents fugitive and stack air releases per year and per day, based on information in the
2017 NEI database, along with the number of release days per year. Table 3-86 presents land releases per
year based on information in the TRI database along with the number of release days per year. Table 3-87

2 https://www.epa.gov/hwpermitting/hazardoiis~waste~management~raciIities~and~iHiits

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3966	presents water releases per year and per day based on information in the 2017 to 2022 TRI/DMR

3967	databases, along with the number of release days per year, with medians and maxima presented from

3968	across the 6-year reporting range. The Draft Summary of Results for Identified Environmental Releases

3969	to Air for Dibutyl Phthalate (DBP), Draft Summary of Results for Identified Environmental Releases to

3970	Landfor Dibutyl Phthalate (DBP), and Draft Summary of Results for Identified Environmental Releases

3971	to Water for Dibutyl Phthalate (DBP) contain additional information about these identified releases and

3972	their original sources; refer to Appendix F for a reference to these supplemental documents.

3973

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3974 Table 3-83. Summary of Air Releases from TRI for Waste Handling, Treatment, and Disposal

Site Identity

Maximum
Annual
Fugitive
Air Release
(kg/year)

Maximum
Annual
Stack Air
Release
(kg/year)

Median
Annual
Fugitive Air
Release
(kg/year)

Median
Annual
Stack Air
Release
(kg/year)

Annual
Release
Days
(days/year)

Maximum

Daily
Fugitive Air
Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

Median
Daily
Fugitive Air
Release
(kg/day)

Median
Daily
Stack Air
Release
(kg/day)

Clean Harbors Deer Park LLC

4.5E-02

1.06

2.5E-02

4.5E-02

286

3.5E-04

8.1E-03

1.6E-04

3.5E-04

Clean Harbors Aragonite LLC

2.3E-02

0.35

4.5E-03

2.0E-02

286

1.7E-04

2.7E-03

7.1E-05

1.6E-04

Heritage Thermal of Texas LLC

0

9.1E-03

0

9.1E-03

286

0

7.0E-05

3.2E-05

7.0E-05

Buzzi Unicem USA-Cape
Girardeau

0.45

0

0.45

0

286

3.5E-03

0

0

0

Eq Detroit Inc

0

738

0

127

286

0

5.69

0.44

0.98

Eco-Services Operations

0

5.0E-02

0

4.5E-02

286

0

3.8E-04

1.6E-04

3.5E-04

Heidelberg Materials Us Cement
LLC

0

0

0

0

286

0

0

0

0

Heritage Thermal Services

9.1E-03

0.20

4.5E-03

2.0E-02

286

7.0E-05

1.5E-03

7.1E-05

1.6E-04

Clean Harbors Environmental
Services Inc

4.5E-02

162

2.7E-02

43

286

3.5E-04

1.25

0.15

0.34

Clean Harbors El Dorado LLC

4.5E-02

0.98

2.5E-02

9.1E-02

286

3.5E-04

1.3

3.2E-04

7.0E-04

Ross Incineration Services Inc

2.59

0.25

1.8E-02

0

286

2.0E-02

1.9E-03

0

0

EBV Explosives Environmental
Co

0

72

0

2.5

286

0

0.56

8.6E-03

1.9E-02

Tradebe Treatment & Recycling
LLC

0

0

0

0

286

0

0

0

0

Chemtron Corp

6.6

0

3.4

0

286

5.1E-02

0

0

0

Burlington Environmental LLC

0

0

0

0

286

0

0

0

0

US Army Fort Stewart (Part)

0

0

0

0

286

0

0

0

0

Chemical Waste Management of
The Northwest Inc.

0

0

0

0

286

0

0

0

0

Wayne Disposal Inc

7.7E-02

0.14

4.5E-03

5.9E-02

286

5.9E-04

1.1E-03

2.1E-04

4.5E-04

Veolia Es Technical Solutions
LLC Port Arthur Facility

1.8

0

1.8

0

286

1.4E-02

0

0

0

US Ecology Michigan Inc.

0

0

0

0

286

0

0

0

0

3975

Page 164 of 291


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PUBLIC RELEASE DRAFT
May 2025

3976	Table 3-84. Summary of Air Releases from NEI (2020) for Waste Handling, Treatment, and

3977	Disposal						

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual
Stack Air
Release
(kg/year)

Annual
Release Days
(days/year)

Maximum

Daily
Fugitive
Air Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

Ventura Wastewater Plant

2.1E-03

0

364

5.7E-06

0

Mutual Materials Company

1.35

N/A

286

4.7E-03

N/A

Lakewood Brick & Tile Co

N/A

0

286

N/A

0

Summit Pressed Brick - Brick Mfg Pit

N/A

0

286

N/A

0

General Shale - Denver Brick Plant #60

N/A

0

286

N/A

0

Clean Harbors El Dorado, LLC

4.5E-02

0

286

1.6E-04

0

Meridian Brick LLC

N/A

217

286

N/A

0.76

Meridian Brick LLC

N/A

0.91

286

N/A

3.2E-03

Acme Brick Company

N/A

1.10

286

N/A

3.9E-03

Acme Brick Co - Perla Plant

N/A

0

364

N/A

0

Simi Vly County Sanitation

7.1E-03

0

286

2.5E-05

0

Boral Bricks - Augusta Plants 3, 4, & 5

N/A

0.37

365

N/A

1.0E-03

Howco Environmental Services, Inc.

N/A

5.3E-03

199

N/A

2.7E-05

Salina Mun. Solid Waste Landfill

3.5E-06

N/A

365

9.5E-09

N/A

Glen Gery Corp/Bigler Div

N/A

0

15

N/A

0

Bnz Materials Inc/Zelienople

N/A

0.45

301

N/A

1.5E-03

Kansas Brick & Tile

N/A

0.10

364

N/A

2.9E-04

Elgin Facility

N/A

1.6E-05

365

N/A

4.4E-08

Denton Plant

N/A

0

365

N/A

0

Delta Solid Waste Management
Authority

N/A

0

180

N/A

0

Acme Brick Bennett Plant

N/A

0.16

365

N/A

4.4E-04

Oak Grove Landfill

1.3E-05

N/A

364

3.5E-08

N/A

Meridian Brick LLC - Columbia Facility

N/A

160

364

N/A

0.44

Pabco Building Products (F#4070)

1.37

N/A

364

3.8E-03

N/A

Athens Facility

N/A

1.2E-04

365

N/A

3.2E-07

Texas Clay Plant

N/A

0

365

N/A

0

Elgin Plant

N/A

0

365

N/A

0

Glen-Gery Corp/York Division

N/A

0

209

N/A

0

Argos USA - Martinsburg

6.9E-05

0.91

286

2.8E-07

3.7E-03

General Shale Products Inc

N/A

42

286

N/A

0.15

Southbridge Landfill Gas Management

N/A

0

286

N/A

0

RJF - Morin Brick LLC - Auburn

N/A

5.4E-03

286

N/A

1.9E-05

Mineral Wells Facility

N/A

0

365

N/A

0

HRSD Boat Harbor Sewage Treatment
Plant

3.5E-02

N/A

286

1.2E-04

N/A

Page 165 of 291


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PUBLIC RELEASE DRAFT
May 2025

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual
Stack Air
Release
(kg/year)

Annual
Release Days
(days/year)

Maximum

Daily
Fugitive
Air Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

Meridian Brick LLC - Stanton Plant

N/A

0

286

N/A

0

Redland Brick

N/A

406

260

N/A

1.56

EQ Detroit, Inc. (Dba US Ecology -
Detroit South)

N/A

0

286

N/A

0

Continental Brick - Martinsburg Facility

1.72

N/A

220

7.8E-03

N/A

Bowerston Shale Company
(0145000010)

N/A

0

365

N/A

0

Sealy Plant

N/A

0

365

N/A

0

40 Acre Facility

9.1E-02

N/A

365

2.5E-04

N/A

Hazardous Waste Disposal

N/A

0.57

365

N/A

1.5E-03

Clean Harbors Deer Park

4.5E-02

0

286

1.6E-04

0

City Of Midland Utilities Division

N/A

0

162

N/A

0

Glen-Gery Corporation - Harmar Plant

N/A

0

230

N/A

0

Clinton County Solid W/Wayne Twp
Ldfl

N/A

0

365

N/A

0

Mutual Materials

N/A

0

364

N/A

0

Watsontown Brick Co/Watsontown Pit

N/A

1.4E-03

365

N/A

3.9E-06

Outagamie County Landfill

N/A

0

260

N/A

0

MMSD-Jones Island Water Reclamation
Facility

N/A

0

286

N/A

0

Carson City Block Plant

N/A

0

286

N/A

0

Henry Brick Company, Inc.

N/A

0

286

N/A

0

JS&H

N/A

0

286

N/A

0

Redland Brick

N/A

0

286

N/A

0

EBV Explosives Environmental Co
Joplin

N/A

0

286

N/A

0

River Cement Co. Dba Buzzi Unicem
Usa Selma Plant

N/A

5.3E-03

286

N/A

1.8E-05

Ash Grove Cement Co

N/A

0

286

N/A

0

Central Valley Water Reclamation
Facility Wastewater Treatment Plant

N/A

1.09

112

N/A

9.7E-03

Belden Brick Plant 3 (0679005018)

N/A

0

356

N/A

0

Harbisonwalker International, Inc.

N/A

60

286

N/A

0.21

Harbisonwalker International, Inc.
(1667090000)

N/A

0

364

N/A

0

Resco Products Inc (1576000771)

N/A

3.0E-04

365

N/A

8.3E-07

Mcavoy Vitrified Brick Co/Phoenixville

N/A

0

214

N/A

0

Clean Harbors Aragonite LLC:
Hazardous Waste Storage Incineration

N/A

69

302

N/A

0.23

Lone Star Industries Inc

N/A

0

286

N/A

0

Page 166 of 291


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PUBLIC RELEASE DRAFT
May 2025

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual
Stack Air
Release
(kg/year)

Annual
Release Days
(days/year)

Maximum

Daily
Fugitive
Air Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

Glen-Gery Corp. Iberia Plant
(0351000051)

N/A

0

282

N/A

0

Interstate Brick Company: Brick
Manufacturing Plant

N/A

4.7E-05

365

N/A

1.3E-07

Mineral Wells East Facility

N/A

3.26

365

N/A

8.9E-03

Lehigh Cement Company - Mason City

N/A

0

315

N/A

0

Clean Harbors Env Services Inc

56

4.5E-04

365

0.15

1.2E-06

Triangle Brick Company - Wadesboro
Brick Manufacturing Plant

N/A

0

364

N/A

0

Chemung County Landfill

4.6E-06

N/A

286

1.6E-08

N/A

Tri-State Brick LLC

N/A

2.6E-05

286

N/A

9.0E-08

Endicott Clay Products Co

N/A

0

364

N/A

0

USB Tennessee LLC - Gleason

N/A

3.63

286

N/A

1.3E-02

Meridian Brick, LLC Bessemer Plant
No. 6

N/A

0

286

N/A

0

General Shale Brick, Inc. - Moncure
Facility

N/A

4.71

260

N/A

1.8E-02

Meridian Brick LLC - Salisbury Facility

N/A

207

364

N/A

0.57

Wewoka Plant

1.85

0

365

5.1E-03

0

Whitacre-Greer (0250000005)

N/A

0

365

N/A

0

State sville Brick Company

N/A

62

364

N/A

0.17

Lee Brick And Tile Company, Inc.

N/A

22

364

N/A

6.1E-02

Ironrock Capital, Inc. (1576051149)

N/A

0

365

N/A

0

Continental Cement Company -
Davenport Plant

N/A

0.53

364

N/A

1.4E-03

Cloud Ceramics

N/A

6.80

364

N/A

1.9E-02

Muskogee Plant

N/A

16

260

N/A

6.3E-02

Hebron Brick Company - Hebron Brick
Plant

N/A

48

286

N/A

0.17

Atlantic County Utilities Authority
Landfill

N/A

0

286

N/A

0

Lafarge Building Materials Inc

N/A

0.45

286

N/A

1.6E-03

Holcim (Us) Inc. Dba Lafarge Alpena
Plant

N/A

1.8E-06

317

N/A

5.7E-09

Ross Incineration Services, Inc.
(0247050278)

1.8E-03

N/A

286

6.3E-06

N/A

St Marys Cement Charlevoix Plant

N/A

0

365

N/A

0

3M - Cottage Grove - Corporate
Incinerator

6.9E-07

34

286

2.4E-09

0.12

Page 167 of 291


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PUBLIC RELEASE DRAFT
May 2025

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual
Stack Air
Release
(kg/year)

Annual
Release Days
(days/year)

Maximum

Daily
Fugitive
Air Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

Lehigh Cement Company - Union
Bridge

N/A

0

260

N/A

0

Glen-Gery Corp

N/A

0

286

N/A

0

Harbisonwalker International, Inc Fulton
Brick Plant

N/A

9.07

286

N/A

3.2E-02

Harbison-Walker International, Inc.
Vandalia Plant

N/A

9.0E-02

286

N/A

3.2E-04

Glen Gery Corp/Mid Atlantic Pit

N/A

0.10

363

N/A

2.8E-04

Meridian Brick

N/A

0

365

N/A

0

Columbus Brick Company Inc

N/A

15

286

N/A

5.3E-02

Bowerston Shale Company
(0634000012)

N/A

0

365

N/A

0

Glen Gery Corp/Hanley Plant

N/A

3.6E-02

365

N/A

9.9E-05

Palmetto Brick

N/A

551

365

N/A

1.51

Fulton County Mud Rd Sanitary Landfill

1.1E-04

N/A

286

3.9E-07

N/A

Pine Hall Brick Co., Inc.

N/A

0.46

364

N/A

1.3E-03

Owensboro Brick LLC

N/A

12

286

N/A

4.0E-02

Triangle Brick Company-Merry Oaks
Brick Manufacturing Plant

N/A

23

364

N/A

6.2E-02

Summitville Tiles, Inc. - Minerva Plant
(0210000047)

N/A

0

365

N/A

0

Olmsted County Waste-To-Energy
Facility

N/A

0

286

N/A

0

Madison County Landfill

5.9E-05

N/A

286

2.0E-07

N/A

Glen Gery Corporation (0351000005)

N/A

0

277

N/A

0

Clinton County Regional Landfill

3.1E-05

N/A

286

1.1E-07

N/A

The Belden Brick Company
(0679000118)

N/A

0

365

N/A

0

Ava Landfill

N/A

3.72

286

N/A

1.3E-02

Acme Brick Company

N/A

7.80

286

N/A

2.7E-02

General Shale Brick, Inc. - Plant 40

N/A

0

365

N/A

0

Heritage Thermal Services
(0215020233)

4.5E-03

0

286

1.6E-05

0

Knight Material Technologies, LLC
(1576001851)

N/A

0

365

N/A

0

Hunter Ferrell Landfill

9.9E-07

N/A

2.50

3.9E-07

N/A

Brampton Brick

N/A

0

286

N/A

0

Golden Triangle Regional Solid Waste
Man

1.4E-05

N/A

286

4.8E-08

N/A

Rock Oil Refining Inc

N/A

0

286

N/A

0

Page 168 of 291


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PUBLIC RELEASE DRAFT
May 2025

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual
Stack Air
Release
(kg/year)

Annual
Release Days
(days/year)

Maximum

Daily
Fugitive
Air Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

Chemical Waste Management of The
Northwest, Inc.

N/A

0

286

N/A

0

Dba RB Recycling, Inc.

N/A

0

286

N/A

0

3978

3979

3980	Table 3-85. Summary of Air Releases from NEI (2017) for Waste Handling, Treatment, and

3981	Disposal						

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual
Stack Air
Release
(kg/year)

Annual
Release Days
(days/year)

Maximum

Daily
Fugitive Air
Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

Harbison Walker (Fairfield)

N/A

0

286

N/A

0

Taylor Clay Products, Inc.

N/A

11

286

N/A

3.7E-02

Deffenbaugh Ind. - Johnson Co.
Landfill

N/A

0

286

N/A

0

Meridian Brick LLC Columbia
Facility

N/A

0

286

N/A

0

Richards Brick Co

N/A

0

286

N/A

0

Wayne Disposal Inc

9.1E-03

66

286

3.2E-05

0.23

Met Council - Seneca WWTP

51

223

286

0.18

0.78

Redland Brick Inc/Harmar Pit

N/A

0.59

286

N/A

2.0E-03

Turnkey Recycling &
Environmental Enterp

N/A

0

286

N/A

0

Wheelabrator Concord Company
LP

N/A

0

286

N/A

0

Central Valley Water Reclamation
Fac.: Wastewater Treatment Plant

4.3E-05

0

286

1.5E-07

0

North American Refractories

N/A

9.80

286

N/A

3.4E-02

Sioux City Brick & Tile Company

N/A

0

286

N/A

0

St. Marys Cement Inc

N/A

50

286

N/A

0.17

Holcim Us Inc

N/A

0

286

N/A

0

Meridian Brick LLC - Gleason
Plant

N/A

0

286

N/A

0

NYC-Dep Owls Head WPCP

N/A

3.66

286

N/A

1.3E-02

Forterra Brick, LLC - Roseboro
Facility

N/A

2.06

286

N/A

7.2E-03

Muskogee Pit

N/A

0

286

N/A

0

General Shale Brick, Inc. - Kings
Mountain Facility

N/A

0

286

N/A

0

Illinois Cement Co

N/A

27

286

N/A

9.6E-02

Page 169 of 291


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PUBLIC RELEASE DRAFT
May 2025

Site Identity

Maximum

Annual
Fugitive Air
Release
(kg/year)

Maximum
Annual
Stack Air
Release
(kg/year)

Annual
Release Days
(days/year)

Maximum

Daily
Fugitive Air
Release
(kg/day)

Maximum
Daily Stack
Air Release
(kg/day)

Lehigh Cement Company LLC

0

28

286

0

0.10

Acme Brick - Kanopolis

N/A

0

286

N/A

0

Forterra Brick East, LLC -
Monroe Facility

N/A

0

286

N/A

0

Olmsted Waste-To-Energy
Facility

N/A

6.64

286

N/A

2.3E-02

Florida Brick & Clay Co

N/A

149

286

N/A

0.52

Koch Knight, LLC (1576001851)

N/A

47

286

N/A

0.16

Golden Triangle Regional Solid
Waste Management Authority

N/A

0

286

N/A

0

Sand Draw Landfill

N/A

0.16

286

N/A

5.5E-04

3982

3983

3984	Table 3-86. Summary of Land Releases from TRI for Waste Handling, Treatment, and Disposal

Site Identity

Median Annual Release
(kg/year)

Maximum Annual
Release (kg/year)

Annual Release Days
(days/year)

Chemtron Corp

1.3E04

1.9E04

286

Ross Incineration Services Inc

1.3E-02

2.5E-02

286

Tradebe Treatment & Recycling
LLC

5,065

5,218

286

Wayne Disposal Inc

4,460

6.8E04

286

Us Ecology Michigan Inc.

1.7E04

1.7E04

286

Eq Detroit Inc

2.7E04

7.4E04

286

Clean Harbors Environmental
Services Inc

511

1,537

286

Clean Harbors El Dorado LLC

1.8

4.7

286

Clean Harbors Deer Park LLC

1.4

35

286

Clean Harbors Aragonite LLC

9.7

29

286

Chemical Waste Management of
The Northwest Inc.

1.3E04

1.7E04

286

Burlington Environmental LLC

1.3E04

1.3E04

286

3985

3986

3987	Table 3-87. Summary of Water Releases from DMR/TRI for Waste Handling, Treatment, and Disposal

Site Identity

Source-
Discharge
Type

Median
Annual
Discharge
(kg/year)

Median
Daily
Discharge
(kg/day)

Maximum

Annual
Discharge
(kg/year)

Maximum

Daily
Discharge
(kg/day)

Annual
Release Days
(days/year)

Calleguas Mwd Lake
Bard Water Plant

DMR

1.3E-03

4.6E-06

1.3E-03

4.6E-06

286

Page 170 of 291


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PUBLIC RELEASE DRAFT
May 2025

Site Identity

Source-
Discharge
Type

Median
Annual
Discharge
(kg/year)

Median
Daily
Discharge
(kg/day)

Maximum

Annual
Discharge
(kg/year)

Maximum

Daily
Discharge
(kg/day)

Annual
Release Days
(days/year)

Claude "Bud" Lewis

DMR

0.18

6.4E-04

0.18

6.4E-04

286

Carlsbad Desalination













Plant













Clean Harbors White

DMR

8.5

3.0E-02

8.5

3.0E-02

286

Castle, LLC - White













Castle Landfarm













Edward C. Little WRP

DMR

2.6

9.0E-03

2.6

9.0E-03

286

Eq Detroit Inc

TRIForm R-
Transfer to
POTW

0.18

6.3E-04

0.18

6.3E-04

286

Juanita Millender -

DMR

0.19

6.5E-04

0.19

6.5E-04

286

Mcdonald Carson













Regional WRP













Kahala Hotel & Resort

DMR

33

0.11

33

0.11

286

Lake Of The Pines

DMR

2.5

8.7E-03

2.5

8.7E-03

286

WWTP













Malakoff Diggins State

DMR

1.1E-02

3.9E-05

0.36

1.3E-03

286

Park













Neewc Seawater

DMR

9.3E-02

3.3E-04

9.3E-02

3.3E-04

286

Desalination Test













Facility













San Simeon Acres

DMR

1.4

5.0E-03

1.4

5.0E-03

286

WWTF













SPX Cooling

DMR

4.2E-03

1.5E-05

4.2E-03

1.5E-05

286

Technologies













Us Natl Park Service

DMR

5.6E-02

1.9E-04

7.2E-02

2.5E-04

286

Yosemite Natl Park













Aliso Creek Ocean

DMR

4.9

1.7E-02

4.9

1.7E-02

286

Outfall













Anchor Bay WWTF

DMR

5.0E-04

1.7E-06

5.0E-04

1.7E-06

286

Anderson Wastewater

DMR

3.5E-02

1.2E-04

3.5E-02

1.2E-04

286

Treatment Plant













Arizona City Sanitary

DMR

1.1

3.7E-03

1.3

4.6E-03

286

District - WWTP













Avalon WWTP

DMR

0.15

5.2E-04

0.16

5.6E-04

286

Barbourville STP

DMR

18

6.2E-02

18

6.2E-02

286

Brawley Wastewater

DMR

3.4E-02

1.2E-04

4.2E-02

1.5E-04

286

Treatment Plant













Brentwood Wastewater

DMR

1.5

5.2E-03

1.5

5.2E-03

286

Treatment Plant













Burlingame WWTP

DMR

41

0.14

41

0.14

286

Calipatria WWTP

DMR

6.8E-02

2.4E-04

6.8E-02

2.4E-04

286

Cascade Shores

DMR

0.62

2.2E-03

0.62

2.2E-03

286

WWTP













Cayucos Sanitary

DMR

6.2E-02

2.2E-04

6.2E-02

2.2E-04

286

District WRRF













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Site Identity

Source-
Discharge
Type

Median
Annual
Discharge
(kg/year)

Median
Daily
Discharge
(kg/day)

Maximum

Annual
Discharge
(kg/year)

Maximum

Daily
Discharge
(kg/day)

Annual
Release Days
(days/year)

Charlotte WWTP

DMR

0.36

1.2E-03

0.36

1.2E-03

286

City Of Alturas

DMR

0.14

4.8E-04

0.14

4.8E-04

286

Wastewater Treatment













Plant













City Of Daly City—A-

DMR

334

1.2

334

1.2

286

Street Pump Station













City Of Red Bluff

DMR

2.1

7.2E-03

4.0

1.4E-02

286

Wastewater













Reclamation Plant













City Of Safford - Gila

DMR

5.7

2.0E-02

5.7

2.0E-02

286

Resources WRP













Clear Creek WWTP

DMR

1.1

3.8E-03

1.1

3.8E-03

286

Clovis Sewage

DMR

0.34

1.2E-03

0.34

1.2E-03

286

Treatment and Water













Reuse Facility













Colusa WWTP

DMR

0.18

6.3E-04

0.18

6.3E-04

286

Corning Wastewater

DMR

3.6E-02

1.3E-04

3.6E-02

1.3E-04

286

Treatment Plant













Corona WWTP 1

DMR

17

6.1E-02

23

8.2E-02

286

Fallbrook Pud WWTP

DMR

0.12

4.3E-04

0.12

4.3E-04

286

No.l













Fallon Wastewater

DMR

1.1

3.7E-03

1.1

3.7E-03

286

Treatment Plant













Fort Bragg WWTF

DMR

4.6

1.6E-02

6.1

2.1E-02

286

Grosse lie Twp

DMR

12

4.3E-02

38

0.13

286

WWTP













Guthrie STP

DMR

3.3

1.2E-02

3.3

1.2E-02

286

Healdsburg WWTF

DMR

2.6

9.0E-03

2.6

9.0E-03

286

Lake Wildwood

DMR

12

4.3E-02

12

4.3E-02

286

WWTP













Manteca WWQCF

DMR

8.8

3.1E-02

8.7

3.1E-02

286

Middlesex County

DMR

35

0.12

69

0.24

286

Utilities Authority













Montecito Sd WWTP

DMR

0.18

6.4E-04

0.18

6.4E-04

286

Monterey Regional
WWTP

DMR

0.45

1.6E-03

1.5

5.4E-03

286

Mt. Shasta WWTP

DMR

1.4E-02

4.9E-05

1.4E-02

4.9E-05

286

Northern Edge Casino

DMR

0.28

9.7E-04

0.28

9.7E-04

286

Northern Madison

DMR

1.4

4.9E-03

1.4

4.9E-03

286

County Sanitation













District













Northwest WWTF

DMR

7.3E-02

2.5E-04

7.3E-02

2.5E-04

286

Olivehurst WWTF

DMR

45

0.16

45

0.16

286

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Site Identity

Source-
Discharge
Type

Median
Annual
Discharge
(kg/year)

Median
Daily
Discharge
(kg/day)

Maximum

Annual
Discharge
(kg/year)

Maximum

Daily
Discharge
(kg/day)

Annual
Release Days
(days/year)

Orange County
Sanitation District
Plant 1

DMR

12

4.3E-02

19

6.8E-02

286

Oxnard Wastewater
Treatment Plant
(OWTP)

DMR

11

3.8E-02

11

3.8E-02

286

Pima County - Ina
Road WWTP

DMR

76

0.27

76

0.27

286

Richmond Otter Creek
STP

DMR

69

0.24

69

0.24

286

Richmond Silver Creek
STP

DMR

6.4

2.2E-02

13

4.5E-02

286

Rio Vista WWTF

DMR

0.11

3.9E-04

0.11

3.9E-04

286

San Elijo WPCF

DMR

7.2

2.5E-02

19

6.6E-02

286

Santa Cruz Wastewater
Treatment Plant

DMR

0.80

2.8E-03

11

3.9E-02

286

Sd City Pt Loma
Wastewater Treatment

DMR

63

0.22

79

0.28

286

Sewer Authority Mid-
Coastside

DMR

24

8.5E-02

24

8.5E-02

286

South Bay

International WWTP

DMR

17

5.9E-02

55

0.19

286

South San Francisco-
San Bruno

DMR

417

1.5

417

1.5

286

South San Luis Obispo
Sd WWTP

DMR

1.2

4.1E-03

1.2

4.1E-03

286

Summerland Sd
WWTP

DMR

0.10

3.4E-04

0.10

3.4E-04

286

Town Of Red River

DMR

2,742

9.6

5,324

19

286

Tuba City WWTP

DMR

2.5

8.7E-03

2.5

8.7E-03

286

Willows WWTP

DMR

4.6E-02

1.6E-04

4.6E-02

1.6E-04

286

Woodland WPCF

DMR

0.57

2.0E-03

0.65

2.3E-03

286

Honeywell, Inc.,
Formerly Alliedsignal

DMR

8.5E-02

3.0E-04

8.5E-02

3.0E-04

286

3988

3989	3.15.4 Occupational Exposure Assessment

3990	3.15.4.1 Worker Activities

3991	At waste disposal sites, workers are potentially exposed via dermal contact with waste containing DBP

3992	or via inhalation of DBP vapor or dust. Depending on the concentration of DBP in the waste stream, the

3993	route and level of exposure may be similar to that associated with container unloading activities.

3994

3995	Municipal Waste Incineration

3996	At municipal waste incineration facilities, there may be one or more technicians present on the tipping

3997	floor to oversee operations, direct trucks, inspect incoming waste, or perform other tasks as warranted by

Page 173 of 291


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3998

3999

4000

4001

4002

4003

4004

4005

4006

4007

4008

4009

4010

4011

4012

4013

4014

4015

4016

4017

4018

4019

4020

4021

4022

4023

4024

4025

4026

4027

4028

4029

4030

4031

4032

4033

4034

4035

4036

4037

4038

4039

4040

4041

4042

4043

PUBLIC RELEASE DRAFT
May 2025

individual facility practices. These workers may wear protective gear such as gloves, safety glasses, or
dust masks. Specific worker protocols are largely up to individual companies, although state or local
regulations may specify worker safety standards. Federal operator training requirements pertain more to
the operation of the regulated combustion unit rather than operator health and safety.

Workers are potentially exposed via inhalation of vapors and dust while working on the tipping floor.
Potentially exposed workers include workers stationed on the tipping floor, including front-end loader
operators, crane operators, and truck drivers. The potential for dermal exposures is minimized by the use
of trucks and cranes to handle the wastes.

Hazardous Waste Incineration

EPA did not identify information on the potential for worker exposures during hazardous waste
incineration or for any requirements for personal protective equipment. There is likely a greater potential
for worker exposures for smaller scale incinerators that involve more direct handling of the wastes.

Municipal and Hazardous Waste Landfill

At landfills, typical worker activities include operating refuse vehicles to weigh and unload the waste
materials, operating bulldozers to spread and compact wastes, and monitoring, inspecting, and surveying
and landfill site.3

3.15.4.2 Occupational Inhalation Exposure Results

EPA did not identify inhalation monitoring data to assess exposures to DBP during disposal processes.
Based on the presence of DBP as an additive in plastics (	C. 2015a). EPA assessed worker

inhalation exposures to DBP as an exposure to particulates of discarded plastic materials. Therefore,
EPA estimated worker inhalation exposures during disposal using the PNOR Model (	s21b).

Model approaches and parameters are described in Appendix D.8.

In the model, EPA used a subset of the PNOR Model (\ v < < \ _\V I h) data that came from facilities
with the NAICS code starting with 56 - Administrative and Support and Waste Management and
Remediation Services to estimate plastic particulate concentrations in the air. EPA used the highest
expected concentration of DBP in plastic products to estimate the concentration of DBP present in
particulates. For this OES, EPA identified 45 percent by mass as the highest expected DBP
concentration based on the estimated plasticizer concentrations in flexible PVC given by the 2021
Generic Scenario on Plastic Compounding (	2021c). The estimated exposures assume that

DBP is present in particulates of the plastic at this fixed concentration throughout the working shift.

The PNOR Model (U.S. EPA. 2021b) estimates an 8-hour TWA for particulate concentrations by
assuming exposures outside the sample duration are zero. The model does not determine exposures
during individual worker activities. Due to expected process similarities, EPA used the number of
operating days estimated in the release assessment for the recycling OES to estimate exposure
frequency. The high-end and central tendency exposures use 250 days per year as the exposure
frequency since the 95th and 50th percentiles of operating days in the release assessment exceeded 250
days per year, which is the expected maximum number of working days.

Table 3-88 summarizes the estimated 8-hour TWA concentration, AD, IADD, and ADD for worker
exposures to DBP during disposal. Appendix A describes the approach for estimating AD, IADD, and
ADD. The estimated exposures assume that the worker is exposed to DBP in the form of plastic

3 http://www.calrecvcle.ca.gov/SWfacilities/landfiHs/needfor/Qperations.htm.

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4044

4045

4046

4047

4048

4049

4050

4051

4052

4053

4054

4055

4056

4057

4058

4059

4060

4061

4062

4063

4064

4065

4066

PUBLIC RELEASE DRAFT
May 2025

particulates and does not account for other potential inhalation exposure routes, such as from the
inhalation of vapors, which EPA expects to be de minimis. The Draft Occupational Inhalation Exposure
Monitoring Results for Dibutyl Phthalate (DBP) contains further information on the identified inhalation
exposure data, information on the PNOR Model parameters used, and assumptions used in the
assessment; refer to Appendix F for a reference to this supplemental document.

Table 3-88. Summary of

Estimated Worker Inhalation Exposures for Dis

posal

Modeled Scenario

Exposure Concentration Type

Central
Tendency"

High-End"

Average Adult Worker

8-hour TWA Exposure Concentration (mg/m3)

0.11

1.6

Acute Dose (AD) (mg/kg-day)

1.4E-02

0.20

Intermediate Non-Cancer Exposures (IADD) (mg/kg-
day)

9.9E-03

0.14

Chronic Average Daily Dose, Non-Cancer Exposures
(ADD) (mg/kg-day)

9.2E-03

0.13

Female of Reproductive
Age

8-hour TWA Exposure Concentration (mg/m3)

0.11

1.6

Acute Dose (AD) (mg/kg-day)

1.5E-02

0.22

Intermediate Non-Cancer Exposures (IADD) (mg/kg-
day)

1.1E-02

0.16

Chronic Average Daily Dose, Non-Cancer Exposures
(ADD) (mg/kg-day)

1.0E-02

0.15

ONU

8-hour TWA Exposure Concentration (mg/m3)

0.11

0.11

Acute Dose (AD) (mg/kg-day)

1.4E-02

1.4E-02

Intermediate Non-Cancer Exposures (IADD) (mg/kg-
day)

9.9E-03

9.9E-03

Chronic Average Daily Dose, Non-Cancer Exposures
(ADD) (mg/kg-day)

9.2E-03

9.2E-03

aTo calculate dust exposure using the PNOR Model, EPA assumed concentration of DBP in disposal products is
equal to estimated DBP concentrations in flexible PVC to estimate the concentration of DBP. EPA multiplied the
concentration of DBP with the central tendency and HE estimates of the relevant NAICS code from the PNOR
Model to calculate the central tendency and HE estimates for this OES.

3.15.4.3 Occupational Dermal Exposure Results

EPA estimated dermal exposures for this OES using the dermal approach outlined in Section 2.4.3 and
Appendix C. For occupational dermal exposure assessment, EPA assumed a standard 8-hour workday
and the chemical is contacted at least once per day. Because DBP has low volatility and relatively low
absorption, it is possible that the chemical remains on the surface of the skin after dermal contact until
the skin is washed. So, in absence of exposure duration data, EPA has assumed that absorption of DBP
from occupational dermal contact with materials containing DBP may extend up to 8 hours per day
(	). However, if a worker uses proper PPE or washes their hands after contact with DBP

or DBP-containing materials dermal exposure may be eliminated. Therefore, the assumption of an 8-
hour exposure duration for DBP may lead to overestimation of dermal exposure. The various "Exposure
Concentration Types" from Table 3-89 are explained in Appendix A. Since there may be dust deposited
on surfaces from this OES, dermal exposures to ONUs from contact with dust on surfaces were
assessed. In the absence of data specific to ONU exposure, EPA assumed that worker central tendency
exposure was representative of ONU exposure. Table 3-89 summarizes the APDR, AD, IADD, and
ADD for average adult workers, female workers of reproductive age, and ONUs. The Draft
Occupational Dermal Exposure Modeling Results for Dibutyl Phthalate (DBP) also contains

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4067	information about model equations and parameters and contains calculation results; refer to Appendix F

4068	for a reference to this supplemental document.

4069

4070	Table 3-89. Summary of Estimated Worker Dermal Exposures for Disposal		

Modeled
Scenario

Exposure Concentration Type

Central
Tendency

High-
End



Dose Rate (APDR, mg/day)

1.4

2.7

Average Adult

Acute (AD, mg/kg-day)

1.7E-02

3.4E-02

Worker

Intermediate (IADD, mg/kg-day)

1.2E-02

2.5E-02



Chronic, Non-Cancer (ADD, mg/kg-day)

1.2E-02

2.3E-02



Dose Rate (APDR, mg/day)

1.1

2.3

Female of

Acute (AD, mg/kg-day)

1.6E-02

3.1E-02

Reproductive Age

Intermediate (IADD, mg/kg-day)

1.1E-02

2.3E-02



Chronic, Non-Cancer (ADD, mg/kg-day)

1.1E-02

2.1E-02



Dose Rate (APDR, mg/day)

1.4

1.4



Acute Dose (AD) (mg/kg/day)

1.7E-02

1.7E-02

ONU

Intermediate Average Daily Dose, Non-Cancer Exposures
(IADD) (mg/m3)

1.2E-02

1.2E-02



Chronic Average Daily Dose, Non-Cancer Exposures (ADD)
(mg/kg/day)

1.2E-02

1.2E-02

Note: For high-end estimates, EPA assumed the exposure surface area was equivalent to mean values for two-hand
surface areas {i.e., 1.070 cm2 for male workers and 890 cm2 for female workers) (U.S. EPA, 2011). For central

tendency estimates, EPA assumed the exposure surface area was equivalent to only a single hand (or one side of two
hands) and used half the mean values for two-hand surface areas (i.e.. 535 cm2 for male workers and 445 cm2for

female workers).







4071	3.15.4.4 Occupational Aggregate Exposure Results

4072	Inhalation and dermal exposure estimates were aggregated based on the approach described in Appendix

4073	A.3 to arrive at the aggregate worker and ONU exposure estimates in the table below. The assumption

4074	behind this approach is that an individual worker could be exposed by both the inhalation and dermal

4075	routes, and the aggregate exposure is the sum of these exposures.

4076

4077	Table 3-90. Summary of Estimated Worker Aggregate Exposures for Disposal		

Modeled Scenario

Exposure Concentration Type
(mg/kg-day)

Central
Tendency

High-End

Average Adult Worker

Acute (AD, mg/kg-day)

3.0E-02

0.23

Intermediate (IADD, mg/kg-day)

2.2E-02

0.17

Chronic, Non-Cancer (ADD, mg/kg-day)

2.1E-02

0.16

Female of Reproductive Age

Intermediate (IADD, mg/kg-day)

3.0E-02

0.25

Chronic, Non-Cancer (ADD, mg/kg-day)

2.2E-02

0.18

Chronic, Cancer (LADD, mg/kg-day)

2.1E-02

0.17

ONU

Acute (AD, mg/kg-day)

3.0E-02

3.0E-02

Chronic, Non-Cancer (ADD, mg/kg-day)

2.2E-02

2.2E-02

Chronic, Cancer (LADD, mg/kg-day)

2.1E-02

2.1E-02

Note: A worker could be exposed by both the inhalation and dermal routes, and the aggregate exposure is the sum of
these exposures.

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4078

4079

4080

4081

4082

4083

4084

4085

4086

4087

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PUBLIC RELEASE DRAFT
May 2025

3.16 Distribution in Commerce

3,16,1 Process Description

For purposes of assessment in this risk evaluation, distribution in commerce consists of the
transportation associated with the moving of DBP or DBP-containing products and/or articles between
sites manufacturing, processing, and use COUs, or the transportation of DBP containing wastes to
recycling sites or for final disposal. EPA expects all the DBP or DBP-containing products and/or articles
to be transported in closed system or otherwise to be transported in a form (e.g., articles containing
DBP) such that there is negligible potential for releases except during an incident. Therefore, no
occupational exposures are reasonably expected to occur, and no separate assessment was performed for
estimating releases and exposures from distribution in commerce.

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4089

4090

4091

4092

4093

4094

4095

4096

4097

4098

4099

4100

4101

4102

4103

4104

4105

4106

4107

4108

4109

PUBLIC RELEASE DRAFT
May 2025

4 WEIGHT OF SCIENTIFIC EVIDENCE CONCLUSIONS
4.1 Environmental Releases

For each OES, EPA considered the assessment approach; the quality of the data and models; and the
strengths, limitations, assumptions, and key sources of uncertainties in the assessment results to
determine a weight of the scientific evidence rating. EPA considered factors that increase or decrease the
strength of the evidence supporting the release estimate (e.g., quality of the data/information), the
applicability of the release or exposure data to the OES (e.g., temporal relevance, locational relevance),
and the representativeness of the estimate for the whole industry. EPA used the descriptors of robust,
moderate, slight, or indeterminant to categorize the available scientific evidence using its best
professional judgment, according to EPA's Application of Systematic Review in TSCA Risk Evaluations
(I	). EPA used slight to describe limited information that does not sufficiently cover all

sites within the OES, and for which the assumptions and uncertainties are not fully known or
documented. See EPA's Application of Systematic Review in TSCA Risk Evaluations (	321a)

for additional information on weight of the scientific evidence conclusions. Release data was primarily
sourced from 2017 to 2022 TRI(l v	: ), 2017 and 2020 NEI ( * ซ ซ \ 2023a. .Or), and

DMR (	324a). NEI data has a high data quality rating from EPA's systematic review process;

TRI and DMR have high data quality ratings.

Table 4-1 and Table 4-2 provide a summary of EPA's overall weight of scientific evidence conclusions
in its environmental release estimates for each OES.

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4110 Table 4-1. Summary of the Data Sources Used for Environmental Releases by PES

OES

Release Media

Reported Data"

Data Quality
Ratings for
Reported Data''

Modeling

Data Quality
Ratings for
Modeling'

Weight of Scientific
Evidence Conclusion

Manufacturing

Fugitive air

X

N/A

y^

M

Moderate

Stack air

X

N/A

y^

M

Water, incineration, or landfill

X

N/A

y^

M

Import and repackaging

Water



M-H

X

N/A

Moderate to Robust

Fugitive air



M-H

X

N/A

Stack air



M-H

X

N/A

Land



M-H

X

N/A

Incorporation into
formulation, mixture, or
reaction product

Water



M-H

X

N/A

Moderate to Robust

Fugitive air



M-H

X

N/A

Stack air



M-H

X

N/A

Land



M-H

X

N/A

PVC plastics
compounding

Water



M-H

X

N/A

Moderate to Robust (Air
and Water)

Moderate (Land)

Fugitive air



M-H

X

N/A

Stack air



M-H

X

N/A

Land



M-H

X

N/A

PVC plastics
converting

Water



M-H

X

N/A

Moderate to Robust
(Air)

Moderate (Land and
Water)

Fugitive air



M-H

X

N/A

Stack air



M-H

X

N/A

Land



M-H

X

N/A

Non-PVC plastic
manufacturing
(compounding and
converting)

Water



M-H

X

N/A

Moderate to Robust

Fugitive air



M-H

X

N/A

Stack air



M-H

X

N/A

Land



M-H

X

N/A

Application of
adhesives and sealants

Water

3c

N/A

y^

M

Moderate to Robust
(Air)

Fugitive air



M-H

X

N/A

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OES

Release Media

Reported Data"

Data Quality
Ratings for
Reported Data''

Modeling

Data Quality
Ratings for
Modeling'

Weight of Scientific
Evidence Conclusion



Stack air

y^

M-H

X

N/A

Moderate (Land and
Water)

Land

X

N/A



M

Application of paints
and coatings

Water

X

N/A



M

Moderate to Robust
(Air)

Moderate (Land and
Water)

Fugitive air

y^

M-H

3c

N/A

Stack air

y^

M-H

3c

N/A

Incineration or landfill

X

N/A



M

Water, incineration, or landfill

X

N/A



M

Unknown (air, water,
incineration, or landfill)

X

N/A



M

Industrial process
solvent use

Water

X

N/A

3C

N/A

Moderate to Robust
(Air)

Moderate (Land)

Fugitive air

y^

M-H

3C

N/A

Stack air

i/

M-H

3C

N/A

Land

i/

M-H

3C

N/A

Use of laboratory
chemicals (liquid)

Fugitive air

i/

H

3C

N/A

Moderate to Robust
(Air)

Moderate (Land and
Water)

Water, incineration, or landfill

X

N/A



M

Use of laboratory
chemicals (solid)

Fugitive air

i/

H



M

Moderate to Robust
(Air)

Moderate (Land and
Water)

Incineration or landfill

X

N/A



M

Water, incineration, or landfill

X

N/A



M

Unknown media (air, water,
incineration, or landfill)

X

N/A



M

Unknown (air, water,
incineration, or landfill)

X

N/A



M

Use of lubricants and
functional fluids

Land

X

N/A



M

Moderate

Water

X

N/A



M

Recycling

X

N/A



M

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OES

Release Media

Reported Data"

Data Quality
Ratings for
Reported Data''

Modeling

Data Quality
Ratings for
Modeling'

Weight of Scientific
Evidence Conclusion



Fuel blending (incineration)

X

N/A



M



Use of penetrants and
inspection fluids

Fugitive air

X

N/A



M

Moderate

Water, incineration, or landfill

X

N/A



M

Fabrication or use of
final product or articles

No data were available to estimate releases for this OES and there were no suitable surrogate release data or models. This
release is described qualitatively.

Recycling

Water



M-H

X

N/A

Moderate

Fugitive air



M-H

X

N/A

Stack air



M-H

X

N/A

Land



M-H

X

N/A

Waste handling,
treatment, and disposal

Water



M-H

X

N/A

Moderate to Robust

Fugitive air



M-H

X

N/A

Stack air



M-H

X

N/A

Land



M-H

X

N/A

a Reported data includes data obtained from EPA databases (i.e., TRI, NEI, DMR).

b Data quality ratings for reported data are based on EPA systematic review and include ratings Low (L), Medium (M), and High (H)
c Data quality ratings for models include ratings of underlying literature sources used to select model approaches and input values/distributions such as a
GS/ESD used in tandem with Monte Carlo modeling.

4111

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4113	OES

OES

Weight of Scientific Evidence Conclusion in Release Estimates

Manufacturing

EPA found limited chemical specific data for the manufacturing OES and assessed environmental releases using models and model
parameters derived from CDR, the 2023 Methodology for Estimating Environmental Releases from Sampling Wastes ( A,
2023c). and sources identified through systematic review (including surrogate—DINP and DIDP—industrv-supplied data). EPA
used EPA/OPPT models combined with Monte Carlo modeling to estimate releases to the environment, with media of release
assessed using appropriate default input parameters from EPA/OPPT models and industry supplied data. EPA believes a strength of
the Monte Carlo modeling approach is that variation in model input values allow for estimation of a range of potential release values
that are more likely to capture actual releases than a discrete value. Additionally, Monte Carlo modeling uses a large number of data
points (simulation runs) and considers the full distributions of input parameters. EPA used facility-specific DBP manufacturing
volumes for all facilities that reported this information to CDR. For facilities that did not report DBP manufacturing volumes to
CDR, operating parameters were derived using data from a current U.S. manufacturing site for DIDP and DINP that is assumed to
operate using similar operating parameters as DBP manufacturing. This information was used to provide more accurate estimates
than the generic values provided by the EPA/OPPT models. These strengths increase the weight of evidence.

The primary limitation of EPA's approach is the uncertainty in the representativeness of release estimates toward the true
distribution of potential releases. In addition, one DBP manufacturing site and two manufacturing and/or import sites claimed their
DBP production volume as CBI for the purpose of CDR reporting; therefore, DBP throughput estimates for these sites are based on
the national aggregate PV and reported import volumes from other sites. Additional limitations include uncertainties in the
representativeness of the surrogate industry-provided operating parameters from DIDP and DINP and the generic EPA/OPPT
models used to calculate environmental releases for DBP manufacturing sites. These limitations decrease the weight of evidence.

As discussed above, the strength of the analysis includes using Monte Carlo modeling, which can use a range as an input, increases
confidence in the analysis. However, several uncertainties discussed above, such as using surrogate parameters, reduced the
confidence of the analysis. Therefore, EPA concluded that the weight of scientific evidence for this assessment is moderate,
considering the strengths and limitations of the reasonably available data.

Import and
repackaging

Air releases are assessed using reported releases from 2017-2022 TRI (U.S. EPA. 2024e). and 2017 and 2020 NEI (U.S. EPA.
2023a. 2019). NEI captures additional sources that are not included in TRI due to reporting thresholds. Factors that decrease the
overall confidence for this OES include the uncertainty in the accuracy of reported releases, and the limitations in representativeness
to all sites because TRI and NEI may not capture all relevant sites. The air releases assessment is based on 10 reporting sites in NEI
and 4 reporting sites in TRI. Based on the NAICS and SIC codes used to map data from the reporting databases (CDR, DMR, etc.),
there may be 14 additional repackaging sites that we do not have reported releases for this media in this assessment.

Land releases are assessed using reported releases from 2017-2022 TRI. The primary limitation is that the land releases assessment
is based on two reporting sites (two sites only reported air releases), and EPA did not have additional sources to estimate land
releases from this OES. Based on the NAICS and SIC codes used to map data from the reporting databases (CDR, DMR, NEI, etc.),
there may be 26 additional repackaging sites that do not have reported releases for this media in this assessment.

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Weight of Scientific Evidence Conclusion in Release Estimates



Water releases are assessed using reported releases from 2017-2022 TRI and DMR. The primary strength of TRI data is that TRI
compiles the best readily available release data for all reporting facilities. The primary limitation is that the water release assessment
is based on one reporting site under DMR and four reporting sites in TRI (two sites only reported air releases), and EPA did not
have additional sources to estimate water releases from this OES. Based on the NAICS and SIC codes used to map data from the
reporting databases (CDR, NEI, etc.), there may be 23 additional repackaging sites that do not have reported releases for this media
in this assessment.

As discussed above, the strength of the analysis includes using industry reported release data to various EPA databases. However,
several uncertainties discussed above, such as not capturing all release sources, slightly reduced the confidence of the analysis.
Therefore, EPA concluded that the weight of scientific evidence for this assessment is moderate to robust, considering the strengths
and limitations of reasonably available data.

Incorporation into
formulations,
mixtures, and
reaction products

Air releases are assessed using reported releases from 2017-2022 TRI (U.S. EPA. 2024e). and 2017 and 2020 NEI (U.S. EPA.
2023a. 2019). The primary strength of TRI data is that TRI compiles the data reported directlv bv facilities that manufacture,
process, and/or use DBP. NEI captures additional sources that are not included in TRI due to reporting thresholds. Factors that
decrease the overall confidence for this OES include the uncertainty in the accuracy of reported releases, and the limitations in
representativeness to all sites because TRI and NEI may not capture all relevant sites. The air releases assessment is based on 32
reporting sites under NEI and 18 reporting sites in TRI (two sites reported under both TRI and NEI). Based on the NAICS and SIC
codes used to map data from the reporting databases (CDR, DMR, etc.), there may be two additional incorporation into formulation,
mixture, or reaction product sites that do not have reported releases for this media in this assessment. The relatively large number of
reporting sites is a strength for these release estimates as they add variability to the assessment and as a result are more likely to be
representative of the industry as a whole.

Land releases are assessed using reported releases from 2017-2022 TRI. The primary limitation is that the land releases assessment
is based on three reporting sites, and EPA did not have additional sources to estimate land releases from this OES. Based on the
NAICS and SIC codes used to map data from the reporting databases (CDR, DMR, NEI, etc.), there may be 47 additional
incorporation into formulation, mixture, or reaction product sites that do not have reported releases for this media in this assessment.

Water releases are assessed using reported releases from 2017-2022 TRI. Factors that decrease the overall confidence for this OES
include the uncertainty in the accuracy of reported releases, the limitations in representativeness to all sites because TRI may not
capture all relevant sites, and EPA did not have additional sources to estimate water releases from this OES. The water releases
assessment is based on 11 reporting sites in TRI. Based on the NAICS and SIC codes used to map data from the reporting databases
(CDR, NEI, etc.), there may be 39 additional incorporation into formulation, mixture, or reaction product sites that do not have
reported releases for this media in this assessment.

As discussed above, the strength of the analysis includes using industry reported release data to various EPA databases. However,
several uncertainties discussed above, such as not capturing all release sources, slightly reduced the confidence of the analysis.

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Weight of Scientific Evidence Conclusion in Release Estimates



Therefore, EPA concluded that the weight of scientific evidence for this assessment is moderate to robust, considering the strengths
and limitations of reasonably available data.

PVC plastics
compounding

Air releases are assessed usine reported releases from 2017-2022 TRI (U.S. EPA, 2024e). and 2017 and 2020 NEI (U.S. EPA,
2023a. 2019). The primary strength of TRI data is that TRI compiles the data reported directlv bv facilities that manufacture,
process, and/or use DBP. NEI captures additional sources that are not included in TRI due to reporting thresholds. Factors that
decrease the overall confidence for this OES include the uncertainty in the accuracy of reported releases, and the limitations in
representativeness to all sites because TRI and NEI may not capture all relevant sites. The air releases assessment is based on one
reporting site under NEI and one reporting site in TRI. Based on the NAICS and SIC codes used to map data from the reporting
databases (CDR, DMR, etc.), there may be 15 additional PVC plastics compounding sites that do not have reported releases for this
media in this assessment.

TRI reporters identified for this OES reported zero releases for land; however, it is uncertain if that is representative for PVC
compounding sites as a whole. Because of this, EPA assessed land releases using surrogate data from sites that were identified under
the OES for non-PVC materials manufacturing. Releases were estimated using reported releases from 2017-2022 TRI. The primary
limitation is that the land releases assessment is based on three reporting sites, and EPA did not have additional sources to estimate
land releases from this OES.

Water releases are assessed using reported releases from to DMR (U.S. EPA. 2024a). The primarv strength of DMR data is that it
may capture additional sources that are not included in TRI due to reporting thresholds. A factor that decreases the overall
confidence for this OES include the uncertainty in the accuracy of reported releases. The water releases assessment is based on 14
reporting sites. Based on the NAICS and SIC codes used to map data from the reporting databases (CDR, NEI, etc.), there may be
three PVC plastics compounding sites that do not have reported releases for this media in this assessment.

As discussed above, the strength of the analysis includes using industry reported release data to various EPA databases. However,
several uncertainties discussed above, such as not capturing all release sources, slightly reduced the confidence of the analysis.
Therefore, EPA concluded that the weight of scientific evidence for this assessment is moderate to robust, considering the strengths
and limitations of reasonably available data.

PVC plastics
converting

Air releases are assessed usina reported releases from 2017-2022 TRI (U.S. EPA, 2024e). and 2017 and 2020 NEI (U.S. EPA,
2023a. 2019). The primarv strength of TRI data is that TRI compiles the data reported directlv bv facilities that manufacture,
process, and/or use DBP. NEI captures additional sources that are not included in TRI due to reporting thresholds. Factors that
decrease the overall confidence for this OES include the uncertainty in the accuracy of reported releases, and the limitations in
representativeness to all sites because TRI and NEI may not capture all relevant sites. The air releases assessment is based on seven
reporting sites under NEI and one reporting site in TRI. Based on the NAICS and SIC codes used to map data from the reporting
databases (CDR, DMR, etc.), there may be two additional PVC plastics converting sites that do not have reported releases for this
media in this assessment.

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OES

Weight of Scientific Evidence Conclusion in Release Estimates



EPA did not identify land release data from TRI reporters for this OES. These releases were assessed using surrogate data from sites
that were identified under the OES for non-PVC materials manufacturing due to expected similarities in the processes that occur at
the sites. Releases were estimated using reported releases from 2017-2022 TRI. The primary limitation is that the land releases
assessment is based on three reporting sites, and EPA did not have additional sources to estimate land releases from this OES.

EPA did not identify water release data from TRI and DMR reporters for this OES. These releases are assessed using surrogate data
from sites that were identified under the OES for PVC plastics compounding due to expected similarities in the processes that occur
at the sites. Water releases are assessed using reported releases from to DMR ("U.S. EPA. 2024a). The primarv strength of DMR data
is that it may capture additional sources that are not included in TRI due to reporting thresholds. A factor that decreases the overall
confidence for this OES include the uncertainty in the accuracy of reported releases. The water releases assessment is based on 14
reporting sites.

As discussed above, the strength of the analysis includes using industry reported release data to various EPA databases. However,
several uncertainties discussed above, such as not capturing all release sources, slightly reduced the confidence of the analysis.
Therefore, EPA concluded that the weight of scientific evidence for this assessment is moderate to robust, considering the strengths
and limitations of reasonably available data.

Non-PVC material
manufacturing

Air releases are assessed usina reported releases from 2017-2022 TRI (U.S. EPA, 2024e). and 2017 and 2020 NEI (U.S. EPA,
2023a. 2019). NEI captures additional sources that are not included in TRI due to reporting thresholds. Factors that decrease the
overall confidence for this OES include the uncertainty in the accuracy of reported releases, and the limitations in representativeness
to all sites because TRI and NEI may not capture all relevant sites. The air releases assessment is based on 49 reporting sites under
NEI and 4 reporting sites in TRI (one site reported under both TRI and NEI). The relatively large number of reporting sites is a
strength for these release estimates as they add variability to the assessment and as a result are more likely to be representative of the
industry as a whole.

Land releases are assessed using reported releases from 2017-2022 TRI. The primary limitation is that the land releases assessment
is based on three reporting sites, and EPA did not have additional sources to estimate land releases from this OES. Based on the
NAICS and SIC codes used to map data from the reporting databases (CDR, DMR, NEI, etc.), there may be 49 additional non PVC-
material manufacturing sites that do not have reported releases for this media in this assessment.

Water releases are assessed using reported releases from 2017-2022 TRI. The primary strength of TRI data is that TRI compiles the
best readily available release data for all reporting facilities. Factors that decrease the overall confidence for this OES include the
uncertainty in the accuracy of reported releases, the limitations in representativeness to all sites because TRI may not capture all
relevant sites, and EPA did not have additional sources to estimate water releases from this OES. The water releases assessment is
based on 1 reporting site in TRI. Based on the NAICS and SIC codes used to map data from the reporting databases (CDR, NEI,
etc.), there may be 51 additional sites that do not have reported releases for this media in this assessment.

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Weight of Scientific Evidence Conclusion in Release Estimates



As discussed above, the strength of the analysis includes using industry reported release data to various EPA databases. However,
several uncertainties discussed above, such as not capturing all release sources, slightly reduced the confidence of the analysis.
Therefore, EPA concluded that the weight of scientific evidence for this assessment is moderate to robust, considering the strengths
and limitations of reasonably available data.

Application of
adhesives and
sealants

Air releases are assessed using reported releases from 2017 and 2020 NEI ("U.S. EPA. 2023a. 2019). NEI captures additional sources
that are not included in TRI due to reporting thresholds. Another factor that increases the strength of the data is that air release data
was provided by 166 reporting sites, which adds variability to the assessment. Factors that decrease the overall confidence for this
OES include the uncertainty in the accuracy of reported releases, the fact that the type of end-use product is uncertain between
adhesives/sealants and paint/coatings, and the limitations in representativeness to all sites because NEI may not capture all relevant
sites.

EPA was unable to identify chemical and site-specific releases to land and water and assessed these releases using the ESD on the
Use of Adhesives (OECD, 2015). EPA used EPA/O PPT models combined with Monte Carlo modeling to estimate releases to the
environment, and media of release using appropriate default input parameters from the ESD and EPA/OPPT models. EPA believes a
strength of the Monte Carlo modeling approach is that variation in model input values allow for estimation of a range of potential
release values that are more likely to capture actual releases than a discrete value. Monte Carlo modeling also considers a large
number of data points (simulation runs) and the full distributions of input parameters. Additionally, EPA used DBP-specific data on
concentration and application methods for different DBP-containing adhesives and sealant products in the analysis. These data
provide more accurate estimates than the generic values provided by the ESD. These strengths increase the weight of evidence.

The primary limitation of EPA's approach to land and water releases is the uncertainty in the representativeness of estimated release
values toward the true distribution of potential releases at all sites in this OES. Specifically, the generic default values in the ESD
may not represent releases from real-world sites that incorporate DBP into adhesives and sealants. Based on the number of
formulated products identified, the overall production volume of DBP for this OES was estimated by assuming that the portion of
DBP with uncertain end-use will be split between adhesives/sealants and paint/coating products. EPA lacks data on DBP-specific
facility use volume and number of use sites; therefore, EPA based facility throughput estimates and number of sites on industry-
specific default facility throughputs from the ESD, DBP product concentrations, and the overall production volume range from CDR
data which has a reporting threshold of 25,000 lb. These limitations decrease the weight of evidence.

As discussed above, the strength of the analysis includes using industry reported release data to various EPA databases. However,
several uncertainties discussed above, such as not capturing all release sources, slightly reduced the confidence of the analysis.
Therefore, EPA concluded that the weight of scientific evidence for this assessment is moderate to robust, considering the strengths
and limitations of reasonably available data.

Application of
paints and coatings

Air releases are assessed usina reported releases from 2017 and 2020 NEI (U.S. EPA, 2023a. 2019). NEI captures additional sources
that are not included in TRI due to reporting thresholds. Another factor that increases the strength of the data is that air release data
was provided by 166 reporting sites, which adds variability to the assessment. Factors that decrease the overall confidence for this
OES include the uncertainty in the accuracy of reported releases, the fact that the type of end-use product is uncertain between

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Weight of Scientific Evidence Conclusion in Release Estimates



adhesives/sealants and paint/coatings, and the limitations in representativeness to all sites because NEI may not capture all relevant
sites.

EPA was unable to identify chemical and site-specific releases to land and water and assessed these releases using the ESD on the
Application of Radiation Curable Coatings, Inks and Adhesives and the GS on Coating Application via Spray Painting in the
Automotive Refinishine Industry (OECD. 201 la. b). EPA used EPA/OPPT models combined with Monte Carlo modeling to
estimate releases to the environment. EPA assessed media of release using appropriate default input parameters from the ESD, GS,
and EPA/OPPT models and a default assumption that all paints and coatings are applied via spray application. EPA believes a
strength of the Monte Carlo modeling approach is that variation in model input values allow for estimation of a range of potential
release values that are more likely to capture actual releases than a discrete value. Monte Carlo modeling also considers a large
number of data points (simulation runs) and the full distributions of input parameters. Additionally, EPA used DBP-specific data on
concentration for different DBP-containing paints and coatings in the analysis. These data provide more accurate estimates than the
generic values provided by the GS and ESD. These strengths increase the weight of evidence.

The primary limitation of EPA's approach to land and water releases is the uncertainty in the representativeness of estimated release
values toward the true distribution of potential releases at all sites in this OES. Specifically, the generic default values in the GS and
ESD may not represent releases from real-world sites that incorporate DBP into paints and coatings. Additionally, EPA assumes
spray applications of the coatings, which may not be representative of other coating application methods. In addition, EPA lacks
data on DBP-specific facility use volume and number of use sites; therefore, EPA based throughput estimates on values from ESD,
GS, and CDR data which has a reporting threshold of 25,000 lb and an annual DBP production volume range. Finally, EPA
estimated the overall production volume of DBP for this OES by assuming that the portion of DBP with uncertain end-use will be
split between adhesives/sealants and paint/coating products. These limitations decrease the weight of evidence.

As discussed above, the strength of the analysis includes using industry reported release data to NEI and using Monte Carlo
modeling which can use range as an input. However, several uncertainties discussed above, such as the unavailability of reported
releases for land and water, slightly reduced the confidence of the analysis. Therefore, EPA concluded that the weight of scientific
evidence for this assessment is moderate to robust, considering of the strengths and limitations of reasonably available data.

Industrial process
solvent use

Air releases are assessed using reported releases from 2017-2022 TRI (U.S. EPA. 2024e). and 2017 and 2020 NEI (U.S. EPA.
2023a. 2019). NEI captures additional sources that are not included in TRI due to reporting thresholds. Factors that decrease the
overall confidence for this OES include the uncertainty in the accuracy of reported releases, and the limitations in representativeness
to all sites because TRI and NEI may not capture all relevant sites. The air releases assessment is based on two reporting sites under
NEI and one reporting site in TRI (site reported under both TRI and NEI). Based on the NAICS and SIC codes used to map data
from the reporting databases (CDR, DMR, etc.), there may be one additional industrial process solvent use site that is not accounted
for in this assessment.

EPA was unable to identify land release data from TRI reporters for this OES. These releases were assessed using surrogate data
from sites that were identified under the OES for incorporation into formulation, mixtures, or reaction products due to expected

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Weight of Scientific Evidence Conclusion in Release Estimates



similarities in the processes that occur at the sites. Land releases were estimated using reported releases from 2017-2022 TRI. The
primary limitation is that the land releases assessment is based on three reporting sites, and EPA did not have additional sources to
estimate land releases from this OES.

EPA was unable to identify water release data from TRI and DMR reporters for this OES; however, based on the specifics of DBP's
use in the process, EPA does not expect water releases for this OES. This is based on process information provided by Huntsman
Corporation, which was rated hiah in svstematic review ("Huntsman. 2015).

As discussed above, the strength of the analysis includes using industry reported release data to various EPA databases. However,
several uncertainties discussed above, such as not capturing all release sources or using surrogate reported releases, slightly reduced
the confidence of the analysis. Therefore, EPA concluded that the weight of scientific evidence for this assessment is moderate to
robust, considering of the strengths and limitations of reasonably available data.

Use of laboratory
chemicals

Air releases are assessed usine reported releases from 2017 and 2020 NEI (U.S. EPA, 2023a. 2019). NEI captures additional sources
that are not included in TRI due to reporting thresholds. NEI data was collected from two reporting sites. Factors that decrease the
overall confidence for this OES include the uncertainty in the accuracy of reported releases, and the limitations in representativeness
to all sites because NEI may not capture all relevant sites.

EPA were unable to identify chemical and site-specific releases to land and water and assessed these releases using the Draft GS on
the Use of laboratory chemicals (U.S. EPA. 2023d). EPA used EPA/OPPT models combined with Monte Carlo modeling to estimate
releases to the environment, and media of release using appropriate default input parameters from the GS and EPA/OPPT models for
solid and liquid DBP materials. EPA believes a strength of the Monte Carlo modeling approach is that variation in model input
values allow for estimation of a range of potential release values that are more likely to capture actual releases than a discrete value.
Monte Carlo modeling also considers a large number of data points (simulation runs) and the full distributions of input parameters.
EPA used SDSs from identified laboratory DBP products to inform product concentration and material states. These strengths
increase the weight of evidence.

EPA believes the primary limitation of the land and water release assessments to be the uncertainty in the representativeness of
values toward the true distribution of potential releases. In addition, EPA lacks data on DBP-specific laboratory chemical throughput
and number of laboratories; therefore, EPA based the number of laboratories and throughput estimates on stock solution throughputs
from the Draft GS on the Use of laboratory chemicals and on CDR reporting thresholds. Additionally, because no entries in CDR
indicate a laboratory use and there were no other sources to estimate the volume of DBP used in this OES, EPA developed a high-
end bounding estimate based on the CDR reporting threshold of 25,000 lb or 5 percent of total product volume for a given use,
which by definition is expected to over-estimate the average release case. These limitations decrease the weight of evidence.

As discussed above, the strength of the analysis includes using industry reported release data to NEI and using Monte Carlo
modeling which can use range as an input. However, several uncertainties discussed above, such as the unavailability of reported

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Weight of Scientific Evidence Conclusion in Release Estimates



releases for land and water, slightly reduced the confidence of the analysis. Therefore, EPA concluded that the weight of scientific
evidence for this assessment is moderate to robust, considering of the strengths and limitations of reasonably available data.

Use of lubricants
and functional fluids

EPA found limited chemical specific data for the use of lubricants and functional fluids OES and assessed releases to the
environment using the ESD on the Lubricant and Lubricant Additives. EPA used EPA/OPPT models combined with Monte Carlo
modeling to estimate releases to the environment, and media of release using appropriate default input parameters from the ESD and
EPA/OPPT models. EPA believes the strength of the Monte Carlo modeling approach is that variation in model input values and a
range of potential release values are more likely to capture actual releases than discrete values. Monte Carlo modeling also considers
a large number of data points (simulation runs) and the full distributions of input parameters. EPA did not identify a lubricant or
functional fluid product that contained DBP but identified one DINP-containing functional fluid for use in Monte Carlo analysis for
the Risk Evaluation for that chemical. Therefore, EPA used products containing DINP as surrogate for concentration and use data in
the analysis. This data provides more accurate estimates than the generic values provided by the ESD.

The primary limitation of EPA's approach is the uncertainty in the representativeness of estimated release values toward the true
distribution of potential releases at all sites in this OES. Specifically, the generic default values in the ESD may not represent
releases from real-world sites using DBP-containing lubricants and functional fluids. In addition, EPA lacks information on the
specific facility use rate of DBP-containing products and number of use sites; therefore, EPA estimated the number of sites and
throughputs based on CDR, which has a reporting threshold of 25,000 lb (i.e., not all potential sites represented), and an annual DBP
production volume range that spans an order of magnitude. The respective share of DBP use for each OES presented in the EU Risk
Assessment Report may differ from actual conditions adding some uncertainty to estimated releases. Furthermore, EPA lacks
chemical-specific information on concentrations of DBP in lubricants and functional fluids and primarily relied on surrogate data.
Actual concentrations may differ adding some uncertainty to estimated releases.

As discussed above, the strength of the analysis includes using Monte Carlo modeling, which can use a range as an input, increases
confidence in the analysis. However, several uncertainties discussed above, such as the lack of availability of reported releases,
reduced the confidence of the analysis. Therefore, EPA concluded that the weight of scientific evidence for this assessment is
moderate, considering the strengths and limitations of the reasonably available data.

Use of penetrants
and inspection
fluids

EPA found limited chemical specific data for the use of penetrants and inspection fluids OES and assessed releases to the
environment usine the ESD on the Use of Metal work ins* Fluids (OECD, 201 lc). EPA used EPA/OPPT models combined with
Monte Carlo modeling to estimate releases to the environment, and media of release using appropriate default input parameters from
the ESD, and EPA/OPPT models. EPA believes the strength of the Monte Carlo modeling approach is that variation in model input
values and a range of potential release values are more likely to capture actual releases than discrete values. Monte Carlo modeling
also consider a large number of data points (simulation runs) and the full distributions of input parameters. EPA assessed an aerosol
and non-aerosol application method based on surrogate DINP-specific penetrant data which also provided DINP concentration. The
safety and product data sheets that EPA used to obtain these values provide more accurate estimates than the generic values
provided by the ESD.

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The primary limitation of EPA's approach is the uncertainty in the representativeness of estimated release values toward the true
distribution of potential releases at all sites in this OES. Specifically, the generic default values in the ESD and the surrogate
material parameters may not be representative of releases from real-world sites that use DBP-containing inspection fluids and
penetrants. Additionally, because no entries in CDR indicate this OES use case and there were no other sources to estimate the
volume of DBP used in this OES, EPA developed a high-end bounding estimate based on CDR reporting threshold, which by
definition is expected to overestimate the average release case.

As discussed above, the strength of the analysis includes using Monte Carlo modeling, which can use a range as an input, increases
confidence in the analysis. However, several uncertainties discussed above, such as the lack of availability of reported releases,
reduced the confidence of the analysis. Therefore, EPA concluded that the weight of scientific evidence for this assessment is
moderate, considering the strengths and limitations of the reasonably available data.

Fabrication or use
of final product or
articles

No data were available to estimate releases for this OES and there were no suitable surrogate release data or models. This release is
described qualitatively.

Recycling

EPA found limited chemical specific data for the recycling OES. EPA assessed releases to the environment from recycling activities
usina the Revised Draft GS for the Use of Additives in Plastic Compounding (US. EPA. 2021c) as surrogate for the recvclina
process. EPA/OPPT models were combined with Monte Carlo modeling to estimate releases to the environment. EPA believes the
strength of the Monte Carlo modeling approach is that variation in model input values and a range of potential release values are
more likely to capture actual releases than discrete values. Monte Carlo modeling also considers a large number of data points
(simulation runs) and the full distributions of input parameters. EPA referenced the Quantification and evaluation of plastic waste in
the United States (Milbrandt et aL 2022). to estimate the rate of PVC recvclina in the U.S. EPA estimated the DBP PVC market
share (based on the surrogate market shares from DINP and DIDP) to define an approximate recycling volume of PVC containing
DBP. These strengths increase the weight of evidence.

The primary limitation of EPA's approach is the uncertainty in the representativeness of estimated release values toward the true
distribution of potential releases at all sites in this OES. Specifically, the generic default values and release points in the GS
represent all types of plastic compounding sites and may not represent sites that recycle PVC products containing DBP. In addition,
EPA lacks DBP-specific PVC recycling rates and facility production volume data; therefore, EPA based throughput estimates on
PVC plastics compounding data and U.S. PVC recycling rates, which are not specific to DBP, and may not accurately reflect current
U.S. recycling volume. DBP may also be present in non-PVC plastics that are recycled; however, EPA was unable to identify
information on these recycling practices. These limitations decrease the weight of evidence.

As discussed above, the strength of the analysis includes using Monte Carlo modeling, which can use a range as an input, increases
confidence in the analysis. However, several uncertainties discussed above, such as the lack of availability of reported releases,
reduced the confidence of the analysis. Therefore, EPA concluded that the weight of scientific evidence for this assessment is
moderate, considering the strengths and limitations of the reasonably available data.

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Waste handling,
treatment, and
disposal

General Waste Handling, Treatment, and Disposal

Air releases for non-POTW sites are assessed using reported releases from 2017-2022 TRI, and 2017 and 2020 NEI. NEI captures
additional sources that are not included in TRI due to reporting thresholds. Factors that decrease the confidence for this OES include
the uncertainty in the accuracy of reported releases, and the limitations in representativeness to all sites because TRI and NEI may
not capture all relevant sites. The air release assessment is based on 147 sites under NEI and 20 sites in TRI (with 9 sites reporting
under both NEI and TRI). Based on other reporting databases (CDR, DMR, etc), there are 12 additional non-POTW sites that do not
have reported releases for this media in this assessment.

Land releases for non-POTW are assessed using reported releases from 2017-2022 TRI. The primary limitation is that the land
releases assessment is based on 12 reporting sites, and EPA did not have additional sources to estimate land releases from this OES.
Based on the reporting databases (CDR, DMR, NEI, etc.), there are 214 additional waste handling, treatment, and disposal sites that
do not have reported releases for this media in this assessment.

Water releases for non-POTW sites are assessed using reported releases from 2017-2022 TRI and DMR. The primary strength of
TRI data is that TRI compiles the best readily available release data for all reporting facilities. For non-POTW sites, the primary
limitation is that the water release assessment is based on 13 reporting sites under DMR and one reporting site in TRI, and EPA did
not have additional sources to estimate water releases from this OES. Based on other reporting databases (CDR, NEI, etc), there are
156 additional sites that do not have reported releases for this media in this assessment.

As discussed above, the strength of the analysis includes using industry reported release data to various EPA databases. However,
several uncertainties discussed above, such as not capturing all release sources, slightly reduced the confidence of the analysis.
Therefore, EPA concluded that the weight of scientific evidence for this assessment is moderate to robust, considering the strengths
and limitations of reasonably available data.

Waste Handling, Treatment, and Disposal (POTW and Remediation)

Water releases for POTW and remediation sites are assessed using reported releases from 2017-2022 DMR, which has a high
overall data quality determination from the systematic review process. A strength of using DMR data and the Pollutant Loading
Tool used to pull the DMR data is that the tool calculates an annual pollutant load by integrating monitoring period release reports
provided to the EPA and extrapolating over the course of the year. However, this approach assumes average quantities,
concentrations, and hydrologic flows for a given period are representative of other times of the year. A total of 57
POTW/remediation sites reported releases of DBP to DMR. Based on this information, for POTW releases, EPA has concluded that
the weight of scientific evidence for this assessment is moderate to robust, considering the strengths and limitations of reasonably
available data.

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4.2 Occupational Exposures

Judgment on the weight of scientific evidence is based on the strengths, limitations, and uncertainties
associated with the exposure estimates. The Agency considers factors that increase or decrease the
strength of the evidence supporting the exposure estimate—including quality of the data/information,
applicability of the exposure data to the COU (including considerations of temporal and locational
relevance) and the representativeness of the estimate for the whole industry. The best professional
judgment is summarized using the descriptors of robust, moderate, slight, or indeterminant, in
accordance with the Draft Systematic Review Protocol Supporting TSCA Risk Evaluations for Chemical
Substances, Version 1.0: A Generic TSCA Systematic Review Protocol with Chemical-Specific
Methodologies (also called "Draft Systematic Review Protocol") (	2021a). For example, a

conclusion of moderate weight of scientific evidence is appropriate where there is measured exposure
data from a limited number of sources, such that there is a limited number of data points that may not be
representative of worker activities or potential exposures. A conclusion of slight weight of scientific
evidence is appropriate where there is limited information that does not sufficiently cover all potential
exposures within the COU, and the assumptions and uncertainties are not fully known or documented.
See the Draft Systematic Review Protocol (	1021a) for additional information on weight of

scientific evidence conclusions.

Table 4-3 provides a summary of EPA's overall confidence in its occupational exposure estimates for
each of the OESs assessed.

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Table 4-3. Summary of Assumptions, Uncertainty, and Overall Confidence in Inhalation Exposure Estimates by PES

OES

Weight of Scientific Evidence Conclusion in Exposure Estimates

Manufacturing

EPA considered the assessment approach, the quality of the data, and uncertainties in assessment results to determine a weight of
scientific evidence conclusion for the full-shift TWA inhalation exposure estimates for the Manufacturing OES. The primary
strength of this approach is the use of directly applicable monitoring data, which is preferrable to other assessment approaches, such
as modeling or the use of occupational exposure limits (OELs). EPA used personal breathing zone (PBZ) air concentration data
pulled from three sources to assess inhalation exposures (ECB. 2008. 2004; SRC, 2001). All three data sources received a ratine of
medium from EPA's systematic review process. These data were DBP-specific, though it is uncertain whether the measured
concentrations accurately represent the entire industry.

The primary limitations of these data include the uncertainty of the representativeness of these data toward the true distribution of
inhalation concentrations for this scenario. Additionally, the dataset is only built on limited data points (3 data source) with a
significant spread of measurements. The SRC source cites an ACC study that provides a datapoint as a worst-case scenario, the
ECJRC, 2008 source only provides a single datapoint with uncertain statistics and the ECJRC, 2004 source provided a dataset with
an uncertain range and number of samples. EPA also assumed eight exposure hours per day and 250 exposure days per year based
on continuous DBP exposure each working day for a typical worker schedule; it is uncertain whether this captures actual worker
schedules and exposures.

Although the use of monitoring data specific to this OES increases the strength of the analysis, but few uncertainties discussed in the
paragraph above reduces confidence of the analysis. Therefore, based on these strengths and limitations, EPA concluded that the
weight of scientific evidence for this assessment is moderate to robust.

Import and
repackaging

EPA used surrogate monitoring data from DBP manufacturing facilities to estimate worker inhalation exposures, due to no relevant
OES-specific data availability for import and repackaging inhalation exposures. The primary strength of this approach is the use of
monitoring data, which is preferrable to other assessment approaches, such as modeling or the use of OELs. EPA used personal
breathing zone (PBZ) air concentration data pulled from three sources to assess inhalation exposures (ECB. 2008. 2004; SRC.
2001). All three data sources received a rating of medium from EPA's systematic review process. These data were DBP-specific.
though it is uncertain whether the measured concentrations accurately represent the entire industry.

The primary limitations of these data include uncertainty in the representativeness of these data for this OES and true distribution of
inhalation concentrations in this scenario. Additionally, the dataset is only built on limited data points (3 data source) with a
significant spread of measurements. The SRC source cites an ACC study that provides a datapoint as a worst-case scenario, the
ECJRC, 2008 source only provides a single datapoint with uncertain statistics and the ECJRC, 2004 source provided a dataset with
an uncertain range and number of samples. EPA also assumed 8 exposure hours per day and 250 exposure days per year based on
continuous DBP exposure each working day for a typical worker schedule; it is uncertain whether this captures actual worker
schedules and exposures.

Although the use of surrogate monitoring data increases the strength of the analysis, but few uncertainties discussed in the paragraph
above reduces confidence of the analysis. Therefore, based on these strengths and limitations, EPA concluded that the weight of
scientific evidence for this assessment is moderate.

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Incorporation into
formulations,
mixtures, or
reaction products

EPA used surrogate monitoring data from DBP manufacturing facilities to estimate worker inhalation exposures, due to no data
availability for Incorporation into formulations, mixtures, or reaction products (adhesives, coatings, and other) inhalation exposures.
The primary strength of this approach is the use of monitoring data, which is preferrable to other assessment approaches, such as
modeling or the use of OELs. EPA used personal breathing zone (PBZ) air concentration data pulled from three sources to assess
inhalation exposures (ECB. 2008. 2004; SRC. 2001). All three data sources received a rating of medium from EPA's systematic
review process. These data were DBP-specific, though it is uncertain whether the measured concentrations accurately represent the
entire industry.

The primary limitations of these data include uncertainty in the representativeness of these data for this OES and the true distribution
of inhalation concentrations in this scenario. Additionally, the dataset is only built on limited data points (3 data source) with a
significant spread of measurements. The SRC source cites an ACC study that provides a datapoint as a worst-case scenario, the
ECJRC, 2008 source only provides a single datapoint with uncertain statistics and the ECJRC, 2004 source provided a dataset with
an uncertain range and number of samples. EPA also assumed 8 exposure hours per day and 250 exposure days per year based on
continuous DBP exposure each working day for a typical worker schedule; it is uncertain whether this captures actual worker
schedules and exposures.

Although the use of surrogate monitoring data increases the strength of the analysis, but few uncertainties discussed in the paragraph
above reduces confidence of the analysis. Therefore, based on these strengths and limitations, EPA concluded that the weight of
scientific evidence for this assessment is moderate.

PVC plastics
compounding

EPA considered the assessment approach, the quality of the data, and the uncertainties in the assessment results to determine a
weight of scientific evidence conclusion for the 8-hour TWA inhalation exposure estimates for PVC plastics compounding. EPA
used surrogate monitoring data from a PVC converting facility to estimate worker inhalation exposures due to no relevant OES-
specific data. The primary strength of this approach is the use of monitoring data, which is preferrable to other assessment
approaches, such as modeling or the use of occupational exposure limits (OELs). EPA used personal breathing zone (PBZ) air
concentration data pulled from one source to assess inhalation exposures to vapor. This source provided worker exposures from two
different studies (ECB, 2004) and received a ratine of medium from EPA's svstematic review process.

EPA also expects compounding activities to generate dust from solid PVC plastic products; therefore, EPA incorporated the PNOR
Model (U.S. EPA, 2021b) into the assessment to estimate worker inhalation exposures to solid particulate. A strength of the model is
that the respirable PNOR range was refined using OSHA CEHD datasets, which EPA tailored to the Plastics and Rubber
Manufacturing NAICS code (NAICS 326). and the resulting dataset contains 237 discrete sample data points (OSHA. 2019). EPA
estimated the highest expected concentration of DBP based on the Generic Scenario for the Use of Additives in Plastic
Compounding (U.S. EPA, 2021c).

The primary limitations of these data include uncertainty in the representativeness of the vapor monitoring data and the PNOR
Model in capturing the true distribution of inhalation concentrations for this OES. Additionally, the vapor monitoring dataset
consisted of just four datapoints for workers, none of the datapoints indicate the worker tasks, and two of the data points are for an
unspecified sector of the "polymer industry". Further, the OSHA CEHD dataset used in the PNOR Model is not specific to DBP.

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Finally, EPA assumed 8 exposure hours per day and 250 exposure days per year based on continuous DBP exposure during each
working day for a typical worker schedule. It is uncertain whether this assumption captures actual worker schedules and exposures.

Although the use of surrogate monitoring data increases the strength of the analysis, but few uncertainties discussed in the paragraph
above reduces confidence of the analysis. Therefore, based on these strengths and limitations, EPA concluded that the weight of
scientific evidence for this assessment is moderate.

PVC plastics
converting

EPA considered the assessment approach, the quality of the data, and the uncertainties in the assessment results to determine a
weight of scientific evidence conclusion for the 8-hour TWA inhalation exposure estimates for PVC plastics converting. EPA used
personal breathing zone (PBZ) air concentration data pulled from one source to assess inhalation exposures to vapor. The primary
strength of this approach is the use of directly applicable monitoring data, which is preferrable to other assessment approaches, such
as modeling or the use of occupational exposure limits (OELs). This source provided worker exposures from two different studies
(ECB, 2004) and received a rating of medium from EPA's svstematic review process.

EPA also expects converting activities to generate dust from solid PVC plastic products; therefore, EPA incorporated the PNOR
Model (U.S. EPA. 2021b) into the assessment to estimate worker inhalation exposures to solid particulate. A strength of the model is
that the respirable PNOR range was refined using OSHA CEHD datasets, which EPA tailored to the Plastics and Rubber
Manufacturing NAICS code (NAICS 326) and the resulting dataset contains 237 discrete sample data points (OSHA, 2019). EPA
estimated the highest expected concentration of DBP based on the Generic Scenario for the Use of Additives in Plastic
Compounding (U.S. EPA. 2021c).

The primary limitations of these data include uncertainty in the representativeness of the vapor monitoring data and the PNOR
Model in capturing the true distribution of inhalation concentrations for this OES. Additionally, the vapor monitoring dataset
consisted of just four datapoints for workers, none of the datapoints indicate the worker tasks, and two of the data points are for an
unspecified sector of the "polymer industry". Further, the OSHA CEHD dataset used in the PNOR Model is not specific to DBP.
Finally, EPA assumed 8 exposure hours per day and 250 exposure days per year based on continuous DBP exposure during each
working day for a typical worker schedule. It is uncertain whether this assumption captures actual worker schedules and exposures.

Although the use of monitoring data specific to this OES increases the strength of the analysis, but few uncertainties discussed in the
paragraph above reduces confidence of the analysis. Therefore, based on these strengths and limitations, EPA concluded that the
weight of scientific evidence for this assessment is moderate to robust.

Non-PVC materials
compounding and
converting

EPA considered the assessment approach, the quality of the data, and the uncertainties in the assessment results to determine a
weight of scientific evidence conclusion for the 8-hour TWA inhalation exposure estimates for non-PVC materials compounding
and converting. EPA used surrogate monitoring data from a PVC converting facility to estimate worker inhalation exposures due to
no relevant OES-specific data. The primary strength of this approach is the use of monitoring data, which is preferrable to other
assessment approaches, such as modeling or the use of occupational exposure limits (OELs). EPA used personal breathing zone
(PBZ) air concentration data pulled from one source to assess inhalation exposures to vapor. This source provided worker exposures
from two different studies (ECB, 2004) and received a ratine of medium from EPA's svstematic review process.

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EPA also expects compounding activities to generate dust from solid PVC plastic products; therefore, EPA incorporated the PNOR
Model (U.S. EPA, 2021b) into the assessment to estimate worker inhalation exposures to solid particulate. A strength of the model is
that the respirable PNOR range was refined using OSHA CEHD datasets, which EPA tailored to the Plastics and Rubber
Manufacturing NAICS code (NAICS 326) and the resulting dataset contains 237 discrete sample data points (OSHA. 2019). EPA
estimated the highest expected concentration of DBP based on the Emission Scenario Document on Additives in Rubber Industry
(OECD. 2004a).

The primary limitations of these data include uncertainty in the representativeness of the vapor monitoring data and the PNOR
Model in capturing the true distribution of inhalation concentrations for this OES. Additionally, the vapor monitoring dataset
consisted of just four datapoints for workers, none of the datapoints indicate the worker tasks, and two of the data points are for an
unspecified sector of the "polymer industry". Further, the OSHA CEHD dataset used in the PNOR Model is not specific to DBP.
Finally, EPA assumed 8 exposure hours per day and 250 exposure days per year based on continuous DBP exposure during each
working day for a typical worker schedule. It is uncertain whether this assumption captures actual worker schedules and exposures.

Although the use of surrogate monitoring data increases the strength of the analysis, but few uncertainties discussed in the paragraph
above reduces confidence of the analysis. Therefore, based on these strengths and limitations, EPA concluded that the weight of
scientific evidence for this assessment is moderate.

Application of
adhesives and
sealants

EPA considered the assessment approach, the quality of the data, and the uncertainties in the assessment results to determine a
weight of scientific evidence conclusion for the 8-hour TWA inhalation exposure estimates for the application of adhesives and
sealants. EPA used monitoring data from a NIOSH HHE that documented exposures at a single furniture assembly site to estimate
worker inhalation exposures to vapor. The primary strength of this approach is the use of directly applicable monitoring data, which
is preferrable to other assessment approaches, such as modeling or the use of occupational exposure limits (OELs). EPA used
personal breathing zone (PBZ) air concentration data from this source to assess inhalation exposures (NIOSH, 1977). The source
received a rating of medium from EPA's systematic review process.

The primary limitations of these data include uncertainty in the representativeness of the vapor monitoring data in capturing the true
distribution of inhalation concentrations for this OES. Only one use site type, furniture manufacturing, is represented by the data and
this may not represent the entire adhesive and sealant industry. Additionally, 100% of the vapor monitoring datapoints were below
the LOD and therefore the actual exposure concentration is unknown with the LOD used as an upper limit of exposure. Finally, EPA
assumed 8 exposure hours per day and 232-250 exposure days per year based on continuous DBP exposure during each working day
for a typical worker schedule with the exposure days representing the 5 0th-95th percentile of the exposure day distribution. It is
uncertain whether this assumption captures actual worker schedules and exposures.

Although the use of monitoring data specific to this OES increases the strength of the analysis, but few uncertainties discussed in the
paragraph above reduces confidence of the analysis. Therefore, based on these strengths and limitations, EPA concluded that the
weight of scientific evidence for this assessment is moderate to robust and provides an upper-bound estimate of exposures.

Application of
paints and coatings

EPA considered the assessment approach, the quality of the data, and the uncertainties in the assessment results to determine a
weight of scientific evidence conclusion for the 8-hour TWA inhalation exposure estimates for the application of paints and

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coatings. EPA identified two full-shift PBZ monitoring samples in OSHA's CEHD and a monitoring dataset from an industry
sponsored study found through EPA's literature search. The primary strength of this approach is the use of directly applicable
monitoring data, which is preferrable to other assessment approaches, such as modeling or the use of occupational exposure limits
(OELs). EPA used personal breathing zone (PBZ) air concentration data from the two sources, which represent three different use
facilities, to assess inhalation exposures (OSHA. 2019 Rohm & Haas. 1990. 1332993). The OSHA CEHD source received a rating
of high and the Rohm & Haas source received a rating of low from EPA's systematic review process.

The primary limitations of these data include uncertainty in the representativeness of the monitoring data in capturing the true
distribution of inhalation concentrations for this OES. Three different use sites are represented by the data but these may not
represent the overall DBP-containing paint and coating industry. Finally, EPA assumed 8 exposure hours per day and 250 exposure
days per year based on continuous DBP exposure during each working day for a typical worker schedule. It is uncertain whether this
assumption captures actual worker schedules and exposures.

Although the use of monitoring data specific to this OES increases the strength of the analysis, but few uncertainties discussed in the
paragraph above reduces confidence of the analysis. Therefore, based on these strengths and limitations, EPA concluded that
the weight of scientific evidence for this assessment is moderate to robust.

Use of industrial
process solvents

EPA considered the assessment approach, the quality of the data, and the uncertainties in the assessment results to determine a
weight of scientific evidence conclusion for the 8-hour TWA inhalation exposure estimates for the Use of industrial process
solvents. Due to no relevant OES-specific data, EPA used surrogate monitoring data from DBP manufacturing facilities to estimate
worker inhalation exposures. The primary strength of this approach is the use of monitoring data, which is preferrable to other
assessment approaches, such as modeling or the use of OELs. EPA used personal breathing zone (PBZ) air concentration data pulled
from three sources to assess inhalation exposures (ECB, 2008. 2004; SRC, 2001). All three data sources received a ratine of medium
from EPA's systematic review process. These data were DBP-specific, though it is uncertain whether the measured concentrations
accurately represent the entire industry.

The primary limitations of these data include uncertainty in the representativeness of these data for this OES and true distribution of
inhalation concentrations in this scenario. Additionally, the dataset is only built on limited data points (3 data source) with a
significant spread of measurements. The SRC source sites an ACC conversation that provides a datapoint as a worst-case scenario,
the ECJRC, 2008 source only provides a single datapoint with uncertain statistics and the ECJRC, 2004 source provided a dataset
with an uncertain range and number of samples. EPA also assumed 8 exposure hours per day and 250 exposure days per year based
on continuous DBP exposure each working day for a typical worker schedule; it is uncertain whether this captures actual worker
schedules and exposures.

Although the use of surrogate monitoring data increases the strength of the analysis, but few uncertainties discussed in the paragraph
above reduces confidence of the analysis. Therefore, based on these strengths and limitations, EPA concluded that the weight of
scientific evidence for this assessment is moderate.

Use of laboratory
chemicals

EPA considered the assessment approach, the quality of the data, and the uncertainties in the assessment results to determine a
weight of scientific evidence conclusion for the 8-hour TWA inhalation exposure estimates for the Use of laboratory chemicals. Due

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to no relevant OES-specific data, EPA used surrogate monitoring data from a NIOSH HHE for Application of adhesives and
sealants OES to estimate worker vapor inhalation exposures, and the PNOR Model (U.S. EPA, 2021b) to characterize worker
particulate inhalation exposures. The primary strength of this approach is the use of monitoring data, which are preferrable to other
assessment approaches, such as modeling or the use of OELs. EPA used personal breathing zone (PBZ) air concentration data from
the NIOSH HHE to assess inhalation exposures (NIOSH. 1977). The source received a rating of medium from EPA's svstematic
review process.

EPA utilized the PNOR Model (U.S. EPA. 2 ) to estimate worker inhalation exposure to solid particulate. The model data is
based on OSHA CEHD data (OSHA, 2019). EPA used a subset of the respirable particulate data from the generic model identified
with the Professional, Scientific, and Technical Services NAICS code (NAICS code 54) to assess this OES, which EPA expects to
be the most representative subset of the particulate data for use of laboratory chemicals in the absence of DBP-specific data. EPA
estimated the highest expected concentration of DBP in identified DBP-containing products applicable to this OES.

The primary limitation of this approach is uncertainty in the representativeness of the vapor monitoring data and the PNOR Model in
capturing the true distribution of inhalation concentrations for this OES. Additionally, the vapor monitoring data come from one
source where the identified samples were below the LOD and therefore the actual exposure concentration is unknown with the LOD
used as an upper limit of exposure. Further, the OSHA CEHD dataset used in the PNOR Model is not specific to DBP. EPA also
assumed 8 exposure hours per day and 250 exposure days per year based on continuous DBP exposure each working day for a
typical worker schedule; it is uncertain whether this captures actual worker schedules and exposures.

Although the use of surrogate monitoring data increases the strength of the analysis, but few uncertainties discussed in the paragraph
above reduces confidence of the analysis. Therefore, based on these strengths and limitations, EPA concluded that the weight of
scientific evidence for this assessment is moderate and provides an upper-bound estimate of exposures.

Use of lubricants
and functional fluids

EPA considered the assessment approach, the quality of the data, and the uncertainties in the assessment results to determine a
weight of scientific evidence conclusion for the 8-hour TWA inhalation exposure estimates for the Use of lubricants and functional
fluids. Due to no relevant OES-specific data, EPA used surrogate monitoring data from the OES for application of adhesives
containing DBP to estimate worker vapor inhalation exposures. The primary strength of this approach is the use of monitoring data,
which are preferrable to other assessment approaches, such as modeling or the use of OELs. EPA used personal breathing zone
(PBZ) air concentration data from this source to assess inhalation exposures (NIOSH. 1977). The source received a rating of
medium from EPA's systematic review process.

The primary limitation of this approach is uncertainty in the representativeness of the vapor monitoring data in capturing the true
distribution of inhalation concentrations for this OES. Additionally, the vapor monitoring data come from one source and 100% of
the data were below the LOD. EPA also assumed 8 exposure hours per day and 2 to 4 exposure days per year based on a typical
equipment maintenance schedule; it is uncertain whether this captures actual worker schedules and exposures.

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Although the use of surrogate monitoring data increases the strength of the analysis, but few uncertainties discussed in the paragraph
above reduces confidence of the analysis. Therefore, based on these strengths and limitations, EPA concluded that the weight of
scientific evidence for this assessment is moderate and provides an upper-bound estimate of exposures

Use of penetrants
and inspection
fluids

EPA considered the assessment approach, the quality of the data, and uncertainties in assessment results to determine a weight of
scientific evidence conclusion for the 8-hour TWA inhalation exposure estimates. EPA developed a Penetrant and Inspection Fluid
Near-Field/Far-Field Inhalation Exposure Model which uses a near-field/far-field approach and the inputs to the model were derived
from references that received ratings of medium-to-high for data quality in the systematic review process. EPA combined this model
with Monte Carlo modeling to estimate occupational exposures in the near-field (worker) and far-field (ONU) inhalation exposures.
A strength of the Monte Carlo modeling approach is that variation in model input values and a range of potential exposure values is
more likely than a discrete value to capture actual exposure at sites, the high number of data points (simulation runs), and the full
distributions of input parameters. EPA identified and used a DINP-containing penetrant/inspection fluid product as surrogate to
estimate concentrations, application methods, and use rate.

The primary limitation is the uncertainty in the representativeness of values toward the true distribution of potential inhalation
exposures. EPA lacks facility and DBP-specific product use rates, concentrations, and application methods, therefore, estimates are
made based on surrogate DINP-containing product. EPA only found one product to represent this use scenario, however, and its
representativeness of all DBP-containing penetrants and inspection fluids is not known. Also, EPA based exposure days and
operating davs as specified in the ESD on the Use of Metalworkina Fluids (OE( ). which mav not be representative of all
facilities and workers that use these products.

Although the use of Monte Carlo modeling increases the strength of the analysis, but few uncertainties discussed in the paragraph
above reduces confidence of the analysis. Therefore, based on these strengths and limitations, EPA has concluded that the weight of
scientific evidence for this assessment is moderate.

Fabrication or use
of final product and
articles

EPA considered the assessment approach, the quality of the data, and uncertainties in assessment results to determine a weight of
scientific evidence conclusion for the full-shift TWA inhalation exposure estimates for the fabrication or use of final products or
articles OES. EPA used monitoring data from a facility melting, shaping, and gluing plastics and a facility welding plastic roofing
components (ECB, 2004; Rudel et ah, 2001) to assess worker inhalation exposures to vapor. Both sources received a ratine of
medium from EPA's svstematic review process. The Aeencv utilized the PNOR Model (U.S. EPA, 2021b) to estimate worker
inhalation exposure to solid particulate. The primary strength of this approach is the use of monitoring data, which is preferrable to
other assessment approaches, such as modeling or the use of OELs. For the vapor exposure, EPA used workplace DBP air
concentration data found from two sources to assess inhalation exposures to vapor. This data was DBP-specific and from facilities
manipulating finished DBP-containing articles.

The respirable particulate concentrations used bv the generic model is based on OSHA CEHD data (OSHA, 2019). EPA used a
subset of the respirable particulate data from the generic model identified with the Furniture and Related Product Manufacturing
NAICS code (NAICS code 337) to assess this OES, which EPA expects to be the most representative subset of the particulate data
for this OES. EPA estimated the highest expected concentration of DBP in particulates during product fabrication using plasticizer

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additive concentration information from the Use of Additives in Plastic Converting Generic Scenario ( 2004a). These
strengths increase the weight of evidence.

The primary limitation is the uncertainty in the representativeness of values toward the true distribution of potential inhalation
exposures. Specifically, EPA lacks facility-specific particulate concentrations in air, and the representativeness of the data set used
in the model towards sites that actually handle DBP is uncertain. Further, the model lacks metadata on worker activities. EPA also
assumed eight exposure hours per day based on continuous DBP particulate exposure while handling DBP-containing products on
site each working day for atypical worker schedule; it is uncertain whether this captures actual worker schedules and exposures.
EPA set the number of exposure days for both central tendency and high-end exposure estimates at 250 days per year based on EPA
default assumptions. Vapor exposures are not expected to significantly contribute to overall inhalation exposure compared to
particulate exposures. These limitations decrease the weight of evidence.

Although the use of monitoring data specific to this OES increases the strength of the analysis, but few uncertainties discussed in the
paragraph above reduces confidence of the analysis. Therefore, based on these strengths and limitations, EPA has concluded that the
weight of scientific evidence for this assessment is moderate and provides an upper-bound estimate of exposures.

Recycling

EPA considered the assessment approach, the quality of the data, and uncertainties in assessment results to determine a weight of
scientific evidence conclusion for the full-shift TWA inhalation exposure estimates for the recycling OES. EPA utilized the PNOR
Model (U.S. EPA. 2021b) to estimate worker inhalation exposure to solid particulate. The respirable particulate concentrations used
bv the generic model are based on OSHA CEHD data (OSHA. 2019). EPA used a subset of the respirable particulate data from the
generic model identified with the Administrative and Support and Waste Management and Remediation Services NAICS code
(NAICS code 56) to assess this OES, which EPA expects to be the most representative subset of the particulate data for this OES.
EPA estimated the highest expected concentration of DBP in plastic using plasticizer additive concentration information from the
Use of Additives in Plastic Converting Generic Scenario (U.S. EPA, 2004a). These strengths increase the weight of evidence.

The primary limitation is the uncertainty in the representativeness of values toward the true distribution of potential inhalation
exposures. Specifically, EPA lacks facility-specific particulate concentrations in air, and the representativeness of the data set used
in the model towards sites that actually handle DBP is uncertain. Further, the model lacks metadata on worker activities. EPA set the
number of exposure days for both central tendency and high-end exposure estimates at 250 days per year based on EPA default
assumptions. Also, it was assumed that each worker is potentially exposed for 8 hours per workday; however, it is uncertain whether
this captures actual worker schedules and exposures. These limitations decrease the weight of evidence.

Although the use of PNOR Model which is based on OSHA CEHD monitoring data increases the strength of the analysis, but few
uncertainties discussed in the paragraph above reduces confidence of the analysis. Therefore, based on these strengths and
limitations, EPA has concluded that the weight of scientific evidence for this assessment is moderate and provides an upper-bound
estimate of exposures.

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Weight of Scientific Evidence Conclusion in Exposure Estimates

Waste handling,
treatment, and
disposal

EPA considered the assessment approach, the quality of the data, and uncertainties in assessment results to determine a weight of
scientific evidence conclusion for the full-shift TWA inhalation exposure estimates for the waste handling, treatment, and disposal
OES. EPA utilized the PNOR Model (U.S. EPA, 2021b) to estimate worker inhalation exposure to solid particulate. The respirable
particulate concentrations used bv the aeneric model are based on OSHA CEHD data (OSHA. 2019). EPA used a subset of the
respirable particulate data from the generic model identified with the Administrative and Support and Waste Management and
Remediation Services NAICS code (NAICS code 56) to assess this OES, which EPA expects to be the most representative subset of
the particulate data for this OES. EPA estimated the highest expected concentration of DBP in plastic using plasticizer additive
concentration information from the Generic Scenario for the Use of Additives in Plastic Compounding (U.S. EPA. 2021c). These
strengths increase the weight of evidence.

The primary limitation is the uncertainty in the representativeness of values toward the true distribution of potential inhalation
exposures. Specifically, EPA lacks facility-specific particulate concentrations in air, and the representativeness of the data set used
in the model towards sites that actually handle DBP is uncertain. Further, the model lacks metadata on worker activities. EPA set the
number of exposure days for both central tendency and high-end exposure estimates at 250 days per year based on EPA default
assumptions. Also, it was assumed that each worker is potentially exposed for 8 hours per workday; however, it is uncertain whether
this captures actual worker schedules and exposures. These limitations decrease the weight of evidence.

Although the use of PNOR Model, which is based on OSHA CEHD monitoring data increases the strength of the analysis, but few
uncertainties discussed in the paragraph above reduces confidence of the analysis. Therefore, based on these strengths and
limitations, EPA has concluded that the weight of scientific evidence for this assessment is moderate and provides an upper-bound
estimate of exposures.

Dermal - liquids

EPA used dermal absorption data for seven percent oil-in-water DBP formulations to estimate occupational dermal exposures for
liquid (Doan et al., 2010). The tests were performed on guinea pins, which have more permeable skin than humans (OECD, 2004c).
meaning the dermal absorption value is likely protective for human skin. However, it is acknowledged that variations in chemical
concentration and co-formulant components affect the rate of dermal absorption. Additionally, it is unclear how representative the
data from Doan et al. (2010) are for neat DBP. Since. EPA assumed absorptive flux of DBP measured from guinea pis experiments
serves as an upper-bound of potential absorptive flux of chemical into and through the skin for dermal contact with all liquid
products. EPA is confident that the dermal absorption data using guinea pigs provides an upper-bound of dermal absorption of DBP.

For occupational dermal exposure assessment, EPA assumed a standard 8-hour workday and the chemical is contacted at least once
per day. Because DBP has low volatility and relatively low absorption, it is possible that the chemical remains on the surface of the
skin after dermal contact until the skin is washed. So, in absence of exposure duration data, EPA has assumed that absorption of
DBP from occupational dermal contact with materials containing DBP mav extend up to 8 hours per dav (U.S. EPA, 1991).
However, if a worker uses proper personal protective equipment (PPE) or washes their hands after contact with DBP or DBP-
containing materials dermal exposure may be eliminated. Therefore, the assumption of an 8-hour exposure duration for DBP may
lead to overestimation of dermal exposure. For average adult workers, the surface area of contact was assumed equal to the area of
one hand (i.e., 535 cm2), or two hands (i.e., 1,070 cm2), for central tendency exposures, or high-end exposures, respectively (U.S.
EPA. 2011). Other parameters such as frequency and duration of use. and surface area in contact, are well understood and

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Weight of Scientific Evidence Conclusion in Exposure Estimates



representative. Despite moderate confidence in the estimated values themselves, EPA has robust confidence that the dermal liquid
exposure estimates are upper-bound of potential exposure scenarios.

Dermal - solids

It is expected that dermal exposure to solid matrices would result in far less absorption, but there are no studies that report dermal
absorption of DBP from a solid matrix. For cases of dermal absorption of DBP from a solid matrix, EPA assumed that DBP will first
migrate from the solid matrix to a thin layer of moisture on the skin surface. Therefore, absorption of DBP from solid matrices is
considered limited bv aaueous solubilitv and is estimated usine an aaueous absorption model (U.S. EPA, 2023b. 2004b).
Nevertheless, it is assumed that absorption of the aqueous material serves as a reasonable upper-bound for contact with solid
materials. Also, EPA acknowledges that variations in chemical concentration and co-formulant components affect the rate of dermal
absorption. For OES with lower concentrations of DBP in the solid, it is possible that the estimated amount absorbed using the
modeled flux value would exceed the amount of DBP available in the dermal load. In these cases, EPA capped the amount absorbed
to the maximum amount of DBP in the solid (i.e., the product of the dermal load and the weight fraction of DBP). For occupational
dermal exposure assessment, EPA assumed a standard 8-hour workday and the chemical is contacted at least once per day. Because
DBP has low volatility and relatively low absorption, it is possible that the chemical remains on the surface of the skin after dermal
contact until the skin is washed. So, in absence of exposure duration data, EPA has assumed that absorption of DBP from
occupational dermal contact with materials containing DBP mav extend up to 8 hours per dav (U.S. EPA. 1991). However, if a
worker uses proper personal protective equipment (PPE) or washes their hands after contact with DBP or DBP-containing materials
dermal exposure may be eliminated. Therefore, the assumption of an 8-hour exposure duration for DBP may lead to overestimation
of dermal exposure. EPA also assumed an area of contact for average adult workers ranging from 535 cm2 (central tendency) to
1.070 cm2 (hiah-end) (U.S. EPA. 2011). The occupational dermal exposure assessment is limited in that it docs not consider the
uniqueness of each material potentially contacted. But, the dermal exposure estimates are expected to be representative of materials
potentially encountered in occupational settings.

Therefore, the dermal absorption estimates assume that dermal absorption of DBP from solid objects would be limited by the
aqueous solubility of DBP. EPA has moderate confidence in the aspects of the exposure estimate for solid articles because of the
high uncertainty in the assumption of partitioning from solid to liquid, and because subsequent dermal absorption is not well
characterized. Additionally, there are uncertainties associated to the flux-limited approach which likely results in overestimations
due to the assumption about excess DBP in contact with skin for the entire work duration. Other parameters such as frequency and
duration of use, and surface area in contact have unknown uncertainties due to lack of information about use patterns. Despite
moderate confidence in the estimated values themselves, EPA has robust confidence that the exposure estimates are upper-bound of
potential exposure scenarios.

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5). Generic scenario for automobile spray coating: Draft report. (EPA Contract No. 68-
D2-0157). Washington, DC: U.S. Environmental Protection Agency.

1004a). Additives in plastics processing (converting into finished products) -generic scenario
for estimating occupational exposures and environmental releases. Draft. Washington, DC.

1004b). Risk Assessment Guidance for Superfund (RAGS), volume I: Human health
evaluation manual, (part E: Supplemental guidance for dermal risk assessment).
(EPA/540/R/99/005). Washington, DC: U.S. Environmental Protection Agency, Risk
Assessment Forum, https://www.epa.eov/risk/risk-assessment-eiiidance-superfimd-raes-part-e

1004c). Spray coatings in the furniture industry - generic scenario for estimating
occupational exposures and environmental releases.

E004d). Spray coatings in the furniture industry - generic scenario for estimating
occupational exposures and environmental releases: Draft. Washington, DC.
https://www.epa.eov/tsca-screenine-tools/usine-predictive-methods-assess-exposiire-and-fate-
under-tsca

I v < < \ 101 Manufacture and use of printing inks - generic scenario for estimating occupational
exposures and environmental releases: Draft. Washington, DC. https://www.epa.eov/tsca-
screening-tools/chemsteer-chemical-screening-tool-exposures-and-environmental-

releases#eenericscenarios

Exposure factors handbook: 2011 edition [EPA Report], (EPA/600/R-090/052F).
Washington, DC: U.S. Environmental Protection Agency, Office of Research and Development,
National Center for Environmental Assessment.
https://nepis.epa.eov/Exe/ZyPIJRL.cei?Dockey=P 100F2QS.txt

Final peer review comments for the OPPT trichloroethylene (TCE) draft risk
assessment [Website], https://www.epa.eov/sites/production/files/!

06/docum ents/tce consolidated peer review comments septemb	;

1014a). Formulation of waterborne coatings - Generic scenario for estimating occupational
exposures and environmental releases -Draft. Washington, DC. https://www.epa.eov/tsca-
screenine-tools/usine-predictive-methods-assess-exposure-and-fate-under-tsca

1014b). Use of additive in plastic compounding - generic scenario for estimating
occupational exposures and environmental releases: Draft. Washington, DC.

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https://www.epa.gov/tsca-screening-tools/using-predictive-methods-assess-exposure-and-fate-
under-tsca

I v << \	Use of additives in the thermoplastic converting industry - generic scenario for

estimating occupational exposures and environmental releases. Washington, DC.

https://www.epa.eov/tsca-screenine-tools/usine-predictive-methods-assess-exposiire-and-fate-
under-tsca

1015). ChemSTEER user guide - Chemical screening tool for exposures and environmental
releases. Washington, D.C. https://www.epa.gov/sites/production/files/2Q15-
05/docum ents/user eui de.pdf

1, c. i i1 \ ^,201 I Learn the Basics of Hazardous Waste, https://www.epa.gov/hw/learn-basics-
hazardous-waste

I v  202 fc). Use of additives in plastic compounding - Generic scenario for estimating

occupational exposures and environmental releases (Revised draft) [EPA Report], Washington,
DC: Office of Pollution Prevention and Toxics, Risk Assessment Division.

I v < < \ * 202 I) !l Use of additives in plastics converting - Generic scenario for estimating

occupational exposures and environmental releases (revised draft). Washington, DC: Office of
Pollution Prevention and Toxics.

1022a). Chemical repackaging - Generic scenario for estimating occupational exposures and
environmental releases (revised draft) [EPA Report], Washington, DC.

1022b). Chemicals used in furnishing cleaning products - Generic scenario for estimating
occupational exposures and environmental releases (revised draft). Washington, DC: Office of
Pollution Prevention and Toxics.

1022c). Discharge Monitoring Report (DMR) data for 1,4-dioxane, 2013-2019. Washington,
DC. https://echo.epa.eov/trends/loadine-tool/water-pollution-search

1023a). 2020 National Emissions Inventory (NEI) Data (August 2023 version) (August 2023
ed.). Washington, DC: US Environmental Protection Agency, https://www.epa.gov/air-
emissions-inventories/2020-national-emissions-inventory-nei-data

Consumer Exposure Model (CEM) Version 3.2 User's Guide. Washington, DC.
https://www.epa.eov/tsca-screenine-tools/consiimer-exposure-model-cem-versio jters-
guide

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1023c). Methodology for estimating environmental releases from sampling waste (revised
draft). Washington, DC: Office of Pollution Prevention and Toxics, Chemical Engineering
Branch.

1023d). Use of laboratory chemicals - Generic scenario for estimating occupational
exposures and environmental releases (Revised draft generic scenario) [EPA Report],
Washington, DC: U.S. Environmental Protection Agency, Office of Pollution Prevention and
Toxics, Existing Chemicals Risk Assessment Division.

1024a). Discharge Monitoring Report (DMR) data: Dibutyl phthalate (DBP), reporting years
2017-2022. Washington, DC.

1024b). Draft environmental release and occupational exposure assessment for diisononyl
phthalate (DINP). Washington, DC: Office of Pollution Prevention and Toxics.

1024c). Environmental Release and Occupational Exposure Assessment for Diisodecyl
Phthalate (DIDP). Washington, DC: Office of Pollution Prevention and Toxics.

E024d). Risk Evaluation for Diisodecyl Phthalate (DIDP). Washington, DC: Office of
Pollution Prevention and Toxics.

V324e). Toxics Release Inventory (TRI) data: Dibutyl phthalate (DBP), reporting years
2017-2022. Washington, DC.

1025a). Draft Risk Calculator For Occupational Exposures For Dibutyl Phthalate (DBP).
Washington, DC: Office of Pollution Prevention and Toxics.

1025b). Draft Risk Evaluation for Dibutyl Phthalate (DBP). Washington, DC: Office of
Pollution Prevention and Toxics.

1025c). Risk Evaluation for Diisononyl Phthalate (DINP). Washington, DC: Office of
Pollution Prevention and Toxics.

Vainiotalo. S; Pfaftl	). Air impurities in the PVC plastics processing industry. Ann Occup Hyg

34: 585-590. http://dx.doi.<	3/annhyg/34.6.585

Xu N t oh en Hub a I I \ 1 tul^ ป• •. i ฆ> Predicting residential exposure to phthalate plasticizer
emitted from vinyl flooring: Sensitivity, uncertainty, and implications for biomonitoring.

Environ Health Perspect 1 18: 253-258. http://dx.doi.org h' l „ 89/ehp.0900^^ฐ

Zhu. L. f: Rejection of organic micropollutants by clean and fouled nanofiltration membranes. J
Chem 2015: 1-9. http://dx.doi.org/iO. I 155/2015/934318

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APPENDICES

Appendix A EQUATIONS FOR CALCULATING ACUTE,

INTERMEDIATE, AND CHRONIC (NON-CANCER)
INHALATION AND DERMAL EXPOSURES

This report assesses DBP inhalation exposures to workers in occupational settings, presented as 8-hour
time weighted average (TWA). The full-shift TWA exposures are then used to calculate acute doses
(AD), intermediate average daily doses (IADD), and average daily doses (ADD) for chronic non-cancer
risks. This report also assesses DBP dermal exposures to workers in occupational settings, presented as a
dermal acute potential dose rate (APDR). The APDRs are then used to calculate the AD, IADD, and
ADD. This appendix presents the equations and input parameter values used to estimate each exposure
metric.

A.l Equations for Calculating Acute, Intermediate, and Chronic (Non-
Cancer) Inhalation Exposure

EPA used AD to estimate acute risks {i.e., risks occurring as a result of exposure for <1 day) from
workplace inhalation exposures, per EquationApx A-l.

EquationApx A-l.

C x ED x BR
AD =-

BW
Where:

AD	=	Acute dose (mg/kg-day)

C	=	Contaminant concentration in air (TWA mg/m3)

ED	=	Exposure duration (h/day)

BR	=	Breathing rate (m3/h)

BW	=	Body weight (kg)

EPA used IADD to estimate intermediate risks from workplace exposures as follows:

Equation Apx A-2.

C x ED x EFint x BR

IADD =	—	

BW x ID

Where:

IADD = Intermediate average daily dose (mg/kg-day)

EFi„t = Intermediate exposure frequency (days)

ID = Intermediate duration (days)

EPA used ADD to estimate chronic non-cancer risks from workplace exposures. EPA estimated ADD as
follows:

Equation Apx A-3.

C x ED x EF XWY x BR
ADD =		

BW x 365^^ x WY
yr

Where:

ADD =	Average daily dose for chronic non-cancer risk calculations

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EF =	Exposure frequency (day/year)

WY =	Working years per lifetime (years)

A.2 Equations for Calculating Acute, Intermediate, and Chronic (Non-
Cancer) Dermal Exposures

EPA used AD to estimate acute risks from workplace dermal exposures using EquationApx A-4.
EquationApx A-4.

APDR
AD BW

Where:

AD = Acute retained dose (mg/kg-day)

APDR = Acute potential dose rate (mg/day)

BW = Body weight (kg)

EPA used IADD to estimate intermediate risks from workplace dermal exposures using Equation Apx
A-5.

Equation Apx A-5.

APDR X EFint-

IADD =	—

BW x ID

Where:

IADD = Intermediate average daily dose (mg/kg-day)

EFm = Intermediate exposure frequency (days)

ID = Days for intermediate duration (days)

EPA used ADD to estimate chronic non-cancer risks from workplace dermal exposures using
Equation Apx A-6.

Equation Apx A-6.

APDR x EF x WY
ADD =	

BW x 365^^ x WY

yr
Where:

ADD = Average daily dose for chronic non-cancer risk calculations
EF = Exposure frequency (day/year)

WY = Working years per lifetime (year)

A.3 Calculating Aggregate Exposure

EPA combined the expected dermal and inhalation exposures for each OES and worker type into a
single aggregate exposure to reflect the potential total dose from both exposure routes.

Equation Apx A-7.

Where:

ADaggregaie AD dermai + AD inhalati0n

ADDermai	= Dermal exposure acute retained dose (mg/kg-day)

AD inhalation = Inhalation exposure acute retained dose (mg/kg-day)
ADAggregate = Aggregated acute retained does (mg/kg-day).

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IADD and ADD also follow the same approach for defining aggregate exposures.

A.4 Acute, Intermediate, and Chronic (Non-Cancer) Equation Inputs

EPA used the input parameter values in TableApx A-l to calculate acute, intermediate, and chronic
inhalation exposure risks. Where EPA calculated exposures using probabilistic modeling, EPA
integrated the calculations into a Monte Carlo simulation. The EF and EFmt used for each OES can differ,
and the appropriate sections of this report describe these values and their selection. This section
describes the values that EPA used in the equations in Appendices A. 1 and A.2 and summarized in
Table Apx A-l.

Table Apx A-l. Parameter Values for Calculating Inhalation Exposure Estimates

Parameter Name

Symbol

Value

Unit

Exposure Duration

ED

8

h/day

Breathing Rate

BR

1.25

m3/h

Exposure Frequency

EF

208-250a

days/year

Exposure Frequency, Intermediate

EFint

22

days

Days for Duration, Intermediate

ID

30

days

Working Years

WY

31 (50th percentile)
40 (95th percentile)

years

Body Weight

BW

80 (average adult worker)
72.4 (female of reproductive age)

kg

a Depending on OES

A.4.1 Exposure Duration (ED)

EPA generally used an exposure duration of 8 hours per day for averaging full-shift exposures.

A.4.2 Breathing Rate (BR)

EPA used a breathing rate, based on average worker breathing rates. The breathing rate accounts for the
amount of air a worker breathes during the exposure period. The typical worker breathes about 10 m3 of
air in 8 hours or 1.25 m3/h(	).

A.4.3 Exposure Frequency (EF)	

EPA generally used a maximum exposure frequency of 250 days per year based on the assumptions of
daily exposure during each working day, 5 workdays per week, and 2 weeks of vacation per year.
However, for some OES where a range of exposure frequencies were possible, EPA used probabilistic
modeling to estimate exposures and the associated exposure frequencies, resulting in exposure
frequencies below 250 days per year. The relevant sections of this report describe EPA's estimation of
exposure frequency and the associated distributions for each OES.

EF is expressed as the number of days per year a worker is exposed to the chemical being assessed. In
some cases, it may be reasonable to assume a worker is exposed to the chemical on each working day. In
other cases, it may be more appropriate to assume a worker's exposure to the chemical occurs during a
subset of the worker's annual working days. The relationship between exposure frequency and annual
working days can be described mathematically as follows:

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EquationApx A-8.

EF = AWD X /

Where:

EF = Exposure frequency, the number of days per year a worker is exposed to the
chemical (day/year)

A WD = Annual working days, the number of working days per year for an individual
worker (day/year)

/ = Fractional number of annual working days during which a worker is exposed to
the chemical (unitless)

BLS provides data on the total number of work hours and total number of employees by each industry
NAICS code. BLS provides these data from the 3- to 6-digit NAICS level (where 3-digit NAICS are less
granular and 6-digit NAICS are the most granular). Dividing the total, annual hours worked by the
number of employees yields the average number of hours worked per employee per year for each
NAICS.

EPA identified approximately 140 NAICS codes applicable to the multiple conditions of use for the first
10 chemicals that underwent risk evaluation. For each NAICS code of interest, EPA looked up the
average hours worked per employee per year at the most granular NAICS level available (i.e., 4-, 5-, or
6-digit). EPA converted the working hours per employee to working days per year per employee
assuming employees work an average of 8 hours per day. The average number of working days per year,
or AWD, ranges from 169 to 282 days per year, with a 50th percentile value of 250 days per year. EPA
repeated this analysis for all NAICS codes at the 4-digit level. The average AWD for all 4-digit NAICS
codes ranges from 111 to 282 days per year, with a 50th percentile value of 228 days per year. Two
hundred fifty days per year is approximately the 75th percentile of the distribution AWD for the 4-digit
NAICS codes. In the absence of industry- and DBP-specific data, EPA assumed the parameter, f, is
equal to 1 for all OESs.

A.4.4 Intermediate Exposure Frequency (EFint)	

For DBP, the ID was set at 30 days. EPA estimated the maximum number of working days within the
ID, using the following equation and assuming 5 working days/week:

Equation Apx A-9.

working days 30 total days
EFint(max) = 5	;	x — . ,	= 21.4 days, rounded up to 22 days

14//c	r7 vOuCLL clccvs

1	

A.4.5 Intermediate Duration (ID)

EPA assessed an intermediate duration of 30 days based on the available health data.

A.4.6 Working Years (WY)

EPA developed a triangular distribution for number of lifetime working years using the following
parameters:

•	Minimum value: BLS CPS tenure data with current employer as a low-end estimate of the
number of lifetime working years: 10.4 years;

•	Mode value: The 50th percentile of the tenure data with all employers from SIPP as a mode
value for the number of lifetime working years: 36 years; and

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• Maximum value: The maximum of the average tenure data with all employers from SIPP as a
high-end estimate on the number of lifetime working years: 44 years.

This triangular distribution has a 50th percentile value of 31 years and a 95th percentile value of 40
years. EPA uses these values to represent the central tendency and high-end number of working years in
the ADC calculations.

The U.S. BLS (2014) provides information on employee tenure with current employer obtained from the
Current Population Survey (CPS). CPS is a monthly sample survey of about 60,000 households that
provides information on the labor force status of the civilian non-institutional population ages 16 years
and over. BLS releases CPS data every 2 years. The data are available by demographic characteristics
and by generic industry sectors, but not by NAICS codes.

The U.S. Census Bureau (2 ) Survey of Income and Program Participation (SIPP) provides
information on lifetime tenure with all employers. SIPP is a household survey that collects data on
income, labor force participation, social program participation and eligibility, and general demographic
characteristics through a continuous series of national panel surveys of between 14,000 and 52,000
households (U.S. BLS. 2023). EPA analyzed the 2008 SIPP Panel Wave 1, a panel that began in 2008
and covers the interview months of September 2008 through December 2008 (U.S. Census Bureau.
2019). For this panel, lifetime tenure data are available by Census Industry Codes, which can be cross
walked with NAICS codes.

SIPP data include fields that describe, for each surveyed worker, the industry in which they work
(TJBIND1); their age (TAGE); and years of work experience with all employers over the surveyed
individual's lifetime.4 Census household surveys use different industry codes than the NAICS codes, so
EPA converted these industry codes to NAICS using a published crosswalk (	:msus Bureau. 2012).

EPA calculated the average tenure for the following age groups: (1) workers aged 50 (years) and older;
(2) workers aged 60 (years) and older; and (3) workers of all ages employed at time of survey. The
Agency used tenure data for age group "50 and older" to determine the high-end lifetime working years,
because the sample size in this age group is often substantially higher than the sample size for age group
"60 and older." For some industries, the number of workers surveyed, or the sample size, was too small
to provide a reliable representation of the worker tenure in that industry. Therefore, EPA excluded data
where the sample size was less than 5 from the analysis.

Table Apx A-2 summarizes the average tenure for workers aged 50 and older from SIPP data. Although
the tenure may differ for any given industry sector, there is no significant variability between the 50th
and 95th percentile values of average tenure across manufacturing and non-manufacturing sectors.

4 To calculate the number of years of work experience EPA took the difference between the year first worked
(TMAKMNYEAR) and the current data year (i.e., 2008). The Agency then subtracted any intervening months when not
working (ETIMEOFF).

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Table Apx A-2. Overview of Average Worker Tenure from U.S. Census SIPP (Age Group 50+)

Industry Sectors

Working Years

Average

50th
Percentile

95th
Percentile

Maximum

Manufacturing sectors (NAICS 31-33)

35.7

36

39

40

Non-manufacturing sectors (NAICS 42-81)

36.1

36

39

44

Source: ("U.S. BLS. 2023)

Note: Industries where sample size was <5 were excluded from this analysis.

BLS CPS data provide the median years of tenure that wage and salary workers had been with their
current employer. Table Apx A-3 presents CPS data for all demographics (men and women) by age
group from 2008 to 2012. To estimate the low-end value for number of working years, EPA used the
most recent (2014) CPS data for workers aged 55 to 64 years, which indicates a median tenure of 10.4
years with their current employer. The use of this low-end value represents a scenario where workers are
only exposed to the chemical of interest for a portion of their lifetime working years, as they may
change jobs or move from one industry to another throughout their career.

Table Apx A-3. Median Years of Tenure with Current Employer by Age Group

Age

January 2008

January 2010

January 2012

January 2014

16+ years

4.1

4.4

4.6

4.6

16-17 years

0.7

0.7

0.7

0.7

18-19 years

0.8

1.0

0.8

0.8

20-24 years

1.3

1.5

1.3

1.3

25+ years

5.1

5.2

5.4

5.5

25-34 years

2.7

3.1

3.2

3.0

35-44 years

4.9

5.1

5.3

5.2

45-54 years

7.6

7.8

7.8

7.9

55-64 years

9.9

10.0

10.3

10.4

65+ years

10.2

9.9

10.3

10.3

Source: (U.S. BLS. 2014)

A.4.7 Body Weight (BW)	

EPA assumed a BW of 80 kg for average adult workers. EPA assumed a BW of 72.4 kg for females of
reproductive age, per Chapter 8 of the Exposure Factors Handbook (	:011).

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Appendix B SAMPLE CALCULATIONS FOR CALCULATING
ACUTE, INTERMEDIATE, AND CHRONIC (NON-
CANCER) OCCUPATIONAL EXPOSURES

Sample calculations for high-end and central tendency acute, intermediate, and chronic (non-cancer)
doses for one condition of use, PVC plastics compounding, are demonstrated below for an average adult
worker. The explanation of the equations and parameters used is provided in Appendix A.

B.l Inhalation Exposures

B.l.l Example High-End AD, IADD, and ADD Calculations

Calculating ADhe:

Calculating IADDhe:

CHE x ED x BR

ADhf = —	

HE	BW

2.9mx8J!!Lxl.2s!ฃ m

ADhe = m3		h-L = 0.36

80 kg	day

CHE x ED x BR x EFint
_ _ฃ™

BW x ID

2.9!Mx8ป!lxl.25!!!x22iffiฃ	TM

MDD„=—^^^	^1 = 0.26 kg

80 kg x	dav

a year

Calculating ADDhe:

CHE x ED x BRx EF XWY

ADD™ = 		d^Ts	

BW x 365	WY

year

2.9 H^x 8^x1.25^x 250^x40years m

ADDhe = —^^	i	= 0.25

80 kg x 365 —x 40years	a^

a	year J

B.1.2 Example Central Tendency AD, IADD, and ADD Calculations

Calculating ADct:

Cct x ED x BR

ADct = —	

CT	BW

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,3

0.34^1 x 8-^x 1.2532-	m

ADct =	m3		!SL = 4.3 X 10-2 kg

80 kg	day

Calculating IADDct:

Cct x ED x BRx EFint

IADDrr = —	—

CT	BW x ID

0.34 xs^lx 1.25?! x 22 *221	M.

IADDCT =		d^y	JL	Zฃฃฃ= 3.1X10-^ kg

80 kg x 30^^	day

a year

Calculating ADDct:

Cct x ED x BRx EF x WY
ADDct = —	-j	

BW x 365	WY

year

0.34 2!# xSฃ-x 1.25?! x 250^X31 years m
ADDcr =	^^	!H.	ZฃfE	i	= 2.9 x 10-2 *9

80 kg x 365 x 31 years

a	year J

B.2 Dermal Exposures

B.2.1 Example High-End AD, IADD, and ADD Calculations

Calculating ADhe:

ADhe —

APDR
BW

0.36

adhe —

80 kg

mg

day „ ^ , mg
= 4.5 x 10 ฆ

kg-day

Calculate IADDhe:

IADDhe —

APDR x EF,-

int

IADDhf =

0.36^-X 22

day

BW x ID
day

yr

day

80 kg x 30--^-

= 3.3 x 10-3

mg

kg-day

Calculate ADDhe (non-cancer):

ADDhf =

yr

APDR x EF x WY
day

BW x 365-—^- x WY

yr

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0.36^7^x 250^^x40 years

ADDhe =	y		 = 3.1 x 10--^-

80 kg x 365 —— x 40 years	& a^

yr

B.2.2 Example Central Tendency AD, IADD, and ADD Calculations

Calculating ADct:

ADct —

APDR
BW

0.18

ADct —

80 kg

mg

^ = 2.3X10-3. m9

kg-day

Calculating IADDct:

IADDct =

APDR X EF,

int

IADDct

0.18^2- X 22

day

BW x ID
days

yr

80 kg x 30

days
yr

= 1.7 x 10~3

mg

kg-day

Calculate ADDct (non-cancer):

ADDct =

APDR x EF x WY
BW x AT

0.18-^x 223^^1x31 years	mn

ADDct =	^ay		 = 1.4 x 10-

80 kg x 365 —— x 31 years	& ay

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Appendix C DERMAL EXPOSURE ASSESSMENT METHOD

€.1 Dermal Dose Equation

As described in Section 2.4.3, occupational dermal exposures to DBP are characterized using a flux-
based approach to dermal exposure estimation. EPA capped the dermal dose based on typical dermal
loading values (Q). Therefore, EPA used the lesser of Equation Apx C-l and EquationApx C-2 to
estimate the acute potential dose rate (APDR) from occupational dermal exposures. The APDR (units of
mg/day) characterizes the quantity of chemical that is potentially absorbed by a worker on a given
workday.

Equation Apx C-l.

J xS x tabs

APDR = 	—

PF

Where:

J	=	Average absorptive flux through and into skin (mg/cm2/h);

S	=	Surface area of skin in contact with the chemical formulation (cm2);

tabs	=	Duration of absorption (h/day)

PF	=	Glove protection factor (unitless, PF > 1)

Equation Apx C-2.

Q x Fw x S

APDR = -—	

PF

Where:

Q	= Dermal loading of liquid or solid formulation (mg/cm2);

Fw = Weight fraction of DBP in the liquid or solid formulation (unitless);

The inputs to the dermal dose equation are described in Appendix C.2.

C.2 Parameters of the Dermal Dose Equation

Table Apx C-l summarizes the dermal dose equation parameters and their values for estimating dermal
exposures. Additional explanations of EPA's selection of the inputs for each parameter are provided in
the subsections after this table.

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Table Apx C-l. Summary of Dermal Dose Equation Values

Input Parameter

Symbol

Value

Unit

Rationale

Absorptive Flux

J

Dermal Contact with Liquids: 2.35E-02
Dermal Contact with Solids: 3.17E-04

mg/cm2/h

See Appendix C.2.1

Surface Area

S

Workers:

535 (central tendency)
1,070 (high-end)

Females of reproductive age:
445 (central tendency)
890 (high-end)

cm2

See Appendix C.2.2

Absorption Time

tabs

8

hr

See Appendix C.2.3

Dermal Loading

Q

Liquid Contact:

1.4 (central tendency)

2.1 (high-end)

Liquid Immersion:

3.8 (central tendency)

10.3 (high-end)

Solids Contacta:

900 (central tendency)

3,100 (high-end)

Solid contact with container

surfaces/solders/pastes:

450 (central tendency)

1,100 (high-end)

mg/cm2
(liquids)

mg/day
(solids)

See Appendix C.2.4

DBP Weight
Fraction

F„

OES-specific

Unitless

See Appendix C.2.5

Glove Protection
Factor

PF

1; 5; 10; or 20

Unitless

See Appendix C.2.6

a Solid skin loading values are presented as a product of Q and S based on available data.

C.2.1 Absorptive Flux

Dermal data were sufficient to characterize occupational dermal exposures to liquids or formulations
containing DBP; however, dermal data were not sufficient to estimate dermal exposures to solids or
articles containing DBP. Therefore, modeling efforts were used to estimate dermal exposures to solids or
articles containing DBP. Dermal exposures to vapors are not expected to be significant due to the
extremely low volatility of DBP, and therefore, are not included in the dermal exposure assessment of
DBP.

C.2.1.1 Dermal Contact with Liquids or Formulations Containing DBP

As described in Section 2.4.3.2, EPA uses the steady-state flux of neat DBP over a 24-hour period from
a 7-percent aqueous emulsion of 2.35 10 2 mg/cm:/h estimated from Doan et al. (2010). EPA assumes
the same average absorptive flux would be representative of dermal contact with liquids or formulations
containing DBP that may occur in occupational settings over an 8-hour work shift.

C.2.1.1 Dermal Contact with Solids or Articles Containing DBP

As described in Section 2.4.3.3, the average absorptive flux of DBP from solid matrices is expected to
vary between 0.32 and 0.89 |ig/cm2/h for durations between 1-hour and 8-hours based on aqueous
absorption modeling from U.S. EPA (2004b). Using Equation 2- from Section 2.4.3.3, the average
absorptive flux of DBP over an 8-hour exposure period is calculated as 0.32 |ig/cm2/h. Because it is

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assumed that DBP must first migrate from the solid matrix to a thin film of moisture on the surface of
the skin, and that solubility of DBP by the moisture layer limits absorption, the 8-hour time weighted
average aqueous flux value of 0.32 |ig/cm2/h was chosen as a representative value for dermal exposures
to solids or articles containing DBP.

C.2.2 Surface Area	

Regarding surface area of occupational dermal exposure, EPA assumed a high-end value of 1,070 cm2
for male workers and 890 cm2 for female workers. These high-end occupational dermal exposure
surface area values are based on the mean two-hand surface area for adults of age 21 years or older from
Chapter 7 of EPA's Exposure Factors Handbook (	011). For central tendency estimates,

EPA assumed the exposure surface area was equivalent to only a single hand (or one side of two hands)
and used half the mean values for two-hand surface areas {i.e., 535 cm2 for male workers and 445 cm2
for female workers).

It should be noted that while the surface area of exposed skin is derived from data for hand surface area,
EPA did not assume that only the workers hands may be exposed to the chemical. Nor did EPA assume
that the entirety of the hands is exposed for all activities. Rather, the Agency assumed that dermal
exposures occur to some portion of the hands plus some portion of other body parts {e.g., arms) such
that the total exposed surface area is approximately equal to the surface area of one or two hands for the
central tendency and high-end exposure scenario, respectively.

C.2.3 Absorption Time

Though a splash or contact-related transfer of material onto the skin may occur instantaneously, the
material may remain on the skin surface until the skin is washed. Because DBP does not rapidly absorb
or evaporate, and the worker may contact the material multiple times throughout the workday, EPA
assumes that absorption of DBP in occupational settings may occur throughout the entirety of an 8-hour
work shift (	).

C.2.4 Dermal Loading

C.2.4.1 Liquid Dermal Loading

For contact with liquids in occupational settings, EPA assumed a range of dermal loading of 0.7 to 2.1
mg/cm2 (U.S.	) for tasks such as product sampling, loading/unloading, and cleaning as

shown in the ChemSTEER Manual (	) More specifically, EPA has utilized the raw data

of the (U	>2b) study to determine a central tendency (50th percentile) dermal loading value

of 1.4 mg/cm2 and a high-end (95th percentile) dermal loading value of 2.1 mg/cm2 for dermal exposure
to liquids. For scenarios where liquid immersion occurs, EPA assumed a range of dermal loading of 1.3
to 10.3 mg/cm2 (	) for tasks such as spray coating as shown in the ChemSTEER Manual

(I	E015). More specifically, EPA has utilized the raw data of the (	3) study to

determine a central tendency (50th percentile) value of 3.8 mg/cm2 and a high-end (95th percentile)
value of 10.3 mg/cm2 for scenarios aligned with dermal immersion in liquids.

C.2.4.2 Solid Dermal Loading

For contact with solids or powders in occupational settings, EPA generally assumed a range of dermal
loading of 900 to 3,100 mg/day (50—95th percentile from Lansink et a/. (1996)) as shown in the
ChemSTEER Manual (U.S. EPA. 2015). For contact with materials such as solder/pastes in
occupational settings, EPA assumed a range of dermal loading of 450 to 1,100 mg/day (50-95th
percentile from Lansink et al. (1996)) as shown in the ChemSTEER Manual (U.S. EPA. 2015).

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The average absorptive flux of DBP for an 8-hour absorption period, as determined through modeling
efforts (	1023b. 2004b). would result in maximum absorption of 2.5 10 ^ mg/cnr over an 8-

hour period (2.71 mg/day for high-end worker exposures and 1.36 mg/day for central tendency worker
exposures). Therefore, the high-end dermal exposure estimate for neat solid DBP is reasonable with
respect to the amount of material that may be available for absorption in an occupational setting.
However, for OES where more dilute formulations of DBP may be used, it is possible that the estimated
amount absorbed using the modeled flux value would exceed the amount of DBP available in the dermal
load. In these cases, EPA capped the amount absorbed to the maximum amount of DBP in the
formulation {i.e., the product of the dermal load and the weight fraction of DBP).

C.2.5 DBP Weight Fraction

Due to uncertainties around how different formulations of DBP may impact the overall dermal
absorption, EPA used the maximum weight fraction of DBP in each OES to provide the most protective
dermal exposure assessment. The details of the range of expected weight fractions of DBP in each OES
are described for each OES in Section 3. Table Apx C-2 presents the weight fraction of DBP used for
the dermal exposure of each OES.

Table Apx C-2. Summary of DBP Weight Fractions for Dermal Exposure Estimates

OES

Physical Form

Weight Fraction

Manufacturing

Liquid

1

Import and repackaging

Liquid

1

Incorporation into formulation, mixture, or reaction product

Liquid

1

PVC plastics compounding

Liquid

1

Solid

0.45

PVC plastic converting

Solid

0.45

Non-PVC material manufacturing

Liquid

1

Solid

0.2

Application of adhesives and sealants

Liquid

0.75

Application of paints and coatings

Liquid

0.1

Use of laboratory chemicals

Liquid

0.1

Solid

0.2

Industrial process solvent use

Liquid

1

Use of lubricants and functional fluids

Liquid

0.075

Use of penetrants and inspection fluids

Liquid

0.2

Recycling

Solid

0.45

Fabrication or use of final product or articles

Solid

0.45

Waste handling, treatment, and disposal

Solid

0.45

C.2.6 Glove Protection Factors

Gloves may mitigate dermal exposures, if used correctly and consistently. However, data about the
frequency of effective glove use—that is, the proper use of effective gloves—is very limited in industrial
settings. Initial literature review suggests that there is unlikely to be sufficient data to justify a specific
probability distribution for effective glove use for a chemical or industry. Instead, the impact of effective

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glove use should be explored by considering different percentages of effectiveness (e.g., 25 vs. 50%
effectiveness).

Gloves only offer barrier protection until the chemical breaks through the glove material. Using a
conceptual model, Cherrie et al. (2004) proposed a glove workplace protection factor: the ratio of
estimated uptake through the hands without gloves to the estimated uptake though the hands while
wearing gloves (this protection factor is driven by flux and varies with time). The ECETOC TRA Model
represents the protection factor of gloves as a fixed, PF equal to 5, 10, or 20 (Marquart et al.. 2017).
Where, similar to the APR for respiratory protection, the inverse of the protection factor is the fraction
of the chemical that penetrates the glove.

Given the limited state of knowledge about the protection afforded by gloves in the workplace, it is
reasonable to utilize the PF values of the ECETOC TRA Model (Marquart et al.. ), rather than
attempt to derive new values.

TableApx C-3 presents the PF values from ECETOC TRA Model (v3). In the exposure data used to
evaluate the ECETOC TRA Model, (Marquart et al.. 2017) reported that the observed glove protection
factor was 34, compared to PF values of 5 or 10 used in the model.

Table Apx C-3. Exposure Control Efficiencies and Protection Factors for Different Dermal
Protection Strategies from ECETOC TRA V3 			

Dermal Protection Characteristics

Affected User

Indicated

Protection

Group

Efficiency (%)

Factor (PF)

a. Any glove/gauntlet without permeation data and
without employee training



0

1

b. Gloves with available permeation data indicating
that the material of construction offers good
protection for the substance

Both industrial and
professional users

80

5

c. Chemically resistant gloves (i.e., as b above) with
"basic" employee training



90

10

d. Chemically resistant gloves in combination with
specific activity training (e.g., procedure for glove
removal and disposal) for tasks where dermal

Industrial users only

95

20

exposure can be expected to occur







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Appendix D MODEL APPROACHES AND PARAMETERS

This appendix presents the modeling approach and model equations used in estimating environmental
releases and occupational exposures for each of the applicable OESs. The models were developed
through review of the literature and consideration of existing EPA/OPPT models, ESDs, and/or GSs. An
individual model input parameter could either have a discrete value or a distribution of values. EPA
assigned statistical distributions based on reasonably available literature data. A Monte Carlo simulation
(a type of stochastic simulation) was conducted to capture variability in the model input parameters. The
simulation was conducted using the Latin Hypercube sampling method in @Risk Industrial Edition,
Version 8.0.0 (Palisade. 2022). The Latin Hypercube sampling method generates a sample of possible
values from a multi-dimensional distribution and is considered a stratified method, meaning the
generated samples are representative of the probability density function (variability) defined in the
model. EPA performed the model at 100,000 iterations to capture a broad range of possible input values,
including values with low probability of occurrence.

EPA used the 95th and 50th percentile Monte Carlo simulation model result values for assessment. The
95th percentile value represents the high-end release amount or exposure level, whereas the 50th
percentile value represents the central tendency release amount or exposure level. The following
subsections detail the model design equations and parameters for each of the OESs.

D.l EPA/OPPT Standard Models

This appendix discusses the standard models used by EPA to estimate environmental releases of
chemicals and occupational inhalation exposures. All the models presented in this appendix are models
that were previously developed by EPA and are not the result of any new model development work for
this risk evaluation. Therefore, this appendix does not provide the details of the derivation of the model
equations which have been provided in other documents such as the ChemSTEER User Guide (U.S.

), Chemical Engineering Branch Manual for the Preparation of Engineering Assessments,
Volume 1 (	), Evaporation of Pure Liquids from Open Surfaces ( >ld and En eel.

2001). Evaluation of the Mass Balance Model Used by the References Environmental Protection
Agency for Estimating Inhalation Exposure to New Chemical Substances (Fehrenbacher and Hummel.
1996). and Releases During Cleaning of Equipment (Associates. 1988). The models include loss fraction
models as well as models for estimating chemical vapor generation rates used in subsequent model
equations to estimate the volatile releases to air and occupational inhalation exposure concentrations.
The parameters in the equations of this appendix are specific to calculating environmental releases and
occupational inhalation exposures to DBP.

The EPA/OPPT Penetration Model estimates releases to air from evaporation of a chemical from an
open, exposed liquid surface (U.S. EPA.! ). This model is appropriate for determining volatile
releases from activities that are performed indoors or when air velocities are expected to be less than or
equal to 100 feet per minute. The EPA/OPPT Penetration Model calculates the average vapor generation
rate of the chemical from the exposed liquid surface using the following equation:

EquationApx D-l.

(8.24 X 10 ) * (MWDbp ) * FcorrectionJ actor * VP * yj P&t&air_speed * (0.257TZ) opening")

r	— 		

uactivity	(

'ฑ + —L

29 ^ MWn

T0 05 * jDopening * 4P
Where:

Gactivity	= Vapor generation rate for activity (g/s)

MWdbp	= DBP molecular weight (g/mol)

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"correction_f actor

VP
Rate,

D
T
P

air_speed
opening

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Vapor pressure correction factor (unitless)

DBP vapor pressure (torr)

Air speed (cm/s)

Diameter of opening (cm)

Temperature (K)

Pressure (torr)

The EPA/OPPT Mass Transfer Coefficient Model estimates releases to air from the evaporation of a
chemical from an open, exposed liquid surface (\ v < < \ I ). This model is appropriate for
determining this type of volatile release from activities that are performed outdoors or when air
velocities are expected to be greater than 100 feet per minute. The EPA/OPPT Mass Transfer
Coefficient Model calculates the average vapor generation rate of the chemical from the exposed liquid
surface using the following equation:

EquationApx D-2.

(1.93 x 10 7) * (MWdbpฐ-7B) * FcorrectionJactor * VP * Rateฐ™speed * (0.25?zD,

opening J

ฆ +

29 1 MWn

uactivity

Where:

uactivity

MWdbp

Fcorrection_f actor

VP
Rate,

air_speed

D

opening

To.4Do.n	_ 5 87}2/3

1 ^opening vv 1 >->•*->/ j

Vapor generation rate for activity (g/s)

DBP molecular weight (g/mol)

Vapor pressure correction factor (unitless)

DBP vapor pressure (torr)

Air speed (cm/s)

Diameter of opening (cm)

Temperature (K)

The EPA's Office of Air Quality Planning and Standards (OAQPS) AP-42 Loading Model estimates
releases to air from the displacement of air containing chemical vapor as a container/vessel is filled with
a liquid (U.S. EPA. ). This model assumes that the rate of evaporation is negligible compared to the
vapor loss from the displacement and is used as the default for estimating volatile air releases during
both loading activities and unloading activities. This model is used for unloading activities because it is
assumed while one vessel is being unloaded another is to be loaded. The EPA/OAQPS AP-42 Loading
Model calculates the average vapor generation rate from loading or unloading using the following
equation:

Equation Apx D-3.

saturation

ion_f actor *MWjjBp*Vcontainer *3785.4-

gal correctiฐn_factor*VP*

RATE

fill

1 activity

3600

hr

R*T

Where:

u activity

Fsaturationj actor

MWdbp

^container
Fcorrection_f actor

VP

Vapor generation rate for activity (g/s)
Saturation factor (unitless)

DBP molecular weight (g/mol)

Volume of container (gal/container)

Vapor pressure correction factor (unitless)
DBP vapor pressure (torr)

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4990

4991

4992

4993

4994

4995

4996

4997

4998

4999

5000

5001

5002

5003

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RATEfiu	= Fill rate of container (containers/h)

R	= Universal gas constant (L*torr/mol-K)

T	= Temperature (K)

For each of the vapor generation rate models, the vapor pressure correction factor (Fcorrection jactor)
can be estimated using Raoult's Law and the mole fraction of DBP in the liquid of interest. However, in
most cases, EPA did not have data on the molecular weights of other components in the liquid
formulations; therefore, the Agency approximated the mole fraction using the mass fraction of DBP in
the liquid of interest. Using the mass fraction of DBP to estimate mole fraction does create uncertainty
in the vapor generation rate model. If other components in the liquid of interest have similar molecular
weights as DBP, then mass fraction is a reasonable approximation of mole fraction. However, if other
components in the liquid of interest have much lower molecular weights than DBP, the mass fraction of
DBP will be an overestimate of the mole fraction. If other components in the liquid of interest have
much higher molecular weights than DBP, the mass fraction of DBP will underestimate the mole
fraction.

If calculating an environmental release, the vapor generation rate calculated from one of the above
models (EquationApx D-l, EquationApx D-2, and EquationApx D-3) is then used along with an
operating time to calculate the release amount:

Equation Apx D-4.

s	kg

RBlBCLSB^BCLVactipity TilTl6activity * ^activity * 3600 * 0.001

Where:

Release_Yearactivity = DBP released for activity per site-year (kg/site-year)

Timeactivity	= Operating time for activity (h/site-year)

Gactivity	= Vapor generation rate for activity (g/s)

In addition to the vapor generation rate models, EPA uses various loss fraction models to calculate
environmental releases, including the following:

•	EPA/OPPT Small Container Residual Model;

•	EPA/OPPT Drum Residual Model;

•	EPA/OPPT Generic Model to Estimate Dust Releases from Transfer/Unloading/Loading
Operations of Solid Powders;

•	EPA/OPPT Multiple Process Vessel Residual Model;

•	EPA/OPPT Single Process Vessel Residual Model;

•	EPA/OPPT Solid Residuals in Transport Containers Model; and

•	March 2023 Methodology for Estimating Environmental Releases from Sampling Waste.

The loss fraction models apply a given loss fraction to the overall throughput of DBP for the given
process. More information for each model can be found in the ChemSTEER User Guide (

2015). The loss fraction value or distribution of values differs for each model; however, each model
follows the same general equation based on the approaches described for each OES:

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EquationApx D-5.

Where:

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Release Yearactivity = PV

* Factivity_loss

Release_Yearactivity = DBP released for activity per site-year (kg/site-year)
PV	= Production volume throughput of DBP (kg/site-year)

Factivityjoss	= Loss fraction for activity (unitless)

The EPA/OPPT Generic Model to Estimate Dust Releases from Transfer/Unloading/Loading Operations
of Solid Powders estimates a loss fraction of dust that may be generated during the
transferring/unloading of solid powders. This model can be used to estimate a loss fraction of dust both
when the facility does not employ capture technology (i.e., local exhaust ventilation, hoods) or dust
control/removal technology (i.e., cyclones, electrostatic precipitators, scrubbers, or filters), and when the
facility does employ capture and/or control/removal technology. The model explains that when dust is
uncaptured, the release media is fugitive air, water, incineration, or landfill. When dust is captured but
uncontrolled, the release media is to stack air. When dust is captured and controlled, the release media is
to incineration or landfill, depending on the control technology. The EPA/OPPT Generic Model to
Estimate Dust Releases from Transfer/Unloading/Loading Operations of Solid Powders calculates the
amount of dust not captured, captured but not controlled, and both captured and controlled, using the
following equations (	V' I h):

Equation Apx D-6.

Elocaldust not captured — Elocaldust generation * (l — Fdustcapture)

Where:

Elocaldust not captured= Daily amount emitted from transfers/unloading that is not

captured (kg not captured/site-day)

Elocaldust^eneration = Daily release of dust from transfers/unloading (kg generated/site-

day)

Fdust_capture	= Capture technology efficiency (kg captured/kg generated)

Equation Apx D-7.

Elocaldust cap uncontroi — Elocaldustgeneration * ^dust_capture * (l — ^dust_controi)

Where:

Elocaldust cap uncontr-oi = Daily amount emitted from capture technology from

transfers/unloading (kg not controlled/site-day)
Elocaldust^eneration	= Daily release of dust from transfers/unloading (kg

generated/ site-day)

Fdust_capture	= Capture technology efficiency (kg captured/kg generated)

Fdust_controi	= Control technology removal efficiency (kg controlled/kg

captured)

Equation Apx D-8.

Elocaldllst capcontrol ~ Elocaldustgeneration * ^dust_capture * ^dust_controi

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Where:

Elocal

dust_cap_control

Daily amount captured and removed by control technology from

transfers/unloading (kg controlled/site-day)

Daily release of dust from transfers/unloading (kg generated/site-

day)

Capture technology efficiency (kg captured/kg generated)

Control technology removal efficiency (kg controlled/kg captured)

Elocal,

dust generation

EPA uses the above equations in the DBP environmental release models, and EPA references the model
equations by model name and/or equation number within Appendix D.

D.2 Manufacturing Model Approaches and Parameters

This appendix presents the modeling approach and equations used to estimate environmental releases for
DBP during the Manufacturing OES. This approach utilizes CDR data (	320a) combined

with Monte Carlo simulation (a type of stochastic simulation).

Based on DBP's physical properties and a virtual tour of the manufacturing processes for other
phthalates (DIDP and DINP) (ExxonMobil. 2022b). EPA identified the following potential release
sources from manufacturing operations:

•	Release source 1: Vented Losses to Air During Reaction/Separations/Other Process Operations

•	Release source 2: Product Sampling Wastes

•	Release source 3: Equipment Cleaning Wastes

•	Release source 4: Open Surface Losses to Air During Equipment Cleaning

•	Release source 5: Transfer Operation Losses to Air from Packaging Manufactured DBP into
Transport Containers

Environmental releases for DBP during manufacturing are a function of DBP's physical properties,
container size, mass fractions, and other model parameters. While physical properties are fixed, some
model parameters are expected to vary. EPA used a Monte Carlo simulation to capture variability in the
following model input parameters: DBP concentration, production volume, air speed, diameter of
openings, saturation factor, container size, and loss fractions. EPA used the outputs from a Monte Carlo
simulation with 100,000 iterations and the Latin Hypercube sampling method in @Risk to calculate
release amounts and exposure concentrations for this OES.

D.2.1 Model Equations

Table Apx D-l provides the models and associated variables used to calculate environmental releases
for each release source within each iteration of the Monte Carlo simulation. EPA used these
environmental releases to develop a distribution of release outputs for the Manufacturing OES. The
variables used to calculate each of the following values include deterministic or variable input
parameters, known constants, physical properties, conversion factors, and other parameters. The values
for these variables are provided in Appendix D.2.2. The Monte Carlo simulation calculated the total
DBP release (by environmental media) across all release sources during each iteration of the simulation.
EPA then selected 50th and 95th percentile values to estimate the central tendency and high-end
releases, respectively.

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Table Apx D-l. Models and Variables Applied for Release Sources in the Manufacturing PES

Release Source

Model(s) Applied

Variables Used

Release source 1: Vented
Losses to Air During
Reaction/Separations/Other
Process Operations

See Equation Apx D-9

QoBP_day> ^DBP_SPERC

Release source 2: Product
Sampling Wastes

March 2023 Methodology for
Estimating Environmental
Releases from Sampling
Waste (Appendix D.l)

QDBP_day> LFsampling

Release source 3: Equipment
Cleaning Wastes

EPA/OPPT Multiple Process
Vessel Residual Model
(Appendix D.l)

QDBP_day> LFequip_clean

Release source 4: Open
Surface Losses to Air During
Equipment Cleaning

EPA/OPPT Penetration
Model or EPA/OPPT Mass
Transfer Coefficient Model,
based on air speed (Appendix
D.l)

Vapor Generation Rate: FDBP; MW; VP;
RATEair_speed, Dequip_clean> T, P

Operating Time: OHequip ciean

Release source 5: Transfer
Operation Losses to Air from
Packaging Manufactured
DBP into Transport
Containers

EPA/OAQPS AP-42 Loading
Model (Appendix D.l)

Vapor Generation Rate: FDBP; VP; fsat; MW; R;
T; RATEfui_drum

Operating Time: NcontJoad^ear;
RATEfin_drum; OD

Release source 1 daily release (Vented Losses to Air During Reaction/Separations/Other Process
Operations) is calculated using the following equation:

EquationApx D-9.

ReleasejperDayRP1 = QoBP_day * Fdbp_sperc

Where:

Release_perDayRP1 = DBP released for release source 1 (kg/site-day)

QDBP_day	= Facility throughput of DBP (kg/site-day)

FDbp_sperc	= Loss fraction for unit operations (unitless)

D.2.2 Model Input Parameters

Table Apx D-2 summarizes the model parameters and their values for the Manufacturing Monte Carlo
simulation. Additional explanations of EPA's selection of the distributions for each parameter are
provided after this table.

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5118 Table Apx D-2. Summary of Parameter Values and Distributions Used in the Manufacturing Models

Input Parameter

Symbol

Unit

Deterministic
Values

Uncertainty Analysis Distribution Parameters

Rationale/Basis

Value

Lower-
Bound

Upper-
Bound

Mode

Distribution

Type

Number of Sites with CBI

Ns

sites

4

-

-

-

-

See D.2.3

Facility Production Rate - Known
Site

PV1

kg/site-year

23,520

-

-

-

Uniform

See D.2.4

Facility Production Rate - Sites
with CBI

PV2

kg/site-year

2,382,450

49,689

2,382,450

-

Uniform

See D.2.4

Manufactured DBP Concentration
(Known Site)

Fdbpj

kg/kg

1.0

0.90

1.0

-

Uniform

See D.2.7

Manufactured DBP Concentration
(Sites with CBI)

F DBP2

kg/kg

1.0

0.01

1.0

-

Uniform

See D.2.7

Air Speed

RATEair speed

ft/min

19.7

2.56

398

-

Lognormal

See D.2.8

Diameter of Equipment Opening

Dequip clean

cm

92

-

-

-

-

See D.2.9

Saturation Factor

fsat

dimensionless

0.5

0.5

1.45

0.5

Triangular

See D.2.10

Drum Size

V drum

gal

100

20

1000

100

Triangular

See D.2.11

Fraction of DBP Lost During
Sampling - 1 (QDBP_day<50 kg/site-
day)

F sampling 1

kg/kg

2.0E-02

2.0E-03

2.0E-02

2.0E-02

Triangular

See D.2.12

Fraction of DBP Lost During
Sampling - 2 (QDBP_day 50-200
kg/site-day)

F sampling 2

kg/kg

5.0E-03

6.0E-04

5.0E-03

5.0E-03

Triangular

See D.2.12

Fraction of DBP Lost During
Sampling - 3 (Qdbp day 200-5000
kg/site-day)

F sampling 3

kg/kg

4.0E-03

5.0E-04

4.0E-03

4.0E-03

Triangular

See D.2.12

Fraction of DBP Lost During
Sampling - 4 (QDBP_day >5,000
kg/site-day)

F sampling 4

kg/kg

4.0E-04

8.0E-05

4.0E-04

4.0E-04

Triangular

See D.2.12

Operating Days

OD

days/year

300

-

-

-

-

See D.2.13

Vapor Pressure at 25 ฐC

VP

mmHg

2.0E-05

-

-

-

-

Physical property

Vapor Pressure at 375 ฐF

VP375

mmHg

37

-

-

-

-

Physical property

Molecular Weight

MW

g/mol

278

-

-

-

-

Physical property

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Input Parameter

Symbol

Unit

Deterministic
Values

Uncertainty Analysis Distribution Parameters

Rationale/Basis

Value

Lower-
Bound

Upper-
Bound

Mode

Distribution

Type

Density of DBP

RHO

kg/L

1.04

-

-

-

-

Physical property

Gas Constant

R

atm-

cm3/gmol-L

82.05

-

-

-

-

Universal
constant

Process Operation Emission Factor

Fdbpsperc

kg/kg

1.0E-05

-

-

-

-

See D.2.14

Temperature

T

K

298

-

-

-

-

Process parameter

Pressure

P

atm

1.0

-

-

-

-

Process parameter

Equipment Cleaning Loss Fraction

LFequip clean

kg/kg

2.0E-02

-

-

-

-

See D.2.15

Drum Fill Rate

RATEfiH drum

drums/h

20

-

-

-

-

See D.2.16

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D.2.3 Number of Sites

EPA used 2020 CDR data (U.S. EPA. 2020a) to identify the number of sites that manufacture DBP. In
CDR, two sites reported domestic manufacturing of DBP, Dystar LP located in Reidsville, North
Carolina and one site, Polymer Additives Inc, that reported their PV as CBI. An additional three sites
reported both their locations and site activities as CBI; EPA assumed that these sites may manufacture
DBP. This resulted in a total of five potential DBP manufacturing sites. Table Apx D-3 presents the
names and locations of these sites.

Table Apx D-3. Sites Reporting to CDR for Domestic Manufacture of DBP

Facility Name

Facility Location

Dystar LP

Reidsville, NC

Polymer Additives, Inc.

Bridgeport, NJ

3 additional CBI sites

CBI

D.2.4 Throughput Parameters

EPA ran the Monte Carlo model separately to estimate releases and exposures from the single site with a
known production volume (Dystar LP) and to estimate releases and exposures from the other four sites
that claimed their production volumes (PVs) as CBI. EPA used 2020 CDR data (	2020a) to

identify annual facility PV for each site. Dystar LP reported 51,852 lb (23,520 kg) of DBP
manufactured.

For the other four sites, EPA used a uniform distribution set within the national PV range for DBP. EPA
calculated the bounds of the range by taking the total PV range in CDR and subtracting out the PVs that
belonged to known sites (both manufacturing and import). Then, for each bound of the PV range for the
remaining sites with CBI PVs, EPA divided the value by the remaining four sites. CDR estimates a total
national DBP PV of 1,000,000 to 10,000,000 lb. Based on the known PVs from importers and
manufacturers, the total PV associated with the four sites with CBI PVs is 109,546 to 5,252,403 lb/year.
After converting from lb to kg, EPA set a uniform distribution for the PV for the four sites with CBI or
withheld PVs with lower-bound of 49,689 kg/year, and an upper-bound of 2,382,450 kg/year.

The daily throughput of DBP is calculated using EquationApx D-10 by dividing the annual PV by the
number of operating days.

Equation Apx D-10.

Qdbp

PV

day

OD * Nsites

Where:

QDBP_day
PV

Nsites

OD

Facility daily throughput of DBP (kg/site-day)

Annual production volume (kg/site-year)

Number of sites (1 known or 4 with CBI PVs depending on the run
[see Appendix D.2.3])

Operating days (see Appendix D.2.13) (days/year)

D.2.5 Number of Containers Per Year

The number of product containers filled with manufactured DBP by a site per year is calculated using

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the following equation:

EquationApx D-ll.

PV

Ncont_load_year ~ T7

*drum

Where:

Ncontjoadjyear	= Annual number of product containers (container/site-year)

PV	= Annual production volume (see Appendix D.2.4) [kg/site-year])

Vdrum	= Product container volume (see Appendix D.2.11) [gal/container])

D.2.6 Operating Hours

EPA estimated operating hours or hours of duration for the applicable activities using data provided
from the ChemSTEER User Guide (	I and/or through calculation from other parameters.

Release points with operating hours provided from that User Guide include an estimate of 4 hours for
equipment cleaning (release point 4).

The operating hours for loading of DBP into transport containers (release point 5) is calculated based on
the number of product containers filled at the site and the fill rate using the following equation:

Equation Apx D-12.

Where:

TimeRP 5
N,

cont_load_year

RATEfiu drum

OD

TimeRPS =

Ncont_load_year

RATE findrum * OD

Operating time for release point 5 (h/site-day)

Annual number of product containers (see Appendix D.2.5)

(containers/site-year)

Fill rate of container (see Appendix D.2.16) [containers/h])
Operating days (see Appendix D.2.13) (days/site-year)

D.2.7 Manufactured DBP Concentration

EPA used the manufactured DBP concentration range reported in CDR (	!020a) to make a

uniform distribution of 90 to 100 percent DBP for the run using the known site PV. For the second run
for the sites that reported CBI, EPA assumed a uniform distribution from 1 to 100 percent DBP based on
reported information in the 2020 CDR.

D.2.8 Air Speed	

Baldwin and Maynard measured indoor air speeds across a variety of occupational settings in the United
Kingdom (Baldwin and Mavm M). Fifty-five work areas were surveyed across a variety of
workplaces. EPA analyzed the air speed data from Baldwin and Maynard and categorized the air speed
surveys into settings representative of industrial facilities and representative of commercial facilities.
EPA fit separate distributions for these industrial and commercial settings and used the industrial
distribution for this OES.

EPA fit a lognormal distribution for the data set as consistent with the authors' observations that the air
speed measurements within a surveyed location were lognormally distributed and the population of the
mean air speeds among all surveys were lognormally distributed (Baldwin and Maynard. 1998). Since
lognormal distributions are bound by zero and positive infinity, EPA truncated the distribution at the
largest observed value among all of the survey mean air speeds.

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EPA fit the air speed surveys representative of industrial facilities to a lognormal distribution with the
following parameter values: mean of 22.414 cm/s and standard deviation of 19.958 cm/s. In the model,
the lognormal distribution is truncated at a minimum allowed value of 1.3 cm/s and a maximum allowed
value of 202.2 cm/s (largest surveyed mean air speed observed in Baldwin and Maynard) to prevent the
model from sampling values that approach infinity or are otherwise unrealistically small or large
(Baldwin and Maynard. 1998).

Baldwin and Maynard only presented the mean air speed of each survey. The authors did not present the
individual measurements within each survey. Therefore, these distributions represent a distribution of
mean air speeds and not a distribution of spatially variable air speeds within a single workplace setting.
However, a mean air speed (averaged over a work area) is the required input for the model. EPA
converted the units to ft/min prior to use within the model equations.

D.2.9 Diameters of Opening

The ChemSTEER User Guide indicates diameters for the openings for various vessels that may hold
liquids in order to calculate vapor generation rates during different activities (	). For

equipment cleaning operations (release point 4), the ChemSTEER User Guide indicates a single default
value of 92 cm (	).

D.2.10 Saturation Factor

The Chemical Engineering Branch Manual for the Preparation of Engineering Assessments, Volume 1
(also called "CEB Manual") indicates that during splash filling, the saturation concentration was reached
or exceeded by misting with a maximum saturation factor of 1.45 (	). The CEB Manual

indicates that saturation concentration for bottom filling was expected to be about 0.5 (	).

The underlying distribution of this parameter is not known; therefore, EPA assigned a triangular
distribution based on the lower-bound, upper-bound, and mode of the parameter. Because a mode was
not provided for this parameter, EPA assigned a mode value of 0.5 for bottom filling as bottom filling
minimizes volatilization (	). This value also corresponds to the typical value provided in

the ChemSTEER User Guide for the EPA/OAQPS AP-42 Loading Model (U.S. EPA. 2015).

D.2.11 Container Size

Based on the PV range assessed, EPA assumed that DBP may be packaged in drums or totes. According
to the ChemSTEER Manual Guide, drums are defined as containing between 20 and 100 gallons of
liquid, with a default of 55 gallons while totes are defined as containing between 100 and 1,000 gallons,
with a default of 550 gallons (\ v < < \ < I ). Therefore, EPA modeled packaged container size using
a triangular distribution with a lower-bound of 20 gallons, an upper-bound of 1,000 gallons, and a mode
of 100 gallons (the maximum for drums and minimum for totes).

D.2.12 Sampling Loss Fraction

Sampling loss fractions were estimated using the March 2023 Methodology for Estimating
Environmental Releases from Sampling Wastes (	23c). In this methodology, EPA

completed a search of over 300 Initial Review Engineering Report (IRERs) completed in the years 2021
and 2022 for sampling release data, including a similar proportion of both Pre-Manufacture Notices
(PMNs) and Low Volume Exemptions (LVEs). Of the searched IRERs, 60 data points for sampling
release loss fractions, primarily for sampling releases from submitter-controlled sites (-75% of IRERs),
were obtained. The data points were analyzed as a function of the chemical daily throughput and
industry type. This analysis showed that the sampling loss fraction generally decreased as the chemical
daily throughput increased. Therefore, the methodology provides guidance for selecting a loss fraction

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based on chemical daily throughput. TableApx D-4 presents a summary of the chemical daily
throughputs and corresponding loss fractions.

Table Apx D-4. Sampling Loss Fraction Data from the March 2023 Methodology for Estimating
Environmental Releases from Sampling Waste		

Chemical Daily
Throughput
(kg/site-day)
( Qchcm_sitc_ilny )

Number
of Data
Points

Sampled Quantity
(kg chemical/day)

Sampling Loss Fraction

(LFsiimpling)

50th
Percentile

95th
Percentile

50th
Percentile

95th Percentile

<50

13

0.03

0.20

0.002

0.02

50 to <200

10

0.10

0.64

0.0006

0.005

200 to <5,000

25

0.37

3.80

0.0005

0.004

>5,000

10

1.36

6.00

0.00008

0.0004

All

58

0.20

5.15

0.0005

0.008

For each range of daily throughputs, EPA estimated sampling loss fractions using a triangular
distribution of the 50th percentile value as the lower-bound, and the 95th percentile value as the upper-
bound and mode. The sampling loss fraction distribution was chosen based on the calculation of daily
throughput, as shown in Appendix D.2.4.

D.2.13 Operating Days	

EPA was unable to identify specific information for operating days for the manufacturing of DBP.
Therefore, EPA assumed a constant value of 300 days/year, which assumes the production sites operate
six days per week and 50 weeks per year, with 2 weeks down for turnaround.

D.2.14 Process Operations Emission Factor	

In order to estimate releases from reactions, separations, and other process operations, EPA used an
emission factor from the European Solvents Industry Group (ESIG). According to the ESD on Plastic
Additives, the processing temperature during manufacture of plasticizers is 375ฐF (OECD. 2009b).
However, the rate of release is expected to be limited by the ambient temperature of the manufacturing
facility. At room temperature, the vapor pressure of DBP is less than 1 Pa. The ESIG Specific
Environmental Release Category for Industrial Substance Manufacturing (solvent-borne) states that a
chemical with a vapor pressure of less than 1 Pa will have an emission factor of 0.00001 (ESIG. 2012).
Therefore, EPA used this emission factor as a constant value for process operation releases.

D.2.15 Equipment Cleaning Loss Fraction

EPA used the EPA/OPPT Multiple Process Residual Model to estimate the releases from equipment
cleaning. That model, as detailed in the ChemSTEER User Guide (	), provides an overall

loss fraction of 2 percent from equipment cleaning.

D.2.16 Container Fill Rates

The ChemSTEER User Guide (U.S. EPA. 2015) provides a typical fill rate of 20 containers per hour for
containers with 20 to 1,000 gallons of material.

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D.3 Application of Adhesives and Sealants Model Approaches and
Parameters

This appendix presents the modeling approach and equations used to estimate environmental releases for
DBP during the Application of adhesives and sealants OES. This approach utilizes the Emission
Scenario Document on Use of Adhesives (OECD. 2015) combined with Monte Carlo simulation (a type
of stochastic simulation). EPA assessed this OES with DBP arriving on site as an additive in liquid
adhesive or sealant formulations; therefore, solid releases are not expected.

Based on the ESD, EPA identified the following release sources from the Application of adhesives and
sealants OES:

•

Release

source

1:

Transfer Operation Losses from Unloading

•

Release

source

2:

Container Cleaning Residues

•

Release

source

3:

Open Surface Losses to Air During Container Cleaning

•

Release

source

4:

Equipment Cleaning Releases

•

Release

source

5:

Open Surface Losses to Air During Equipment Cleaning

•

Release

source

6:

Process Releases During Adhesive Applications

•

Release

source

7:

Open Surface Losses to Air During Curing/Drying

•

Release

source

8:

Trimming Wastes

Environmental releases for DBP during use of adhesives and sealants are a function of DBP's physical
properties, container size, mass fractions, and other model parameters. While physical properties are
fixed, some model parameters are expected to vary. EPA used a Monte Carlo simulation to capture
variability in the following model input parameters: product throughput, DBP concentrations, air speed,
container size, loss fractions, control technology efficiencies, and operating days. The Agency used the
outputs from a Monte Carlo simulation with 100,000 iterations and the Latin Hypercube sampling
method in @Risk to calculate release amounts for this OES.

D.3.1 Model Equations

TableApx D-5 provides the models and associated variables used to calculate environmental releases
for each release source within each iteration of the Monte Carlo simulation. EPA used these
environmental releases to develop a distribution of release outputs for the Application of adhesives and
sealants OES. The variables used to calculate each of the following values include deterministic or
variable input parameters, known constants, physical properties, conversion factors, and other
parameters. The values for these variables are provided in Appendix D.l. The Monte Carlo simulation
calculated the total DBP release (by environmental media) across all release sources during each
iteration of the simulation. EPA then selected 50th and 95th percentile values to estimate the central
tendency and high-end releases, respectively.

Table Apx D-5. Models and Variables Applied for Release Sources in the Application of
Adhesives and Sealants OES

Release Source

Model(s) Applied

Variables Used

Release source 1: Transfer
Operation Losses from
Unloading

Not assessed, release
estimated using data from NEI
and TRI

N/A

Release source 2: Container
Cleaning Residues

EPA/OPPT Drum Residual
Model or EPA/OPPT Bulk
Transport Residual Model,

QDBP_day> ^drum_residue > ^cont_residue >
Vcont; Fdbp', RHO

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Release Source

Model(s) Applied

Variables Used



based on container size
(Appendix D.l)



Release source 3: Open Surface
Losses to Air During Container
Cleaning

Not assessed, release
estimated using data from NEI
and TRI

N/A

Release source 4: Equipment
Cleaning Releases

EPA/OPPT Multiple Process
Vessel Residual Model
(Appendix D.l)

QDBP_day> Fequipmentjcleaning

Release source 5: Open Surface
Losses to Air During Equipment
Cleaning

Not assessed, release
estimated using data from NEI
and TRI

N/A

Release source 6: Process
Releases Losses During
Adhesive Application

Unable to estimate due to lack
of substrate surface area data

N/A

Release source 7: Open Surface
Losses to Air During
Curing/Drying

Unable to estimate due to a
lack of the required data for
DBP pertaining to curing
times and conditions

N/A

Release source 8: Trimming
Wastes

See Equation Apx D-13

QDBP_day> Ftrimming

Release source 8 daily release (Trimming Wastes) is calculated using the following equation:
EquationApx D-13.

Release_perDayRP8 Q D B P _day * Ftrimming

Where:

Release_perDayRP8 = DBP released for release source 8 (kg/site-day)

QDBP_day	= Facility throughput of DBP (see Appendix D.3.4) (kg/site-day)

Ftrimming	= Fraction of DBP released as trimming waste (see Appendix

D.3.11)

(kg/kg)

D.3.2 Model Input Parameters	

Table Apx D-6 summarizes the model parameters and their values for the Application of Adhesives and
Sealants Monte Carlo simulation. Additional explanations of EPA's selection of the distributions for
each parameter are provided after this table.

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5331 Table Apx D-6. Summary of Parameter Values and Distributions Used in the Application of Adhesives and Sealants Model

Input Parameter

Symbol

Unit

Deterministic
Values

Uncertainty Analysis Distribution Parameters

Rationale/Basis

Value

Lower-
Bound

1 ppe I'-
ll ound

VI ode

Distribution

Type

DBP Production Volume for
Adhesives/Sealants

PV

kg/year

2.1E06

9.9E04

2.1E06

-

Uniform

See D.3.3

Annual Facility Throughput of
Adhesive/Sealant

Qproduct_year

kg/site-year

1.4E04

1,500

1.4E05

1.4E04

Triangular

See D.3.4

Adhesive/Sealant DBP
Concentration

Fdbp

kg/kg

0.10

1.0E-03

0.75

0.10

Triangular

See D.3.7

Operating Days

OD

days/year

260

50

365

260

Triangular

See D.3.8

Container Volume

Vcont

gal

5.0

5.0

20

5.0

Triangular

See D.3.9

Container Residual Loss
Fraction

Fcont residue

kg/kg

3.0E-03

3.0E-04

6.0E-03

3.0E-03

Triangular

See D.3.10

Fraction of DBP Released as
Trimming Waste

F trimming

kg/kg

4.0E-02

0

4.0E-02

4.0E-02

Triangular

See D.3.11

Vapor Pressure at 25 ฐC

VP

mmHg

2.0E-05

-

-

-

-

Physical property

Molecular Weight

MW

g/mol

278

-

-

-

-

Physical property

Gas Constant

R

atm-

cm3/gmol-L

82

-

-

-

-

Universal constant

Density of DBP

RHO

kg/L

1.0

-

-

-

-

Physical property

Temperature

T

K

298

-

-

-

-

Process parameter

Pressure

P

atm

1.0

-

-

-

-

Process parameter

Small Container Fill Rate

RATEfillcont

containers/h

60

-

-

-

-

See D.3.12

Equipment Cleaning Loss
Fraction

Fequipment cleaning

kg/kg

2.0E-02







-

See D.3.13

5332

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D.3.3 Production Volume

EPA estimated the total DBP production volume for adhesive and sealant products using a uniform
distribution with a lower-bound of 99,157 kg/year and an upper-bound of 2,140,323 kg/year. This range
is based on DBP CDR data of site production volumes, national aggregate production volumes, and
percentages of the production volumes going to various industrial sectors (	20a).

There were two reporters that reported to CDR for use of DBP in adhesive/sealant or paint/coating
products: G.J. Chemical Co, Inc. in Somerset, New Jersey, who reported a volume of 139,618 lb; and
MAK Chemicals in Clifton, NJ, who reported a use volume of 105,884 lb of DBP. This equates to a
total known use volume of 245,502 lb of DBP; however, there is still a large portion of the aggregate PV
range for DBP that is not attached to a known use. A breakdown of the known production volume
information is provided in TableApx D-7.

TableApx D-7. CDR Reported Site Information for Use in Calculation of Use of Adhesives,

Sealants, Paints, and Coatings Proc

uction Volume

Site Name

Site Location

Reported Production
Volume (lb/year)

Reported Use Industry/Products

Dystar LP

Reidsville, NC

51,852

Textiles, apparel, and leather
manufacturing

Covalent Chemical

Raleigh, NC

88,184

Plastics material and resin
manufacturing

MAK Chemicals

Clifton, NJ

105,884

Exterior car waxes, polishes, and
coatings

GJ Chemical Co
Inc

Newark, NJ

139,618

Hot-melt adhesives

Industrial
Chemicals Inc

Vestavia Hills,
AL

422,757

Plastics product manufacturing

According to CDR, the national aggregate PV range for manufacture and import of DBP in 2019 was
between 1,000,000 to 10,000,000 lb. The sum of known production volumes for all uses is 808,295 lb
(562,794 lb not associated with use of adhesives/sealants or paints and coatings). Due to uncertainty in
the expected use of DBP and the number of identified products for these uses, EPA assumed that the
remaining PV with unknown use is split between the use of adhesives and sealants and paint and coating
products. Subtracting the PV with known use that are not associated with
adhesives/sealants/paints/coatings from the aggregate national PV range equates to a range of

•	Low-end: 1,000,000 lb to 562,793 lb = 437,207 lb (198,314 kg); and

•	High-end: 10,000,000 lb to 562,793 lb = 9,437,207 lb (4,280,645 kg).

EPA assumed half of the calculated PV above is used in paints and coatings while the other half is used
in adhesives and sealants. This results in a PV range of 99,157 to 2,140,323 kg/year across all sites for
the application of adhesives and sealants.

D.3.4 Throughput Parameters

The annual throughput of adhesive and sealant product is modeled using a triangular distribution with a
lower-bound of 1,500 kg/year, an upper-bound of 141,498 kg/year, and mode of 13,500 kg/year. This is
based on the Emission Scenario Document on Use of Adhesives (	). The ESD provides

default adhesive use rates based on end-use category. EPA compiled the end-use categories that were

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relevant to downstream uses for adhesives and sealants containing DBP, which included computer and
electronic product manufacturing, motor and non-motor vehicles, vehicle parts and tire manufacturing,
and general assembly. The lower- and upper-bound adhesive use rates for these categories was 1,500 to
141,498 kg/year. The mode is based on the ESD default for unknown end-use markets.

The annual throughput of DBP in adhesives/sealants is calculated using EquationApx D-14 by
multiplying the annual throughput of all adhesives and sealants by the concentration of DBP in the
adhesive s/seal ants.

Equation Apx D-14.

QDBP_year ~ Qproduct_year * FDBP

Where:

QDBP_year	= Facility annual throughput of DBP (kg/site-year)

Qproductjyear	= Facility annual throughput of all adhesives/sealants (kg/site-year)

FDbp	= Concentration of DBP in adhesives/sealants (see Appendix D.3.7)

(kg/kg)

The daily throughput of DBP is calculated using Equation Apx D-15 by dividing the annual production
volume by the number of operating days. The number of operating days is determined according to
Appendix D.3.8.

Equation Apx D-15.

^	_ QDBP_year

VDBP_day ~

Where:

QDBP_day	~

QDBP_year	~

OD

D.3.5 Number of Sites

Per 2020 U.S. Census Bureau data for the NAICS codes identified in the Emission Scenario Document
on Use of Adhesives ("OECD. i ), there are 10,144 adhesive and sealant use sites (	23).

Therefore, this value is used as a bounding limit, not to be exceeded by the calculation. Number of sites
is calculated using a per-site throughput and total production volume with the following equation:

Facility daily throughput of DBP (kg/site-day)
Facility annual throughput of DBP (kg/site-year)
Operating days (see Appendix D.3.8) (days/year)

Equation Apx D-16.

PV

Ns =-	

VDBP_year

Where:

Ns	= Number of sites (sites)

PV	= DBP production volume for adhesives/sealants (kg/year)

QDBP_year	= Facility annual throughput of DBP (kg/site-year)

D.3.6 Number of Containers Per Year

The number of DBP raw material containers received and unloaded by a site per year is calculated using
the following equation:

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EquationApx D-17.

Q product_y ear

Ncont_unload_year ~	/	i

RHO * [ 3.79 t-tt I * Vcont

(3-79 Wi)

Where:

Ncont_unioad_year = Annual number of containers unloaded (container/site-year)
Qproductjyear	= Facility annual throughput of all adhesives/sealants (see Appendix

D.3.4) (kg/site-year)

RHO	= DBP density (kg/L)

Vcont	= Container volume (see Appendix D.3.9) (gal/container)

D.3.7 Adhesive/Sealant DBP Concentration

EPA determined DBP concentrations in final adhesive/sealant products using compiled SDS information
(see Appendix E for EPA identified DBP-containing products for this OES). For final adhesive/sealant
products, EPA developed the triangular distribution of DBP concentration using a lower-bound of 0.1
percent, an upper-bound of 75 percent, and a mode of 10 percent. The lower- and upper-bounds are
based on the minimum and maximum concentrations compiled from SDS for multiple adhesives and
sealant products containing DBP, excluding products with 0 or 100 percent DBP. The mode is based on
the overall median of all high-end values of the provided product ranges.

D.3.8 Operating Days

EPA modeled the operating days per year using a triangular distribution with a lower-bound of 50
days/year, an upper-bound of 365 days/year, and a mode of 260 days/year. To ensure that only integer
values of this parameter were selected, EPA nested the triangular distribution probability formula within
a discrete distribution that listed each integer between (and including) 50 and 365 days/year. This is
based on the Emission Scenario Document on Use of Adhesives ( ID. 2015). The ESD provides
operating days for several end-use categories. The range of operating days for the end-use categories is
50 to 365 days/year. The mode of the distribution is based on the ESD's default of 260 days/year for
unknown or general adhesive use cases.

D.3.9 Container Size

Based on identified products, EPA assumed that sites would receive adhesives and sealants in small
containers (see Appendix E for a list of the DBP-containing products identified for this OES). According
to the ChemSTEER User Guide, small containers are defined as containing between 5 and 20 gallons of
material with a default size of 5 gallons (I. c. < ^ \ < i ). EPA modeled container size using a
triangular distribution with a lower-bound of 5 gallons, an upper-bound of 20 gallons, and a mode of 5
gallons based on the defaults defined by the ChemSTEER User Guide.

D.3.10 Small Container Residue Loss Fraction	

EPA used data from the PE1 Associates Inc. study (Associates. 1988) for emptying drums by pouring
along with central tendency and high-end values from the EPA/OPPT Small Container Residual Model.
For unloading drums by pouring in the PEI Associates Inc. study (Associates. 1988). EPA found that the
average percent residual from the pilot-scale experiments showed a range of 0.03 to 0.79 percent and an
average of 0.32 percent. The EPA/OPPT Small Container Residual Model from the ChemSTEER User
Guide (	015) recommends a default central tendency loss fraction of 0.3 percent and a high-

end loss fraction of 0.6 percent.

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The underlying distribution of the loss fraction parameter for small containers is not known; therefore,
EPA assigned a triangular distribution, since triangular distributions require least assumptions and are
completely defined by range and mode of a parameter. The Agency assigned the mode and maximum
values for the loss fraction probability distribution using the central tendency and high-end values,
respectively, prescribed by the EPA/OPPT Small Container Residual Model in the ChemSTEER User
Guide (	). EPA assigned the minimum value for the triangular distribution using the

minimum average percent residual measured in the PEI Associates, Inc. study (Associates. 1988) for
emptying drums by pouring.

D.3.11 Fraction of DBP Released as Trimming Waste	

EPA modeled the fraction of DBP released as trimming waste using a triangular distribution with a
lower-bound of 0, an upper-bound of 0.04, and a mode of 0.04. This is based on the Emission Scenario
Document on Use of Adhesives (OECD. 2015). The ESD states that trimming losses should only be
assessed if trimming losses are expected for the end use. Because not all adhesive and sealant end uses
will result in trimming losses, EPA assigned a lower-bound of 0. The upper-bound and mode are based
on the ESD's default trimming waste loss fraction of 0.04 kg chemical in trimmings/kg chemical
applied.

D.3.12 Container Fill Rate

The ChemSTEER User Guide (U.S. EPA. 2015) provides a typical fill rate of 60 containers per hour for
containers with less than 20 gallons of liquid.

D.3.13 Equipment Cleaning Loss Fraction	

EPA used the EPA/OPPT Multiple Process Residual Model to estimate the releases from equipment
cleaning. This model, as detailed in the ChemSTEER User Guide (	), provides an overall

loss fraction of 2 percent from equipment cleaning.

D.4 Application of Paints and Coatings Model Approaches and
Parameters

This appendix presents the modeling approach and equations used to estimate environmental releases for
DBP during the Application of paints and coatings OES. This approach utilizes the Emission Scenario
Document on Coating Application via Spray-Painting in the Automotive Refinishing Industry (OECD.
201 la). Emission Scenario Document on the Coating Industry (Paints, Lacquers, and Varnishes)

(OECD. 2009c). and Emission Scenario Document on the Application of Radiation Curable Coatings,
Inks, and Adhesives via Spray, Vacuum, Roll, and Curtain Coating (	) combined with

Monte Carlo simulation. DBP is used in standard liquid paints and coatings as well as components of
two-part coating systems. All product SDSs identified indicate that DBP is present in liquid form (see
Appendix E for EPA-identified, DBP-containing products for this OES). EPA modeled spray application
as opposed to other application methods because it provides a more protective estimate of releases and
exposures with the prevalence of each application method unknown for DBP-containing coatings. Based
on the ESDs, EPA identified the following release sources from the application of paints and coatings:

•	Release source 1: Transfer Operation Losses from Unloading

•	Release source 2: Open Surface Losses to Air During Raw Material Sampling

•	Release source 3: Container Cleaning Wastes

•	Release source 4: Open Surface Losses to Air During Container Cleaning

•	Release source 5: Process Releases During Application Operations

•	Release source 6: Equipment Cleaning Wastes

•	Release source 7: Open Surface Losses to Air During Equipment Cleaning

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• Release source 8: Raw Material Sampling Wastes

Environmental releases for DBP during the application of paints and coatings are a function of DBP's
physical properties, container size, mass fractions, and other model parameters. While physical
properties are fixed, some model parameters are expected to vary. EPA used a Monte Carlo simulation
to capture variability in the following model input parameters: production volume, paint and coating
throughput, DBP concentrations, container size, loss fractions, control technology efficiencies, transfer
efficiency, and operating days. EPA used the outputs from a Monte Carlo simulation with 100,000
iterations and the Latin Hypercube sampling method in @Risk to calculate release amounts for this
OES.

D.4.1 Model Equations

TableApx D-8 provides the models and associated variables used to calculate environmental releases
for each release source within each iteration of the Monte Carlo simulation. EPA used these
environmental releases to develop a distribution of release outputs for the Application of paints and
coatings OES. The variables used to calculate each of the following values include deterministic or
variable input parameters, known constants, physical properties, conversion factors, and other
parameters. The values for these variables are provided in Appendix D.l. The Monte Carlo simulation
calculated the total DBP release (by environmental media) across all release sources during each
iteration of the simulation. EPA then selected 50th and 95th percentile values to estimate the central
tendency and high-end releases, respectively.

Table Apx D-8. Models and Variables Applied for Release Sources in the Application of Paints
and Coatings OES			

Release Source

Model(s) Applied

Variables Used

Release source 1: Transfer
Operation Losses from
Unloading

Not assessed, release
estimated using data from NEI
and TRI

N/A

Release source 2: Open
Surface Losses to Air During
Raw Material Sampling

Not assessed, release
estimated using data from NEI
and TRI

N/A

Release source 3: Container
Cleaning Wastes

EPA/OAQPS AP-42 Small
Container Residual Model
(Appendix D.l)

QDBP_day> Fcontjresidue • Fdrum_residueฆ RHO;
Fdbp'> Vcont

Release source 4: Open
Surface Losses to Air During
Container Cleaning

Not assessed, release
estimated using data from NEI
and TRI

N/A

Release source 5: Process
Releases During Operations

See EquationApx D-18
through Equation Apx D-22

QoBPjday ^transfer_eff> ^capture_eff>
Fsolid.rem_eff

Release source 6: Equipment
Cleaning Wastes

EPA/OPPT Multiple Process
Vessel Residual Model
(Appendix D.l)

QoBPjday LFequip_clean

Release source 7: Open
Surface Losses to Air During
Equipment Cleaning

Not assessed, release
estimated using data from NEI
and TRI

N/A

Release source 8: Raw
Material Sampling Wastes

March 2023 Methodology for
Estimating Environmental

QDBP_day> LFsampling

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Release Source

Model(s) Applied

Variables Used



Releases from Sampling
Waste (Appendix D.l)



Release source 5 (Process Releases During Operations) is partitioned out by release media depending
upon the paint and coating overspray control technology employed. EPA modeled two scenarios: one
scenario in the absence of control technology with a total release from release source 5 to unknown
media {i.e., a release to fugitive air, water, incineration, or landfill); and one scenario with control
technology and releases partitioned to landfill, stack air, or water for release source 5 based on capture
and removal efficiencies. In order to calculate the total release from release source 5, the following
equation was used:

EquationApx D-18.

Release_perDayRpS total — Q OBP _day * (l — Ftransfer_eff)

Where:

Release_perDayRP5 totai = DBP released for release source 5 to all release media

(kg/site-day)

QDBP_day	= Facility throughput of DBP (see Appendix) (kg/site-

day)

Ftransfer_eff	= Paint/coating transfer efficiency fraction (see Appendix

D.4.12) (unitless)

Transfer efficiency is determined according to Appendix D.4.12. For the scenario in which control
technologies are accounted for, the percent of the total release that is released to water is calculated
using the following equation:

Equation Apx D-19.

Where:

%

water
^capture_eff

solidrem_ef f

%

water

~ ^capture_eff *

(l Fsolidrem_ef /)

Percent of release 5 that is released to water (unitless)

Booth capture efficiency for spray-applied paints/coatings (see
Appendix D.4.15) (kg/kg)

Fraction of solid removed in the spray mist of sprayed
paints/ coatings (see Appendix D.4.16) (kg/kg)

Booth capture efficiency is determined according to Appendix D.4.15, and solid removal efficiency is
determined according to Appendix D.4.16. The percent of the total release that is released to stack air is
calculated using the following equation:

Equation Apx D-20.

Where:

%r.

capture_eff

ฐ/ฐair ~ (l Fcapture_eff)

Percent of release 5 that is released to stack air (unitless)

Booth capture efficiency for spray-applied paints/ coatings (see
Appendix D.4.15) (kg/kg)

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The percent of the total release that is released to landfill is calculated using the following equation:
EquationApx D-21.

ฐ/ฐland ~ ^capture_eff * Fsolidrem_ef f

Where:

ฐ/oiand	= Percent of release 5 that is released to landfill (unitless)

^capture_eff	= Booth capture efficiency for spray-applied paints/ coatings (see

Appendix D.4.15) (kg/kg)

Fsoiidrem_eff	= Fraction of solid removed in the spray mist of sprayed

paints/ coatings (see Appendix D.4.16) (kg/kg)

If control technologies are used, the release amounts to each media are calculated using the following
equation:

Equation Apx D-22.

Release_perDayRPS media	* ฐ/ฐmedia

Where:

Release_perDayRPS media = Amount of release 5 that is released to water, air, or landfill

(kg/site-day)

Release_perDayRP5 totai = DBP released for release source 5 to all release media

(kg/site-day)

%media	= Percent of release 5 that is released to water, air, or landfill

(unitless)

D.4.2 Model Input Parameters

Table Apx D-9 summarizes the model parameters and their values for the Application of Paints and
Coatings Monte Carlo simulation. Additional explanations of EPA's selection of the distributions for
each parameter are provided after this table.

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5589 Table Apx D-9. Summary of Parameter Values and Distributions Used in the Application of Paints and Coatings Model

Input Parameter

Symbol

Unit

Deterministic
Values

Uncertainty Analysis Distribution
Parameters

Rationale / Basis

Value

Lower-
Bound

Upper-
Bound

Mode

Distribution

Type

Production Volume of DBP

PV

kg/year

2.1E06

9.9E04

2.1E06

-

-

See D.4.3

Annual Facility Throughput of
Paint/Coating

Qcoat_year

kg/site-year

5,704

946

4.5E05

5,704

Triangular

See D.4.5

Paint/Coating DBP Concentration

Fdbp

kg/kg

2.5E-02

1.0E-03

0.60

2.5E-02

Triangular

See D.4.7

Operating Days

OD

days/year

250

225

300

250

Triangular

See D.4.8

Container Size

Vcont

gal

5.0

5.0

20

5.0

Triangular

See D.4.9

Container Residual Loss Fraction

Fcont residue

kg/kg

3.0E-03

3.0E-04

6.0E-03

3.0E-03

Triangular

See D.4.10

Fraction of DBP Lost During
Sampling - 1 (QDBP_day<50 kg/site-
day)

F sampling 1

kg/kg

2.0E-03

2.0E-03

2.0E-02

2.0E-02

Triangular

See D.4.11

Fraction of DBP Lost During
Sampling - 2 (QDBP_day 50-200
kg/site-day)

F sampling 2

kg/kg

6.0E-04

6.0E-04

5.0E-03

5.0E-03

Triangular

See D.4.11

Fraction of DBP Lost During
Sampling - 3 (Qdbp day 200-5,000
kg/site-day)

F sampling 3

kg/kg

5.0E-04

5.0E-04

4.0E-03

4.0E-03

Triangular

See D.4.11

Fraction of DBP Lost During
Sampling - 4 (QDBP_day >5,000
kg/site-day)

F sampling 4

kg/kg

8.0E-05

8.0E-05

4.0E-04

4.0E-04

Triangular

See D.4.11

Transfer Efficiency Fraction

Ftransfer eff

unitless

0.65

0.20

0.80

0.65

Triangular

See D.4.12

Small Container Fill Rate

RATEfillcont

containers/h

60

-

-

-

-

See D.4.13

Vapor Pressure at 25 ฐC

VP

mmHg

2.01E-05

-

-

-

-

Physical property

Molecular Weight

MW

g/mol

278

-

-

-

-

Physical property

Gas Constant

R

atm-

cm3/gmol-L

82.05

-

-

-

-

Universal constant

Density of DBP

RHO

kg/L

1.0

-

-

-

-

Physical property

Temperature

T

K

298

-

-

-

-

Process parameter

Pressure

P

atm

1.0

-

-

-

-

Process parameter

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Input Parameter

Symbol

Unit

Deterministic
Values

Uncertainty Analysis Distribution
Parameters

Rationale / Basis

Value

Lower-
Bound

Upper-
Bound

Mode

Distribution

Type

Equipment Cleaning Loss Fraction

Fequipment cleaning

kg/kg

2.0E-02

-

-

-

-

See D.4.14

Capture Efficiency for Spray
Booth

Fcapture eff

kg/kg

0.90

-

-

-

-

See D.4.15

Fraction of Solid Removed in
Spray Mist

Fsolidrem eff

kg/kg

1.0

-

-

-

-

See D.4.16

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D.4.3 Production Volume

EPA estimated the total DBP production volume for paint and coating products using a uniform
distribution with a lowerbound of 99,157 kg/year and an upperbound of 2,140,323 kg/year. This range is
based on DBP CDR data of site production volumes, national aggregate production volumes, and
percentages of the production volumes going to various industrial sectors (	20a).

There were two reporters that reported to CDR for use of DBP in adhesive/sealant or paint/coating
products: G.J. Chemical Co, Inc. in Somerset, New Jersey, who reported a volume of 139,618 lb; and
MAK Chemicals in Clifton, NJ, who reported a use volume of 105,884 lb of DBP. This equates to a
total known use volume of 245,502 lb of DBP; however, there is still a large portion of the aggregate PV
range for DBP that is not attached to a known use.

According to CDR, the national aggregate PV range for manufacture and import of DBP in 2019 was
between 1,000,000 to 10,000,000 lb. The total known production volumes for all uses add to 808,295 lb
(562,794 lb not associated with use of adhesives/sealants or paints and coatings). Due to uncertainty in
the expected use of DBP and the number of identified products for these uses, EPA assumed that the
remaining PV with unknown use is split between the use of adhesives and sealants and paint and coating
products (See Table Apx D-7). Subtracting the known use PV that are not associated with
adhesives/sealants/paints/coatings from the aggregate national PV range equates to a range of

•	Low-end: 1,000,000 lb to 562,793 lb = 437,207 lb (198,314 kg); and

•	High-end: 10,000,000 lb to 562,793 lb = 9,437,207 lb (4,280,645 kg).

EPA assumed half this PV is used in paints and coatings while the other half is used in adhesives and
sealants. This results in a PV range of 99,157 to 2,140,323 kg/year across all sites for this use.

D.4.4 Number of Sites	

Per 2020 U.S. Census Bureau data for the NAICS codes identified in the Emission Scenario Document
on Coating Application via Spray-Painting in the Automotive Refinishing Industry (<	),

Emission Scenario Document on the Coating Industry (Paints, Lacquers, and Varnishes) (OECD.
2009c). and Emission Scenario Document on the Application of Radiation Curable Coatings, Inks, and
Adhesives via Spray, Vacuum, Roll, and Curtain Coating ((	), there are 83,456 paints and

coatings use sites (U.S. BLS. 2023). Therefore, this value is used as a bounding limit, not to be exceeded
by the calculation. Number of sites is calculated using the following equation:

EquationApx D-23.

PV

Ns =-	

VDBP_year

Where:

Ns	= Number of sites (sites)

PV	= Production volume of DBP (kg/year)

QDBP_year = Facility annual throughput of DBP (see Appendix D.4.5) (kg/site-
year)

D.4.5 Throughput Parameters

The annual site throughput of paint and coating product is modeled using a triangular distribution with a
lower-bound of 946 kg/site-year, an upper-bound of 446,600 kg/site-year, and mode of 5,704 kg/site-
year. The upper-bound is based on the Generic Scenario for Spray Coatings in the Furniture Industry
(I	I004d). which provides a range of 5,000 to 446,600 L of furniture coatings used per year

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based on plant size, with an assumption of 1 kg/L as the density of the coating. The mode is based on the
default use rate for coating products from the Emission Scenario Document on Coating Application via
Spray-Painting in the Automotive Refinishing Industry (CXE	|). The ESD provides a default site

use rate for a coating product as 1,505 gal/site-year, which is converted to 5,704 kg/site-year using an
assumption of 1 kg/L for product density. The lower-bound is based on a summary table of available use
rates in the Emission Scenario Document on Coating Application via Spray-Painting in the Automotive
Refinishing Industry (OECD. 201 la). EPA selected a lower-bound from this table of 1 gallon of coating
product used per site for 250 days/year (e.g., 250 gallons/site-year or 946 L/site-year) and an assumption
of 1 kg/L for product density.

The annual throughput of DBP in the Application of paints and coatings OES is calculated using
EquationApx D-24 by multiplying the annual throughput of all paints and coatings by the concentration
of DBP found in the paints and coatings.

Equation Apx D-24.

Qdbp

'_year

Qcoat_year * FDBP

Where:

QBBP_year
Q coat_y ear
Fn

BBP

Facility annual throughput of DBP (kg/site-year)

Facility annual throughput of all paints/coatings (kg/site-year)
Concentration of DBP in paints/ coatings (see Appendix D.4.7)
(kg/kg)

The daily throughput of DBP is calculated using Equation Apx D-25 by dividing the annual throughput
by the number of operating days. The number of operating days is determined according to Appendix
D.4.8.

Equation Apx D-25.

Qdbp

Qdbp

day

year

OD

Where:

QDBP_day
QDBP_year

OD

Facility daily throughput of DBP (kg/site-day)
Facility annual throughput of DBP (kg/site-year)
Operating days (see Appendix D.4.8) (days/year)

D.4.6 Number of Containers per Year

The number of solid DBP-containing coating additive containers received and unloaded by a site per
year is calculated using the following equation:

Equation Apx D-26.

_	Q coat _y ear

Ncont_unload_year

RHO * [3.79—

Where:

Ncont_unioad_year = Annual number of containers unloaded (container/site-year)
Qcoat_year	= Facility annual throughput of all paints/coatings (kg/site-year)

RHO	= DBP density (kg/L)

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Vcont	= Container volume (see Appendix D.4.9) (gal/container)

D.4.7 Paint/Coating DBP Concentration

EPA modeled DBP concentrations in the final paint and coating products using compiled SDS
information (see Appendix E for EPA identified DBP-containing products for this OES). EPA assumed
a triangular distribution with a lower-bound of 0.1 percent, upper-bound of 10 percent, and mode of 2.5
percent. The lower and upper bounds represent the minimum and maximum reported concentrations in
the SDSs. The mode represents the mode of the upper-bound of the range endpoints reported in the
SDSs.

D.4.8 Operating Days

EPA modeled the operating days per year using a triangular distribution with a lower-bound of 225
days/year, an upper-bound of 300 days/year, and a mode of 250 days/year. To ensure that only integer
values of this parameter were selected, EPA nested the triangular distribution probability formula within
a discrete distribution that listed each integer between (and including) 225 and 300 days/year. The
lower-bound is based on ESIG's Specific Environmental Release Category Factsheet for Industrial
Application of Coatings by Spraying (ESIG. 2020a). which estimates 225 days/year as the number of
emission days. The upper-bound is based on the European Risk Report for DBP (ECB. 2004). which
provided a default of 300 days/year. The mode is based on the Generic Scenario for Automobile Spray
Coating (	36), which estimates 250 days/year, based on 5 days/week operation that takes

place 50 weeks/year.

D.4.9 Container Size

Based on identified products, EPA assumed that sites would receive paints and coatings in small
containers (see Appendix E for a list of the DBP-containing products identified for this OES). According
to the ChemSTEER User Guide, small containers are defined as containing between 5 and 20 gallons of
material with a default size of 5 gallons (I. S < ^ \ < i ). EPA modeled container size using a
triangular distribution with a lower-bound of 5 gallons, an upper-bound of 20 gallons, and a mode of 5
gallons based on the defaults defined by the ChemSTEER User Guide.

D.4.10 Small Container Residue Loss Fraction

EPA used data from the PEI Associates Inc. study (Associates. 1988) for emptying drums by pouring
along with central tendency and high-end values from the EPA/OPPT Small Container Residual Model.
For unloading drums by pouring in the PEI Associates Inc. study (Associates. 1988). EPA found that the
average percent residual from the pilot-scale experiments showed a range of 0.03 to 0.79 percent and an
average of 0.32 percent. The EPA/OPPT Small Container Residual Model from the ChemSTEER User
Guide (	015) recommends a default central tendency loss fraction of 0.3 percent and a high-

end loss fraction of 0.6 percent.

The underlying distribution of the loss fraction parameter for small containers is not known; therefore,
EPA assigned a triangular distribution, since triangular distributions require the least assumptions and
are completely defined by range and mode of a parameter. EPA assigned the mode and maximum values
for the loss fraction probability distribution using the central tendency and high-end values, respectively,
prescribed by the EPA/OPPT Small Container Residual Model in the ChemSTEER User Guide (U.S.

). EPA assigned the minimum value for the triangular distribution using the minimum
average percent residual measured in the PEI Associates, Inc. study (Associates. 1988) for emptying
drums by pouring.

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D.4.11 Sampling Loss Fraction

Sampling loss fractions were estimated using the March 2023 Methodology for Estimating
Environmental Releases from Sampling Wastes (	23c). In this methodology, EPA

completed a search of over 300 IRERs completed in the years 2021 and 2022 for sampling release data,
including a similar proportion of both PMNs and LVEs. Of the searched IRERs, 60 data points for
sampling release loss fractions, primarily for sampling releases from submitter-controlled sites (-75% of
IRERs), were obtained. The data points were analyzed as a function of the chemical daily throughput
and industry type. This analysis showed that the sampling loss fraction generally decreased as the
chemical daily throughput increased. Therefore, the methodology provides guidance for selecting a loss
fraction based on chemical daily throughput. TableApx D-10 presents a summary of the chemical daily
throughputs and corresponding loss fractions.

Table Apx D-10. Sampling Loss Fraction Data from the March 2023 Methodology for Estimating
Environmental Releases from Sampling Waste		

Chemical Daily
Throughput
(kg/site-day)

(Qclu'm_siU'_il:iv)

Number of
Data Points

Sampled Quantity
(kg chemical/day)

Sampling Loss Fraction
(LFsjiinpliiij;)

50th Percentile

95th Percentile

50th Percentile

95th Percentile

<50

13

0.03

0.20

0.002

0.02

50 to <200

10

0.10

0.64

0.0006

0.005

200 to <5,000

25

0.37

3.80

0.0005

0.004

>5,000

10

1.36

6.00

0.00008

0.0004

All

58

0.20

5.15

0.0005

0.008

For each range of daily throughputs, EPA estimated sampling loss fractions using a triangular
distribution of the 50th percentile value as the lower-bound, and the 95th percentile value as the upper-
bound and mode. The sampling loss fraction distribution was chosen based on the calculation of daily
throughput, as shown in Appendix D.4.5.

D.4.12 Transfer Efficiency Fraction

EPA modeled paint and coating spray application transfer efficiency fraction using a triangular
distribution with a lower-bound of 0.2, an upper-bound of 0.8, and a mode of 0.65. The lower-bound and
mode are based on the EPA/OPPT Automobile OEM Overspray Loss Model. Per the model, the transfer
efficiency varies based on the type of spray gun used. For high volume, low pressure (HVLP) spray
guns, the default transfer efficiency is 0.65. For conventional spray guns, the default transfer efficiency
is 0.2 by mass. Across all spray technologies, the ESD on Coating Industry (OECD. 2009c) estimates a
transfer efficiency of 30 to 80 percent. Therefore, EPA used 0.8 as the upper-bound.

D.4.13 Container Unloading Rate

The ChemSTEER User Guide (U.S. EPA. 2015) provides a typical fill rate of 60 containers per hour for
containers with less than 20 gallons of liquid.

D.4.14 Equipment Cleaning Loss Fraction

EPA used the EPA/OPPT Multiple Process Residual Model to estimate the releases from equipment
cleaning. This mode, as detailed in the Chem STEER User Guide (	2015). provides an overall

loss fraction of 2 percent from equipment cleaning.

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D.4.15 Capture Efficiency for Spray Booth

The Emission Scenario Document on the Application of Radiation Curable Coatings, Inks, and
Adhesives via Spray, Vacuum, Roll, and Curtain Coating ((	) uses the EPA/OPPT

Automobile Refinish Coating Overspray Loss Model to estimate releases from spray coating. This
model assumes a spray booth capture efficiency of 90 percent.

D.4.16 Fraction of Solid Removed in Spray Mist

The Emission Scenario Document on the Application of Radiation Curable Coatings, Inks, and
Adhesives via Spray, Vacuum, Roll, and Curtain Coating ((	) uses the EPA/OPPT

Automobile Refinish Coating Overspray Loss Model to estimate releases from spray coating. The model
assumes both a capture efficiency and a solid removal efficiency for spray booths. The solid removal
efficiency refers to the fraction of overspray material that is disposed to incineration or landfill after
being captured. This model assumes a solid removal efficiency of 100 percent.

D.5 Use of Laboratory Chemicals Model Approaches and Parameters

This appendix presents the modeling approach and equations used to estimate environmental releases for
DBP during the Use of laboratory chemicals OES. This approach utilizes the Generic Scenario on Use
of Laboratory Chemicals (U.S. EPA. 2023 d) and CDR data (	)20a) combined with Monte

Carlo simulation.

Based on the GS, EPA identified the following release sources from use of laboratory chemicals:

•	Release source 1: Release from Transferring DBP from Transport Containers (Liquids Only)

•	Release source 2: Dust Emissions from Transferring Powders Containing DBP (Solids Only)

•	Release source 3: Releases from Transport Container Cleaning

•	Release source 4: Release from Cleaning Containers Used for Volatile Chemicals (Liquids Only)

•	Release source 5: Labware Equipment Cleaning

•	Release source 6: Releases during Labware Cleaning (Liquids Only)

•	Release source 7: Releases During Laboratory Analysis (Liquids Only)

•	Release source 8: Releases from Laboratory Waste Disposal

Environmental releases for DBP during the use of laboratory chemicals are a function of DBP's physical
properties, container size, mass fractions, and other model parameters. While physical properties are
fixed, some model parameters are expected to vary. EPA used a Monte Carlo simulation to capture
variability in the following model input parameters: facility throughput, DBP concentrations, air speed,
saturation factor, container size, control technology efficiency, loss fractions, and diameters of
equipment openings. EPA used the outputs from a Monte Carlo simulation with 100,000 iterations and
the Latin Hypercube sampling method in @Risk to calculate release amounts for this OES.

D.5.1 Model Equations	

Table Apx D-l 1 provides the models and associated variables used to calculate environmental releases
for each release source within each iteration of the Monte Carlo simulation. EPA used these
environmental releases to develop a distribution of release outputs for the Use of laboratory chemicals
OES. The variables used to calculate each of the following values include deterministic or variable input
parameters, known constants, physical properties, conversion factors, and other parameters. The values
for these variables are provided in Appendix D.5.2. The Monte Carlo simulation calculated the total
DBP release (by environmental media) across all release sources during each iteration of the simulation.
EPA then selected 50th and 95th percentile values to estimate the central tendency and high-end
releases, respectively.

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TableApx D-ll. Models and Variables Applied for Release Sources in the Use of Laboratory
Chemicals OES

Release Source

IVIodel(s) Applied

Variables Used

Release source 1: Release
from Transferring DBP from
Transport Containers (Liquids
Only)

Not assessed, release estimated
using data from NEI and TRI

N/A

Release source 2: Dust
Emissions from Transferring
Powders Containing DBP
(Solids Only)

EPA/OPPT Generic Model to
Estimate Dust Releases from
T ransfer/Unloading/Loading
Operations of Solid Powders
(Appendix D.l)

QDBP_day_S> Fdust_generation>
Fdust_capture> F,dust_control

Release source 3: Releases
from Transport Container
Cleaning

Small Container Residual Model
or EPA/OPPT Solid Residuals in
Transport Containers Model, based
on physical form (Appendix D.l)

QDBP_day_L- QoBP_day_Sฆ>

Fcontainer _residue-L>

Fcontainer_residue-S > ^contฆ> RHO, Fdbp-S?
Fdbp-Lฆ> Qcont_solid? Qcontjiquid

Release source 4: Release
from Cleaning Containers
Used for Volatile Chemicals
(Liquids Only)

Not assessed, release estimated
using data from NEI and TRI

N/A

Release source 5: Labware
Equipment Cleaning

EPA/OPPT Multiple Process
Vessel Residual Model or
EPA/OPPT Solids Residuals in
Transport Container Model, based
on physical form (Appendix D.l)

QoBP_day_L5 QDBP_day_S- Fla.b_reSidUe-L>
Flab_residue-S

Release source 6: Releases
during Labware Cleaning
(Liquids Only)

Not assessed, release estimated
using data from NEI and TRI

N/A

Release source 7: Releases
During Laboratory Analysis
(Liquids Only)

Not assessed, release estimated
using data from NEI and TRI

N/A

Release source 8: Releases
from Laboratory Waste
Disposal

See Equation Apx D-27 and
Equation Apx D-28

QDBP_day_L> QDBP_day_S-
Fcontainer_residue-S 5
Fcontainer_residue-L > Fla.b_reSidUe-S ฆ>
Flab_residue-L> Fdust_generation>

Release Points 1, 6, and 7

For liquid DBP, release source 8 (Laboratory Waste Disposal) is calculated via a mass-balance, using
the following equation:

EquationApx D-27.

Release _perD ayRPq_l

~ (QDBP_day_ L — Release _perDayRP1 — Release_perDayRP6 — Release j>erDayRP7^

*	Fcontainer_residue—L ^\ab_residue—L)

Where:

Release_perDayRP8_L= Liquid DBP released for release source 8 (kg/site-day)
QoBP_day_L	= Facility throughput of DBP (see Appendix D.5.3) (kg/site-day)

Release_perDayRP1 = Liquid DBP released for release source 1 (kg/site-day)

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ReleasejperD ayRP6
Release_perDayRP7

Fcontainer _residue-L

Flab_residue-L

For solids containing DBP, release source 8 (Laboratory Waste Disposal) is calculated via a mass-
balance, via the following equation:

EquationApx D-28.

Release J)erDayRPQ_s — QoBP_day_S * (l — Fdust_generation ~ Fcontainer residue-S ~ ^Iafc_residue_s)

Where:

Release_perDayRP8_s= Solid DBP released for release source 8 (kg/site-day)
QoBP_day_s	= Facility throughput of DBP (see Appendix D.5.3) (kg/site-day)

Fdust generation = Fraction of DBP lost during unloading of solid powder (see

D.5.2 Model Input Parameters

Table Apx D-12 summarizes the model parameters and their values for the Use of Laboratory
Chemicals Monte Carlo simulation. Additional explanations of EPA's selection of the distributions for
each parameter are provided following this table.

Flab_residue_S

Fcontainer residue-S

Appendix D.5.10) (kg/kg)

Fraction of solid DBP remaining in transport containers (see
Appendix D.5.9) (kg/kg)

Fraction of solid DBP remaining in lab equipment (see Appendix
D.5.12) (kg/kg)

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Table Apx D-12. Summary of Parameter Va

ues and Disl

tributions Used in the Use of Laboratory Chemicals Model

Input Parameter

Symbol

Unit

Deterministic
Values

Uncertainty Analysis Distribution
Parameters

Rationale/Basis

Value

Lower-
Bound

Upper-
Bound

Mode

Distribution

Type

Production Volume

PV

kg/year

9.8E04

-

-

-

-

See D.5.3

Facility Throughput of Solid DBP

Qstock site day S

g/site-day

255

3.0E-03

510

-

Uniform

See D.5.3

Facility Throughput of Liquid
DBP

Qstock site day L

mL/site-day

2,000

0.50

4,000

-

Uniform

See D.5.3

DBP Solid Lab Chemical
Concentration

F DBPsolid

kg/kg

3.0E-03

3.0E-03

0.2

3.0E-03

Triangular

See D.5.6

DBP Liquid Lab Chemical
Concentration

FdBP liquid

kg/kg

1.0E-03

1.0E-03

0.1

1.0E-03

Triangular

See D.5.6

Operating Days

OD

days/year

365

-

-

-

-

See D.5.7

Liquid Container Size

Vcont

gal

1.0

0.50

1.0

1.0

Triangular

See D.5.8

Solid Container Size

Qcont solid

kg

1.0

0.5

1.0

1.0

Triangular

See D.5.8

Fraction of DBP Remaining in
Container as Residue - Solid

Fcontainer residue-
solid

kg/kg

1.0E-02

-

-

-

-

See D.5.9

Fraction of DBP Remaining in
Container as Residue - Liquid

Fcontainer residue-
liquid

kg/kg

3.0E-03

3.0E-04

6.0E-03

3.0E-03

Triangular

See D.5.9

Fraction of chemical lost during
transfer of solid powders

F dust generation

kg/kg

5.0E-03

1.0E-03

3.0E-02

5.0E-03

Triangular

See D.5.10

Dust Capture Technology
Efficiency

Fdust capture

kg/kg

0.95

0

1.0

0.95

Triangular

See D.5.10

Dust Control Technology
Removal Efficiency

Fdust control

kg/kg

0.99

0

1.0

0.99

Triangular

See D.5.10

Vapor Pressure at 25 ฐC

VP

mmHg

2.0E-05

-

-

-

-

Physical property

Molecular Weight

MW

g/mol

278

-

-

-

-

Physical property

Gas Constant

R

atm-

cm3/gmol-L

82

-

-

-

-

Universal constant

Density of DBP

RHO

kg/L

1.0

-

-

-

-

Physical property

Temperature

T

K

298

-

-

-

-

Process parameter

Pressure

P

atm

1.0

-

-

-

-

Process parameter

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Input Parameter

Symbol

Unit

Deterministic
Values

Uncertainty Analysis Distribution
Parameters

Rationale/Basis

Value

Lower-
Bound

Upper-
Bound

Mode

Distribution

Type

Small Container Fill Rate

RATEfin

containers/h

60

-

-

-

-

See D.5.11

Fraction of DBP Remaining in
Container as Residue Lab
Equipment - Liquid

Flab residue L

kg/kg

2.0E-02









See D.5.12

Fraction of DBP Remaining in
Container as Residue Lab
Equipment - Solid

Flab residue S

kg/kg

1.0E-02









See D.5.12

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5851

5852

5853

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D.5.3 Production Volume and Throughput Parameters

No sites reported to CDR for use of DBP in laboratory chemicals. EPA estimated the total production
volume (PV) for all sites of 215,415 lb/year (97,710 kg/year) that was estimated based on the reporting
requirements for CDR. The threshold for CDR reporters requires a site to report processing and use for a
chemical if the usage exceeds 5 percent of its reported PV or if the use exceeds 25,000 lb per year. For
the 12 sites that reported to CDR for the manufacture or import of DBP, EPA assumed that each site
used DBP for laboratory chemicals in volumes up to the reporting threshold limit of 5 percent of their
reported PV. If 5 percent of each site's reported PV exceeded the 25,000 lb reporting limit, EPA
assumed the site used only 25,000 lb annually as an upper-bound. If the site reported a PV that was CBI,
EPA assumed the maximum PV contribution of 25,000 lb. The CDR sites and their PV contributions to
this OES are shown in Table Apx D-13.

Table Apx D-13. CDR Reported Site Information for Use in Calculation of Laboratory
Chemicals Production Volume

Site Name

Site Location

Reported Production
Volume (lb/year)

Threshold
Limit

Used

Production
Volume Added to
Total (lb/year)

Huntsman Corporation - The
Woodlands Corporate Site

The Woodlands, TX

CBI

25,000 lb

25,000

Covalent Chemical

Raleigh, NC

88,184

5%

4,409.2

Greenchem

West Palm Beach, FL

CBI

25,000 lb

25,000

Dystar LP

Reidsville, NC

51,852

5%

2,592.6

The Sherwin-Williams
Company

Cleveland, OH

CBI

25,000 lb

25,000

GJ Chemical Co. Inc.

Newark, NJ

139,618

5%

6,908.9

Polymer Additives, Inc.

Bridgeport, NJ

CBI

25,000 lb

25,000

MAK Chemicals

Clifton, NJ

105,884

5%

5,294.2

Industrial Chemicals, Inc.

Vestavia Hills, AL

422,757

5%

21,137.85

Shrieve Chemical Company,
LLC

Spring, TX

CBI

25,000 lb

25,000

2 sites marked as CBI

CBI

CBI

25,000 lb

50,000

The Use of Laboratory Chemicals - Generic Scenario for Estimating Occupational Exposures and
Environmental Releases (	:023 d) provides daily throughput of DBP required for laboratory

stock solutions. According to the GS, laboratory liquid use rates range from 0.5 mL up to 4 L per day,
and laboratory solid use rates range from 0.003 to 510 g per day. Laboratory stock solutions are used for
multiple analyses and eventually need to be replaced. The expiration or replacement times range from
daily to 6 months (U.S. EPA. 2023d). For this scenario, EPA assumes stock solutions are prepared daily
per the GS. EPA assigned a uniform distribution for the daily throughput of laboratory stock solutions
with upper- and lower-bounds corresponding to the high and low use rates, respectively.

The daily throughput of DBP in liquid laboratory chemicals is calculated using Equation Apx D-29 by
multiplying the daily throughput of all laboratory solutions by the concentration of DBP in the solutions
and converting volume to mass.

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5880

5881

5882

5883

5884

5885

5886

5887

5888

5889

5890

5891

5892

5893

5894

5895

5896

5897

5898

5899

5900

5901

5902

5903

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5908

5909

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EquationApx D-29.

PUBLIC RELEASE DRAFT
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0.001L

QDBP_day_L = Qstock_site_day_L * f DBP-L * RHO *

Where:

QoBP_day_L	= Facility daily throughput of liquid DBP (kg/site-day)

Qstock_site_day_L = Facility annual throughput of liquid laboratory chemicals (mL/site-

day)

Fdbp-l	= Concentration of DBP in liquid laboratory chemicals (see

Appendix D.5.6) (kg/kg)

RHO	= Density of DBP (kg/L)

The daily throughput of DBP in solid laboratory chemicals is calculated using Equation Apx D-30 by
multiplying the daily throughput of all laboratory solids by the concentration of DBP in the solids.

Equation Apx D-30.

n	n	^	0.001 kg

QDBP_day_S ~ Qstock_site_day_S * FDBP-S * ~

Where:

QoBP_day_s	= Facility daily throughput of solid DBP (kg/site-day)

Qstock_site_day_s = Facility annual throughput of solid laboratory chemicals (g/site-

day)

Fdbp-s	= Concentration of DBP in solid laboratory chemicals (see Appendix

D.5.6) (kg/kg)

To avoid cases where the number of sites is greater than the bounding estimate of 36,873 sites (see
Appendix D.5.4), EPA calculated an adjusted value for the daily throughput of DBP. If the number of
sites is less than the bounding estimate, then the adjusted facility throughput of DBP will be the same as
the facility throughput calculated in Equation Apx D-30. Otherwise, the adjusted facility throughput is
calculated using Equation Apx D-31 by dividing the facility production rate by the maximum number of
sites and operating days. The number of operating days is determined according to Appendix D.5.7.

Equation Apx D-31.

PV

QDBP_day_adj

Ns * OD

QDBP_day_adj = Adjusted daily facility throughput of DBP (kg/site-day)
Ns	= Maximum number of sites (see Appendix D.5.4) (sites)

PV	= Facility production rate of DBP in laboratory chemicals

(see Appendix D.5.3) (kg/kg)

OD	= Operating days (see Appendix D.5.7) (days/site-year)

D.5.4 Number of Sites

Per 2020 U.S. Census Bureau data for the NAICS codes identified in the Use of Laboratory Chemicals -
Generic Scenario for Estimating Occupational Exposures and Environmental Releases (U.S.

2023d). there are 36,873 laboratory chemical use sites (	2023). Therefore, this value is used as

a bounding limit, not to be exceeded by the calculation. Number of sites is calculated using a per-site

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5928

5929

5930

5931

5932

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throughput and DBP production volume with the following equation:

EquationApx D-32.

Ns =

PV

QDBPday * OD

Where:

Ns
PV

QDBP_day

OD

Number of sites (sites)

Production volume of DBP (kg/year)

Facility daily throughput of DBP (kg/site-day)
Operating days (see Appendix D.5.7) (days/site-year)

D.5.5 Number of Containers per Year

The number of liquid DBP laboratory containers unloaded by a site per year is calculated using the
following equation:

Equation Apx D-33.

Where:

JV,

Qdbp

cont_unload_year

'_day_L

* OD

N'cont_unload_year
QDBP_day_L

OD

Fdbp-l
RHO

Vcont

DBP-L

_i * RHO *

(3.79 ^j) . Vcont

Annual number of containers unloaded (container/site-year)
Facility daily throughput of liquid DBP (kg/site-day)
Operating days (see Appendix D.5.7) (days/site-year)

Mass fraction of DBP in liquid (see Appendix D.5.6) (kg/kg)
DBP density (kg/L)

Container volume (see Appendix D.5.8) (gal/container)

The number of laboratory containers containing solids with DBP unloaded by a site per year is
calculated using the following equation:

Equation Apx D-34.

JV,

QDBP_day_S * OD

Where:

N'cont_unload_year
QDBP_day_S

OD

Fdbp-s
Qcont solid

cont_unload_year ~ p	p.

rDBP-S * Vcont_solid

Annual number of containers unloaded (container/site-year)
Facility daily throughput of solid DBP (kg/site-day)

Operating days (see Appendix D.5.7) (days/site-year)

Mass fraction of DBP in solids (see Appendix D.5.6) (kg/kg)
Mass in container of solids (see Appendix D.5.8) (kg/container)

D.5.6 DBP Concentration in Laboratory Chemicals

EPA modeled DBP concentration in liquid laboratory chemicals using SDS concentrations for four
liquid lab products. EPA modeled concentrations using a triangular distribution with a lower-bound of
0.1 percent, an upper-bound of 10 percent, and a mode of 0.1 percent. For solid laboratory chemicals,
EPA modeled concentrations using a triangular distribution with a lower-bound of 0.3 percent, upper-
bound of 20 percent, and mode of 0.3 percent, based on the concentration ranges reported in four SDSs
found for solid laboratory chemicals. The lower- and upper-bounds represent the minimum and
maximum reported concentrations in the SDSs for both liquid and solid laboratory chemicals. The mode

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represents the median of all high-end range endpoints reported in the SDSs (see Appendix E for EPA-
identified, DBP-containing products for this OES).

D.5.7 Operating Days	

Two sites reporting to NEI for the use of DBP in laboratory chemicals reported air releases occurring
over 365 days/year. EPA was unable to identify additional specific information for operating days for
the use of DBP in laboratory chemicals. Therefore, EPA assumed that the operating days for laboratories
would be 365 days per year (U.S. EPA. 2023a. 2019).

D.5.8 Container Size

The Use of Laboratory Chemicals - Generic Scenario for Estimating Occupational Exposures and
Environmental Releases (	,023d) states that, in the absence of site-specific information, a

default liquid volume of 1 gallon and a default solid quantity of 1 kg may be used. Laboratory products
containing DBP showed container sizes less than 1 gallon or 1 kg. Based on model assumptions of site
daily throughput, EPA decided to allow for a lower-bound of 0.5 gallon or 0.5 kg to account for smaller
container sizes while maintaining the daily number of containers unloaded per site at a reasonable value.
Therefore, EPA built a triangular distribution for liquid volumes with a lower-bound of 0.5 gallon and
an upper-bound and mode of 1 gallon. EPA similarly built a triangular distribution for solid quantities
with a lower-bound of 0.5 kg and an upper-bound and mode of 1 kg.

D.5.9 Container Loss Fractions	

EPA used data from the PEI Associates Inc. study (Associates. 1988) for emptying drums by pouring
along with central tendency and high-end values from the EPA/OPPT Small Container Residual Model.
For unloading drums by pouring in the PEI Associates Inc. study (Associates. 1988). EPA found that the
average percent residual from the pilot-scale experiments showed a range of 0.03 percent to 0.79 percent
and an average of 0.32 percent. The EPA/OPPT Small Container Residual Model from the ChemSTEER
User Guide (U.S. EPA. 2015) recommends a default central tendency loss fraction of 0.3 percent and a
high-end loss fraction of 0.6 percent.

The underlying distribution of the loss fraction parameter for small containers is not known; therefore,
EPA assigned a triangular distribution because triangular distributions require the least assumptions and
are completely defined by range and mode of a parameter. EPA assigned the mode and maximum values
for the loss fraction probability distribution using the central tendency and high-end values, respectively,
prescribed by the EPA/OPPT Small Container Residual Model in the ChemSTEER User Guide (U.S.

). EPA assigned the minimum value for the triangular distribution using the minimum
average percent residual measured in the PEI Associates, Inc. study (Associates. 1988) for emptying
drums by pouring.

For solid containers, EPA used the EPA/OPPT Solid Residuals in Transport Containers Model to
estimate residual releases from solid container cleaning. The EPA/OPPT Solid Residuals in Transport
Containers Model, as detailed in the ChemSTEER User Guide (	) provides an overall

loss fraction of 1 percent from container cleaning.

D.5.10 Dust Generation Loss Fraction, Dust Capture Efficiency, and Dust Control
Efficiency

The EPA/OPPT Generic Model to Estimate Dust Releases from Transfer/Unloading/Loading Operations
of Solid Powders (Dust Release Model) compiled data for loss fractions of solids from various sources
in addition to the capture and removal efficiencies for control technologies in order to estimate releases
of dust to the environment during transfer operations. Dust releases estimated from the model are based

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6015

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on three different parameters: the initial loss fraction, the fraction captured by the capture technology,
and the fraction removed/controlled by the control technology. The underlying distributions for each of
these parameters is not known; therefore, EPA assigned triangular distributions because a triangular
distribution requires least assumptions and is completely defined by range and mode of a parameter.

EPA assigned the range and mode for each of the three parameters using the data presented in the Dust
Release Model. For the initial loss fraction, the Agency assigned a range of 6.Ox 10~6 to 0.045 with a
mode of 0.005 by mass. EPA assigned the mode based on the recommended default value for the
parameter in the Dust Release Model. The range of initial loss fraction values comes from the range of
values compiled from various sources and considered in the development of the Dust Release Model

(I	>021 by

For the fraction of dust captured, EPA assigned a range of 0 to 1.0 with a mode of 0.95 by mass. EPA
assigned the range for the fraction captured based on the minimum and maximum estimated capture
efficiencies listed in the data compiled for the Dust Release Model. EPA assigned the mode for the
fraction captured based on the capture efficiency for laboratory fume hoods because the Agency expects
that capture technology will likely be used.

For the fraction of captured dust that is removed/controlled, EPA assigned a range of 0 to 1.0 with a
mode of 0.99 by mass. The Agency assigned the range for the fraction controlled based on the minimum
and maximum estimated control efficiencies listed in the data compiled for the Dust Release Model.
EPA assigned the mode for the fraction controlled based on control efficiency for filtering systems.

D.5.11 Small Container Fill Rate

The ChemSTEER User Guide (U.S. EPA. 2015) provides a typical fill rate of 60 containers per hour for
containers with less than 20 gallons of liquid.

D.5.12 Equipment Cleaning Loss Fraction

For liquids, EPA used the EPA/OPPT Multiple Process Residual Model to estimate the releases from
equipment cleaning. This model, as detailed in the ChemSTEER User Guide (	), provides

an overall loss fraction of 2 percent from equipment cleaning.

For solids, used the EPA/OPPT Solid Residuals in Transport Containers Model to estimate the releases
from equipment cleaning. This model, as detailed in the ChemSTEER User Guide (	W15)m

provides an overall loss fraction of 1 percent from equipment cleaning.

D.6 Use of Lubricants and Functional Fluids Model Approach and
Parameters

This appendix presents the modeling approach and equations used to estimate environmental releases for
DBP during the Use of lubricants and functional fluids OES. This approach utilizes the Emission
Scenario Document on Lubricants and Lubricant Additives (OECD. 2004b) combined with Monte Carlo
simulation.

Based on the ESD, EPA identified the following release sources from the use of lubricants and
functional fluids:

•	Release source 1: Release During the Use of Equipment

•	Release source 2: Release During Changeout of Lubricants and Functional Fluids

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Environmental releases for DBP during the use of lubricants and fluids are a function of DBP's physical
properties, container size, mass fractions, and other model parameters. While physical properties are
fixed, some model parameters are expected to vary. EPA used a Monte Carlo simulation to capture
variability in the following model input parameters: production volume, DBP concentrations, product
density, container size, loss fractions, and operating days. EPA used the outputs from a Monte Carlo
simulation with 100,000 iterations and the Latin Hypercube sampling method in @Risk to calculate
release amounts for this OES.

D.6.1 Model Equations

TableApx D-14 provides the models and associated variables used to calculate environmental releases
for each release source within each iteration of the Monte Carlo simulation. EPA used these
environmental releases to develop a distribution of release outputs for the Use of lubricants and fluids
OES. The variables used to calculate each of the following values include deterministic or variable input
parameters, known constants, physical properties, conversion factors, and other parameters. The values
for these variables are provided in Appendix D.6.2. The Monte Carlo simulation calculated the total
DBP release (by environmental media) across all release sources during each iteration of the simulation.
EPA then selected 50th and 95th percentile values to estimate the central tendency and high-end
releases, respectively.

Table Apx D-14. Models and Variables Applied for Release Sources in the Use of Lubricants and
Functional Fluids OES

Release Source

Model(s) Applied

Variables Used

Release source 1: Release
During the Use of Equipment

See Equation Apx D-3 5
through Equation Apx D-3 9

QDBP_day> LFiand_u.se'> LFwater use

Release source 2: Release
During Changeout of Lubricants
and Functional Fluids

QoBP_day LFiand_disposal> LFwater_disposal

Release source 1 (Release During the Use of Equipment) and 2 (Release During Changeout) are
partitioned out by release media. Loss fractions are described in the model parameter sections below.
For both water and land media, release 1 is then calculated using the following equation:

QDBP_day * (]LFiand_use LFX

water_use,

EquationApx D-35.

Release _perDayRPllandiwater

Where:

Release _perDayRP1 jand/water	~

QDBP_day	~

LFland_uSe	~

LFwciter_uSe	~

DBP loss to land/water for release source 1
(kg/site-day)

Facility throughput of DBP (see Appendix D.6.3)
(kg/site-day)

Loss fraction to land during the use of equipment
(see Appendix D.6.7) (unitless)

Loss fraction to water during the use of equipment
(see Appendix D.6.7) (unitless)

A similar equation is used to calculate release 2 to water and land:

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6099

6100

6101

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6103

6104

6105

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6108

6109

6110

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EquationApx D-36.

Release _per Day RP2 jand/water Qdbp_

day * (j^Pland_disposal LFwater_disposal,

Where:

Release _perD ay RP2 jand/water

QDBP_day

LFi

land_disposal

LF

water _dispo sal

DBP loss to land/water for release source 2
(kg/site-day)

Facility throughput of DBP (see Appendix D.6.3)
(kg/site-day)

Loss fraction to land during lubricant disposal (see
Appendix D.6.7) (unitless)

Loss fraction to water during lubricant disposal (see
Appendix D.6.7) (unitless)

If the sum of LF,,

land_use> LFWater_use> L,r land_disposal

,LFU

i, and LF,

water _disposal

exceeds 100 percent, EPA
creates adjusted loss fractions based on weighted contributions to equal exactly 100 percent. The
releases per day are then recalculated using the adjusted loss fractions. For example, the adjusted land
use loss fraction would be calculated using the following equation:

Equation Apx D-37.

LF

LF

land_use

land_use _ad jvsted

(LFX

land vse

+ LF,

water vse

Where:

LFiand disposai + LFwater disposal)

LFiand Use ad jvsted
LFiand vse

LFU

water _vse

LF,

land_disposal

LF

water _disposal

Adjusted loss fraction to land during the use of equipment
(unitless)

Loss fraction to land during the use of equipment (see
Appendix D.6.7) (unitless)

Loss fraction to water during the use of equipment (see
Appendix D.6.7) (unitless)

Loss fraction to land during lubricant disposal (see
Appendix D.6.7) (unitless)

Loss fraction to water during lubricant disposal (see
Appendix D.6.7) (unitless)

Finally, EPA will assess any DBP not released to the environment after accounting for release sources 1
and 2 as going to recycling and fuel blending (incineration). If all DBP is released during release sources
1 and 2, then the release to recycling and fuel blending will not be calculated. The following equations
are used to calculate the amount of remaining DBP sent for recycling and fuel blending:

Equation Apx D-38.

Release jperDayRP2_recycle

= (QoBP_day ~ ReleCLSeperDayRplJand ~ Re^easeperDayRPl water-ReleCLSeperDayRP2 land

— Release_perDayRP2_water) * Fwaste_recycie

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EquationApx D-39.

Release jier Day RP2 Juei blend

= (ซ

DBP_day ReleCLSeperDayRplland RelecLseperDay Rplwater_ReleaseperDay Rp2 d

Release _per Dayt

RP2 water

)*

waste incineration

Where:

Release _perDayRP2_recycle

Release_perDayRP2 Juei_biend
QDBP_day

Release_perD ayRPlland
Release _per DayRPlwater

ReleasejperDayRP2 land

Release _perDayRP2water
Fwaste_recycle

Fwastejncineration

DBP recycled (kg/site-day)

DBP sent for fuel blending (kg/site-day)

Facility throughput of DBP (see Appendix D.6.3) (kg/site-

day)

DBP released for release source 1 to land (kg/site-day)
DBP released for release source 1 to water (kg/site-day)
DBP released for release source 2 to land (kg/site-day)
DBP released for release source 2 to water (kg/site-day)
Fraction of DBP that goes to recycling (see Appendix
D.6.8) (kg/kg)

Fraction of DBP that goes to fuel blending (see Appendix
D.6.9) (kg/kg)

D.6.2 Model Input Parameters

Table Apx D-15 summarizes the model parameters and their values for the Use of Lubricants and
Fluids Monte Carlo simulation. Additional explanations of EPA's selection of the distributions for each
parameter are provided after this table.

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6148 Table Apx D-15. Summary of Parameter Values and Distributions Used in the Use of Lubricants and Functional Fluids Model

Input Parameter

Symbol

Unit

Deterministic
Values

Uncertainty Analysis Distribution
Parameters

Rationale/
Basis

Value

Lower-
Bound

Upper-
Bound

Mode

Distribution

Type

Total Production Volume of DBP at All Sites

PVtotal

kg/year

9.8E04

-

-

-

-

See D.6.3

Mass Fraction of DBP in Product

Fdbp

kg/kg

7.5E-02

1.0E-05

7.5E-02

-

Uniform

See D.6.4

Density of DBP-based Products

RI 10 c:

kg/m3

900

840

1,000

900

Triangular

See D.6.4

Operating Days

OD

days/year

4

1

4

-

Uniform

See D.6.5

Container Size

Vcont

gal

55

20

330

55

Triangular

See D.6.6

Loss Fraction to Land During Use

LFland use

kg/kg

0.16

1.4E-02

0.16

-

Uniform

See D.6.7

Loss Fraction to Water During Use

LFwater use

kg/kg

0.45

3.0E-03

0.45

-

Uniform

See D.6.7

Loss Fraction to Land During Disposal

LFland disposal

kg/kg

0.30

1.0E-02

0.30

-

Uniform

See D.6.7

Loss Fraction to Water During Disposal

LFwater disposal

kg/kg

0.37

0.23

0.37

-

Uniform

See D.6.7

Percentage of Waste to Recycling

F wasterecycle

kg/kg

4.3E-02

-

-

-

-

See D.6.8

Percentage of Waste to Fuel Blending

Fwaste incineration

kg/kg

0.96

-

-

-

-

See D.6.9

6149

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D.6.3 Production Volume and Throughput Parameters

No sites reported to CDR for use of DBP in lubricants or functional fluids. EPA estimated the total
production volume (PV) for all sites assuming a static value of 215,415 lb/year (97,710 kg/year) that
was estimated based on the reporting requirements for CDR. The threshold for CDR reporters requires a
site to report processing and use for a chemical if the usage exceeds 5 percent of its reported PV or if the
use exceeds 25,000 lb per year. For the 12 sites that reported to CDR for the manufacture or import of
DBP, EPA assumed that each site used DBP for laboratory chemicals in volumes up to the reporting
threshold limit of 5 percent of their reported PV. If 5 percent of each site's reported PV exceeds the
25,000 lb reporting limit, EPA assumed the site used only 25,000 lb annually as an upper-bound. If the
site reported a PV that was CBI, EPA assumed the maximum PV contribution of 25,000 lb. The CDR
sites and their PV contributions to this OES are shown in Table Apx D-13.

Product throughput is calculated by converting container volume to mass using the product density and
multiplying by operating days. EquationApx D-40 assumes that each site uses one container of product
each day. Container size is determined according to Appendix D.6.6. Product density is determined
according to Appendix D.6.4. Operating days are determined according to Appendix D.6.5.

Equation Apx D-40.

m3

Qproduct_year = Vcont * 0.00379 —^*RHOproduct * OD

Where:

Q product_y ear

Vcont
RHO

OD

product

Facility annual throughput of lubricant/fluid (kg/site-year)
Container size (see Appendix D.6.6) (gal)

Product density (see Appendix D.6.4) (kg/m3)

Operating days (see Appendix D.6.5) (days/year)

The annual throughput of DBP is calculated using Equation Apx D-41 by multiplying product annual
throughput by the concentration of DBP in the product. The concentration of DBP in the product is
determined according to Appendix D.6.4.

Equation Apx D-41.

Where:

QDBP_year
Q product_y ear

DBP

QDBP_year ~ Qproduct_year * FDBP

Facility annual throughput of DBP (kg/site-year)

Facility annual throughput of lubricant/fluid
(kg/site-year)

Concentration of DBP in lubricant/fluid (see Appendix D.6.4)
(kg/kg)

The daily throughput of DBP is calculated using by dividing the annual production volume by the
number of operating days. The number of operating days is determined according to Appendix D.6.5.

Equation Apx D-42.

Qdbp

Qdbp_

day

year

OD

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Where:

QDBP_day	=	Facility throughput ofDBP (kg/site-day)

Q DBP_year	=	Facility annual throughput ofDBP (kg/site-year)

OD	=	Operating days (see Appendix D.6.5) (days/year)

D.6.4 Mass Fraction ofDBP in Lubricant/Fluid and Product Density

EPA modeled DBP mass fraction in lubricants and fluids using a uniform distribution with a lower-
bound of 0.001 percent and an upper-bound of 7.5 percent. EPA modeled product density using a
triangular distribution with a lower-bound of 840 kg/m3, an upper-bound of 1,000 kg/m3, and a mode of
900 kg/m3. EPA was not able to identify products for this use that contained DBP. For that reason, EPA
based the concentration and density estimates on compiled SDS information for lubricants and fluids
containing DIDP and assumed that DBP-containing lubricants and fluids would have similar
concentrations and density ranges. The DIDP-containing product are identified in Appendix F of the
Environmental Release and Occupational Exposure Assessment for Diisodecyl Phthalate (DIDP) (U.S.
I 24 c).

D.6.5 Operating Days

EPA modeled operating days per year using a uniform distribution with a lower-bound of 1 day/year and
an upper-bound of 4 days/year. To ensure that only integer values of this parameter were selected, EPA
nested the uniform distribution probability formula within a discrete distribution that listed each integer
between (and including) 1 to 4 days/year. Both bounds are based on the ESD on Lubricants and
Lubricant Additives (OECD. 2004b). The ESD states that changeout rates for 1 ubricant/functional fluids
range from 3 to 60 months. This corresponds to one to four changeouts per year, which EPA assumes is
equal to operating days. Where changeout frequency occurs over 12 months, EPA used a value one
container per 12 months as a representative value.

D.6.6 Container Size

EPA modeled container size using a triangular distribution with a lower-bound of 20 gallons, an upper-
bound of 330 gallons, and a mode of 55 gallons. This was based on SDS and technical data sheets for
DIDP-containing lubricants, as lubricant products containing DBP were not identified. In this data, EPA
identified lubricants in containers from less than 1 gallon to 330 gallons. The mode of the reported
container sizes was 55 gallons; however, when running the model, smaller use rates produced an
unreasonable number of use sites. Therefore, EPA assumed this to be an indication that it is unlikely that
sites only have one small piece of equipment. Based on this and the remaining technical data, EPA
selected 20 gallons as the lower-bound (I. c. < ^ \ \
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D.6.9 Percentage of Waste to Fuel Blending

The ESD on Lubricants and Lubricant Additives (OECD. 2004bTestimates that 95.7 percent of all
lubricant/functional fluids are reused for fuel oil or other general incineration releases.

D.7 Use of Penetrants and Inspection Fluids Release Model Approaches
and Parameters

This appendix presents the modeling approach and equations used to estimate environmental releases for
DBP during the Use of penetrants and inspection fluids OES. This approach utilizes the Emission
Scenario Document on the Use of Metal working Fluids (OECD. 2011c) combined with Monte Carlo
simulation. EPA assessed the environmental releases for this OES separately for non-aerosol penetrants
and for aerosol-applied penetrants.

Based on the ESD, EPA identified the following release sources from the use of non-aerosol penetrants:

•	Release source 1: Transfer Operation Losses to Air from Unloading Penetrant

•	Release source 2: Container Cleaning Wastes

•	Release source 3: Open Surface Losses to Air During Container Cleaning

•	Release source 4: Equipment Cleaning Wastes

•	Release source 5: Open Surface Losses to Air During Equipment Cleaning

•	Release source 7: Disposal of Used Penetrant

Based on the ESD, EPA identified the following release sources from the use of aerosol-applied
penetrants:

•	Release source 2: Container Cleaning Wastes

•	Release source 6: Aerosol Application of Penetrant

Environmental releases for DBP during the use of penetrants are a function of DBP's physical
properties, container size, mass fractions, and other model parameters. Although physical properties are
fixed, some model parameters are expected to vary. EPA used a Monte Carlo simulation to capture
variability in the following model input parameters: DBP concentrations, air speed, saturation factor,
container size, loss fractions, and operating days. EPA also used the outputs from a Monte Carlo
simulation with 100,000 iterations and the Latin Hypercube sampling method in @Risk to calculate
release amounts for this OES.

D.7.1 Model Equations

Table Apx D-16 provides the models and associated variables used to calculate environmental releases
for each release source within each iteration of the Monte Carlo simulation. EPA used these
environmental releases to develop a distribution of release outputs for the Use of penetrants OES. The
variables used to calculate each of the following values include deterministic or variable input
parameters, known constants, physical properties, conversion factors, and other parameters. The values
for these variables are provided in Appendix D.7.2. The Monte Carlo simulation calculated the total
DBP release (by environmental media) across all release sources during each iteration of the simulation.
EPA then selected 50th and 95th percentile values to estimate the central tendency and high-end
releases, respectively.

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TableApx D-16. Models and Variables Applied for Release Sources in the Use of Penetrants and
Inspection Fluids PES			

Release Source

Model(s) Applied

Variables Used

Release source 1: Transfer
Operation Losses to Air from
Unloading Penetrant

EPA/OAQPS AP-42 Loading
Model (Appendix D.l)

Vapor Generation Rate: FDBP; VP; fsat;
MW; R; T; Vcont; RATE^m c:ont;

RA TEfi i icirum

Operating Time: QDBp_year ; Vcont; OD;
RATEfui_cont; RATEfm_drum; RHO;
Fdbp

Release source 2: Container
Cleaning Wastes

EPA/OPPT Drum Residual
Model or EPA/OPPT Bulk
Transport Residual Model,
based on container size
(Appendix D.l)

QoBPjday LPdrum? LFCOnt? Vcont? RHO,
OD; Fdbp

Release source 3: Open Surface
Losses to Air During Container
Cleaning

EPA/OPPT Penetration Model
or EPA/OPPT Mass Transfer
Coefficient Model, based on air
speed (Appendix D.l)

Vapor Generation Rate: FDBP; MW; VP;
RATEair speed; Dcont_ciean; T; P

Operating Time: QDBPJear ; Vcont; OD;
RATEfm_cont; RATE^ni_cirum; RHO;
Fdbp

Release source 4: Equipment
Cleaning Wastes

EPA/OPPT Multiple Process
Vessel Residual Model
(Appendix D.l)

QoBP_day LFeqUip

Release source 5: Open Surface
Losses to Air During Equipment
Cleaning

EPA/OPPT Penetration Model
or EPA/OPPT Mass Transfer
Coefficient Model, based on air
speed (Appendix D.l)

Vapor Generation Rate: FDBP; MW; VP;
RATEair speed, DeqUip Ciean, T, P

Operating Time: OHequip clean

Release source 6: Aerosol
Application of Penetrant

See Equation Apx D-43 and
EquationApx D-44

QoBP_day 0//ฐair> %uncertainฆ> Release
point 2

Release source 7: Disposal of
Used Penetrant

See Equation Apx D-45

Qdbp day'? Release points 1 through 5

Release source 6 (Aerosol Application of Penetrant) is partitioned out by release media. In order to
calculate the releases to each media, the total release is calculated first using the following equation:

EquationApx D-43.

Release_perDayRP6 = QoBP_day ~ Release_perDayRP2

Where:

Release_perDayRP6 = DBP released for release source 6 to all release media

(kg/site-day)

QDBP_day	= Facility throughput of DBP (see Appendix D.7.3) (kg/site-day)

Release_perDayRP2 = DBP released for release source 2 (kg/site-day)

Then, the release amounts to each media are calculated using the following equation:

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EquationApx D-44.

ReleasejperDayRP6 media = Release_perDayRP6 * %media

Where:

Release_perDayRP6 media = Amount of release 6 that is released to selected media

(kg/site-day)

Release_perDayRP6	= DBP released for release source 6 to all release media

(kg/site-day)

%media	= Percent of release 6 that is released to selected media

(unitless)

Release source 7 (Disposal of Used Penetrant) is calculated via a mass-balance, via the following
equation:

Equation Apx D-45.

5

Release_perDayRP7 = QDBP day — ^ Release_perDayRPi

i=1

Where:

Release_perDayRP7	= DBP released for release source 7 (kg/site-day)

QDBP_day	= Facility throughput of DBP (see Appendix D.7.3) (kg/site-

day)

ฃf=1 Release_perDayRPi = The sum of release points 1 to 5 emissions (kg/site-day)

D.7.2 Model Input Parameters

Table Apx D-17 summarizes the model parameters and their values for the Use of Penetrants and
Inspection Fluids Monte Carlo simulation. Additional explanations of EPA's selection of the
distributions for each parameter are provided after this table.

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6319	TableApx D-17. Summary of Parameter Values and Distributions Used in the Release Estimation of Penetrants and Inspection

6320	Fluids

Input Parameter

Symbol

Unit

Deterministic
Values

Uncertainty Analysis Distribution Parameters

Rationale/Basis

Value

Lower-
Bound

Upper-
Bound

VI ode

Distribution

Type

Total Production Volume
of DBP at All Sites

P V total

kg/year

9.8E04

-

-

-

-

See D.7.3

Penetrant DBP
Concentration

Fdbp

kg/kg

0.2

0.1

0.2

-

Uniform

See D.7.7

Operating Days

OD

days/year

247

246

249

247

Triangular

See D.7.8

Air Speed

RATEair speed

ft/min

19.7

2.56

398

-

Lognormal

See D.7.9

Saturation Factor

fsat

dimensionless

0.5

0.5

1.45

0.5

Triangular

See D.7.10

Container Size

Vcont

gal

0.082

0.082

55

0.082

Triangular

See D.7.11

Small Container Loss
Fraction

LF cont

kg/kg

0.003

0.003

0.006

0.003

Triangular

See D.7.12

Drum Residual Loss
Fraction

LF drum

kg/kg

0.025

0.017

0.03

0.025

Triangular

See D.7.12

Equipment Cleaning Loss
Fraction

LF equip

kg/kg

0.002

0.0007

0.01

0.002

Triangular

See D.7.13

Vapor Pressure at 25 ฐC

VP

mmHg

2.01E-05

-

-

-

-

Physical property

Molecular Weight

MW

g/mol

278

-

-

-

-

Physical property

Gas Constant

R

atm-

cm3/gmol-L

82

-

-

-

-

Universal constant

Density of DBP

RHO

kg/L

1.0

-

-

-

-

Physical property

Temperature

T

K

298

-

-

-

-

Process parameter

Pressure

P

atm

1

-

-

-

-

Process parameter

Small Container Fill Rate

RATEfillcont

containers/h

60

-

-

-

-

See D.7.14

Drum Fill Rate

RATEfiH drum

containers/h

20

-

-

-

-

See D.7.14

Diameter of Opening -
Container Cleaning

Dcont clean

cm

5.08

-





-

See D.7.15

Diameter of Opening -
Equipment Cleaning

Dequip clean

cm

92

-





-

See D.7.15

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Input Parameter

Symbol

Unit

Deterministic
Values

Uncertainty Analysis Distribution Parameters

Rationale/Basis

Value

Lower-
Bound

Upper-
Bound

VI ode

Distribution

Type

Equipment Cleaning
Duration

Otlequip clean

h/day

0.5

—

—

—

—

See D.7.6

Penetrant User per Job

Qpenetrantjob

oz/job

10.5

-

-

-

-

See D.7.16

Application Jobs per Day

Njobs day

jobs/day

8

-

-

-

-

See D.7.17

Percentage of Aerosol
Released to Fugitive Air

%air

unitless

0.15

-





-

See D.7.18

Percentage of Aerosol
Released to Uncertain
Media

/Ouncertain

unitless

0.85









See D.7.18

6321

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D.7.3 Production Volume and Number of Sites

No sites reported to CDR for use of DBP in penetrants or inspection fluids. EPA estimated the total
production volume (PV) for all sites assuming a static value of 215,415 lb/year (97,710 kg/year) that
was estimated based on the reporting requirements for CDR. The threshold for CDR reporters requires a
site to report processing and use for a chemical if the usage exceeds 5 percent of its reported PV or if the
use exceeds 25,000 lb per year. For the 12 sites that reported to CDR for the manufacture or import of
DBP, EPA assumed that each site used DBP for laboratory chemicals in volumes up to the reporting
threshold limit of 5 percent of their reported PV. If 5 percent of each site's reported PV exceeds the
25,000 lb reporting limit, EPA assumed the site used only 25,000 lb annually as an upper-bound. If the
site reported a PV that was CBI, EPA assumed the maximum PV contribution of 25,000 lb. The CDR
sites and their PV contributions to this OES are show in Table Apx D-13.

The number of sites is calculated using the following equation:

EquationApx D-46.

Where:

Ns

PV

Qdbp

year

Ns =

PV

Qdbp

year

Number of sites (sites)

Production volume (kg/year)

Facility annual throughput of DBP (see Appendix D.7.4) (kg/site-
year)

D.7.4 Throughput Parameters	

The daily throughput of DBP in penetrants is calculated using Equation Apx D-49 by multiplying the
amount of penetrant per job by the number of jobs per day, density, and concentration of DBP. The
amount of penetrant used per job is determined according to Appendix D.7.16. The number of jobs per
day is determined according to Appendix D.7.17.

Equation Apx D-47.

0.00781gal	L

QDBP_day ~ Qpenetrantjob * ^jobs_day * ~~~ * 0.264 * RHO *

Where:

QDBP_day =	Facility throughput of DBP (kg/site-day)

Qpenetrantjob =	Amount of penetrant used per job (see Appendix D.7.16) (oz/job)

Njobs_day =	Application jobs of penetrant per day (see Appendix D.7.17)

(jobs/day)

RHO	=	Density of DBP (assessed as density of the product) (kg/m3)

FDbp	=	Concentration of DBP in penetrants (see Appendix D.7.7) (kg/kg)

The annual throughput of DBP is calculated using Equation Apx D-48 by multiplying the daily
production volume by the number of operating days. The number of operating days is determined
according to Appendix D.7.8.

Equation Apx D-48.

QDBP_year = QDBP_day * OD

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Where:

QDBP_year
QDBP_day

OD

Facility annual throughput of DBP (kg/site-year)
Facility throughput of DBP (kg/site-day)
Operating days (see Appendix D.7.8) (days/year)

D.7.5 Number of Containers per Year

The number of containers unloaded by a site per year is calculated using the following equation:

EquationApx D-49.

N,

Qdbp

year

cont_unload_year

FDbp * RHO * I 3.79

(3-79 w)

* V,

cont

Where:

JV,
V,

cont_unload_y ear

cont

Qdbp_

RHO

Fdbp

year

Annual number of containers unloaded (container/site-year)
Container volume (see Appendix D.7.11) (gal/container)

Facility annual throughput of DBP (see Appendix D.7.4) (kg/site-
year)

DBP density (kg/L)

Mass fraction of DBP in product (see Appendix D.7.7) (kg/kg)

D.7.6 Operating Hours

EPA estimated operating hours or hours of duration using data provided from the Emission Scenario
Document on the Use of Metalworking Fluids (	), ChemSTEER User Guide (

2015). and/or through calculation from other parameters. Release points with operating hours provided
from these sources include unloading, container cleaning, equipment cleaning, and aerosol application.

For unloading and container cleaning (release points 1 and 3), the operating hours are calculated based
on the number of containers unloaded at the site and the unloading rate using the following equation:

Equation Apx D-50.

OH,

N,

RP1/RP3

cont _unload_y ear

RATEfni drum/cont * OD

Where:

OHrp i/Rp3
RATE fin drum/cont

N,

cont_unload_year

OD

Operating time for release points 1 and 3 (h/site-day)
Container fill rate, depending on container size (see Appendix
D.7.14) (containers/h)

Annual number of containers unloaded (see Appendix D.7.5)
(container/ site-year)

Operating days (see Appendix D.7.8) (days/site-year)

For equipment cleaning (release point 5), the ChemSTEER User Guide (	1015) provides a

typical equipment cleaning duration of 0.5 h/day for cleaning a single, small vessel.

For aerosol application (release point 6), EPA treats this activity as container unloading. Therefore, EPA
calculates the operating duration for this release using Equation Apx D-50.

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D.7.7 Penetrant DBP Concentration

EPA modeled DBP concentration in paints and coatings using a uniform distribution with a lower-bound
of 10 percent and upper-bound of 20 percent. This is based on compiled SDS information for penetrants
containing DINP. EPA was not able to identify products for this use that contained DBP. For that
reason, EPA based the concentration estimate on compiled SDS information for penetrants and
inspection fluids containing DINP and assumed that DBP-containing products would have similar
concentrations ranges. The DINP-containing product is identified in Appendix F of the Environmental
Release and Occupational Exposure Assessment for Diisononyl Phthalate (DINP) (	).

D.7.8 Operating Days

EPA modeled the operating days per year using a triangular distribution with a lower-bound of 246
days/year, an upper-bound of 249 days/year, and a mode of 247 days/year. To ensure that only integer
values of this parameter were selected, EPA nested the triangular distribution probability formula within
a discrete distribution that listed each integer between (and including) 246 to 249 days/year. This is
based on the Emission Scenario Document on the Use of Metal working Fluids (OEC	). The

ESD cites a general average for metal shaping operations to be 246 to 249 days/year, and it recommends
a default value of 247 days/year.

D.7.9 Air Speed

Baldwin and Maynard measured indoor air speeds across a variety of occupational settings in the United
Kingdom (Baldwin and Maynao.j 1l">98). Fifty-five work areas were surveyed across a variety of
workplaces. EPA analyzed the air speed data from Baldwin and Maynard and categorized the air speed
surveys into settings representative of industrial facilities and representative of commercial facilities.
The Agency fit separate distributions for these industrial and commercial settings and used the industrial
distribution for this OES.

EPA fit a lognormal distribution for the data set as consistent with the authors' observations that the air
speed measurements within a surveyed location were lognormally distributed and the population of the
mean air speeds among all surveys were lognormally distributed (Baldwin and Mayr >98). Because
lognormal distributions are bound by zero and positive infinity, EPA truncated the distribution at the
largest observed value among all of the survey mean air speeds.

EPA fit the air speed surveys representative of industrial facilities to a lognormal distribution with the
following parameter values: mean of 22.414 cm/s and standard deviation of 19.958 cm/s. In the model,
the lognormal distribution is truncated at a minimum allowed value of 1.3 cm/s and a maximum allowed
value of 202.2 cm/s (largest surveyed mean air speed observed in Baldwin and Maynard) to prevent the
model from sampling values that approach infinity or are otherwise unrealistically small or large
(Baldwin and Maynard. 1998).

Baldwin and Maynard only presented the mean air speed of each survey. The authors did not present the
individual measurements within each survey. Therefore, these distributions represent a distribution of
mean air speeds and not a distribution of spatially variable air speeds within a single workplace setting.
However, a mean air speed (averaged over a work area) is the required input for the model. EPA
converted the units to ft/min prior to use within the model equations.

D.7.10 Saturation Factor

The CEB Manual indicates that during splash filling, the saturation concentration was reached or
exceeded by misting with a maximum saturation factor of 1.45 (U.S. EPA. 1991). The CEB Manual
indicates that saturation concentration for bottom filling was expected to be about 0.5 (	).

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The underlying distribution of this parameter is not known; therefore, EPA assigned a triangular
distribution based on the lower-bound, upper-bound, and mode of the parameter. Because a mode was
not provided for this parameter, EPA assigned a mode value of 0.5 for bottom filling as bottom filling
minimizes volatilization (	). This value also corresponds to the typical value provided in

the ChemSTEER User Guide for the EPA/OAQPS AP-42 Loading Model (U.S. EPA. 2015).

D.7.11 Container Size

EPA modeled container size using a triangular distribution with a lower-bound of 0.082 gallons, an
upper-bound of 55 gallons, and a mode of 0.082 gallons. EPA identified penetrants in 10.5-oz (0.082-
gallon) aerosol cans, and 1-, 5-, and 55-gallon containers. EPA used 10.5-oz cans as the mode because
most products indicated using 10.5-oz cans. The product is identified in Appendix F of the
Environmental Release and Occupational Exposure Assessment for Diisononyl Phthalate (DINP) (U.S.
24b).

D.7.12 Container Loss Fractions

The

recommends a default central tendency loss fraction of 0.3 percent and a high-end loss fraction of 0.6
percent.

The underlying distribution of the loss fraction parameter for small containers is not known; therefore,
EPA assigned a triangular distribution because triangular distributions are completely defined by range
and mode of a parameter. The Agency assigned the mode and maximum values for the loss fraction
probability distribution using the central tendency and high-end values, respectively, prescribed by the
EPA/OPPT Small Container Residual Model in the ChemSTEER User Guide (U.S. EPA. 2015). EPA
assigned the minimum value for the triangular distribution using the minimum average percent residual
measured in the PEI Associates, Inc. study (Associates. 1988) for emptying drums by pouring.

D.7.13 Equipment Cleaning Loss Fraction

EPA used the EPA/OPPT Single Vessel Residual Model to estimate the releases from equipment
cleaning. This model, as detailed in the ChemSTEER User Guide (	) provides a default

loss fraction of 0.002 for equipment cleaning. In addition, the model provides non-default loss fractions
of 0.01 and 0.0007. Therefore, developed a triangular distribution for equipment cleaning, with a lower-
bound of 0.0007, an upper-bound of 0.01, and a mode of 0.002, based on the ChemSTEER User Guide
n*s \v\ 20151

D.7.14 Container Fill Rates

The ChemSTEER User Guide (U.S. EPA. 2015) provides a typical fill rate of 60 containers per hour for
containers with less than 20 gallons of liquid.

D.7.15 Diameters of Opening

The ChemSTEER User Guide indicates diameters for the openings for various vessels that may hold
liquids in order to calculate vapor generation rates during different activities (	). For

equipment cleaning operations, the ChemSTEER Manual indicates a single default value of 92 cm (U.S.

). For container cleaning activities, the ChemSTEER User Guide indicates a single default
value of 5.08 cm for containers less than 5,000 gallons (	).

D.7.16 Penetrant Used per Job

EPA identified 10.5 oz as a standard size for aerosol cans. EPA assumed that one container is used per
job, so the amount of penetrant used per job is 10.5 oz. The product is identified in Appendix E of the

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6511

6512

6513

6514

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6518

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May 2025

Environmental Release and Occupational Exposure Assessment for Diisononyl Phthalate (DINP) (U.S.
I 24b).

D.7.17 Jobs per Day	

EPA assumed eight penetrant jobs occur per day. As there was no available usage data, EPA assumed a
duration of 1 hour per job, and eight jobs/day due to a typical shift being 8 hours long. Therefore, EPA
could not develop a distribution of values for this parameter and used the single value of eight jobs/day.

D.7.18 Percentage of Aerosol Released to Fugitive Air and Uncertain Media

According to the Generic Scenario on Chemicals Used in Furnishing Cleaning Products (U.S. EPA.
2022b). 15 percent of spray application releases are to fugitive air and 85 percent are to water,
incineration, or landfill.

D.8 Inhalation Exposure to Respirable Particulates Model Approach and
Parameters

The PNOR Model (	) estimates worker inhalation exposure to respirable solid

particulates using personal breathing zone Particulate, Not Otherwise Regulated (PNOR) monitoring
data from OSHA's Chemical Exposure Health Data (CEHD) data set. The CEHD data provides PNOR
exposures as 8-hour TWAs by assuming exposures outside the sampling time are zero, and the data also
include facility NAICS code information for each data point. To estimate particulate exposures for
relevant OESs, EPA used the 50th and 95th percentiles of respirable PNOR values for applicable
NAICS codes as the central tendency and high-end exposure estimates, respectively.

Due to lack of data on the concentration of DBP in the particulates, EPA assumed DBP is present in
particulates at the same mass fraction as in the bulk solid material, whether that is a plastic product or
another solid article. Therefore, EPA calculates the 8-hour TWA exposure to DBP present in dust and
particulates using the following equation:

Equation Apx D-51.

TableApx D-18 provides a summary of the OESs assessed using the PNOR Model (U.S. EPA. 2021b)
along with the associated NAICS code, PNOR 8-hour TWA exposures, DBP mass fraction, and DBP 8-
hour TWA exposures assessed for each OES.

CdBPMv-TWA — CpNOR,8hr-TWA X FDBP

Where:

8-hour TWA exposure to DBP (mg/m3)
8-hour TWA exposure to PNOR (mg/m3)
Mass fraction of DBP in PNOR (mg/mg)

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6532	TableApx D-18. Summary of DBP Exposure Estimates for OESs Using the Generic Model for

6533	Exposure to PNOR				

Occupational
Exposure Scenario

NAICS Code Assessed

Respirable PNOR 8-
Hour TWA from Model
(mg/mJ)

DBP

Mass
Fraction

Assessed

DBP 8-Hour TWA
(mg/mJ)

Central
Tendency

High-End

Central
Tendency

High-End

PVC plastics
compounding

326 - Plastics and Rubber
Manufacturing

0.23

4.7

0.45

0.10

2.1

PVC plastics
converting

326 - Plastics and Rubber
Manufacturing

0.23

4.7

0.45

0.10

2.1

Non-PVC materials
compounding

326 - Plastics and Rubber
Manufacturing

0.23

4.7

0.20

4.6E-02

0.94

Non-PVC materials
converting

326 - Plastics and Rubber
Manufacturing

0.23

4.7

0.20

4.6E-02

0.94

Use of laboratory
chemicals (solid)

54 - Professional,
Scientific, and Technical
Services

0.19

2.7

0.20

3.8E-02

0.54

Recycling

56 - Administrative and
Support and Waste
Management and
Remediation Services

0.24

3.5

0.45

0.11

1.6

Fabrication or use
of final product/
articles containing
DBP

337 - Furniture and
Related Product
Manufacturing

0.20

1.8

0.45

9.0E-02

0.81

Distribution in
commerce

48 to 49 - Transportation
and Warehousing

7.6E-02

5.0

0.45

3.4E-02

2.3

Waste handling,
treatment, and
disposal

56 - Administrative and
Support and Waste
Management and
Remediation Services

0.24

3.5

0.45

0.11

1.6

6534	D,9 Inhalation Exposure Modeling for Penetrants and Inspection Fluids

6535	This appendix presents the modeling approach and model equations used in the near-field/far-field

6536	exposure modeling of the use of penetrants and inspection fluids. EPA developed the model through

6537	review of the literature and consideration of existing EPA/OPPT exposure models. This model is based

6538	on a near-field/far-field approach (	,009). where an aerosol application located inside the near-

6539	field generates a mist of droplets, and indoor air movements lead to the convection of the droplets

6540	between the near- and far-field. The model assumes workers are exposed to DBP droplets in the near-

6541	field, while occupational non-users are exposed in the far-field.

6542

6543	The model uses the following parameters to estimate exposure concentrations in the near- and far-field:

6544	• Far-field size;

6545	• Near-field size;

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•	Air exchange rate;

•	Indoor air speed;

•	Concentration of DBP in the aerosol formulation;

•	Amount of product used per job;

•	Number of applications per job;

•	Time duration of j ob;

•	Operating hours per week; and

•	Number of j obs per work shift.

An individual model parameter could be either a discrete value or a distribution of values. EPA assigned
statistical distributions based on available literature data. EPA used a Monte Carlo simulation to capture
variability in the model parameters. EPA conducted the simulation using the Latin hypercube sampling
method in @Risk Industrial Edition, Version 8.0.0. The Latin hypercube sampling method generates
parameter values from a multi-dimensional distribution and is a stratified method, where the generated
samples are representative of the probability density function (variability) defined in the model. EPA
selected 100,000 model iterations to capture a broad range of possible input values, including values
with low probability of occurrence.

Model results from the Monte Carlo simulation are presented as 95th and 50th percentile values in
Section 3.12.4.2. The statistics were calculated directly in @Risk. EPA selected the 95th percentile
value to represent high-end exposure level and the 50th percentile value to represent the central
tendency exposure level. The following subsections detail the model design equations and parameters
for the near-field/far-field model.

D.9.1 Model Design Equations

Penetrant/inspection fluid application generates a mist of droplets in the near-field, resulting in worker
exposures at a DBP concentration Cnf. This concentration is directly proportional to the amount of
penetrant applied by the worker standing in the near-field-zone {i.e., the working zone). The near-field
zone volume is denoted as Vnf. The ventilation rate for the near-field zone (Qnf) determines the rate of
DBP dissipation into the far-field {i.e., the facility space surrounding the near-field), resulting in
occupational bystander exposures to DBP at a concentration Cff. Vff denotes the volume of the far-field
space into which the DBP dissipates from the near-field. The ventilation rate of the surroundings,
denoted as Qff, determines the rate of DBP dissipation from the surrounding space into the outside air.

EPA denoted the top of each 5-minute period for each hour of the day {e.g., 8:00 am, 8:05 am, 8:10 am,
etc.) as tm,n. Here, m has the values of 0, 1, 2, 3, 4, 5, 6, and 7 to indicate the top of each hour of the day
{e.g., 8 am, 9 am, etc.) and n has the values of 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11 to indicate the top of
each 5-minute period within the hour. The worker begins the first penetrant application job during the
first hour, to,o to ti,o {e.g., 8-9 am). The worker applies the penetrant at the top of the second 5-minute
period tm,i {e.g., 8:05 am, 9:05 am, etc.).

The model design equations are presented below in EquationApx D-52 through EquationApx D-72.

Near-Field Mass Balance
Equation Apx D-52.

dCjyp

Vnf dt = ^ffQnf ~ CnfQnf

Far-Field Mass Balance

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EquationApx D-53.

dCFF

^FF~dt~ = ^NF^NF ~ ^ffQnf ~ CffQff

Where:

VNf =

Near-field volume (m3)

VFF =

Far-field volume (m3)

Qnf =

Near-field ventilation rate (m3/h)

Qff =

Far-field ventilation rate (m3/h)

CNf =

Average near-field concentration (mg/m3)

CFF =

Average far-field concentration (mg/m3)

t

Elapsed time (h)

Solving Equation Apx D-52 and Equation Apx D-53 in terms of the time-varying concentrations in the
near- far-field yields Equation Apx D-54 and Equation Apx D-54. EPA assessed Equation Apx D-54
and Equation Apx D-54 for all values of tm,n. For each 5-minute increment, EPA calculated the initial
near-field concentration at the top of each period (tm,n), accounting for the burst of DBP from the
penetrant application (if the 5-minute increment is during an application) and the residual near-field
concentration remaining after the previous 5-minute increment (tm,n-i; except during the first hour and
tm,o of the first penetrant application job, in which case there would be no residual DBP from a previous
application). The initial far-field concentration is equal to the residual far-field concentration remaining
after the previous 5-minute increment. EPA then calculated the decayed concentration in the near- and
far-field at the end of the 5-minute period, just before the penetrant application at the top of the next
period (tm,n+i). EPA then calculated 5-minute TWA exposures for the near- and far-field, representative
of the worker's and ONU's exposures to the airborne concentrations during each 5-minute increment
using Equation Apx D-64 and Equation Apx D-65. k coefficients (Equation Apx D-55 through
Equation Apx D-59) are a function of initial near- and far-field concentrations and are recalculated at
the top of each 5-minute period.

In the equations below, if n-1 is less than zero, the value at "m-1, 11" is used instead. Additionally, if
n+1 is greater than 11, the value at "m+1, 0" is used instead.

Equation Apx D-54.

Cnf t - (h t	-|- /^2 e*)

iyir>Lm,n+1 v	z>Lm,n J

Equation Apx D-55.

CpF t j.1 =(^3t	eXlt — k4t eX2t)

rr>Lm,n+1 v 3,im,n	^>Lm,n J

Equation Apx D-56.

QnF (y-'FF ,0 (tfnji) ~ CNF 0(tmnj^ — A 2 K/v f F, 0 ( ^rn, n )
VNF(Xl — A2)

Equation Apx D-57.

QnF (CwF,o(tm,n) — ^FF,0	^l^NF^NF.oiSm.n)

2,tm'n	vNF{h — ^2)

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EquationApx D-58.

(.QnF + ^1 Vnf)(.QnF (CFF,o(tm,n) ~ ฃW,o(tm,n)) ~ ^-2^NF^NF,0 (tm.n))

3,tm'n	Qnf^nf(^i — ^2)

Equation Apx D-59.

(.QnF + ^2Vnf)(.QnF (CNF,o(tm,n) ~ CpF.oi^m.n)) + ^-l^VF^JVF.O(*771,71))

4'tm,n	Qnf^nf(^i — ^2)

Equation Apx D-60.

Xx = 0.5

1	2

(Qnf^ff + Vnf(Qnf + Qff)\ \( Qnf^ff + Vnf(Qnf + Qff)\ „ /QnfQffn

V ^/VF^FF / -\J V ^/VF^FF

Equation Apx D-61.

)\ _ . /V/VFVFF\
/	\ ^/VF^FF '

Az = 0.5

_ /Qnf^ff + Vnf(Qnf + Qff)\ _ I/Qnf^ff + Vnf(Qnf + Qff)\ _ . /QnfQff\
\	^/VF^FF	/ -J V	^/VF^FF	/	\ ^/VF^FF '

Equation Apx D-62.

f	0, m = 0

CNF,o{pm,n) — j — f 1,000——) + CWF(tmn_1) , n > 0 /or all m where penetrant job occurs
^ Vwf ^ 9 '

Equation Apx D-63.

r	0, m = 0

FF,o\tm,n) — {CFF(trriin^1) , for all n where m > 0

Equation Apx D-64.

{kl,tm,n-l	j ^2-tm,n-l	_ /^l,tmn_1	j ^<2-tm,n-l ^ A-,U \

\ ^1	^2 / \ ^1	J

^NF, 5-min TWA, tm n	7 7

r2 rl

Equation Apx D-65.

li	A2 I \ Ai	a2

CfF, 5-min TWA, tm „	t t

in — Li

After calculating all near-field/far-field 5-minute TWA exposures (i.e., CNFS_mm TwA,tmn and
Cff,5_minTWA,tmn X EPA calculated the near-field/far-field 1-hour and 8-hour TWA concentrations
according to the following equations:

Equation Apx D-66.

r	2jto=0 Hr! = o[C/VF,5-min TWA,tmn X 0.0833 hr\

CNF, 8-hr TWA =	o~TZ '

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6679

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EquationApx D-67.

2m=0 2n=o[^FF,5-minTWA,tmn X 0.0833 hr\

CNF, 8-hr TWA ~	Q~kr~

Equation Apx D-68.

Equation Apx D-69.

n	_ UriiofC/VF.S-min TWA,tmn X 0.0833 hr\

CNF, 1-hr TWA =

r	_ Hn=o[^FF,5-minTWA,tm,n X 0-0833 hr\

CFF, 1-hr TWA =	~\\xr

EPA calculated rolling 1-hour TWAs throughout the workday, while the model reported the maximum
calculated 1-hour TWA.

To calculate the mass transfer to and from the near field, the free surface area (FSA) is defined as the
surface area through which mass transfer can occur. The FSA is not equal to the surface area of the
entire near field. EPA defined the near-field zone to be a hemisphere with its major axis oriented
vertically, against the application surface. The top half of the circular cross-section rests against, and is
blocked by, the surface and is not available for mass transfer. The FSA is calculated as the entire surface
area of the hemisphere's curved surface and half of the hemisphere's circular surface per EquationApx
D-70:

Equation Apx D-70.

FSA = (2 X ^uRnf) + (2 x nR

If.

Where:

Rnf = Radius of the near-field (m)

The near-field ventilation rate, QNF, is calculated from the indoor wind speed, vNF, and FSA, assuming
half of the FSA is available for mass transfer into the near-field and half is available for mass transfer
out of the near-field:

Equation Apx D-71.

1

Qnf — — vnfFSA

The far-field volume, VFF, and the air exchange rate (AER) are used to calculate the far-field ventilation
rate, QFF:

Equation Apx D-72.

QFF = Vpp x AER

Using the model inputs described in Appendix D.9.2, EPA estimated DBP worker inhalation exposures
in the near-field and ONU inhalation exposures in the far-field. EPA then conducted Monte Carlo
simulations using @Risk Version 8.0.0 to calculate exposure results shown in Section 3.12.4.2. The
simulations applied the Latin Hypercube sampling method using 100,000 iterations.

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6706	D.9.2 Model Parameters

6707	Table Apx D-19 summarizes the model parameters for the near-field/far-field modeling of the use

6708	penetrants and inspection fluids. Each parameter is discussed in further detail in the following

6709	subsections.

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6710	TableApx D-19. Summary of Parameter Values Used in the Near-Field/Far-Field Inhalation Exposure Modeling of Penetrants and

6711	Inspection Fluids						

Input Parameter

Symbol

Unit

Constant
Value

Variable Model Parameter Values

Rationale

Lower-
Bound

Upper-
Bound

Mode

Distribution

Type

Far-Field Volume

Vff

m3

-

200

7.1E04

3,769

Triangular

See D.9.2.1

Air Exchange Rate

AER

m3/h

-

1

20

3.5

Triangular

See D.9.2.2

Near-Field Indoor Air Speed

Vnf

cm/s

-

1.3

202

-

Lognormal

See D.9.2.3

ft/min

-

2.6

398

-

Lognormal

Near-Field Radius

Rnf

m3

1.5

-

-

-

-

See D.9.2.4

Application Time

t2

hr

0.0833

-

-

-

-

See D.9.2.5

Averaging Time

tavg

hr

8

-

-

-

-

See D.9.2.6

DBP Product Concentration

Fdbp

kg/kg

-

0.10

0.20

-

Uniform

See D.9.2.7

Volume of Penetrant Used per Job

Qpenetrant J ob

oz/job

-

1.1

2.6

-

Uniform

See D.9.2.8

Number of Applications per Job

Nappjob

applications/job

1

-

-

-

-

See D.9.2.9

Number of Jobs per Work Shift

Njobs day

jobs/day

8

-

-

-

-

See D.9.2.11

a Each parameter is represented either by a constant value or a distribution.

6712

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D.9.2.1 Far-Field Volume

Since EPA was not able to identify any penetrant- or DBP-specific use or exposure data, EPA utilized a
near-field/far-field approach (AIHA. 2009). The far-field volume is based on site visits of 137
automotive maintenance and repair shops in California (	>00). The California Air Resources

Board indicated that shop volumes ranged from 200 to 70,679 m3 with an average shop volume of 3,769
m3. EPA assumed that the range of facility volumes in this data set would also be representative of other
facility types that use DBP-based penetrants and inspection fluids Based on this data EPA assumed a
triangular distribution bound from 200 to 70,679 m3 with a mode of 3,769 m3 (the average of the data
from CARB).

CARB measured the physical dimensions of the brake service work area within each automotive
maintenance and repair shop. CARB did not consider other areas of the facility, such as customer
waiting areas and adjacent storage rooms if they were separated by a normally closed door. If the door
was normally open, CARB considered these areas as part of the area in which brake servicing emissions
could occur (	)00). CARB's methodology for measuring the physical dimensions of the visited

facilities provides the appropriate physical dimensions needed to represent the far-field volume in EPA's
model. Therefore, CARB's reported facility volume data are appropriate for the Agency's modeling
purposes.

D.9.2.2 Air Exchange Rate

The AER is based on data from Demou et al., Hellweg et al., Golsteijn, et al., and information received
from a peer reviewer during the development of the 2014 TSCA Work Plan Chemical Risk Assessment
Trichloroethylene: Degreasing. Spot Cleaning and Arts & Crafts Uses (Golsteijn et al.. 2^ I L I v << \
20.13; Oomou et al.. 2009; Hellweg et al.. 2009). Demou et al. identified typical AERs of 1 h 1 and 3 to
20 h 1 for occupational settings with and without mechanical ventilation systems, respectively.

Similarly, Hellweg et al. identified average AERs for occupational settings using mechanical ventilation
systems to vary from 3 to 20 h Golsteijn, et al. indicated a characteristic AER of 4 h The risk
assessment peer reviewer comments from TCE indicated that values around 2 to 5 h 1 are likely (U.S.

13), in agreement with Golsteijn, et al. and at the low-end of the range reported by Demou et al.
and Hellweg et al. Therefore, EPA used a triangular distribution with a mode of 3.5 h EPA used the
midpoint of the range provided by the risk assessment peer reviewer (3.5 is the midpoint of the range 2-
5 h '), a minimum of 1 h 1 per Demou et al., and a maximum of 20 h 1 per Demou et al. and Hellweg et
al.

D.9.2.3 Near-Field Indoor Air Speed

Baldwin and Maynard measured indoor air speeds within 55 occupational settings in the United
Kingdom (Baldwin and Mavm >8). EPA analyzed the air speed data from Baldwin and Maynard
and categorized the air speed surveys into data representative of industrial facilities and data
representative of commercial facilities. The Agency fit separate distributions for these industrial and
commercial settings and used the industrial distribution for this model.

EPA fit a lognormal distribution for the data set, consistent with the authors' observations that the air
speed measurements within a surveyed location were lognormally distributed, and the population of the
mean air speeds among all surveys were lognormally distributed (Baldwin and Maynard. 1998). Because
lognormal distributions are bound by zero and positive infinity, EPA truncated the distribution at the
largest mean air speed value observed among the surveys.

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EPA's resulting lognormal distribution had a mean of 22.414 ฑ 19.958 cm/s, a minimum allowed value
of 1.3 cm/s, and a maximum allowed value of 202.2 cm/s (largest surveyed mean air speed observed in
Baldwin and Maynard). This was done to prevent the model from sampling values that approach infinity
or are otherwise unrealistically small or large (Baldwin and Maymg |8).

Baldwin and Maynard only presented the mean air speed of each survey. The authors did not present the
individual measurements within each survey. Therefore, these distributions represent a distribution of
mean air speeds and not a distribution of spatially variable air speeds within a single workplace setting.
However, a mean air speed (averaged over a work area) is the required input for the model.

D.9.2.4 Near-Field Volume

EPA defined the near-field zone volume (Vnf) as a hemisphere with its major axis oriented vertically
against the application surface. EPA also defined a near-field radius (Rnf) of 1.5 m (~ 4.9 feet) as an
estimate of the working height of the application surface, as measured from the floor to the center of the
surface.

EquationApx D-73.

1 4

Vnf = 2 x 3 71 ^nf

D.9.2.5 Application Time

EPA modeled the application time at 5-minute intervals, as it is expected that the penetrant will be
sprayed onto the surface, allowed to sit on the surface, and finally wiped away after the surface has been
examined for defects. For this process, it is expected that the application step will only take 5 minutes.

D.9.2.6 Averaging Time

EPA uses 8-hour TWAs for its risk calculations; therefore, EPA used a constant averaging time of 8
hours.

D.9.2.7 DBP Product Concentration

EPA was not able to identify DBP-specific penetrant product information; however, the Agency
assessed the DBP penetrant concentration using surrogate DINP concentration information from a
penetrant and inspection fluid product, Spotcheck ฎ SKL-SP2. EPA used the SDS to develop a range of
concentrations for the product (ITW Inc. 2018) and assessed the DBP product concentration based on
this product, using a uniform distribution ranging from 0.1 to 0.2.

D.9.2.8 Volume of Penetrant Used per Job

EPA utilized a penetrant and inspection fluid containing DINP as surrogate and assessed the product
information using the SDS (ITW Inc. 2018). Based on this information, the Agency estimated that the
amount of penetrant per aerosol container was 10.5 oz. EPA then assumed the quantity of penetrant used
per job as a uniform distribution ranging from 10 to 25 percent of can per job or 1.05 to 2.63 oz.

This throughput range differs from the throughput used to assess the releases for this OES as presented
in Appendix D.7.4. The discrepancy reflects the expected discrepancy in the number of workers
applying the product and working the job at a given site. EPA expects that these tasks will be performed
by multiple workers per day, and that no one worker would regularly apply these products for a full
shift. Thus, the 10 to 25 percent range results in less penetrant per job and is expected be more
representative of aerosol exposures for a single worker.

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6800

6801

6802

6803

6804

6805

6806

6807

6808

6809

6810

6811

6812

6813

6814

6815

6816

6817

6818

6819

6820

6821

6822

PUBLIC RELEASE DRAFT
May 2025

D.9.2.9 Number of Applications per Job

EPA modeled the penetrant scenario with one application per job, as it is expected that the penetrant will
be sprayed onto the surface, allowed to sit on the surface, and finally wiped away after the surface has
been examined for defects.

D.9.2.10 Amount of DBP Used per Application

EPA calculated the amount of DBP used per application using EquationApx D-74. The calculated mass
of DBP per application ranges from 2.09xl0~3 to 4.17xl0~3 g.

Equation Apx D-74.

Amt =

Qpenetrantjob ^ FDBP ^ 28.3495 ^

N,

Where:

appjob

Amt

Qpenetrantjob

DBP
appjob

N,

Amount of DBP used per application (g/application)
Amount of penetrant used per job (oz/job)

Product concentration (kg/kg)

Number of applications per job (applications/job)

D.9.2.11 Number of Jobs per Work Shift

EPA did not identify DBP-specific data on penetrant and inspection fluid application frequency.
Therefore, EPA assessed exposures assuming 8 jobs per work shift, which is equivalent to one job per
hour for a full 8-hour shift. The full-shift assumption may overestimate the application duration as
workers likely have other activities during their shift; however, those activities may also result in
exposures to vapors that volatilize during those activities. Because EPA is not factoring in those vapor
exposures, a full-shift exposure assessment is assumed to be protective of any contribution to exposures
from vapors.

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6823	Appendix E PRODUCTS CONTAINING DBP

6824	This section includes a sample of products containing DBP. This is not a comprehensive list of products

6825	containing DBP. In addition, some manufacturers may appear over-represented in Table Apx E-l. This

6826	may mean that they are more likely to disclose product ingredients online than other manufacturers but

6827	does not imply anything about use of the chemical compared to other manufacturers in this sector.

6828

Table Apx E-l. Products Containing I

>BP

OES

Product

Manufacturer

DBP

Concentration

Source

HERO ID

Adhesives and
sealants

Devcon Weld-It All
Purpose Adhesive

ITW Consumer

Dcvcon/Vcrsach
em

<3% by weight

Walmart (2019);
ITW Consumer
(2008)

6301538

Paints and coatings

Franklin Side Out
Gym Floor Finish

Fuller Brush
Company

<2%, unknown

Neobits Inc.
(2019); Franklin
Cleaning
Technology
(2011)

6301522

Non-TSCA
(gunpowder)

Accurate Solo 1000,
Accurate LT-30,
Accurate LT-32,
Accurate 2015,
Accurate 2495,
Accurate 4064,
Accurate 4350

Western
Powders, Inc.

0-10%, by weight

Western
Powders Inc.
2015

6301493

Use of lab chemicals

Base/Neutrals Mix 1

SPEX CertiPrep,
LLC.

0.2%, unspecified

SPEX CertiPrep
LLC. 2019

6302556

Paints and coatings

Carbocrylic 3358-G

Carboline
Company

1.0-2.5%,
unspecified

Carboline
Company 2018a

6301510

Paints and coatings

Carbocrylic 3359

Carboline
Company

1.0 to <2.5%,
unspecified

Carboline
Company 2019a

6301494

Paints and coatings

Carbocrylic 3359
MC

Carboline
Company

1.0-2.5%,
unspecified

Carboline
Company 2018b

6301531

Paints and coatings

Carbocrylic 3359
Mixed Metal Oxide

Carboline
Company

1.0 to <2.5%,
unspecified

Carboline
Company 2019b

6301511

Non-TSCA (bullets)

Cartridge 9 mm FX
Marking, Toxfree
primer

General
Dynamics -
Ordnance and
Tactical
Systems -
Canada Inc.
[Canada]

Trace, unspecified

General
Dynamics -
Ordnance and
Tactical
Systems -
Canada Inc.
2018

6301539

Use of lab chemicals

COE-RECT
(Powder)

GC America
Inc.

10-20%,
unspecified

GC America
Inc. 2015

6301521

Paints and coatings

CrystalFin Floor
Finish

Daly's Wood

Finishing

Products

1%, unspecified

Daly's Wood
Finishing
Products 2015

11438267

Use of lab chemicals

Custom 8061
Phthalates Mix

Phenova

0.1%, unspecified

Phenova 2017a

6301564

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OES

Product

Manufacturer

DBP

Concentration

Source

HERO ID

Use of lab chemicals

Custom Low ICAL
Mix

Phenova

0.1%, unspecified

Phenova 2017b

6302481

Adhesives and
sealants

D.L.M. Adhesive
22-68

Mon-Eco
Industries, Inc.

1-5%, by weight

Mon-Eco
Industries Inc.
2011

6301550

Use of lab chemicals

DEPEX Mounting
Medium

Electron

Microscopy

Sciences

>2.5 to <10%,
unspecified

Electron
Microscopy
Sciences 2018

6301529

Adhesives and
sealants

Epcon Acrylic 7

ITW Red Head

0.1-5%, by
weight

ITW Red Head
2016

6301527

Paints and coatings

Hydrostop
Premiumcoat Finish
Coat

GAF

0.1 to <1%,
unspecified

GAF 2018

6301537

Paints and coatings

Hydrostop
Premiumcoat
Foundation Coat

GAF

0.1 to <1%,
unspecified

GAF 2017

6301518

Paints and coatings

Hydrostop
Trafficcoat Deck
Coating

GAF

0.1 to <1%,
unspecified

GAF 2016

6301526

Adhesives and
sealants

Lanco Seal

Lanco Mfg.
Corp.

0.05-10%, by
weight

Lanco Mfg.
Corp. 2016

6301543

Paints and coatings

Marine Coating
Antifouling Blue

Rust-Oleum
Corporation

2.5-10%, by
weight

Rust-Oleum
Corporation
2015

6301565

Adhesives and
sealants

Metal Bonding
Adhesive

Ford Motor
Company

1 to <3%,
unspecified

Ford Motor
Company 2015

6301534

Use of lab chemicals

Phthalates in
Poly(vinyl chloride)

SPEX CertiPrep,
LLC.

0.3%, unspecified

SPEX CertiPrep
LLC 2017a

6302509

Use of lab chemicals

Phthalates in
Polyethylene
Standard

SPEX CertiPrep,
LLC.

0.3%, unspecified

SPEX CertiPrep
LLC 2017b

6301560

Use of lab chemicals

Phthalates in
Polyethylene
Standard w/BPA

SPEX CertiPrep,
LLC.

0.3%, unspecified

SPEX CertiPrep
LLC 2017c

6301542

Adhesives and
sealants

Prime Flex 900MV

Prime Resins
Inc.

2.5 to <10%,
unspecified

Prime Resins
Inc. 2018a

6301547

Adhesives and
sealants

Prime Flex 900XLV

Prime Resins
Inc.

2.5 to <10%,
unspecified

Prime Resins
Inc. 2018b

6301561

Adhesives and
sealants

Prime Flex 910

Prime Resins
Inc.

50 to <75%,
unspecified

Prime Resins
Inc. 2018c

6301552

Adhesives and
sealants

Prime Flex 920

Prime Resins
Inc.

25 to <50%,
unspecified

Prime Resins
Inc. 2018d

6301541

Non-TSCA (bullets)

Rimfire Blank
Round - Circuit
Breaker

Olin

Corporation -
Winchester
Division, Inc.

Unknown

Olin

Corporation -
Winchester
Division 2010

6301545

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OES

Product

Manufacturer

DBP

Concentration

Source

HERO ID

Adhesives and
sealants

Sika Loadflex-524
EZ Part B

Sika

Corporation

>50 to <100%,
unspecified

Sika

Corporation
2017

6301546

Paints and coatings

SWC Natureone
100% Aery EN CED

Structures Wood
Care

2-3%, by weight

Structures Wood
Care 2016a

6301556

Paints and coatings

SWC Natureone
Renew

Structures Wood
Care

2-3%, by weight

Structures Wood
Care 2016b

6301548

Non-PVC materials

TC-4485 Part A

BJB Enterprises,
Inc.

1-5%, by weight

BJB Enterprises
2019b

6301507

Non-PVC materials

TC-812 Part B

BJB Enterprises,
Inc.

1-5%, by weight

BJB Enterprises
2018a

6301495

Non-PVC materials

TC-816 Part B

BJB Enterprises,
Inc.

1-5%, by weight

BJB Enterprises
2019a

6301497

Use of lab chemicals

Temp Span
Transparent
Temporary Cement
- Base

Pentron Clinical

5-10%,
unspecified

Pentron Clinical
2014

6301544

6830

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6831

6832

6833

6834

6835

6836

6837

6838

6839

6840

6841

6842

6843

6844

6845

6846

6847

6848

6849

6850

6851

6852

6853

6854

6855

6856

6857

6858

6859

6860

6861

6862

6863

6864

6865

6866

6867

6868

6869

6870

6871

6872

6873

6874

6875

6876

6877

PUBLIC RELEASE DRAFT
May 2025

Appendix F LIST OF SUPPLEMENTAL DOCUMENTS

A list of the supplemental documents that are mentioned in this Draft Environmental Release and
Occupational Exposure Assessment for Dibutyl Phthalate (DBP) as well as a brief description of each of
these documents is provided below. These supplemental documents include spreadsheets that contains
model equations, parameter values, and the results of the probabilistic (stochastic) or deterministic
calculations and are available in Docket EPA-HQ-OPPT-2018-0503.

1.	Draft Manufacturing OES Environmental Release Modeling Results for Dibutyl Phthalate
(DBP).

2.	Draft Occupational Inhalation Exposure Monitoring Results for Dibutyl Phthalate (DBP). This
spreadsheet contains all of the inhalation monitoring data used to assess exposures to vapors and
dust for each OES.

3.	Draft Occupational Dermal Exposure Modeling Results for Dibutyl Phthalate (DBP). This
spreadsheet contains all model equations, parameter values and the results of the deterministic
calculations of the worker dermal exposures to DBP that are associated with each OES.

4.	Draft Summary of Results for Identified Environmental Releases to Landfor Dibutyl Phthalate
(DBP). This document contains identified land releases from TRI that were used in the release
assessments for the majority of the OESs that are covered in the risk evaluation.

5.	Draft Summary of Results for Identified Environmental Releases to Air for Dibutyl Phthalate
(DBP). This document contains identified air releases from TRI and NEI that were used in the
release assessments for the majority of the OESs that are covered in the risk evaluation.

6.	Draft Summary of Results for Identified Environmental Releases to Water for Dibutyl Phthalate
(DBP). This document contains identified water releases from TRI and DMR that were used in
the release assessments for the majority of the OESs that are covered in the risk evaluation.

7.	Draft Application ofAdhesives and Sealants OES Environmental Release Modeling Results for
Dibutyl Phthalate (DBP).

8.	Draft Application of Paints and Coatings OES Environmental Release Modeling Results for
Dibutyl Phthalate (DBP).

9.	Draft Use of Laboratory Chemicals OES Environmental Release Modeling Results for Dibutyl
Phthalate (DBP).

10.	Draft Use of Lubricants and Functional Fluids OES Environmental Release Modeling Results
for Dibutyl Phthalate (DBP).

11.	Draft Use of Penetrants OES Environmental Release Modeling Results for Dibutyl Phthalate
(DBP).

12.	Draft Use of Penetrants OES Occupational Inhalation Exposure Modeling Results for Dibutyl
Phthalate (DBP).

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