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EPA Document# EPA-740-D-24-007
May 2024
United States Office of Chemical Safety and
Environmental Protection Agency Pollution Prevention
(Representative Structure)
Draft Risk Evaluation for Diisodecyl Phthalate
(Drop)
CASRNs: 26761-40-0 and 68515-49-1
May 2024
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TABLE OF CONTENTS
ACKNOWLEDGEMENTS 8
EXECUTIVE SUMMARY 10
1 INTRODUCTION 15
1.1 Scope of the Risk Evaluation 15
1.1.1 Life Cycle and Production Volume 16
1.1.2 Conditions of Use Included in the Risk Evaluation 19
1.1.2.1 Conceptual Models 26
1.1.3 Populations and Durations of Exposure Assessed 31
1.2 Organization of the Risk Evaluation 31
2 CHEMISTRY AND FATE AND TRANSPORT OF DIDP 33
2.1 Summary of Physical and Chemical Properties 33
2.2 Summary of Environmental Fate and Transport 34
3 RELEASES AND CONCENTRATIONS OF DIDP IN THE ENVIRONMENT 36
3.1 Approach and Methodol ogy 36
3.1.1 Manufacturing, Processing, Industrial and Commercial 36
3.1.1.1 Crosswalk of Conditions of Use to Occupational Exposure Scenarios 36
3.1.1.2 Description of DIDP Use for Each OES 39
3.1.2 Estimating the Number of Release Days per Year for Facilities in Each OES 40
3.1.3 Daily Release Estimation 43
3.1.4 Consumer Down-the-Drain and Disposal 43
3.2 Summary of Environmental Releases 44
3.2.1 Manufacturing, Processing, Industrial and Commercial 44
3.2.2 Weight of Scientific Evidence Conclusions for Environmental Releases from
Manufacturing, Processing, Industrial and Commercial Sources 51
3.2.3 Strengths, Limitations, Assumptions, and Key Sources of Uncertainty for the Environmental
Release Assessment 61
3.3 Summary of Concentrations of DIDP in the Environment 61
3.3.1 Weight of Scientific Evidence Conclusion 63
3.3.1.1 Surface Water 63
3.3.1.2 Ambient Air - Air to Soil Deposition 64
4 HUMAN HEALTH RISK ASSESSMENT 65
4.1 Summary of Human Exposures 66
4.1.1 Occupational Exposures 66
4.1.1.1 Approach and Methodol ogy 66
4.1.1.2 Summary of Number of Workers and ONUs 70
4.1.1.3 Summary of Inhalation Exposure Assessment 71
4.1.1.4 Summary of Dermal Exposure Assessment 73
4.1.1.5 Weight of Scientific Evidence Conclusions for Occupational Exposure 74
4.1.1.5.1 Strengths, Limitations, Assumptions, and Key Sources of Uncertainty for the
Occupational Exposure Assessment 84
4.1.2 Consumer Exposures 85
4.1.2.1 Consumer and Indoor Dust Exposure Scenarios and Modeling Approach and
Methodology 85
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4.1.2.2 Modeling Dose Results by COU for Consumer and Indoor Dust 92
4.1.2.3 Monitoring Concentrations of DIDP in the Indoor Environment 95
4.1.2.4 Indoor Aggregate Dust Exposure Approach and Methodology 97
4.1.2.5 Weight of Scientific Evidence Conclusions for Consumer Exposure 99
4.1.2.5.1 Strength, Limitations, Assumptions, and Key Sources of Uncertainty for the
Consumer Exposure Assessment 99
4.1.3 General Population Exposures 101
4.1.3.1 General Population Screening Level Exposure Assessment Results 104
4.1.3.2 Overall Confidence in General Population Screening Level Exposure Assessment... 108
4.1.4 Human Milk Exposures 108
4.1.5 Aggregate and Sentinel Exposures 109
4.2 Summary of Human Health Hazard 109
4.3 Human Health Risk Characterization 112
4.3.1 Risk Assessment Approach 112
4.3.1.1 Estimation of Non-cancer Risks 113
4.3.1.2 Estimation of Non-cancer Aggregate Risks 113
4.3.2 Risk Estimates for Workers 114
4.3.2.1 Overall Confidence in Worker Risks 121
4.3.3 Risk Estimates for Consumers 130
4.3.3.1 Overall Confidence in Consumer Risks 132
4.3.4 Risk Estimates for General Population 141
4.3.5 Potentially Exposed or Susceptible Subpopulations and Sentinel Exposures 141
5 ENVIRONMENTAL RISK ASSESSMENT 143
5.1 Summary of Environmental Exposures 143
5.2 Summary of Environmental Hazards 145
5.3 Environmental Risk Characterization 146
5.3.1 Risk Assessment Approach 146
5.3.2 Qualitative Risk Assessment for Aquatic and Terrestrial Species 148
5.3.3 Overall Confidence and Remaining Uncertainties Confidence in Environmental Risk
Characterization 154
6 UNREASONABLE RISK DETERMINATION 157
6.1 Unreasonable Risk to Human Health 161
6.1.1 Populations and Exposures EPA Assessed to Determine Unreasonable Risk to Human
Health 161
6.1.2 Summary of Unreasonable Risks to Human Health 162
6.1.3 Basis for Unreasonable Risk to Human Health 162
6.1.4 Unreasonable Risk in Occupational Settings 163
6.1.5 Unreasonable Risk to Consumers 166
6.1.6 Unreasonable Risk to the General Population 167
6.2 Unreasonable Risk to the Environment 168
6.2.1 Populations and Exposures EPA Assessed to Determine Unreasonable Risk to the
Environment 169
6.2.2 Summary of Unreasonable Risks to the Environment 169
6.2.3 Basis for Unreasonable Risk of Injury to the Environment 170
6.3 Additional Information Regarding the Basis for the Unreasonable Risk 170
6.3.1 Additional Information about COUs Characterized Qualitatively 170
REFERENCES 180
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APPENDICES 192
Appendix A ABBREVIATIONS AND ACRONYMS 192
Appendix B REGULATORY AND ASSESSMENT HISTORY 194
B.l Federal Laws and Regulations 194
B.2 State Laws and Regulations 196
B.3 International Laws and Regulations 196
B.4 Assessment History 197
Appendix C LIST OF TECHNICAL SUPPORT DOCUMENTS 199
Appendix D UPDATES TO THE DIDP CONDITIONS OF USE TABLE 202
D. 1 Additions and Name Changes to COUs Based on Updated 2020 CDR Reported Data and
Stakeholder Engagement 202
P. 2 Consolidation and Other Changes to Conditions of Use Table 204
Appendix E CONDITIONS OF USE DESCRIPTIONS 209
E.l Manufacturing (Including Import) 209
E. 1.1 Domestic Manufacturing 209
E.l.2 Import 209
E.2 Processing - Incorporation into a Formulation, Mixture, or Reaction Product - Adhesive and
Sealants 209
E.3 Processing - Incorporation into a Formulation, Mixture, or Reaction Product - Laboratory
Chemicals 209
E.4 Processing - Incorporation into a Formulation, Mixture, or Reaction Product - Petroleum
Lubricating Oil Manufacturing; Lubricants and Lubricant Additive Manufacturing 210
E.5 Processing - Incorporation into a Formulation, Mixture, or Reaction Product - Surface
Modifier and Plasticizer in Paint and Coating Manufacturing 210
E.6 Processing - Incorporation into a Formulation, Mixture, or Reaction Product - Plastic
Material and Resin Manufacturing 210
E.7 Processing - Incorporation into a Formulation, Mixture, or Reaction Product - Plasticizers
(Paint and Coating Manufacturing; Pigments; Rubber Manufacturing) 210
E.8 Processing - Incorporation into a Formulation, Mixture, or Reaction Product - Processing
Aids, Specific to Petroleum Production (Oil and Gas Drilling, Extraction, and Support
Activities) 211
E.9 Processing - Incorporation into a Formulation, Mixture, or Reaction Product - Other (Part
of the Formulation for Manufacturing Synthetic Leather) 211
E. 10 Processing - Incorporation into Articles - Abrasives Manufacturing 211
E, 11 Processing - Incorporation into Articles - Plasticizers (Asphalt Paving, Roofing, and
Coating Materials Manufacturing; Construction; Automotive Products Manufacturing, Other
than Fluids; Electrical Equipment, Appliance, and Component Manufacturing; Fabric,
Textile, and Leather Products Manufacturing; Floor Coverings Manufacturing; Furniture
and Related Product Manufacturing; Plastics Product Manufacturing; Rubber Product
Manufacturing; Transportation Equipment Manufacturing; Ink, Toner, and Colorant
Products Manufacturing (Including Pigment); Photographic Supplies Manufacturing; Toys,
Playground, and Sporting Equipment Manufacturing) 212
E,12 Processing - Repackaging 212
E.13 Processing - Recycling 212
E. 14 Distribution in Commerce - Distribution in Commerce 213
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E, 15 Industrial Use - Abrasives - Abrasives (Surface Conditioning and Finishing Discs; Semi-
finished and Finished Goods) 213
E. 16 Industrial Use - Functional Fluids (closed systems) - Functional Fluids (Closed Systems)
(SCBA Compressor Oil) 213
E.17 Industrial Use - Adhesives and Sealants - Adhesives and Sealants 213
E. 18 Industrial Use - Lubricant and Lubricant Additives 213
E.19 Industrial Use - Solvents (for Cleaning or Degreasing) 214
E.20 Commercial Use - Automotive, Fuel, Agriculture, Outdoor Use Products - Automotive
Products, Other than Fluids 214
E.21 Commercial Use - Automotive, Fuel, Agriculture, Outdoor Use Products - Lubricants 214
E.22 Commercial Use - Construction, Paint, Electrical, and Metal Products - Adhesives and
Sealants (Including Plasticizers in Adhesives and Sealants) 214
E.23 Commercial Use - Construction, Paint, Electrical, and Metal Products -
Building/Construction Materials (Wire or Wiring Systems; Joint Treatment, Fire-Proof
Insulation) 215
E.24 Commercial Use - Construction, Paint, Electrical, and Metal Products - Electrical and
Electronic Products 215
E.25 Commercial Use - Construction, Paint, Electrical, and Metal Products - Paints and Coatings
(Including Surfactants in Paints and Coatings) 215
E.26 Commercial Use - Construction, Paint, Electrical, and Metal Products - Lacquers, Stains,
Varnishes, and Floor Finishes (as Plasticizer) 215
E.27 Commercial Use - Furnishing, Cleaning, Treatment/Care Products - Furniture and
Furnishings 215
E.28 Commercial Use - Furnishing, Cleaning, Treatment/Care Products - Construction and
Building Materials Covering Large Surface Areas Including Stone, Plaster, Cement, Glass
and Ceramic Articles; Fabrics, Textiles, and Apparel (as Plasticizer); Floor Coverings (Vinyl
Tiles, PVC-Backed Carpeting, Scraper Mats) 216
E.29 Commercial Use - Furnishing, Cleaning, Treatment/Care Products - Ink, Toner, and
Colorant Products 216
E.30 Commercial Use - Furnishing, Cleaning, Treatment/Care Products - PVC Film and Sheet ..216
E,31 Commercial Use - Furnishing, Cleaning, Treatment/Care Products - Plastic And Rubber
Products (Textiles, Apparel, and Leather; Vinyl Tape; Flexible Tubes; Profiles; Hoses) 216
E.32 Commercial Use - Other Uses - Laboratory Chemicals 216
E.33 Commercial Use - Other Uses - Inspection Fluid/Penetrant 217
E.34 Consumer Use - Automotive, Fuel, Agriculture, Outdoor Use Products - Automotive
Products, Other than Fluids 217
E.35 Consumer Use - Automotive, Fuel, Agriculture, Outdoor Use Products - Lubricants 217
E.36 Consumer Use - Construction, Paint, Electrical, and Metal Products - Adhesives and
Sealants (Including Plasticizers in Adhesives And Sealants) 217
E.37 Consumer Use - Construction, Paint, Electrical, and Metal Products - Building/Construction
Materials Covering Large Surface Areas Including Stone, Plaster, Cement, Glass and
Ceramic Articles (Wire or Wiring Systems; Joint Treatment) 218
E,38 Consumer Use - Construction, Paint, Electrical, and Metal Products - Electrical and
electronic products 218
E.39 Consumer Use - Construction, Paint, Electrical, and Metal Products - Paints and Coatings .218
E.40 Consumer Use - Furnishing, Cleaning, Treatment/Care Products - Fabrics, Textiles, and
Apparel (as Plasticizer) 218
F..41 Consumer Use - Packaging, Paper, Plastic, Hobby Products - Arts, Crafts, and Hobby
Materials (Crafting Paint Applied to Craft) 218
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F..42 Consumer Use - Packaging, Paper, Plastic, Hobby Products - Ink, Toner, and Colorant
Products 219
E.43 Consumer Use - Packaging, Paper, Plastic, Hobby Products - PVC Film and Sheet 219
E.44 Consumer Use - Packaging, Paper, Plastic, Hobby Products - Plastic and Rubber Products
(Textiles, Apparel, and Leather; Vinyl Tape; Flexible Tubes; Profiles; Hoses) 219
E.45 Consumer Use - Packaging, Paper, Plastic, Hobby Products - Toys, Playgrounds, and
Sporting Equipment 219
E.46 Consumer Use - Other - Novelty Products 220
E.47 Disposal 220
Appendix F DRAFT OCCUPATIONAL EXPOSURE VALUE DERIVATION 221
F. 1 Draft Occupational Exposure Value Calculations 221
LIST OF TABLES
Table 1-1. Categories and Subcategories of Use in the Risk Evaluation for DIDP 21
Table 2-1. Physical and Chemical Properties of DIDP 33
Table 2-2. Summary of Environmental Fate Information for DIDP 35
Table 3-1. Crosswalk of Conditions of Use to Assessed Occupational Exposure Scenarios 37
Table 3-2. Description of the Use of DIDP for Each OES 39
Table 3-3. Estimates of Number of Operating Days per Year for Each OES 40
Table 3-4. Summary of EPA's Daily Release Estimates for Each OES and EPA's Overall Confidence in
these Estimates 45
Table 3-5. Summary of Overall Confidence in Environmental Release Estimates by OES 52
Table 3-6. Summary of High-End DIDP Concentrations in Various Environmental Media from
Environmental Releases 63
Table 4-1. Summary of Exposure Monitoring and Modeling Data for Occupational Exposure Scenarios
68
Table 4-2. Summary of Total Number of Workers and ONUs Potentially Exposed to DIDP for Each
OES 70
Table 4-3. Summary of Average Adult Worker Inhalation Exposure Results for Each OES 72
Table 4-4. Summary of Average Adult Worker Dermal Exposure Results for Each OES 73
Table 4-5. Summary of Overall Confidence in Occupational Exposure Estimates by OES 75
Table 4-6. Summary of Consumer COUs, Exposure Scenarios, and Exposure Routes 87
Table 4-7. Sources of Uncertainty in DIDP Dust Monitoring Data 96
Table 4-8. Weight of Scientific Evidence Conclusions for Indoor Dust Ingestion Exposure 97
Table 4-9 Comparison Between Modeled and Monitored Daily Dust Intake Estimates for DIDP 98
Table 4-10. Exposure Scenarios Assessed in General Population Screening Level Analysis 103
Table 4-11. General Population Surface Water and Drinking Water Exposure Summary 106
Table 4-12. Fish Ingestion for Adults in Tribal Populations Summary 107
Table 4-13. General Population Ambient Air to Soil Deposition Exposure Summary 107
Table 4-14. Non-cancer HECs and HEDs Used to Estimate Risks 112
Table 4-15. Exposure Scenarios, Populations of Interest, and Hazard Values 112
Table 4-16. Occupational Risk Summary Table 122
Table 4-17. Consumer Risk Summary Table 133
Table 5-1. Relevant Exposure Pathway to Receptors and Corresponding Risk Assessment Type
(Qualitative) for the DIDP Environmental Risk Characterization 146
Table 5-2. Occupational Exposure Scenarios with Aggregate Media of Release 152
Table 5-3. DIDP Evidence Table Summarizing Overall Confidence Derived for Environmental Risk
Characterization 156
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Table 6-1. Supporting Basis for the Draft Unreasonable Risk Determination for Human Health
(Occupational Conditions of Use) 172
LIST OF FIGURES
Figure 1-1. TSCA Existing Chemical Risk Evaluation Process 15
Figure 1-2. Draft Risk Evaluation Document Summary Map 16
Figure 1-3. DIDP Life Cycle Diagram 18
Figure 1-4. Percentage of DIDP Production Volume by Use 19
Figure 1-5. DIDP Conceptual Model for Industrial and Commercial Activities and Uses: Potential
Exposure and Hazards 27
Figure 1-6. DIDP Conceptual Model for Consumer Activities and Uses: Potential Exposures and
Hazards 28
Figure 1-7. DIDP Conceptual Model for Environmental Releases and Wastes: General Population
Hazards 29
Figure 1-8. DIDP Conceptual Model for Environmental Releases and Wastes: Ecological Exposures and
Hazards 30
Figure 3-1. An Overview of How EPA Estimated Daily Releases for Each OES 43
Figure 4-1. Approaches Used for Each Component of the Occupational Assessment for Each OES 67
Figure 4-2. Acute Dose Rate for DIDP from Ingestion, Inhalation, Dermal Exposure Routes in Infant,
Children, Teenagers and Young Adults, and Adults 93
Figure 4-3. Acute Dose Rate of DIDP from Ingestion of Airborne Dust, Surface Dust, and Mouthing for
Infants, Children, Teenagers and Young Adults, and Adults 94
Figure 4-4. Potential Human Exposure Pathways to DIDP for the General Population 102
Figure 5-1. Trophic Transfer of DIDP in Aquatic and Terrestrial Ecosystems 145
LIST OF APPENDIX TABLES
Table_Apx B-l. Federal Laws and Regulations 194
Table_Apx B-2. State Laws and Regulations 196
TableApx B-3. International Laws and Regulations 196
TableApx B-4. Assessment History of DIDP 197
TableApx D-l. Additions and Name Changes to Categories and Subcategories of Conditions of Use
Based on CDR Reporting and Stakeholder Engagement 202
Table Apx D-2. Subcategory Consolidations and Editing from the Final Scope Document to the Draft
Risk Evaluation 205
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ACKNOWLEDGEMENTS
This report and associated technical support documents were developed by the United States
Environmental Protection Agency (U.S. EPA or the Agency), Office of Chemical Safety and Pollution
Prevention (OCSPP), Office of Pollution Prevention and Toxics (OPPT).
Acknowledgements
The Assessment Team gratefully acknowledges the participation, input, and review comments on the
draft risk evaluation and associated technical support documents from OPPT and OCSPP senior
managers and science advisors and assistance from EPA contractors ICF (Contract No.
68HERC19D0003 and 68HERD22A0001), ERG (Contract No. 68HERD20A0002), and SRC, Inc.
(Contract No. 68HERH19D0022). Special acknowledgement is given for the contributions of technical
experts from EPA's Office of Research and Development (ORD), including Hisham El-Masri, Rogelio
Tornero-Velez, and Elaina Kenyon, for their support in evaluation and interpretation of oral absorption
data for DIDP.
As part of an intra-agency review, the draft DIDP risk evaluation and associated technical support
documents were provided to multiple EPA Program Offices for review. Comments were submitted by
EPA's Office of Air and Radiation (OAR), Office of Children's Health Protection (OCHP), Office of
General Counsel (OGC), Office of Land and Emergency Management (OLEM), ORD, and Office of
Water (OW).
Docket
Supporting information can be found in the public docket, Docket ID (EPA-HQ-OPPT-2024-0073).
Disclaimer
Reference herein to any specific commercial products, process ,or service by trade name, trademark,
manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring
by the United States Government.
Authors:
Anthony Luz (Assessment Lead and Human Health Hazard Assessment Lead), Jennifer Brennan
(Environmental Hazard Assessment Lead), J. Aaron Murray and Yashfin Mahid (Engineering
Assessment Leads), Laura Krnavek (Consumer and Indoor Dust Exposure Assessment Lead), Maiko
Arashiro (General Population Exposure Assessment Lead), Ryan Sullivan (Physical and Chemical, and
Fate Assessment Lead), Rachel McAnallen and Brianne Raccor (Risk Determination Leads), John
Allran (Management Lead), Collin Beachum (Branch Chief), Ana Corado (Branch Chief), Todd
Coleman, Juan Bezares Cruz, Christopher Green, Emily Griffin, Bryan Groza, Christelene Horton, Kiet
Ly, Andrew Middleton, Carolyn Mottley, Mark Myer, Catherine Ngo, Andrew Sayer, and Dyllan Taylor
Contributors:
Azah Abdalla-Mohamed, Sabrina Alam, Tyler Amrine, Sarah Au, Ballav Aryal, Amy Benson, Randall
Bernot, Odani Bowen, Nicholas Castaneda, Maggie Clark, Jone Corrales, Daniel DePasquale, Janine
Fetke, Patricia Fontenot, Ross Geredien, Annie Jacob, June Kang, Grace Kaupas, Roger Kim, Yadi
Lopez, Myles Hodge, Rony Arauz Melendez, Kelsey Miller, Ashley Peppriell, Maxwell Sail, Alex
Smith, Cory Strope, Sailesh Surapureddi, Abigail Ulmer, Joseph Valdez, Leora Vegosen, and Jason
Wight
Technical Support: Mark Gibson and Hillary Hollinger
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343 This draft report and associated technical support documents were reviewed and cleared by
344 OPPT and OCSPP leadership.
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EXECUTIVE SUMMARY
Background
The U.S. Environmental Protection Agency (EPA or the Agency) has evaluated the health and
environmental risks of the chemical diisodecyl phthalate (DIDP) under the Toxic Substances Control
Act (TSCA). In its draft evaluation, EPA's protective, screening-level approaches demonstrated that
DIDP does not pose risk to the environment. Of the forty-seven conditions of use (COUs) that EPA
evaluated, only one has risk estimates that raise concerns for workers' exposure to DIDP, and none raise
such concerns for consumers or the general population. EPA preliminarily finds that DIDP presents an
unreasonable risk of injury to human health, but notes that there is some uncertainty around whether the
single COU of DIDP—the high-pressure spraying of it in the workplace—is currently conducted in
facilities that use DIDP. The Agency expects that public comments on this draft will help address this
uncertainty. Once this draft risk evaluation is informed by public comment and independent, expert peer
review advice, EPA will issue a final risk evaluation that includes its determination as to whether DIDP
presents unreasonable risk to health or the environment under the TSCA COUs.
EPA has evaluated DIDP because, as allowed under TSCA, EPA received a request from ExxonMobil
Chemical Company, through the American Chemistry Council's High Phthalates Panel, to conduct a
TSCA risk evaluation for DIDP. EPA determined that the request met the regulatory criteria and
requirements and in 2019 granted the request. DIDP production in the United States has increased
significantly over the past decade. In 2015 the production volume was between 100 and 250 million
pounds; in 2019 it had increased to between 100 million and 1 billion pounds. (EPA describes
production volumes as a range to protect confidential business information.)
DIDP is used primarily as a plasticizer to make flexible polyvinyl chloride (PVC). It is also used to
make building and construction materials; automotive care and fuel products; and other commercial and
consumer products including adhesives and sealants, paints and coatings, electrical and electronic
products, which are all considered TSCA uses. Workers may be exposed to DIDP when making these
products or otherwise using DIDP in the workplace. When it is manufactured or used to make products,
DIDP can be released into the water, where because of its properties, most of it will end up in the
sediment at the bottom of lakes and rivers. If it is released into the air, DIDP will attach to dust particles
and then be deposited onto land or into water. Indoors, DIDP has the potential over time to come out of
products and adhere to dust particles. If it does, people could inhale or ingest dust that contains DIDP.
Past assessments of DIDP from other regulatory agencies that addressed a broad range of DIDP uses
have concluded that DIDP did not pose risk to human health or the environment based on its
concentration in products and the environment. Notably, the U.S. Consumer Product Safety
Commission's (CPSC) risk assessment—which included consideration of exposure from children's
products as well as from other sources such as personal care products, diet, consumer products, and the
environment—concluded that DIDP exposure comes primarily from diet for women, infants, toddlers,
and children, which is a source of exposure that is not by law subject to TSCA.
In this draft risk evaluation, EPA only evaluated risks resulting from exposure to DIDP from facilities
that use, manufacture, or process DIDP under industrial and/or commercial COUs subject to TSCA and
the products resulting from such manufacture and processing. Human or environmental exposure to
DIDP through uses that are not subject to TSCA (e.g., food, use in food packaging materials, dental
sealants and nail polish, fragrances, medical devices, and pharmaceuticals) were not evaluated by EPA
or taken into account in reaching its preliminary determination of unreasonable risk to injury of human
health, because these uses are explicitly not subject to TSCA. Further, although the production volume
of DIDP has increased over the past decade, it is unknown how TSCA versus non-TSCA sources have
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contributed to this increase. Thus, while EPA is preliminarily concluding in this draft risk evaluation
that only one TSCA COU contributes to its draft unreasonable risk finding for DIDP, this conclusion
cannot be extrapolated to form conclusions about uses of DIDP that are not subject to TSCA and that
EPA did not evaluate.
Determining Unreasonable Risk to Human Health
EPA's TSCA existing chemical risk evaluations must determine whether a chemical substance does or
does not present unreasonable risk under its TSCA COUs. The unreasonable risk must be informed by
science, but EPA, in making the finding of presents unreasonable risk, also considers risk-related
factors as described in its risk evaluation framework rule. Risk-related factors beyond the levels of DIDP
that can cause specific health effects include the type of health effect under consideration, the
reversibility of the health effect being evaluated, exposure-related considerations (e.g., duration,
magnitude, or frequency of exposure), population exposed (including any susceptible subpopulations),
and the confidence in the information used to inform the hazard and exposure values. These
considerations must be included as part of a pragmatic and holistic evaluation of hazard and exposure to
DIDP. If an estimate of risk for a specific scenario exceeds the standard risk benchmarks, then the
formal determination of whether those risks contribute to the unreasonable risk of DIDP under TSCA
must be both case-by-case and context-driven.
Laboratory animal studies have been conducted to study DIDP for a range of cancer and non-cancer
effects on people. EPA reviewed the studies that investigated DIDP's potential to cause cancer and
determined that, following EPA's Guidelines for Carcinogen Risk Assessment, the evidence is not strong
enough to support an assessment of the risk of DIDP to cause cancer in people. The evidence also
suggests that DIDP does not cause effects on the developing male reproductive system consistent with a
disruption of androgen action—what is known as phthalate syndrome—and therefore EPA is not
including DIDP in its cumulative risk assessment for six other phthalate chemicals that do demonstrate
effects on laboratory animals consistent with phthalate syndrome. The human health hazard that EPA
identified as having the strongest evidence to support this draft risk evaluation is developmental toxicity,
which means that laboratory animals dosed with DIDP had litters where more rodent offspring died than
was the case with the litters of rodents that were not dosed with DIDP. Notably, assessments by Health
Canada, U.S. CPSC, European Chemicals Agency (ECHA), European Food Safety Authority (EFSA),
and the Australian National Industrial Chemicals Notification and Assessment Scheme have reached
similar conclusions regarding the effects of DIDP on development.
EPA evaluated the risks to people from being exposed to DIDP at work, indoors, and outdoors. In its
human health evaluation, the Agency used a combination of screening-level and more-refined
approaches to look at how people might be exposed to DIDP through breathing or ingesting dust or
other particulates, or through skin contact. In determining whether DIDP presents an unreasonable risk
of injury to human health, EPA incorporated the following potentially exposed and susceptible
subpopulations (PESS) into its assessment: women of reproductive age, pregnant women, infants,
children and adolescents, people who frequently use consumer products and/or articles containing high-
concentrations of DIDP, and people exposed to DIDP in the workplace. These subpopulations are PESS
because some have greater exposure to DIDP per body weight (e.g., infants, children, adolescents) or
due to age-specific behaviors (e.g., mouthing of toys, wires, and erasers by infants and children), while
some people may experience exposure from multiple sources or experience higher exposure than others.
EPA's robust scientific analysis preliminarily shows DIDP to not result in unreasonable risk to
consumers or the general population, including PESS, except for those exposed to DIDP at work for a
single COU.
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The single COU that EPA identified as preliminarily presenting unreasonable risk was for a scenario in
which unprotected workers were to spray adhesives and sealants that contain DIDP with high-pressure
sprayers, because doing so could create high concentrations of DIDP in mist that an unprotected worker
could inhale. Because the health effects of concern relate to the developing fetus, the population to
which this risk determination is relevant is female workers of reproductive age.
Summary, Considerations, and Next Steps
EPA evaluated a total of 47 TSCA COUs for DIDP. The Agency is preliminarily determining that only
the following COU, considered singularly or in combination with other exposures, contributes to the
unreasonable risk to unprotected female workers of reproductive age and average adult workers:
Industrial use - adhesives and sealants, due to high-pressure spray applications.
The remaining COUs, listed below, are not expected to contribute to the unreasonable risk:
• Domestic manufacturing (including import);
• Processing - repackaging;
• Processing - incorporation into a formulation, mixture, or reaction product - adhesives and
sealants manufacturing;
• Processing - incorporation into a formulation, mixture, or reaction product - laboratory
chemicals manufacturing;
• Processing - incorporation into a formulation, mixture, or reaction product - petroleum
lubricating oil manufacturing; lubricants and lubricant additives manufacturing
• Processing - incorporation into a formulation, mixture, or reaction product - surface modifier in
paint and coating manufacturing;
• Processing - incorporation into a formulation, mixture, or reaction product - plastic material and
resin manufacturing;
• Processing - incorporation into a formulation, mixture, or reaction product - plasticizers (paint
and coating manufacturing; pigments; rubber manufacturing);
• Processing - incorporation into a formulation, mixture, or reaction product - processing aids,
specific to petroleum production (oil and gas drilling, extraction, and support activities);
• Processing - incorporation into a formulation, mixture, or reaction product - other; (part of the
formulation for manufacturing synthetic leather);
• Processing - incorporation into an article - abrasives manufacturing;
• Processing - incorporation into an article - plasticizers (asphalt paving, roofing, and coating
materials manufacturing; construction; automotive products manufacturing, other than fluids;
electrical equipment, appliance, and component manufacturing; fabric, textile, and leather
products manufacturing; floor coverings manufacturing; furniture and related product
manufacturing; plastics product manufacturing; rubber product manufacturing; textiles, apparel,
and leather manufacturing; transportation equipment manufacturing; ink, toner, and colorant
(including pigment) products manufacturing; photographic supplies manufacturing; toys,
playground, and sporting equipment manufacturing);
• Processing - recycling;
• Distribution in commerce;
• Industrial use -abrasives (surface conditioning and finish discs; semi-finished and finished
goods);
• Industrial use - functional fluids (closed systems) (SBCA compressor oil);
• Industrial use - lubricant and lubricant additives;
• Industrial use - solvents (for cleaning and degreasing);
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• Commercial use - automotive, fuel, agriculture, outdoor use products - automotive products
other than fluid;
• Commercial use - automotive, fuel, agriculture, outdoor use products - automotive, fuel,
agriculture, outdoor use products - lubricants;
• Commercial use - construction, paint, electrical, and metal products - adhesives and sealants
(including plasticizers in adhesives and sealants);
• Commercial use - construction, paint, electrical, and metal products - building/construction
materials (wire or wiring systems; joint treatment, fire-proof insulation);
• Commercial use - construction, paint, electrical, and metal products - electrical and electronic
products;
• Commercial use - construction, paint, electrical, and metal products - paints and coatings
(including surfactants in paints and coatings);
• Commercial use - construction, paint, electrical, and metal products - lacquers, stains, varnishes,
and floor finishes (as plasticizer);
• Commercial use - furnishing, cleaning, treatment/care products - furniture and furnishings;
• Commercial use - furnishing, cleaning, treatment/care products - construction and building
materials covering large surface areas including stone, plaster, cement, glass and ceramic
articles; fabrics, textiles, and apparel (as plasticizer) (floor coverings (vinyl tiles, PVC-backed
carpeting, scraper mats));
• Commercial use - furnishing, cleaning, treatment/care products - ink, toner, and colorant
products;
Commercial use - furnishing, cleaning, treatment/care products - PVC film and sheet;
Commercial use - furnishing, cleaning, treatment/care products - plastic and rubber products
(textiles, apparel, and leather; vinyl tape; flexible tubes; profiles; hoses)
Commercial use - other uses - laboratory chemicals;
Commercial use - other uses - inspection fluid/penetrant;
Consumer use - automotive, fuel, agriculture, outdoor use products - automotive products other
than fluids;
Consumer use - automotive, fuel, agriculture, outdoor use products - lubricants;
Consumer use - construction, paint, electrical, and metal products - adhesives and sealants
(including plasticizers in adhesives and sealants);
Consumer use - construction, paint, electrical, and metal products - building/construction
materials covering large surface areas including stone, plaster, cement, glass and ceramic articles
(wire or wiring systems; joint treatment)
Consumer use - construction, paint, electrical, and metal products - electrical and electronic
products;
Consumer use - construction, paint, electrical, and metal products - paints and coatings;
Consumer use - Furnishing, cleaning, treatment/care products - fabrics, textiles, and apparel (as
plasticizer)
Consumer use - packaging, paper, plastic, hobby products - arts, crafts, and hobby materials
(crafting paint applied to craft);
Consumer use - packaging, paper, plastic, hobby products - ink, toner, and colorant products;
Consumer use - packaging, paper, plastic, hobby products - PVC film and sheet;
Consumer use - packaging, paper, plastic, hobby products - plastic and rubber products (textiles,
apparel, and leather; vinyl tape; flexible tubes; profiles; hoses);
• Consumer use - packaging, paper, plastic, hobby products - toys, playgrounds, and sporting
equipment;
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537 • Consumer use - other - novelty products, and
538 • Disposal.
539 This draft risk evaluation has been released for public comment and will undergo independent, expert
540 scientific peer review. EPA will issue a final DIDP risk evaluation after considering input from the
541 public and peer reviewers. If in the final risk evaluation the Agency determines that DIDP presents
542 unreasonable risk to human health or the environment, EPA will initiate regulatory action to mitigate
543 those risks.
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1 INTRODUCTION
EPA has evaluated diisodecyl phthalate (DIDP) under the Toxic Substances Control Act (TSCA) section
6(b). DIDP is a common chemical name for the category of chemical substances that includes the
following substances: 1,2-benzenedicarboxylic acid, 1,2-diisodecyl ester (CASRN 26761-40-0) and 1,2-
benzenedicarboxylic acid, di-C9-11-branched alkyl esters, ClO-rich (CASRN 68515-49-1). Both
CASRNs contain mainly C10 dialkyl phthalate esters. DIDP is primarily used as a plasticizer in
polyvinyl chloride (PVC) in consumer, commercial, and industrial applications. Section 1.1 summarizes
the scope of the draft DIDP risk evaluation and provides information on production volume, a life cycle
diagram (LCD), conditions of use (COUs), and conceptual models used for DIDP. Section 1.2 presents
the organization of this draft risk evaluation. Figure 1-1 describes the major inputs, phases, and
outputs/components of the TSCA risk evaluation process, from scoping to releasing the final risk
evaluation.
Inputs
Existing Laws, Regulations,
and Assessments
Use Document
Public Comments
Public Comments on
Draft Scope Document
Analysis Plan
Testing Results
Data Evaluation Process
• Data Integration
• Public Comments on
Draft RE
• Peer Review Comments
on Draft RE
Phase
Outputs
Figure 1-1. TSCA Existing Chemical Risk Evaluation Process
1.1 Scope of the Risk Evaluation
EPA evaluated risk to human and environmental populations for DIDP. Specifically for human
populations, the Agency evaluated risk to workers and occupational non-users (ONUs) via inhalation
routes; risk to workers via dermal routes; risk to ONUs via dermal routes for occupational exposure
scenarios (OESs) in mists and dusts; risk to consumers via inhalation, dermal, and oral routes; and risks
to bystanders via the inhalation route. As described further in Section 4.1.3, using a screening level
analysis EPA assessed risks to the general population, which considered risk from exposure to DIDP via
oral ingestion of surface water, drinking water, fish, and soil from air to soil deposition. For
environmental populations, EPA evaluated risk to aquatic species via water, sediment, and air as well as
risk to terrestrial species via air, soil, sediment, and water.
The draft DIDP risk evaluation comprises a series of technical support documents. Each technical
support document contains sub-assessments that inform adjacent, "downstream" technical support
documents. A basic diagram showing the layout and relationship of these assessments is provided below
in Figure 1-2. High-level summaries of each relevant technical support document are presented in this
risk evaluation. Detailed information for each technical support document can be found in the
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corresponding documents. Appendix C incudes a list and citations for all technical support documents
and supplemental files included in the draft risk evaluation for DIDP.
These technical support documents leveraged the data and information sources already identified in the
Final Scope of the Risk Evaluation for Di-isodecyl Phthalate (DIDP), CASRN 26761-40-0 and 68515-
49-1 (U.S. EPA. 2021b). OPPT conducted a comprehensive search for "reasonably available
information" to identify relevant DIDP data for use in the risk evaluation. The approach used to identify
specific relevant risk assessment information was discipline-specific and is detailed in Draft Risk
Evaluation for Diisodecyl Phthalate (DIDP) - Systematic Review Protocol (U.S. EPA. 2024k). or as
otherwise noted in the relevant technical support documents.
Human Health
Hazard Assessment
Includes biological PESS
Physical Chemistry
Assessment
Fate Assessment
Human Exposure Assessments
Environmental Media and
General Population
Exposure Assessment
Environmental Release
and Occupational
Exposure Assessment
Consumer and Indoor
Dust Exposure
Assessment
Include exposure PESS
Environmental
Exposure Assessment
Draft Risk Evaluation
Conditions of Use
Human Health
Risk Characterization
Includes PESS
Environmental Risk
Characterization
Unreasonable
Risk Determination
Environmental
Hazard Assessment
Chemical-specific systematic review protocol and data extraction files
Figure 1-2. Draft Risk Evaluation Document Summary Map
1.1.1 Life Cycle and Production Volume
The LCD shown in Figure 1-3 depicts the COUs that are within the scope of the risk evaluation, during
various life cycle stages, including manufacturing, processing, distribution, use (industrial, commercial,
consumer), and disposal. The LCD has been updated since its original inclusion in the final scope
document, with consolidated and/or expanded processing and use steps. The key changes are the
removal of open system functional fluids and photographic supplies as COUs and refinements of other
COUs (e.g., building and construction materials now includes a more specific collection of uses). A
complete list of updates and explanations of the updates made to COUs for DIDP from the final scope
document to this draft risk evaluation is provided in Appendix D. The information in the LCD is
grouped according to the Chemical Data Reporting (CDR) processing codes and use categories
(including functional use codes for industrial uses and product categories for industrial and commercial
uses). The CDR Rule under TSCA Section 8(a) (see 40 CFR Part 711) requires U.S. manufacturers
(including importers) to provide EPA with information on the chemicals they manufacture or import into
the United States. EPA collects CDR data approximately every 4 years with the latest collections
occurring in 2006, 2012, 2016, and 2020.
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603 Descriptions of the industrial, commercial, and consumer use categories identified from the 2019 CDR
604 are included in the LCD (Figure 1-3) ( |20b). The descriptions provide a brief overview of
605 the use category; the Draft Environmental Release and Occupational Exposure Assessment for
606 DiisodecylPhthalate (DIDP) ( 24e) contains more detailed descriptions (e.g., process
607 descriptions, worker activities, process flow diagrams, equipment illustrations) for each manufacturing,
608 processing, use, and disposal category.
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MFG/IMPORT
Manufacture
(Including Import)
PROCESSING
Incorporation into formulation, mixture, or reaction product
Adhesives and sealants manufacturing: Intermediates (e.g..
plastic material and resin manufacturing): Laboratory chemicals
manufacturing: Lubricants and lubricant additives
manufacturing: Petroleum lubricating oil manufacturing: Plastics
product manufacturing: Surface modifier in paint and coating
manufacturing: Plastic material and resin manufacturing;
Plasticizers (e.g.. construction materials other: paint and coating
manufacturing: pigments: rubber productmanufacturing; all
other chemical product and preparation manufacturing):
Processing aids, specific to petroleum production ( e.g., oil and
gas drilling, extraction, and support activities): Other (e.g„ part
of the formulation for manufacturing synthetic leather):
Incorporation into Article
Abrasives manufacturing: Plasticizers (e.g., asphalt paving,
roofing, and coating materials manufacturing: construction:
automotive care products manufacturing: electrical equipment,
appliance, and component manufacturing; fabric, textile, and
leather products manufacturing; floor coverings manufacturing;
furniture and related productmanufacturing; plastics product
manufacturing; rubber pro duct manufacturing; textiles. appareL
and leather manufacturing; transportation equipment
manufacturing; miscellaneous manufacturing; ink. toner, and
colorant products manufacturing; photographic supplies
manufacturing; plastic material and resin manufacturing
INDUSTRIAL, COMMERCIAL, CONSUMER USES
*0
RELEASES AND
WASTE DISPOSAL
Adhesive and sealants 12
Building/construction materials ^
(e.g., wire or wiring systems; joint treatment; fire-proof
insulation; materials covering large surface areas including stone,
plaster cement, glass and ceramic articles)
Paints and coatings
1,2
Electrical and electronic products
Plastic and rubber products
U
PVC film and sheet 2
Miscellaneous uses ^2
(e.g. abrasives1; functional fluids (closed system) ^lubricants
and lubricant additives1-'.; solvents (for cleaning and
degreasing)1; floor coverings1; automotive care products1-2;
Lacquers, stains, varnishes, and floor finishes Furniture and
furnishings 1; ink, toner and colorant products 1-2: inspection
fluid penetrant1; laboratory chemicals 1; toys, playgrounds, and
sporting equipment2; arts, crafts, and hobby materials 2: fabric
textiles, and apparel1*2)
Repackaging
Recycling
See Conceptual Model
for Environmental
Releases and Wastes
~
~
~
Manufacture
(including import)
Processing
Uses:
1. Industrial Commercial
2. Consumer
609
610 Figure 1-3. DIDP Life Cycle Diagram
611 See Table 1-1 for categories and subcategories of conditions of use. Activities related to distribution (e.g., loading, unloading) will be considered
612 throughout the DIDP life cycle, as well as qualitatively through a single distribution scenario.
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The production volume for CASRN 26761-40-0 in 2015 was between 1 and 20 million lbs and
decreased to less than 1 million lbs in 2019 based on the latest 2020 CDR data. The production volume
for CASRN 68515-49-1 in 2015 was between 100 and 250 million lb and increased to between 100
million and 1 billion lb in 2019 based on the latest 2020 CDR data. EPA described production volumes
as a range to protect production volume data claimed as confidential business information (CBI). For the
2016 and 2020 CDR cycle, data collected per chemical included the company name, volume of each
chemical manufactured/imported, the number of workers at each site, and information on whether the
chemical is used in the commercial, industrial, and/or consumer sector(s).
The production volumes for the most recent reporting year available in CDR (2019) are split between
two CAS Registry Numbers (CASRNs) based on the method of manufacture. Due to facility CBI claims
on manufacture and import volume, the known production volume of DIDP is presented as a range. For
CASRN 26761-40-0, the quantity of known sites with known production volume is sufficient to reduce
the uncertainty of production volume for sites reporting their production volume as CBI; there are three
sites with 63,646 lb of DIDP shared between them. For CASRN 68515-49-1, however, there is only one
site with a reported production volume and that volume accounts for only 0.045 percent to 0.00045
percent of the total estimated DIDP production volume as reported in CDR and does not provide any
clarity into the overall production volume of the remaining manufacturing and import sites. Due to
greater than 99 percent of the total manufacturing and import volume being indicated as CBI by
reporting sites, EPA did not have the ability specify the percent of production volume for each OES
based on CDR and instead relied on industry submitted data from the ACC and the EU Risk Assessment
to estimate relative percentages of use for DIDP. In Figure 1-4 the OES remaining in the "Other"
category is comprised of all smaller use case OES, including paints and coatings, adhesives and sealants,
laboratory chemicals, and other formulations, mixture, or reaction products. Due to the limitations in
reporting, these estimates may not fully reflect actual use and each OES may make up a smaller or larger
percentage of the overall production volume of DIDP.
DIDP Uses (% of Production Volume)
1.05% 3.2%
¦ Non-PVC Materials
¦ FVC Plastics
¦ Other (Adhesives and Sealants; Paints and Coatings; Laboratory Chemicals; Other Fomulations, Mixtures, and Reaction
Products)
Figure 1-4. Percentage of DIDP Production Volume by Use
1.1.2 Conditions of Use Included in the Risk Evaluation
The Final Scope of the Risk Evaluation for Di-isodecyl Phthalate (DIDP), CASRN 26761-40-0 and
68515-49-1 (U.S. EPA. 2021b) identified and described the life cycle stages, categories, and
subcategories that comprise TSCA COUs that EPA planned to consider in the risk evaluation. All COUs
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for DIDP included in this draft risk evaluation are reflected in the LCD (Figure 1-3) and conceptual
models (Section 1.1.2.1). Table 1-1 below presents all COUs for DIDP.
In this draft risk evaluation, EPA made updates to the COUs listed in the final scope document (U.S.
21b). These updates reflect EPA's improved understanding of the COUs based on further
outreach, public comments received, and updated industry code names under the CDR for 2020.
Updates included (1) additions and clarification of COUs based on new reporting in CDR for 2020 or
information received from stakeholders, (2) consolidation of redundant COUs from the processing
lifestage based on inconsistencies found in CDR reporting for DIDP processing and uses and
communications with stakeholders about the use of DIDP in industry, and (3) correcting typos or editing
for consistency. A complete list of updates and explanations of the updates made to COUs for DIDP
from the final scope document to this draft risk evaluation is provided in Appendix D. EPA may further
refine COU descriptions for DIDP included in the draft risk evaluation when the final risk evaluation for
DIDP is published based upon further outreach, peer-review, and public comment. Table 1-1 presents
the revised COUs that were included and evaluated in this Draft Risk Evaluation for DIDP.
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Life Cycle
Stage"
Category''
Subcategory'
Reference(s)
(CASRN 26761-40-0)
Reference(s)
(CASRN 68515-49-1)
Manufacturing
Domestic
manufacturing
Domestic manufacturing^
EPA-HO-OPPT-2018-0435 -
0005. ( 020a.
2019a)
EPA-HO-OPPT-2018-0435 -
0005. ( 020a.
2019a)
Importing
Importing^
EPA-HO-OPPT-2018-0435 -
0005. ( 020a.
2019a)
EPA-HO-OPPT-2018-0435 -
0005. ( 020a.
2019a)
Adhesives and sealants manufacturing
( 2019a)
(U.S. EPA. 2019a)
Laboratory chemicals manufacturing
EPA-HO-OPPT-2018-0504-
0019
Petroleum lubricating oil manufacturing;
lubricants and lubricant additives manufacturing
(\cchpp. 202 * n \
2019a)
( 2 HPP. 2023; U.S.
* r \ ^>20a. 2019a)
Incorporation into
formulation,
mixture, or reaction
product
Surface modifier and plasticizer in paint and
coating manufacturing
(U.S. EPA. 2020a)
Plastic material and resin manufacturing
( 2019a)
Processing
Plasticizers (paint and coating manufacturing;
pigments; rubber manufacturing)
(\cchpp. 202 * n \
2020a. 2019a)
( 2 HPP. 2023; U.S.
* r \ ^>20a. 2019a)
Processing aids, specific to petroleum production
(oil and gas drilling, extraction, and support
activities)6
EPA-HO-OPPT-2018-0435 -
0005
EPA-HO-OPPT-2018-0435 -
0005. ( a)
Other (part of the formulation for manufacturing
synthetic leather)
( 2020a)
Abrasives manufacturing
( 2019a)
Incorporation into
articles
Plasticizers (asphalt paving, roofing, and coating
materials manufacturing; construction;
automotive products manufacturing, other than
fluids; electrical equipment, appliance, and
EPA-HO-OPPT-2018-0435 -
0012; CA.CC HPP. 2 :
EPA. 2020a. 2019a)
( 3 HPP. 2023; U.S.
* r \ „^20a. 2019a)
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Life Cycle
Stage"
Category''
Subcategory'
Reference(s)
(CASRN 26761-40-0)
Reference(s)
(CASRN 68515-49-1)
component manufacturing; fabric, textile, and
leather products manufacturing; floor coverings
manufacturing; furniture and related product
manufacturing; plastics product manufacturing;
rubber product manufacturing; transportation
equipment manufacturing; ink, toner, and
colorant products manufacturing (including
pigment); photographic supplies manufacturing;
toys, playground, and sporting equipment
manufacturing)
Repackaging
Repackaging
( 2019a)
(U.S. EPA. 2019a)
Recycling
Recycling
Distribution in
Commerce
Distribution in
commerce
Distribution in commerce
Industrial Uses
Abrasives
Abrasives (surface conditioning and finishing
discs; semi-finished and finished goods)
EPA-HO-OPPT-2018-0435 -
0012
Adhesive and
sealants
Adhesives and sealants^
EPA-HO-OPPT-2018-0435 -
0005. ( a)
EPA-HO-OPPT-2018-0435 -
( a)
Functional fluids
(closed systems)
Functional fluids (closed systems) (SCBA
compressor oil)
EPA-HO-OPPT-2018-0435 -
0012
Lubricant and
lubricant additives
Lubricants and lubricant additives^
EPA-HO-OPPT-2018-0435 -
0005. ( a)
EPA-HO-OPPT-2018-0435 -
0005. ( a)
Solvents (for
cleaning or
degreasing)
Solvents (for cleaning or degreasing)
(Duratherm. 2018; Ouincv
Compressor. 2012)
Commercial
Uses
Automotive, fuel,
agriculture, outdoor
use products
Automotive products, other than fluids^
EPA-HO-OPPT-2018-0435 -
0005
EPA-HO-OPPT-2018-0435 -
.( a)
Lubricants
( \CCHPP. 202 .1 * n \
2019a)
( 2 HPP. 2023; U.S.
* r \ ^«20a. 2019a)
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Life Cycle
Stage"
Category''
Subcategory'
Reference(s)
(CASRN 26761-40-0)
Reference(s)
(CASRN 68515-49-1)
Commercial
Uses
Construction, paint,
electrical, and metal
products
Adhesives and sealants (including plasticizers in
adhesives and sealants)''
EPA-HO-OPPT-2018-0435 -
0005. ( 020a.
2019a)
EPA-HO-OPPT-2018-0435 -
0005. ( 020a.
2019a)
Building/construction materials (wire or wiring
systems; joint treatment, fire-proof insulation)d
EPA-HO-OPPT-2018-0435 -
0005
EPA-HO-OPPT-2018-0435 -
0005
Electrical and electronic products'"
EPA-HO-OPPT-2018-0435 -
0005
EPA-HO-OPPT-2018-0435 -
0005. ( a)
Paints and coatings (including surfactants in
paints and coatings)''
EPA-HO-OPPT-2018-0435 -
0005. ( a)
EPA-HO-OPPT-2018-0435 -
0005. ( 020a.
2019a)
Lacquers, stains, varnishes, and floor finishes (as
plasticizer)
(U.S. EPA. 2020a)
Furnishing, cleaning,
treatment/care
products
Furniture and furnishings
EPA-HO-OPPT-2018-0435 -
0005
EPA-HO-OPPT-2018-0435 -
( a)
Construction and building materials covering
large surface areas including stone, plaster,
cement, glass and ceramic articles; fabrics,
textiles, and apparel (as plasticizer) (Floor
coverings (vinyl tiles, PVC-backed carpeting,
scraper mats))d
( 3 HPP. 2023); EPA-HO-
OPPT-2018-0435-0005
( 2 HPP. 2023; U.S.
„^20a); EPA-HO-
OPPT-2018-0435-0005
Packaging, paper,
plastic, hobby
products
Ink, toner, and colorant products^
EPA-HO-OPPT-2018-0435 -
0005; EPA-HO-OPPT-2018-
0435-0012
EPA-HO-OPPT-2018-0435 -
0005; EPA-HO-OPPT-2018-
0435-0012
PVC film and sheet
EPA-HO-OPPT-2018-0435 -
0012
EPA-HO-OPPT-2018-0435 -
0012
Plastic and rubber products (textiles, apparel, and
leather; vinyl tape; flexible tubes; profiles;
hoses)d
EPA-HO-OPPT-2018-0435 -
0005
EPA-HO-OPPT-2018-0435 -
0012; CA.CC HPP. 2023)
EPA-HO-OPPT-2018-0435 -
0005; CA.CC HPP. 2023;
)
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Life Cycle
Stage"
Category''
Subcategory'
Reference(s)
(CASRN 26761-40-0)
Reference(s)
(CASRN 68515-49-1)
Other uses
Laboratory chemicals
EPA-HO-OPPT-2018-0435 -
0012
EPA-HO-OPPT-2018-0435 -
0012
Inspection fluid/penetrant
EPA-HO-OPPT-2018-0435 -
0023
EPA-HO-OPPT-2018-0435 -
0023
Consumer Uses
Automotive, fuel,
agriculture, outdoor
use products
Automotive products, other than fluids^
EPA-HO-OPPT-2018-0435 -
0005; EPA-HO-OPPT-2018-
0435-0022
EPA-HO-OPPT-2018-0435 -
0005; EPA-HO-OPPT-2018-
0435-0022
Lubricants^
EPA-HO-OPPT-2018-0435 -
0005; CA.CC HPP. 2 :
EPA. 2019a)
EPA-HO-OPPT-2018-0435 -
0005; (ACC HPP. 2023;
)
Construction, paint,
electrical, and metal
products
Adhesives and sealants (including plasticizers in
adhesives and sealants)''
EPA-HO-OPPT-2018-0435 -
0005. ( a)
EPA-HO-OPPT-2018-0435 -
0005. ( 020a.
2019a)
Building/construction materials covering large
surface areas including stone, plaster, cement,
glass, and ceramic articles (wire or wiring
systems; joint treatment)''
EPA-HO-OPPT-2018-0435 -
0005
EPA-HO-OPPT-2018-0435 -
0005
Electrical and electronic products'"
EPA-HO-OPPT-2018-0435 -
0005
EPA-HO-OPPT-2018-0435 -
0005. ( a)
Paints and coatings^
( 2019a)
(U.S. EPA. 2019a)
Furnishing, cleaning,
treatment/care
products
Fabrics, textiles, and apparel (as plasticizer)
( 3 HPP. 2023)
( 3 HPP. 2023; U.S.
* r \ „ < <20a)
Packaging, paper,
plastic, hobby
products
Arts, crafts, and hobby materials (crafting paint
applied to craft)
( 2020a. 2019a)
Ink, toner, and colorant products^
EPA-HO-OPPT-2018-0435 -
EPA-HO-OPPT-2018-0435 -
0005; EPA-HO-OPPT-2018-
0005; EPA-HO-OPPT-2018-
0435-0022; (ACC HPP.
2023)
0435-002 (
2023)
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Life Cycle
Stage"
Category''
Subcategory'
Reference(s)
(CASRN 26761-40-0)
Reference(s)
(CASRN 68515-49-1)
PVC film and sheet
EPA-HO-OPPI-2018-0435 -
0022
EPA-HO-OPPT-2018-0435 -
0022
Plastic and rubber products (textiles, apparel, and
leather; vinyl tape; flexible tubes; profiles;
hoses)d
EPA-HO-OPPT-2018-0435 -
0005; EPA-HO-OPPT-2018-
0435-0022:CACC HPP. 2023)
EPA-HO-OPPT-2018-0435 -
0005; (ACC HPP. 2023;
)
Consumer Uses
Toys, playgrounds, and sporting equipment^
EPA-HO-OPPT-2018-0435 -
0005: (ACC HPP. 2023)
EPA-HO-OPPT-2018-0435 -
0005; (ACC HPP. 2023;
1 ! V \ 2020a. 2019a)
Other
Novelty Products
(Sidc et al. 2023; Stabile.
)
(Sioe et al.. 2023; Stabile.
)
Disposal
Disposal
Disposal®
a Life Cycle Stage Use Definitions (40 CFR 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 conditions of use appear in the Life Cycle Diagram, reflect CDR codes, and broadly represent conditions of use of DIDP in industrial
and/or commercial settings.
c These subcategories reflect more specific conditions of use of DIDP.
d Circumstances on which ACC HPP is requesting that EPA conduct a risk evaluation. DIDP was limited in toys to less than 0.1% until 2018 by the CPSC. EPA
will evaluate risk both from toys that are manufactured with less than .1% of DIDP as well as toys that remain in commerce that were manufactured prior to the
CPSC ban and have DIDP in greater amounts than 0.1%. In addition, DIDP processing into sporting equipment is ongoing and evaluated in this draft risk
evaluation.
'' Identified in EPA's Hydraulic Fracturing for Oil and Gas: Impacts from the Hydraulic Fracturing Water Cycle on Drinking Water Resources in the United
States (EPA-600-R-16-236Fb), December 2016 document to be a chemical reported to be detected in produced water.
' New CDR reporting codes of machinery, mechanical appliances, electrical/electronic articles and other machinery, mechanical appliances, electronic/electronic
articles are represented under the electrical and electronic articles reporting code, so for commercial and consumer uses these conditions of use are combined.
661
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1.1.2.1 Conceptual Models
The conceptual model in Figure 1-5 presents the exposure pathways, exposure routes, and hazards to
human populations from industrial and commercial activities and uses of DIDP. There is potential for
exposures to workers and/or ONUs via inhalation and dermal routes. The conceptual model also
includes potential ONU dermal exposure to DIDP in mists and dusts deposited on surfaces. EPA
evaluated activities resulting in exposures associated with distribution in commerce (e.g., loading,
unloading) throughout the various life cycle stages and COUs (e.g., manufacturing, processing,
industrial use, commercial use, and disposal), as well as qualitatively through a single distribution
scenario.
Figure 1-6 presents the conceptual model for consumer activities and uses, Figure 1-7 presents general
population exposure pathways and hazards for environmental releases and wastes, and Figure 1-8
presents the conceptual model for ecological exposures and hazards from environmental releases and
wastes.
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Industrial and Commercial ° Exposure Pathway Exposure Route Populations Hazards
Activities / Uses
677 Figure 1-5. DIDP Conceptual Model for Industrial and Commercial Activities and Uses: Potential Exposure and Hazards
678 11 Some products are used in both commercial and consumer applications. See Table 1-1 for categories and subcategories of COUs.
679 h Fugitive air emissions are those that are not stack emissions and include fugitive equipment leaks from valves, pump seals, flanges, compressors,
680 sampling connections and open-ended lines; evaporative losses from surface impoundment and spills; and releases from building ventilation systems.
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f ONSl'Mfr.R AC 1 IN I I IKS.
I SI'S
rxvosi RE
PVIIIM -\AS
IXPOSl RK
KOI I I S
POPULATIONS
EXPOSED
HAZARDS
681
682
683
Automotive, fuel, agriculture, outdoor
use products
Construction, paint, electrical, and
metal product,s
Furnishing, cleaning, treatment/care
products
Packaging, paper, plastic, hobby
products
Other; novelty products
f Ha/turds potentially ^
associated with acute.
Intermediate, and
v duurtk exposures j
Kt->
Dash Arrow Pathways and routes that were assessed liquid product and articles
Solid Arrow Pathways and routes ihat were assessed all products and articles
ConMtmcr Handling uf Disposal and
*V aate
Wastewater, Liquid Wastes and Solid
-#• Wastes fSee Environmental Releases
Conceptual Models)
Figure 1-6. DIDP Conceptual Model for Consumer Activities and Uses: Potential Exposures and Hazards
The conceptual model presents the exposure pathways, exposure routes, and hazards to human populations from consumer activities and uses of DIDP.
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RELEASES AND WASTES FROM INDUSTRIAL
COMMERCIAL CONSUMER USES
EXPOSURE PATHWAYS
EXPOSURE ROUTES
POPtXATIONS
HAZARDS
684
685
686
687
Figure 1-7. DIDP Conceptual Model for Environmental Releases and Wastes: General Population Hazards
The conceptual model presents the exposure pathways, exposure routes, and hazards to human populations from releases and wastes from industrial,
commercial, and/or consumer uses of DIDP.
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RELEASES AND WASTES FROM INDUSTRIAL / EXPOSURE PATHWAYS POPULATIONS HAZARDS
C OMMERCIALCONSUMER USES EXPOSED
689 Figure 1-8. DIDP Conceptual Model for Environmental Releases and Wastes: Ecological Exposures and Hazards
690 The conceptual model presents the exposure pathways, exposure routes, and hazards to human populations from releases and wastes from industrial,
691 commercial, and/or consumer uses of DIDP.
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1,1,3 Populations and Durations of Exposure Assessed
Based on the conceptual models presented in Section 1.1.2.1, EPA evaluated risk to environmental and
human populations. Environmental risks were evaluated for acute and chronic exposure scenarios for
aquatic and terrestrial species, as appropriate. Human health risks were evaluated for acute,
intermediate, and chronic exposure scenarios, as applicable based on reasonably available exposure and
hazard data as well as the relevant populations for each. Human populations assessed include:
• Workers, including average adults and women of reproductive age;
• ONUs, including average adults;
• Consumers, including infants (less than 1 year), toddlers (1 to 2 years), children (3 to 5 years and
6 to 10 years), young teens (11 to 15 years), teenagers (16 to 20 years) and adults (21 years and
above);
• Bystanders, including infants (less than 1 year), toddlers (1 to 2 years), and children (3 to 5 years
and 6 to 10 years); and
• General population, including infants, children, youth, and adults.
TSCA Section 6(b)(4)(A) requires that risk evaluations "determine whether a chemical substance
presents an unreasonable risk of injury to health or the environment, without consideration of costs or
other non-risk 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 3(12) states that "the term 'potentially exposed or susceptible subpopulation'
[PESS] means a group of individuals within the general population identified by the Administrator who,
due to either greater susceptibility or greater exposure, may be at greater risk than the general population
of adverse health effects from exposure to a chemical substance or mixture, such as infants, children,
pregnant women, workers, or the elderly."
This risk evaluation considers PESS throughout the human health risk assessment (Section 4), including
throughout the exposure assessment, hazard identification, and dose-response analysis supporting this
assessment. EPA incorporated the following potentially exposed and susceptible populations (PESS)
into its assessment—women of reproductive age, pregnant women, infants, children and adolescents,
people who frequently use consumer products and/or articles containing high-concentrations of DIDP,
people exposed to DIDP in the workplace, and tribes whose diets include large amounts of fish. These
subpopulations are PESS because some have greater exposure to DIDP per body weight (e.g., infants,
children, adolescents) or due to age-specific behaviors (e.g., mouthing of toys, wires, and erasers by
infants and children, assessed in the consumer exposure scenarios), while some experience aggregate or
sentinel exposures.
Section 4.3.5 summarizes how PESS were incorporated into the risk evaluation through consideration of
potentially increased exposures and/or potentially increased biological susceptibility, and summarizes
additional sources of uncertainty related to consideration of PESS.
1.2 Organization of the Risk Evaluation
This draft risk evaluation for DIDP includes five additional major sections, and several appendices,
including:
• Section 2 summarizes basic physical-chemical characteristics as well as the fate and transport of
DIDP.
• Section 3 includes an overview of releases and concentrations of DIDP in the environment.
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• Section 4 presents the human health risk assessment, including the exposure, hazard, and risk
characterization based on the COUs. Section 4 also includes a discussion of PESS based on both
greater exposure and/or susceptibility, as well as a description of aggregate and sentinel
exposures. Section 4 also discusses assumptions and uncertainties and how they potentially
impact the strength of the evidence of draft risk evaluation.
• Section 5 provides a discussion and analysis of the environmental risk assessment, including the
environmental exposure, hazard, and risk characterization based on the COUs for DIDP.
Sections 5 also discusses assumptions and uncertainties and how they potentially impact the
strength of the evidence of draft risk evaluation.
• Section 6 presents EPA's proposed determination of whether the chemical presents an
unreasonable risk to human health or the environment as a whole chemical approach and under
the assessed COUs.
• Appendix A provides a list of abbreviations and acronyms used throughout this draft risk
evaluation.
• Appendix B provides a brief summary of the federal, state, and international regulatory history of
DIDP.
• Appendix C incudes a list and citations for all technical support documents and supplemental
files included in the draft risk evaluation for DIDP.
• Appendix D provides a summary of updates made to COUs for DIDP from the final scope
document to this draft risk evaluation.
• Appendix E provides descriptions of the DIDP COUs evaluated by EPA.
• Appendix F provides the draft occupational exposure value for DIDP that was derived by EPA.
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2 CHEMISTRY AND FATE AND TRANSPORT OF DIDP
Physical and chemical properties determine the behavior and characteristics of a chemical that inform its
condition of use, environmental fate and transport, potential toxicity, exposure pathways, routes, and
hazards. Environmental fate and transport includes environmental partitioning, accumulation,
degradation, and transformation processes. Environmental transport is the movement of the chemical
within and between environmental media, such as air, water, soil, and sediment. Thus, understanding the
environmental fate of DIDP informs the specific exposure pathways, and potential human and
environmental exposed populations that EPA considered in this draft risk evaluation.
Sections 2.1 and 2.2 summarize the physical and chemical properties, and environmental fate and
transport of DIDP, respectively. EPA's Draft I'hysical Chemistry Assessmentfor Diisodecyl Phthalate
( E0241) and Draft Fate Assessment for Diisodecyl Phthalate (U.S. EPA. 2024f) provide
further details.
2.1 Summary of Physical and Chemical Properties
EPA gathered and evaluated physical and chemical property data and information according to process
described in the Draft Risk Evaluation for Diisodecyl Phthalate (DIDP) - Systematic Review Protocol
( |k). During the evaluation of DIDP, EPA considered both measured and estimated
physical and chemical property data/information summarized in Table 2-1, as applicable. Information on
the full, extracted dataset is available in the Draft Risk Evaluation for Diisodecyl Phthalate (DIDP) -
Systematic Review Supplemental File: Data Quality Evaluation and Data Extraction Information for
Physical and Chemical Properties (I v «« \ _ 024q).
Table 2-1. Physical and Chemical Properties of DIDP
Property
Selected Value(s)
Reference(s)
Data Quality
Rating
Molecular formula
C28H46O4
Molecular weight
446.7 g/mol
Physical form
Clear Liquid
(Havnes, 2014)
High
Melting point
-50 °C
(Havnes. 2014)
High
Boiling point
>400 °C
(Havnes. 2014)
High
Density
0.967 g/cm3 at 25 °C
(Cadosan and Howick,
2000)
High
Vapor pressure
5.28E-07 mmHg at 25 °C
CNLM. 2020)
High
Vapor density
15.4 (air = 1)
CNLM. 2020)
High
Water solubility
0.00017 mg/L at 20 °C
(Letinski et aL 2002)
High
Octanol: water partition
coefficient (log Kow)
10.21 (EPI Suite™)
( )
High
Octanol:air partition
coefficient (log Koa)
13.0 (EPI Suite™)
(U.S. EPA. 2017)
High
Henry's Law constant
2.132E-04 atm m3/mol at 25 °C
( sins and Mackav, 2000)
High
Flash point
>200 °C
(ECJRC. 2003a)
High
Autoflammability
402 °C
CNLM. 2020)
Medium
Viscosity
87.797 cP at 20 °C
(Caetano et aL 2005)
High
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2.2 Summary of Environmental Fate and Transport
Reasonably available environmental fate data—including biotic and abiotic biodegradation rates,
removal during wastewater treatment, volatilization from water sources, and organic carbon:water
partition coefficient (log Koc)—are parameters used in the current draft risk evaluation. In assessing the
environmental fate and transport of DIDP, EPA considered the full range of results from the available
highest quality data sources obtained during systematic review. Information on the full extracted dataset
is available in the Draft Risk Evaluation for Diisodecyl Phthalate (DIDP) - Systematic Review
Supplemental File: Data Quality Evaluation and Data Extraction Information for Environmental Fate
and Transport (U.S. EPA. 2024o). Other fate estimates were based on modeling results from EPI
Suite™ (U .S. EPA. ), a predictive tool for physical and chemical properties and environmental fate
estimation. Information regarding the model inputs is available in the Draft Fate Assessment for
Diisodecyl Phthalate (DIDP) (U.S. EPA. 2024f).
EPA evaluated the reasonably available information to characterize the environmental fate and transport
of DIDP, the key points of the Draft Fate Assessment for DIDP ( 024f) are summarized
below and listed in Table 2-2.
Given the consistent results from numerous high-quality studies, there is robust evidence that DIDP
• Is expected to undergo significant direct photolysis and will rapidly degrade in the atmosphere
(ti/2 = 0.32 days).
• Is expected to degrade rapidly via direct and indirect photolysis.
• Is not expected to appreciably hydrolyze under environmental conditions.
• Is expected to have environmental biodegradation half-life in aerobic environments on the order
of days to weeks.
• Is not expected to be subject to long range transport.
• Is expected to transform in the environment and via biotic and abiotic processes to form
monoisodecyl phthalate, isodecanol, and phthalic acid.
• Is expected to show strong affinity and sorption potential for organic carbon in soil and sediment.
• Will be removed at rates greater than 93 percent in conventional wastewater treatment systems.
• When released to air, will not likely exist in gaseous phase, but will show strong affinity for
adsorption to particulate matter.
• Is likely to accumulate and be found in indoor dust.
As a result of limited studies identified, there is moderate confidence that DIDP
• Is not expected to biodegrade under anoxic conditions and may be persistent in anaerobic soils
and sediments.
• Is not bioaccumulative in fish in the water column.
• Is expected to be partially removed in conventional drinking water treatment systems both in the
treatment process, and via reduction by chlorination and chlorination byproducts in post
treatment storage and drinking water conveyance.
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822 Table 2-2. Summary of Environmental Fate Information for DIDP
Parameter
Value
Source(s)
Octanol: water (Log Kow)
10.21
(U.S. EPA. 2017)
Organic carbon:water (Log Koc)
5.04-5.78
(Analytical Bio-Chemistrv
Labs, 1991)
Adsorption coefficient (Log Kd)
2.22-3.60
(Mackav et al„ 2006b; Williams
etaL 1995)
Octanol:air (Log Koa)
13.034 (estimated)
(U.S. EPA. 2017)
Air: water (Log Kaw)
-2.824 (estimated)
( A. 2017)
Aerobic primary biodegradation in water
39% at 9 days,
53% at 21 days
>99% at 28 days
(ECJRC. 2003a)
Aerobic ready biodegradation in water
88% to >99% at 28 days
(ECJRC. 2003a; SRC. 1983)
Aerobic ultimate biodegradation in water
56.2% at 28 days
(SRC. 1983)
Anaerobic biodegradation in sediment
0% after 100 days by CFL
(Eilertsson et aL. 1996)
Hydrolysis
125 days at pH 8 and 25 °C, and
3.4 years at pH 7 and 25 °C
( )
Photolysis
ti/2 (air) = 4.7 to 7.68 hours
(U.S. EPA. 2017)
Environmental degradation half-lives
7.68 hours (air)
( A. 2017)
(selected values for modeling)
10 days (water)
20 days (soil)
90 days (sediment)
Wastewater treatment plant (WWTP)
removal
>94%
(U.S. EPA. 2017)
Aquatic bioconcentration factor (BCF)
<14.4 L/kg wet weight
(Experimental; fish, Cyprinus
carpio)
1.3 L/kg wet weight (upper trophic
Arnot-Gobas estimation)
(U.S. EPA. 2 . :jrc.
2003b)
Aquatic bioaccumulation factor (BAF)
9.9 L/kg wet weight (upper trophic
Arnot-Gobas estimation)
(U.S. EPA. 2017)
Aquatic food web magnification factor
(FWMF)
0.44
(Experimental; 18 marine species)
(Mackintosh et aL, 2004)
Terrestrial bioconcentration factor (BCF)
0.01-0.02
Experimental; earthworms
(Eisenia fetida)
(ECJRC. 2003 b)
823
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3 RELEASES AND CONCENTRATIONS OF DIDP IN THE
ENVIRONMENT
EPA estimated environmental releases and concentrations of DIDP. Section 3.1 describes the approach
and methodology for estimating releases. Estimates of environmental releases are presented in Sections
3.2 and 3.3 present the approach, methodology, and summary of concentrations of DIDP in the
environment.
3.1 Approach and Methodology
This section provides an overview of the approach and methodology for assessing releases to the
environment from industrial, commercial, and consumer uses. Specifically, Section 3.1.1 through
Section 3.1.3 describe the approach and methodology for estimating releases to the environment from
industrial and commercial uses, and Section 3.1.4 describes the approach and methodology for assessing
down-the-drain releases from consumer uses.
3.1.1 Manufacturing, Processing, Industrial and Commercial
This subsection describes the grouping of manufacturing, processing, industrial and commercial COUs
into OESs as well as the use of DIDP within each OES. Specifically, Section 3.1.1.1 provides a
crosswalk of COUs to OESs, and Section 3.1.1.2 provides descriptions for the use of DIDP within each
OES.
3.1.1.1 Crosswalk of Conditions of Use to Occupational Exposure Scenarios
EPA categorized the COUs listed in Table 1-1 into OESs. Table 3-1 provides a crosswalk between
COUs and OESs. 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
in the United States. In some cases, EPA defined only a single OES for multiple COUs, while in other
cases the Agency developed multiple OESs for a single COU. EPA made this determination by
considering variability in release and use conditions and whether the variability required discrete
scenarios or could be captured as a distribution of exposures. The Draft Environmental Release and
Occupational Exposure Assessment for Diisodecyl Phthalate (DIDP) ( Me) provides
further information on each specific OES.
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853 Table 3-1. Crosswalk of Conditions of Use to Assessed Occupational Exposure Scenarios
Life Cycle
Stage
Category
Subcategory
OES
Manufacturing
Domestic
manufacturing
Domestic manufacturing
Manufacturing
Importing
Importing
Import and repackaging
Repackaging
Repackaging
Import and repackaging
Adhesives and sealants manufacturing
Incorporation into adhesives and
sealants
Laboratory chemicals manufacturing
Incorporation into other
formulations, mixtures, or
reaction products
Incorporation
into
formulation,
Petroleum lubricating oil manufacturing;
Lubricants and lubricant additives
manufacturing
Incorporation into other
formulations, mixtures, or
reaction products
Surface modifier in paint and coating
manufacturing
Incorporation into paints and
coatings
mixture, or
reaction
product
Plastic material and resin manufacturing
PVC plastics compounding;
non-PVC material compounding
Plasticizers (paint and coating manufacturing;
colorants (including pigments); rubber
manufacturing)
Incorporation into paints and
coatings;
non-PVC material compounding
Processing
Processing aids, specific to petroleum
production (oil and gas drilling, extraction,
and support activities)
Incorporation into other
formulations, mixtures, or
reaction products
Other (part of the formulation for
manufacturing synthetic leather)
PVC plastics compounding;
non-PVC material compounding
Abrasives manufacturing
Application of adhesives and
sealants
Processing
Incorporation
into articles
Plasticizers (asphalt paving, roofing, and
coating materials manufacturing; construction;
automotive products manufacturing, other
than fluids; electrical equipment, appliance,
and component manufacturing; fabric, textile,
and leather products manufacturing; floor
coverings manufacturing; furniture and related
product manufacturing; plastics product
manufacturing; rubber product manufacturing;
textiles, apparel, and leather manufacturing;
transportation equipment manufacturing; ink,
toner, and colorant (including pigment)
products manufacturing; photographic
supplies manufacturing; toys, playground, and
sporting equipment manufacturing)
PVC plastics converting
non-PVC material converting
Recycling
Recycling
Recycling
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Life Cycle
Stage
Category
Subcategory
OES
Disposal
Disposal
Disposal
Disposal
Distribution in
commerce
Distribution in
commerce
Distribution in commerce
Distribution in commerce
Abrasives
Abrasives (surface conditioning and finishing
discs; semi-finished and finished goods)
Fabrication or use of final
products or articles
Adhesive and
sealants
Adhesives and sealants
Application of adhesives and
sealants
Industrial uses
Functional
fluids (closed
systems)
Functional fluids (closed systems) (SCBA
compressor oil)
Use of lubricants and functional
fluids
Lubricant and
lubricant
additives
Lubricants and lubricant additives
Use of lubricants and functional
fluids
Solvents (for
cleaning or
degreasing)
Solvents (for cleaning or degreasing)
Use of lubricants and functional
fluids
Automotive,
fuel,
Automotive products, other than fluids
Fabrication or use of final
products or articles
agriculture,
outdoor use
products
Lubricants
Use of lubricants and functional
fluids
Adhesives and sealants (including plasticizers
in adhesives and sealants)
Application of adhesives and
sealants
Construction,
paint,
electrical, and
metal products
Building/construction materials (wire or
wiring systems; joint treatment, fire-proof
insulation)
Fabrication or use of final
products or articles
Electrical and electronic products
Fabrication or use of final
products or articles
Commercial
uses
Paints and coatings (including surfactants in
paints and coatings)
Application of paints and coatings
Lacquers, stains, varnishes, and floor finishes
(as plasticizer)
Application of paints and
coatings;
application of adhesives and
sealants
Furniture and furnishings
Fabrication or use of final
products or articles
Furnishing,
cleaning,
treatment/care
products
Construction and building materials covering
large surface areas including stone, plaster,
cement, glass and ceramic articles; fabrics,
textiles, and apparel (as plasticizer) (floor
coverings [vinyl tiles, PVC-backed carpeting,
scraper mats])
Fabrication or use of final
products or articles
Ink, toner, and colorant products
Application of paints and coatings
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Life Cycle
Stage
Category
Subcategory
OES
PVC film and sheet
Fabrication or use of final
products or articles
Commercial
uses
Plastic and rubber products (textiles, apparel,
and leather; vinyl tape; flexible tubes;
profiles; hoses)
Fabrication or use of final
products or articles
Laboratory chemicals
Use of laboratory chemicals
Other uses
Inspection fluid/penetrant
Use of inspection fluid and
penetrant
854 3.1.1.2 Description of DIDP Use for Each OES
855 After EPA characterized the OESs for the occupational exposure assessment of DIDP, the occupational
856 uses of DIDP for all OESs were summarized. Brief summaries of the uses of DIDP for all OESs are
857 presented in Table 3-2.
858
859 Table 3-2. Description of the Use of DIDP for Each OES
OES
Use of DIDP
Manufacturing
DIDP may be produced through the reaction of phthalic anhydride and
isodecyl alcohol using an acid catalyst. The alkyl esters of DIDP are a
mixture of branched hydrocarbon isomers in the C9 through CI 1 ranges,
comprised primarily of CIO isomers of decyl esters.
Import and repackaging
DIDP is imported domestically for use and/or may be repackaged before
shipment to formulation sites.
PVC plastics compounding
DIDP is used as a plasticizer in PVC and plastic resins manufacturing.
PVC plastics converting
DIDP is used as a plasticizer in PVC and plastic resins product
manufacturing.
Incorporation into adhesives and
sealants
DIDP is a plasticizer in adhesives and sealants for industrial and
commercial use.
Incorporation into paints and coatings
DIDP is a plasticizer in paint, coating, ink, and colorant products for
industrial and commercial use.
Incorporation into other formulations,
mixtures, or reaction products, not
covered elsewhere
DIDP is incorporated into products for asphalt applications, functional
fluids, and other product uses.
Non-PVC material compounding
DIDP is used in non-PVC polymers, such as rubber, vinyl resins,
cellulose ester plastics, and flexible fibers.
Non-PVC material converting
DIDP is used in non-PVC polymers, such as rubber, vinyl resins,
cellulose ester plastics, and flexible fibers.
Application of adhesives and sealants
Industrial and commercial sites use DIDP-containing adhesives and
sealants that are roll or bead applied. Products may also be applied using a
syringe, caulk gun, or spray gun.
Application of paints and coatings
Industrial and commercial sites use DIDP-containing paints and coatings
that are roll, brush, trowel, and spray applied.
Use of laboratory chemicals
DIDP is used for laboratory analyses in both solid and liquid forms.
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OES
Use of DIDP
Use of lubricants and functional fluids
DIDP is incorporated into lubricants and functional fluids for air
compressors and found in functional fluids for heat exchanger processes
in both commercial and industrial processes.
Use of penetrants and inspection
fluids
DIDP is found in inspection fluids or penetrants that are used to reveal
surface defects on metal parts, including cracks, folds, or pitting.
Fabrication and final use of products
or articles
DIDP is found in a wide array of different final articles not found in other
OES including automotive care products, abrasives, heat-resistant electric
cords, interior leather for cars, roofing sheets, synthetic leather, tool
handles, and hoses.
Recycling and disposal
Upon manufacture or use of DIDP-containing products, residual chemical
is disposed and released to air, wastewater, or disposal facilities. A
fraction of PVC plastics is recycled either in-house or at PVC recycling
facilities for continuous compounding of new PVC material.
860 3,1.2 Estimating the Number of Release Days per Year for Facilities in Each OES
861 Based on the limited data on the number of releases days for the majority of the OESs, EPA developed
862 generic estimates of the number of operating days (days/year) for facilities in each OES as presented in
863 Table 3-3. Generally, EPA does not have information on the number of operating days for facilities;
864 however, EPA used Generic Scenario (GSs) or Emission Scenario Document (ESDs) to assess the
865 number of operating days for a given OES. EPA estimated average daily releases for facilities by
866 assuming that the number of release days is equal to the number of operating days.
867
Table 3-3. Estimates of >
umber of Operating Days per Year for Each OES
OES
Operating Days
(days/year)
Basis
Manufacturing
180
EPA assumed the number of operating days and release days
equals 180 days/per year, based on industry-provided
information on operating davs (ExxonMobil. 2022b).
Import and repackaging
208 to 260
The 2022 Chemical Repackaging GS estimated the total
number of operating days based on the shift lengths of
operators over the course of a full year, or 174-260 days/year.
Shift lengths include 8, 10, or 12 hour/day shifts. Release
estimates that EPA assessed using Monte Carlo modeling (see
Draft Environmental Release and Occupational Exposure
Assessment for DiisodecvlPhthalate (DIDP) ("U.S. EPA.
2024e)) used a 50th to 95th percentile ranae of 208-260
davs/vear (IIS. EPA. 2022V
Incorporation into
adhesives and sealants
250
EPA assumed year-round site operation, considering a 2-week
downtime, totaling 250 days/year.
Incorporation into paints
and coatings
250
EPA assumed year-round site operation, considering a 2-week
downtime, totaling 250 days/year.
Incorporation into other
formulations, mixtures,
and reaction products not
covered elsewhere
250
EPA assumed year-round site operation, considering a 2-week
downtime, totaling 250 days/year.
PVC plastics
compounding
223 to 254
The 2014 Plastic Compounding GS and 2021 Plastic
Compounding Revised GS estimated the number of operating
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OES
Operating Days
(days/year)
Basis
days as 148-264 days/year. Release estimates that EPA
assessed using Monte Carlo modeling (see Draft
Environmental Release and Occupational Exposure
Assessment for DiisodecvlPhthalate (DIDP) (U.S. EPA,
2024e)) used a 50th to 95th percentile ranae of 223-254
davs/vear (U.S. EPA, 2021e. 2014c).
PVC plastics converting
219 to 251
The 2004 Additives in Plastic Processing (Converting into
Finished Products) GS estimated the number of operating days
as 137 to 254 days/year. Release estimates that EPA assessed
using Monte Carlo modeling (see Draft Environmental
Release and Occupational Exposure Assessment for
Diisodecvl Phthalate (DIDP) (U.S. EPA, 2024e)) used a 50th
to 95th percentile ranae of 219-251 davs/vear (U.S. EPA,
2004a).
Non-PVC material
compounding
234 to 280
The 2014 Plastic Compounding GS, 2021 Plastic
Compounding Revised GS, and the 2020 SpERC Factsheet on
Rubber Production and Processing estimated the total number
of operating days as 148-300 days/year. Release estimates that
EPA assessed using Monte Carlo modeling (see Draft
Environmental Release and Occupational Exposure
Assessment for Diisodecvl Phthalate (DIDP) (U.S. EPA.
2024e)) used a 50th to 95th percentile ranae of 234-280
davs/vear (IIS. EPA, 2021e: ESIG. 2020; U.S. EPA, 2014c)
Non-PVC material
converting
219 to 251
The 2004 Additives in Plastic Processing (Converting into
Finished Products) GS and the 2014 Use of Additives in the
Thermoplastic Converting Industry GS estimated the number
of operating days as 137 to 254 days/year. Release estimates
that EPA assessed using Monte Carlo modeling (see Draft
Environmental Release and Occupational Exposure
Assessment for Diisodecvl Phthalate (DIDP) (U.S. EPA.
2024e)) used a 50th to 95th percentile ranae of 219-251
davs/vear (U.S. EPA. 2004a).
Application of adhesives
and sealants
232 to 325
Based on several end use products categories, the 2015 ESD
on the Use of Adhesives estimated the total number of
operating days as 50-365 days/year. Release estimates that
EPA assessed using Monte Carlo modeling (Draft
Environmental Release and Occupational Exposure
Assessment for Diisodecvl Phthalate (DIDP) (U.S. EPA,
2024e) Appendix E.9.2) used a 50th to 95th percentile ranae
of 232-325 davs/vear (OECD, 2015b).
Application of paints and
coatings
257 to 287
EPA assessed the total number of operating days based on
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 SpERC
Factsheet for Industrial Application of Coatings and Inks by
Spraying. These sources estimated the total number of
operating days as 225-300 days/year. Release estimates that
EPA assessed using Monte Carlo modeling (see Draft
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OES
Operating Days
(days/year)
Basis
Environmental Release and Occupational Exposure
Assessment for DiisodecvlPhthalate (D1DP) ("U.S. EPA.
2024e)) used a 50th to 95th percentile ranee of 257-287
davs/vear fCEPE. 2020: OE . b: U.S. EPA. 2004c).
Use of laboratory
chemicals
Liquid: 235 to
258
Solid: 260
The 2023 Use of Laboratory Chemicals GS estimated the total
number of operating days based on the shift lengths of
operators over the course of a full year as 174-260 days/year.
Shift lengths include 8, 10, or 12 hour/day shifts. Release
estimates that EPA assessed using Monte Carlo modeling (see
Draft Environmental Release and Occupational Exposure
Assessment for Diisodecvl Phthalate (D1DP) ("U.S. EPA.
2024e)) used a 50th to 95th percentile ranee of 235-258
davs/vear (U.S. EPA. 2023e).
Use of lubricants and
functional fluids
2 to 4
EPA assumed 1-4 changeouts per year based on identified
product data for different types of hydraulic fluids and the
ESD on the Lubricant and Lubricant Additives. EPA assumed
each changeout occurs over 1 day. Release estimates that EPA
assessed using Monte Carlo modeling (see Draft
Environmental Release and Occupational Exposure
Assessment for Diisodecvl Phthalate (D1DP) ("U.S. EPA.
2024e)) used a 50th to 95th percentile ranee of 2-4 davs/vear
COECD. 2004b).
Use of penetrants and
inspection fluids
247 to 249
The 2011 Use of Metalworking Fluids ESD estimated the total
number of operating days based on general metal shaping
activities as ranging from 246-249 days/year. Release
estimates that EPA assessed using Monte Carlo modeling (see
Draft Environmental Release and Occupational Exposure
Assessment for Diisodecvl Phthalate (D1DP) (U.S. EPA,
2024e)) estimated a 50th to 95th percentile ranee of 247-249
davs/vear (OECD. 201 lc).
Recycling and disposal
223 to 254
EPA estimated Recycling and Disposal releases separately.
For the PVC recycling OES, the 2014 Plastic Compounding
GS and 2021 Plastic Compounding Revised GS estimated the
number of operating days as 148-264 days/year. Release
estimates that EPA assessed using Monte Carlo modeling (see
Draft Environmental Release and Occupational Exposure
Assessment for Diisodecvl Phthalate (D1DP) (U.S. EPA,
2024e)) used a 50th to 95th percentile ranee of 223-254
davs/vear (U.S. EPA, 2021e. 2014c).
EPA evaluated disposal releases within the assessments for
each OES. EPA provided operating days for individual OES in
this table.
Fabrication and final use
of products or articles
N/A
EPA assumed year-round site operation, considering a two-
week downtime, totaling 250 days/year. However, EPA was
not able to perform a quantitative release assessment for this
OES, because the release parameters were unknown and
unquantifiable.
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869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
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3.1.3 Daily Release Estimation
For each OES, EPA estimated daily releases for each media of release using CDR, GSs and ESDs, EPA
published models, and the previously published European Union DIDP Risk Assessment, as shown in
Figure 3-1. Generally, EPA used 2020 CDR (U.S. EPA. 2020a) and 2004 El IDIDP Risk Assessment
(ECJRC. 2003a) to estimate annual releases. Where available, EPA used GSs or ESDs for applicable
OES to estimate the associated number of release days. Where available, EPA used 2020 CDR, 2020
U.S. County Business Practices, and Monte Carlo modeling data to estimate the number of sites using
DIDP within an OES. Generally, information for reporting sites in CDR was sufficient to accurately
characterize each reporting site's OES. The Draft Environmental Release and Occupational Exposure
Assessment for Diisodecyl Phthalate (DIDP) (U.S. EPA. 2024e) describes EPA's approach and
methodology for estimating daily releases, as well as detailed facility level results for each OES.
EPA estimated DIDP releases for each OES and release into media applicable to the OES. For DIDP,
EPA assumed that releases occur to water, air, or disposal to land.
Figure 3-1. An Overview of How EPA Estimated Daily Releases for Each OES
CDR = Chemical Data Reporting; ESD = Emission Scenario Document; GS =
Generic Scenario
3.1.4 Consumer Down-the-Drain and Disposal
EPA did not evaluate down-the-drain releases of DIDP for consumer COUs. Although EPA
acknowledges that there may be DIDP releases to the environment via the cleaning and disposal of
adhesives, sealants, lacquers, and coatings, the Agency did not quantitatively assess these scenarios due
to limited information, monitoring data, or modeling tools but provides a qualitative assessment using
physical and chemical properties in this section. See EPA's Draft Consumer and Indoor Dust Exposure
Assessment for Diisodecyl Phthalate (DIDP) (U.S. EPA. 2024a) for further details. Adhesives, sealants,
lacquers, and coatings can be disposed down-the-drain while consumer users wash their hands, brushes,
sponges, and other product applying tools. In addition, these products can be disposed of when users no
longer have use for them or have reached the product shelf life and taken to landfills. All other solid
products and articles in Table 4-6 can be removed and disposed in landfills, or other waste handling
locations that properly manage the disposal of products like adhesives, sealants, lacquers, and coatings.
EPA did not identify monitoring data for DIDP in surface and drinking water in the United States, but
some non-U. S. monitoring studies pointed at 98 percent DIDP removal efficiency and additional non-
U.S. sediment data points at DIDP affinity to organic material in sediments (U.S. EPA. 2024d). Based
on the low water solubility and log Kow, DIDP in water is expected to mainly partition to suspended
solids present in water. The available information suggest that the use of flocculants and filtering media
could potentially help remove DIDP during drinking water treatment by sorption into suspended organic
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906
907
908
909
910
911
912
913
914
915
916
917
918
919
PUBLIC RELEASE DRAFT
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matter, settling, and physical removal. Once products/articles are disposed in landfills there is potential
for migration to soils and water. Although there are limited measured data on DIDP in landfill leachates,
the data suggest that DIDP is unlikely to be present in landfill leachates. Further, the small amounts of
DIDP that could potentially be in landfill leachates will have limited mobility and are unlikely to
infiltrate groundwater due to high affinity of DIDP for organic compounds that would be present in
receiving soil and sediment (U.S. EPA. 2024d).
3.2 Summary of Environmental Releases
3,2,1 Manufacturing, Processing, Industrial and Commercial
EPA combined its estimates for total production volume, release days, number of facilities, and hours of
release per day to estimate a range for daily releases for each OES. A summary of these ranges across
facilities is presented in Table 3-4. See the Draft Environmental Release and Occupational Exposure
Assessment for Diisodecyl Phthalate (DIDP) (U. 2024e) for additional detail on deriving the
overall confidence score for each OES. For the Fabrication and final use of products or articles OES
EPA was not able to estimate release.
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920 Table 3-4. Summary of EPA's Daily Release Estimates for Each PES and EPA's Overall Confidence in these Estimates
OES
Estimated Daily Release
across Sites
(kg/site-dav)
Type of Discharge,"
Air Emission,'' or
Transfer tor
Disposal'
Estimated Release
Frequency across
Sites (days)''
Number of
Facilities'
Weight of
Scientific
Evidence Rating'
Sources
Central
Tendency
High-End
Central High-
Tendency End
Manufacturing
2.56E-07
8.52E-07
Fugitive Air
180
1 - Troy
Chemical Corp.,
Phoenix, AZ
Moderate
CDR, Peer-reviewed
literature (GS/ESD)
1.14E-01
Stack Air
1.05E-01
1.89E-01
Wastewater to Onsite
treatment or Discharge
to POTW
2.70
2.84
Onsite Wastewater
Treatment,
Incineration, or
Landfill
1.30
2.25
Landfill
4.24E-06
7.47E-06
Fugitive Air
180
3 generic sites
Moderate
CDR, Peer-reviewed
literature (GS/ESD)
2.31E02
4.01E02
Stack Air
1.93E02
5.06E02
Wastewater to Onsite
Treatment or
Discharge to POTW
4.69E03
8.14E03
Onsite Wastewater
Treatment,
Incineration, or
Landfill
8.69E02
Landfill
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OES
Estimated Daily Release
across Sites
(kg/site-dav)
Type of Discharge,"
Air Emission/' or
Transfer for
Disposal'
Estimated Release
Frequency across
Sites (davs)''
Number of
Facilities'
Weight of
Scientific
Sources
Central
Tendency
High-End
Central
Tendency
High-
End
Evidence Rating'
4.71E-08
6.13E-08
Fugitive Air
1 - LG Hausys
America,
Adairsville, GA
1.57
1.81
Wastewater to Onsite
Treatment, Discharge
to POTW, or Landfill
208
260
Moderate
1.00E-07
1.05E-07
Fugitive Air
1 - Harwick
2.31
2.86
Wastewater to Onsite
Treatment, Discharge
to POTW, or Landfill
208
260
Standard
Distribution
Corp., Akron, OH
Moderate
2.17E-08
4.08E-08
Fugitive Air
4.17E01
5.16E01
Wastewater to Onsite
Treatment, Discharge
to POTW, or Landfill
208
260
1 - Tremco Inc.,
Beachwood, OH
Moderate
4.69E-08
6.10E-08
Fugitive Air
Import and
Repackaging
1.09
1.50
Wastewater to Onsite
Treatment, discharge
to POTW, or Landfill.
208
260
1 - Akrochem
Corp., Stow, OH.
Moderate
CDR, Peer-reviewed
literature (GS/ESD)
1.01E-07
1.06E-07
Fugitive Air
1 - Chemspec,
Ltd., Uniontown,
OH
2.82
3.51
Wastewater to Onsite
Treatment, Discharge
to POTW, or Landfill
208
260
Moderate
7.38E-08
1.01E-07
Fugitive Air
3 generic sites
CASRN
26761-40-0
1.39
1.83
Wastewater to Onsite
Treatment, Discharge
to POTW, or Landfill
208
260
Moderate
2.45E-06
6.99E-06
Fugitive Air
3 generic sites
CASRN
68515-49-1
4.12E03
7.98E03
Wastewater to Onsite
Treatment, Discharge
to POTW, or Landfill
208
260
Moderate
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OES
Estimated Daily Release
across Sites
(kg/site-dav)
Type of Discharge,"
Air Emission/' or
Transfer for
Disposal'
Estimated Release
Frequency across
Sites (davs)''
Number of
Facilities'
Weight of
Scientific
Evidence Rating'
Sources
Central
Tendency
High-End
Central
Tendency
High-
End
PVC plastics
compounding
3.29E01
1.45E02
Fugitive or Stack Air
223
254
98-195 generic
sites
Moderate
CDR, Peer-reviewed
literature (GS/ESD)
4.29E02
6.80E02
Wastewater,
Incineration, or
Landfill
1.09E02
1.64E02
Wastewater
8.29E01
2.73E02
Fugitive air,
Wastewater,
Incineration, or landfill
2.21E01
1.11E02
Incineration or Landfill
PVC plastics
converting
1.57
6.86
Fugitive or Stack Air
219
251
2,128^1,237
generic sites
Moderate
CDR, Peer-reviewed
literature (GS/ESD)
1.54E01
2.35E01
Wastewater,
Incineration, or
Landfill
5.14
7.84
Wastewater
3.94
1.30E01
Fugitive air,
Wastewater,
Incineration, or
Landfill
1.43E01
2.28E01
Incineration or Landfill
Non-PVC
material
compounding
4.39E01
1.44E02
Fugitive or Stack Air
234
280
4-9 generic sites
Moderate
CDR, Peer-reviewed
literature (GS/ESD)
9.07E02
1.66E03
Wastewater,
Incineration, or
Landfill
8.25E01
1.07E02
Wastewater
3.80
1.27E01
Fugitive Air,
Wastewater,
Incineration, or
Landfill
6.35E01
1.87E02
Incineration or Landfill
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OES
Estimated Daily Release
across Sites
(kg/site-dav)
Type of Discharge,"
Air Emission/' or
Transfer tor
Disposal'
Estimated Release
Frequency across
Sites (davs)''
Number of
Facilities'
Weight of
Scientific
Evidence Rating'
Sources
Central
Tendency
High-End
Central
Tendency
High-
End
Non-PVC
material
converting
1.11
3.86
Fugitive or Stack Air
219
251
178-212 generic
sites
Moderate
CDR, Peer-reviewed
literature (GS/ESD)
7.79
1.41E01
Wastewater,
Incineration, or
Landfill
2.05
3.31
Wastewater
1.08E-01
3.53E-01
Fugitive Air,
Wastewater,
Incineration, or
Landfill
6.89
1.23E01
Incineration or Landfill
Incorporation
into adhesives
and sealants
6.63E-09
3.35E-08
Fugitive Air
250
6—50 generic
sites
Moderate
CDR, Peer-reviewed
literature (GS/ESD)
5.70E-09
8.04E-08
Stack Air
4.16E01
1.08E02
Wastewater,
Incineration, or
Landfill
Incorporation
into paints and
coatings
4.46E-09
1.59E-08
Fugitive Air
250
6-38 generic sites
Moderate
CDR, Peer-reviewed
literature (GS/ESD)
5.27E-10
5.12E-09
Stack Air
3.35E01
1.08E02
Wastewater,
Incineration, or
Landfill
Incorporation
into other
formulations,
mixtures, and
reaction
products not
covered
elsewhere
4.13E-07
1.04E-06
Fugitive Air
250
1-2 generic sites
Moderate
CDR, Peer-reviewed
literature (GS/ESD)
1.06E-07
4.97E-07
Stack Air
7.39E02
1.29E03
Wastewater,
Incineration, or
Landfill
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OES
Estimated Daily Release
across Sites
(kg/site-dav)
Type of Discharge,"
Air Emission/' or
Transfer tor
Disposal'
Estimated Release
Frequency across
Sites (davs)''
Number of
Facilities'
Weight of
Scientific
Evidence Rating'
Sources
Central
Tendency
High-End
Central
Tendency
High-
End
Application of
paints and
coatings
with overspray
controls
[No overspray
controls]
2.62E-09
[2.62E-091
6.90E-09
r6.87E-091
Fugitive Air
257
287
222-1,242
generic sites
[223-1,226
generic sites]
Moderate
CDR, Peer-reviewed
literature (GS/ESD)
6.34E-01
[6.321
2.04
r2.04E011
Stack Air [Unknown]
6.29
[5.58E-01]
1.98E01
[1.55]
Wastewater,
Incineration, or
Landfill
Application of
adhesives and
sealants
9.80E-09
3.24E-08
Fugitive or Stack Air
232
325
84-1,056 generic
sites
Moderate
CDR, Peer-reviewed
literature (GS/ESD)
2.61
1.45E01
Wastewater,
Incineration, or
Landfill
Use of
laboratory
chemicals -
liquid
1.94E-09
3.31E-09
Fugitive or Stack Air
235
258
225-2,095
generic sites
Moderate
CDR, Peer-reviewed
literature (GS/ESD)
1.83
3.47
Wastewater,
Incineration, or
Landfill
Use of
laboratory
chemicals -
solid
1.08E-04
2.37E-04
Stack Air
260
36,873
Moderate
9.83E-03
9.88E-03
Wastewater,
Incineration, or
Landfill
Use of
lubricants and
functional
fluids
7.29E01
2.69E02
Wastewater
2
4
2,596-18,387
generic sites
Moderate
CDR, Peer-reviewed
literature (GS/ESD)
3.21E01
1.30E02
Landfill
1.19
6.31
Recycling
2.64E01
1.40E02
Fuel Blending
(Incineration)
Use of
penetrants and
inspection
fluids
3.68E-03
4.80E-3
Fugitive Air
247
249
15,315-21,892
generic sites
Moderate
CDR, Peer-reviewed
literature (GS/ESD)
2.14E-02
2.77E-02
Wastewater,
Incineration, or
Landfill
2.46E-09
4.57E-09
Fugitive Air
2.50E-02
3.25E-02
Wastewater,
Incineration, or
Landfill
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OES
Estimated Daily Release
across Sites
(kg/site-dav)
Type of Discharge,"
Air Emission/' or
Transfer for
Disposal'
Estimated Release
Frequency across
Sites (davs)''
Number of
Facilities'
Weight of
Scientific
Evidence Rating'
Sources
Central
Tendency
High-End
Central
Tendency
High-
End
Recycling
2.33E-02
4.68E-01
Stack Air
223
254
58 generic sites
Moderate
CDR, Peer-reviewed
literature (GS/ESD)
1.84
3.36
Fugitive Air,
Wastewater,
Incineration, or
Landfill
CDR, Peer-reviewed
literature (GS/ESD)
7.80E-01
1.70
Wastewater
CDR, Peer-reviewed
literature (GS/ESD)
"Direct discharge to surface water; indirect discharge to non-POTW; indirect discharge to POTW
b Emissions via fugitive air or stack air, or treatment via incineration
c Transfer to surface impoundment, land application, or landfills
''Where available, EPA used industry provided information, ESDs, or GSs to estimate the number of release days for each condition of use.
' Where available. EPA used 2020 CDR (U.S. EPA. 20203). 2020 U.S. Countv Business Practices (U.S. Census Bureau. 20221 and Monte Carlo models to estimate the
number of sites that use DIDP for each condition of use.
f See Section 3.2.2 for details on EPA's determination of the weight of scientific evidence rating.
921
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922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
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3,2,2 Weight of Scientific Evidence Conclusions for Environmental Releases from
Manufacturing, Processing, Industrial and Commercial Sources
For each OES, EPA considered the assessment approach, the quality of the data and models, and the
uncertainties in the assessment results to determine a level of confidence as presented in Table 3-4.
Integration of the environmental release evidence streams across systematic review and non-systematic
review sources results in an environmental release estimate for the chemical of interest. EPA made a
judgment on the weight of scientific evidence supporting the environmental release estimate based on
the strengths, limitations, and uncertainties associated with the environmental release estimates. EPA
described this judgment using the following confidence descriptors: robust, moderate, slight, or
indeterminate.
In determining the strength of the overall weight of scientific evidence, EPA considered factors that
increase or decrease the strength of the evidence supporting the exposure estimate (whether measured or
estimated), including quality of the data/information, relevance of the data to the exposure scenario
(including considerations of temporal relevance, spatial relevance), and the use of surrogate data when
appropriate. In general, higher rated studies (as determined through data evaluation) increase the weight
of scientific evidence when compared to lower rated studies, and EPA gave preference to chemical- and
scenario-specific data over surrogate data (similar chemical or scenario). For example, a conclusion of
moderate weight of scientific evidence is appropriate where there is measured release data from a
limited number of sources such that there is a limited number of data points that may not cover most or
all of the sites within the COU. A conclusion of slight weight of scientific evidence is appropriate where
there is limited information that does not sufficiently cover all sites within the COU, and the
assumptions and uncertainties are not fully known or documented. See EPA's Draft systematic review
protocol supporting TSCA risk evaluations for chemical substances, Version 1.0: A generic TSCA
systematic review protocol with chemical-specific methodologies ( ) for additional
information on weight of scientific evidence conclusions.
Table 3-5 summarizes EPA's overall weight of scientific evidence conclusions for its release estimates
for each OES. In general, modeled estimates had data quality ratings of medium. As a result, for releases
that used GSs/ESDs, the weight of scientific conclusion was moderate, when used in tandem with Monte
Carlo modeling.
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954 Table 3-5. Summary of Overall Confidence in Environmental Release Estimates by PES
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 (U.S. EPA, 2023c). and sources
identified through systematic review (including industry supplied data). EPA used EPA/OPPT models combined with Monte Carlo modeling
to estimate releases to the environment, with media of release assessed using assumptions from EPA/OPPT models and industry supplied data.
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 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 DIDP manufacturing volumes for all
facilities that reported this information to CDR and DIDP-specific operating parameters derived using data with a high data quality ranking
from a current U.S. manufacturing site to provide more accurate estimates than the generic values provided by the EPA/OPPT models.
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, EPA lacks DIDP facility production volume data for some DIDP manufacturing sites that claim this information
as CBI for the purposes of CDR reporting; therefore, throughput estimates for these sites are based on the CDR reporting threshold of 25,000
lb (i.e., not all potential sites represented) and an annual DIDP production volume range that spans an order of magnitude. Additional
limitations include uncertainties in the representativeness of the industry-provided operating parameters and the generic EPA/OPPT models
for all DIDP manufacturing sites.
Based on this information, EPA concluded that the weight of scientific evidence for this assessment is moderate, and the assessment provides a
plausible estimate of releases considering the strengths and limitations of the reasonably available data.
Import and
repackaging
EPA found limited chemical specific data for the import and repackaging OES and assessed releases to the environment using the assumptions
and values from the Chemical Repackaging GS. which the systematic review process rated high for data duality (U.S. EPA. 2022). EPA also
referenced the 2023 Methodology for Estimating Environmental Releases from Sampling Wastes (U.S. EPA, 2023c) and used EPA/OPPT
models combined with Monte Carlo modeling to estimate releases to the environment. EPA assessed the media of release using assumptions
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 at sites than discrete value. Additionally, Monte Carlo
modeling uses a high number of data points (simulation runs) and the full distributions of input parameters. EPA used facility specific DIDP
import volumes for all facilities that reported this information to CDR.
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, because the default values in the ESD are generic, there is uncertainty in the
representativeness of these generic site estimates in characterizing actual releases from real-world sites that import and repackage DIDP. In
addition, EPA lacks DIDP facility import volume data for some CDR-reporting import and repackaging sites that claim this information as
CBI; therefore, throughput estimates for these sites are based on the CDR reporting threshold of 25,000 lb (i.e., not all potential sites
represented) and an annual DIDP production volume range that spans an order of magnitude.
Based on this information, EPA concluded that the weight of scientific evidence for this assessment is moderate, and the assessment provides a
plausible estimate of releases, considering the strengths and limitations of the reasonably available data.
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OES
Weight of Scientific Evidence Conclusion in Release Estimates
Incorporation
into adhesives
and sealants
EPA found limited chemical specific data for the incorporation into adhesives and sealants OES and assessed releases to the environment
using the ESD on the Formulation of Adhesives, which has a high data quality rating based on the systematic review process (OECD. 2009).
EPA used EPA/OPPT models combined with Monte Carlo modeling to estimate releases to the environment and assessed the media of release
using assumptions 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 at sites 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
DIDP-specific data on concentrations in adhesive and sealant products in the analysis to provide more accurate estimates than the generic
values orovided bv the ESD. EPA based the production volume for the OES on use rates cited bv the ACC (2020) and referenced the 2003 EU
Risk Assessment Report (ECJRC, 2003a) for the expected U.S. DIDP use rates per use scenario.
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 default values in the ESD may not be representative of actual releases from real-
world sites that incorporate DIDP into adhesives and sealants. In addition, EPA lacks data on DIDP-specific facility production volume and
number of formulation sites; therefore, EPA based throughput estimates on CDR which has a reporting threshold of 25,000 lb (i.e., not all
potential sites represented) and an annual DIDP production volume range that spans an order of magnitude. The respective share of DIDP use
for each OES (as presented in the EU Risk Assessment Report) may differ from actual conditions adding additional uncertainty to estimated
releases.
Based on this information, EPA concluded that the weight of scientific evidence for this assessment is moderate, and the assessment provides a
plausible estimate of releases, considering the strengths and limitations of the reasonably available data.
Incorporation
into paints and
coatings
EPA found limited chemical specific data for the incorporation into paints and coatings OES and assessed releases to the environment using
the Draft GS for the Formulation ofWaterborne Coatings, which has a medium data quality ratine based on systematic review (U.S. EPA,
2014a). EPA used EPA/OPPT models combined with Monte Carlo modeling to estimate releases to the environment and assessed the media of
release using assumptions from the GS 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 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 DIDP-specific data on concentrations in paint and coating products to provide more accurate estimates of DIDP concentrations than the
generic values provided by the GS. EPA based the production volume for the OES on rates cited by the ACC (2020) and referenced the 2003
EU Risk Assessment Report (ECJRC. 2003a) for the expected U.S. DIDP use rates per use scenario.
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 GS are specific to waterborne coatings and may not
be representative of releases from real-world sites that incorporate DIDP into paints and coatings, particularly for sites formulating other
coating types (e.g., solvent-borne coatings). In addition, EPA lacks data on DIDP-specific facility production volume and number of
formulation sites; therefore, EPA based throughput estimates on CDR which has a reporting threshold of 25,000 lb (i.e., not all potential sites
represented) and an annual DIDP production volume range that spans an order of magnitude. The share of DIDP use for each OES presented
in the EU Risk Assessment Report may differ from actual conditions adding some uncertainty to estimated releases.
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Weight of Scientific Evidence Conclusion in Release Estimates
Based on this information, EPA concluded that the weight of scientific evidence for this assessment is moderate, and the assessment provides a
plausible estimate of releases, considering the strengths and limitations of the reasonably available data.
Incorporation
into other
formulations,
mixtures, and
reaction products
not covered
elsewhere
EPA found limited chemical specific data for the incorporation into other formulations, mixtures, and reaction products not covered elsewhere
OES and assessed releases to the environment using the Draft GS for the Formulation of Waterborne Coatings, which has a medium data
quality ratine based on systematic review process CU.S. EPA, 2014a). EPA used EPA/OPPT models combined with Monte Carlo modeling to
estimate releases to the environment, and media of release using assumptions from the GS 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. Additionally, EPA used DIDP-specific data on concentrations in other formulation, mixture, and reaction
products in the analysis to provide more accurate estimates than the generic values provided by the GS. The safety and product data sheets that
EPA obtained these values from have high data quality ratings based on the systematic review process. EPA based the production volume for
the OES on rates cited by the ACC (2020) and referenced the 2003 EU Risk Assessment Report (ECJRC, 2003a) for the expected U.S. DIDP
use rates per use scenario.
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 are based on the formulation of paints and
coatings and may not represent releases from real-world sites that incorporate DIDP into other formulations, mixtures, or reaction products. In
addition, EPA lacks data on DIDP-specific facility production volume and number of formulation sites; therefore, EPA based the throughput
estimates on CDR which has a reporting threshold of 25,000 lb (i.e., not all potential sites represented) and an annual DIDP production volume
range that spans an order of magnitude. Finally, the share of DIDP use for each OES presented in the EU Risk Assessment Report may differ
from actual conditions adding some uncertainty to estimated releases.
Based on this information, EPA concluded that the weight of scientific evidence for this assessment is moderate, and the assessment provides a
plausible estimate of releases, considering the strengths and limitations of the reasonably available data.
PVC plastics
compounding
EPA found limited chemical specific data for the PVC plastics compounding OES and assessed releases to the environment using the Revised
Draft GS for the Use of Additives in Plastic Compounding. which has a medium data quality rating based on systematic review (U.S. EPA,
202 le). EPA used EPA/OPPT models combined with Monte Carlo modeling to estimate releases to the environment, and media of release
using assumptions from the GS 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. Additionally, EPA used
DIDP-specific data on concentrations in different DIDP-containing PVC plastic products and PVC-specific additive throughputs in the
analysis. These data provide more accurate estimates than the generic values provided by the GS. The safety and product data sheets that EPA
obtained these values from have high data quality ratings based on systematic review. EPA based production volumes for the OES on rates
cited by the ACC (2020) and referenced the 2003 EU Risk Assessment Report (ECJRC, 2003a) for the expected U.S. DIDP use rates per use
scenario.
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 consider all types of plastic compounding and
may not represent releases from real-world sites that compound DIDP into PVC plastic raw material. In addition, EPA lacks data on DIDP-
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Weight of Scientific Evidence Conclusion in Release Estimates
specific facility production volume and number of compounding sites; therefore, EPA estimated throughput based on CDR which has a
reporting threshold of 25,000 lb (i.e.. not all potential sites represented) and an annual DIDP production volume range that spans an order of
magnitude. The respective share of DIDP use for each OES presented in the EU Risk Assessment Report may differ from actual conditions
adding some uncertainty to estimated releases.
Based on this information, EPA concluded that the weight of scientific evidence for this assessment is moderate, and the assessment provides a
plausible estimate of releases, considering the strengths and limitations of the reasonably available data.
PVC plastics
converting
EPA found limited chemical specific data for the PVC plastics converting OES and assessed releases to the environment using the Revised
Draft GS on the Use of Additives in the Thermoplastics Converting Industry, which has a medium data quality rating based on systematic
review ( 210. EPA used EPA/OPPT models combined with Monte Carlo modeling to estimate releases to the environment, and
media of release using assumptions from the GS 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 is more likely to capture actual releases than discrete values. Monte
Carlo also considers a large number of data points (simulation runs) and the full distributions of input parameters. Additionally, EPA used
DIDP-specific data on concentrations in different DIDP-containing PVC plastic products and PVC-specific additive throughputs in the
analysis. These data provide more accurate estimates than the generic values provided by the GS. The safety and product data sheets that EPA
used to obtain these values have high data quality ratings based on systematic review. EPA based the production volume for the OES on rates
cited bv the ACC (2020) and referenced the 2003 EU Risk Assessment Report (ECJRC. 2003a) for the expected U.S. DIDP use rates per use
scenario.
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 are based on all types of thermoplastics
converting sites and processes and may not represent actual releases from real-world sites that convert DIDP-containing PVC raw material into
PVC articles using a variety of methods, such as extrusion or calendaring. In addition, EPA lacks data on DIDP-specific facility production
volume and number of converting sites; therefore, EPA estimated throughput based on CDR which has a reporting threshold of 25,000 lb (i.e.,
not all potential sites represented) and an annual DIDP production volume range that spans an order of magnitude. The respective share of
DIDP use for each OES presented in the EU Risk Assessment Report may differ from actual conditions adding some uncertainty to estimated
releases.
Based on this information, EPA concluded that the weight of scientific evidence for this assessment is moderate, and the assessment provides a
plausible estimate of releases, considering the strengths and limitations of the reasonably available data.
Non-PVC
material
compounding
EPA found limited chemical specific data for the non-PVC material compounding OES and assessed releases to the environment using the
Revised Draft GS for the Use of Additives in Plastic Compounding and the ESD on Additives in the Rubber Industry. Both sources have a
medium data aualitv ratine based on the systematic review process (U.S. EPA. 2021e; OECD. 2004a). EPA used EPA/OPPT models
combined with Monte Carlo modeling to estimate releases to the environment, and media of release using assumptions from the GS, 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.
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Weight of Scientific Evidence Conclusion in Release Estimates
Additionally, EPA used DIDP-specific concentration data for different DIDP-containing rubber products in the analysis. These data provide
more accurate estimates than the generic values provided by the GS and ESD. The safety and product data sheets that EPA obtained these
values from have high data quality ratings based on systematic review. EPA based the production volume for the OES on rates cited by the
ACC (2020) and referenced the 2003 EURisk Assessment Report (ECJRC, 2003a) for the expected U.S. DIDP use rates per use scenario.
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 GS and ESD are based on all types of plastic
compounding and rubber manufacturing, and the DIDP-specific concentration data only consider rubber products. As a result, these values
may not be representative of actual releases from real-world sites that compound DIDP into non-PVC material. In addition, EPA lacks data on
DIDP-specific facility production volume and number of compounding sites; therefore, EPA estimated throughput based on CDR which has a
reporting threshold of 25,000 lb (i.e.. not all potential sites represented) and an annual DIDP production volume range that spans an order of
magnitude. The respective share of DIDP use for each OES presented in the EU Risk Assessment Report may differ from actual conditions
adding some uncertainty to estimated releases.
Based on this information, EPA concluded that the weight of scientific evidence for this assessment is moderate, and the assessment provides a
plausible estimate of releases, considering the strengths and limitations of the reasonably available data.
Non-PVC
material
converting
EPA found limited chemical specific data for the non-PVC material converting OES and assessed releases to the environment using the
Revised Draft GS on the Use of Additives in the Thermoplastics Converting Industry and the ESD on Additives in the Rubber Industry. Both
documents have a medium data quality ratine based on systematic review (U.S. EPA, 2021f; OECD. 2004a). EPA used EPA/OPPT models
combined with Monte Carlo modeling to estimate releases to the environment, and media of release using assumptions from the GS, 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.
Additionally, EPA used DIDP-specific data on concentrations in different DIDP-containing rubber products in the analysis. These data provide
more accurate estimates than the generic values provided by the GS and ESD. The safety and product data sheets that EPA obtained these
values from have high data quality ratings based on the systematic review process. EPA based the production volume for the OES on rates
cited by the ACC (2020) and referenced the 2003 EU Risk Assessment Report (ECJRC, 2003a) for the expected U.S. DIDP use rates per use
scenario.
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 GS and ESD consider all types of plastic converting
and rubber manufacturing sites, and the DIDP-specific concentration data only considers rubber products. As a result, these generic site
estimates may not represent actual releases from real-world sites that convert DIDP containing non-PVC material into finished articles. In
addition, EPA lacks data on DIDP-specific facility production volume and number of converting sites; therefore, EPA based throughput
estimates on values from industry SpERC documents, CDR data (which has a reporting threshold of 25,000 lb (i.e., not all potential sites
represented), and an annual DIDP production volume range that spans an order of magnitude. The share of DIDP use for each OES presented
in the EU Risk Assessment Report may differ from actual conditions adding some uncertainty to estimated releases.
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Weight of Scientific Evidence Conclusion in Release Estimates
Based on this information, EPA concluded that the weight of scientific evidence for this assessment is moderate, and the assessment provides a
plausible estimate of releases, considering the strengths and limitations of the reasonably available data.
Application of
adhesives and
sealants
EPA found limited chemical specific data for the application of adhesives and sealants OES and assessed releases to the environment using the
ESD on the Use of Adhesives. which has a medium data duality ratine based on systematic review fOECD. 2015a). EPA used EPA/OPPT
models combined with Monte Carlo modeling to estimate releases to the environment, and media of release using assumptions 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. Additionally, EPA used DIDP-specific data on concentration and
application methods for different DIDP-containing adhesives and sealant products in the analysis. These data provide more accurate estimates
than the generic values provided by the ESD. The safety and product data sheets from which these values were obtained have high data quality
ratines from the systematic review process. EPA based OES PV on rates cited bv the ACC (2020). which references the 2003 EURisk
Assessment Report (ECJRC, 2003a) for the expected U.S. DIDP use rates per use scenario.
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
that incorporate DIDP into adhesives and sealants. In addition, EPA lacks data on DIDP-specific facility use volume and number of use sites;
therefore, EPA based throughput estimates on values from industry SpERC documents, CDR data (which has a reporting threshold of 25,000
lb (i.e.. not all potential sites represented), and an annual DIDP production volume range that spans an order of magnitude. The respective
share of DIDP use for each OES as presented in the EU Risk Assessment Report may differ from actual conditions adding some uncertainty to
estimated releases.
Based on this information, EPA concluded that the weight of scientific evidence for this assessment is moderate, and the assessment provides a
plausible estimate of releases, considering the strengths and limitations of reasonably available data.
Application of
paints and
coatings
EPA found limited chemical specific data for the application of paints and coatings OES and assessed releases to the environment using the
ESD on the Application of Radiation Curable Coatings, Inks and Adhesives, the GS on Coating Application via Spray Painting in the
Automotive Refinishing Industry, the GS on Spray Coatings in the Furniture Industry. These documents have a medium data quality rating
based on the systematic review process (U.S. EPA, 2014b; OECD, 201 lb; U.S. EPA, 2004d). EPA used EPA/OPPT models combined with
Monte Carlo modeling to estimate releases to the environment. EPA assessed media of release using assumptions from the ESD, GS, and
EPA/OPPT models and a default assumption that all paints and coatings are applied via spray application. 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. Additionally, EPA used DIDP-specific data on concentration and application methods for different DIDP-containing paints
and coatings in the analysis. These data provide more accurate estimates than the generic values provided by the GS and ESDs. The safety and
product data sheets that EPA obtained these values from have high data quality ratings based on the systematic review process. EPA based
production volumes for these OES on rates cited by the ACC (2020) and referenced the 2003 EU Risk Assessment Report (ECJRC, 2003a) for
the expected U.S. DIDP use rates per use scenario.
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 GS and ESDs may not represent releases from real-
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Weight of Scientific Evidence Conclusion in Release Estimates
world sites that incorporate DIDP 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 DIDP-specific facility use volume and number of use sites;
therefore, EPA based throughput estimates on values from industry SpERC documents, CDR data (which has a reporting threshold of 25,000
lb (i.e.. not all potential sites represented), and an annual DIDP production volume range that spans an order of magnitude. The share of DIDP
use for each OES presented in the EU Risk Assessment Report may differ from actual conditions adding some uncertainty to estimated
releases.
Based on this information, EPA concluded that the weight of scientific evidence for this assessment is moderate, and the assessment provides a
plausible estimate of releases, considering the strengths and limitations of reasonably available data
Use of laboratory
chemicals
EPA found limited chemical specific data for the use of laboratory chemicals OES and assessed releases to the environment using the Draft
GS on the Use of Laboratory Chemicals. which has a high data quality rating based on systematic review (U.S. EPA, 2023e). EPA used
EPA/OPPT models combined with Monte Carlo modeling to estimate releases to the environment, and media of release using assumptions
from the GS and EPA/OPPT models for solid and liquid DIDP materials. 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 used
SDSs from identified laboratory DIDP products to inform product concentration and material states.
EPA believes the primary limitation to be the uncertainty in the representativeness of values toward the true distribution of potential releases.
In addition, EPA lacks data on DIDP 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 case and there were no other sources to estimate the
volume of DIDP used in this OES, EPA developed a high-end bounding estimate based on the CDR reporting threshold, which by definition is
expected to over-estimate the average release case.
Based on this information, EPA concluded that the weight of scientific evidence for this assessment is moderate, and the assessment provides a
plausible estimate of releases, considering 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, which has a medium data quality ratine based on systematic review (O ECD, 2004b). EPA
used EPA/OPPT models combined with Monte Carlo modeling to estimate releases to the environment, and media of release using
assumptions 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. Additionally, EPA used
DIDP-specific data on concentration and uses of different DIDP-containing lubricants and functional fluid products in the analysis. These data
provide more accurate estimates than the generic values provided by the ESD. The safety and product data sheets that EPA used to obtain
these values have high data quality ratings based on systematic review. EPA based production volumes for the OES on rates cited by the ACC
(2020) and referenced the 2003 EU Risk Assessment Report (ECJRC, 2003a) for the expected U.S. DIDP use rates per use scenario.
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
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OES
Weight of Scientific Evidence Conclusion in Release Estimates
using DIDP-containing lubricants and functional fluids. In addition, EPA lacks information on the specific facility use rate of DIDP-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 DIDP production volume range that spans an order of magnitude.
The respective share of DIDP use for each OES presented in the EU Risk Assessment Report may differ from actual conditions adding some
uncertainty to estimated releases.
Based on this information, EPA concluded that the weight of scientific evidence for this assessment is moderate, and the assessment provides a
plausible estimate of releases in consideration of the strengths and limitations of 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 using
the ESD on the Use ofMetalworking Fluids. which has a medium data quality rating based on systematic review (OECD. 2011c). EPA used
EPA/OPPT models combined with Monte Carlo modeling to estimate releases to the environment, and media of release using assumptions
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. Because there were no DIDP-containing
penetrant products identified, 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 have high data quality
ratings based on systematic review and provide more accurate estimates than the generic values provided by the ESD. EPA based production
volumes for the OES on rates cited by the ACC (2020) and referenced the 2003 EU Risk Assessment Report (ECJRC. 2003 a) for the expected
U.S. DIDP use rates per use scenario.
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 DIDP-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 DIDP used in this OES, EPA developed a high-
end bounding estimate based on CDR reporting threshold, which by definition is expected to over-estimate the average release case.
Based on this information, EPA concluded that the weight of scientific evidence for this assessment is moderate, and the assessment provides a
plausible estimate of releases, considering the strengths and limitations of reasonably available data.
Fabrication and
final use of
products 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 and
disposal
EPA found limited chemical specific data for the recycling and disposal OES. EPA assessed releases to the environment from recycling
activities using the Revised Draft GS for the Use of Additives in Plastic Compounding as surrogate for the recycling process. The GS has a
medium data aualitv ratine based on systematic review (U.S. EPA. 202leY EPA used EPA/OPPT models combined with Monte Carlo
modeling to estimate releases to the environment, and media of release using assumptions from the GS 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. Additionally, EPA used DIDP-specific data on concentrations in different DIDP-containing PVC
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OES
Weight of Scientific Evidence Conclusion in Release Estimates
plastic products in the analysis to provide more accurate estimates than the generic values provided by the GS. The safety and product data
sheets that EPA used to obtain these values have high data quality ratings based on systematic review. EPA referenced the Quantification and
evaluation of plastic waste in the United States, which has a medium quality rating based on systematic review (Milbrandt et aL, 2022). to
estimate the rate of PVC recycling in the U.S. and applied it to DIDP PVC market share to define an approximate recycling volume of PVC
containing DIDP.
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 GS represent all types of plastic compounding sites
and may not represent sites that recycle PVC products containing DIDP. In addition, EPA lacks DIDP-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 DIDP, and may not accurately reflect current U.S. recycling volume.
Based on this information, EPA concluded that the weight of scientific evidence for this assessment is moderate, yet the assessment still
provides a plausible estimate of releases, considering the strengths and limitations of the reasonably available data.
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3,2,3 Strengths, Limitations, Assumptions, and Key Sources of Uncertainty for the
Environmental Release Assessment
Manufacturers and importers of DIDP submit CDR data to EPA if they meet reporting threshold
requirements. Sites are only required to load production data into CDR if their yearly production volume
exceeds 25,000 lb. Sites can claim their production volume as CBI, thereby further limiting the
production volume information in CDR. As a result, some sites that produce or use DIDP may not be
included in the CDR dataset and the total production volume for a given OES may be under or
overestimated. The extent to which sites that are not captured in the CDR reports release DIDP into the
environment is unknown. The media of release for these sites is also unknown.
CDR information on the downstream use of DIDP at facilities is also limited; therefore, there is some
uncertainty as to the production volume attributed to a given OES. For OES with limited CDR data,
EPA used a 2004 DIDP Risk Assessment published by the European Union, Joint Research Centre and a
DIDP report presented by the American Chemistry Council (ACC) to determine approximate production
volumes (ECJRC. 2003a). The ACC report indicates that the use rate of DIDP in the United States is
similar to the production volume in the European Union (ACC. 2020). EPA calculated the production
volume for a given OES as the use rate percentage of the total production volume for the relevant OES
as defined in the EU Risk Assessment. Specifically, the EU Risk Assessment assumed that 1.1 percent
of the total DIDP production volume was used in non-polymer materials (e.g., paints, coatings,
adhesives, sealants). EPA spilt this percentage equally between paint/coating, adhesive/sealant, and
other formulation use cases. Due to these uncertainties, the total production volume attributed to a given
OES may be under or overestimated.
Furthermore, DIDP releases at each site may vary from day-to-day such that on any given day the actual
daily release rate may be higher or lower than the estimated average daily release rate.
• Use of Census Bureau for Number of Facilities - In some cases, EPA estimated the maximum
number of facilities for a given OES using data from the U.S. Census. In such cases, the
maximum number of sites for use in Monte Carlo estimations were determined based on industry
data from the U.S. Census Bureau, County and Business Patterns dataset. (\] S Census Bureau.
2022).
• Uncertainties Associated with Number of Release Days Estimate - For most OES, EPA
estimated the number of release days using data from GSs, ESDs, or SpERC factsheets. In such
cases, EPA used applicable sources to estimate a range of release days over the course of an
operating year. Due to uncertainty in DIDP-specific facility operations, release days may be
under or overestimated.
• Uncertainties Associated with DIDP-Containing Product Concentrations - In most cases,
the number of identified products for a given OES were limited. In such cases, EPA estimated a
range of possible concentrations for products in the OES. However, the extent to which these
products represent all DIDP-containing products within the OES is uncertain. For OES with
little-to-no product data, EPA estimated DIDP concentrations from GSs or ESDs. Due to these
uncertainties, the average product concentrations may be under or overestimated.
3.3 Summary of Concentrations of DIDP in the Environment
Based off the environmental release assessment summarized in Section 3.2 and presented in EPA's
Draft Environmental Release and Occupational Exposure Assessment for Diisodecyl Phthalate (DIDP)
( ), DIDP is expected to be released to the environment via air, water, biosolids, and
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disposal to landfills. Environmental media concentrations were quantified in ambient air, soil from
ambient air deposition, surface water, and sediment. Additional analysis of surface water used as
drinking water was conducted for the Human Health Risk Assessment (Section 4.1.3). Given the
physical chemical properties and fate parameters of DIDP (Section 2), concentrations of DIDP in soil
and groundwater from releases to biosolids and landfills were not quantified. Instead, DIDP in soil and
groundwater are discussed qualitatively. EPA relied on its fate assessment to determine which
environmental pathways to consider for its screening level analysis of environmental exposure and
general population exposure. Details on the environmental partitioning and media assessment can be
found in Draft Fate Assessment for DIDP ( 024f) and its use for determining pathways to
assess are detailed in Draft Environmental Media and General Population Screening for Diisodecyl
Phthalate (DIDP) ( 2024d). Briefly, based on DIDP's fate parameters, EPA anticipated DIDP
to be expected predominantly in water, soil, and sediment, with DIDP in soils attributable to air to soil
deposition and land application of biosolids. Therefore, EPA quantitatively assessed concentrations of
DIDP in surface water, sediment, and soil from air to soil deposition. Ambient air concentrations were
quantified for the purpose of estimating soil concentrations from air to soil deposition but was not used
for the exposure assessment as DIDP was not assumed to be persistent in the air (ti/2 = 7.6 hours
(Mackav et al. 2006b)) and partitioning analysis showed DIDP partitions primarily to soil, compared to
air, water, and sediment, even in air releases. Soil concentration of DIDP from land applications and
resulting concentrations in groundwater were not quantitatively assessed in the screening level analysis
as DIDP was expected to have limited persistence potential and mobility in soils receiving biosolids.
Further detail on the screening-level assessment of each environmental pathway can be found in EPA's
Draft Environmental Media and General Population Screening for Diisodecyl Phthalate (DIDP) (U.S.
E 24d). Screening level assessments are useful when there is little location- or scenario-specific
information available. Because of limited environmental monitoring data and lack of location data for
DIDP releases, EPA began its environmental and general population exposure assessment with a
screening-level approach using the highest modeled environmental media concentrations for the
environmental pathways expected to be of greatest concern. Details on the use of screening-level
analyses in exposure assessment can be found in EPA's Guidelines for Human Exposure Assessment
(U.S. EPA. 2019b)
In addition to considering the most likely environmental pathways for DIDP exposure based on the fate
properties of DIDP, EPA considered the highest potential environmental media concentrations for the
purpose of a screening-level analysis. The highest environmental media concentrations were estimated
using the release estimates for an OES associated with a COU that resulted in the greatest modeled
concentration of DIDP in a given environmental media type. Therefore, EPA did not estimate
environmental concentrations of DIDP resulting from all OES presented in Table 3-1. The OES
resulting in the highest environmental concentration of DIDP varied by environmental media as shown
in Table 3-6.
High-end concentration of DIDP in surface water and soil from air to soil deposition were estimated for
the purpose of risk screening for environmental exposure described in EPA's Draft Environmental
Exposure Assessment for DIDP (\ c< « ^ \ I.) and for general population exposure described in
EPA's Draft Environmental Media and General Population Screening for Diisodecyl Phthalate (DIDP)
( Z024d). Ambient air concentrations were quantified to estimate soil concentrations from air
to soil deposition. However, ambient air concentrations themselves were not used for the environmental
or general population exposure as it was not expected to be a major exposure pathway of concern. Table
3-6 summarizes the highest concentrations of DIDP estimated in different environmental media based
on releases to the environment from various OES associated with COUs. This means that the PVC
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Plastics Compounding OES yielded the highest water concentrations using a 7Q10 flow and highest soil
concentration compared to any other OES. The Use of Lubricants and Functional Fluids OES yielded
the highest water concentration using a 30Q5 flow compared to any other OES. The summary table also
indicates whether the high-end estimate was used for environmental exposure assessment or general
population exposure assessment. For the screening-level analysis, if the high-end environmental media
concentrations did not result in potential environmental or human health risk, no further OES were
assessed. For the surface water component of this screening analysis, only the OES resulting in the
highest estimated sediment concentrations was carried forward to the environmental risk assessment
(PVC plastics compounding), and only the OES resulting in the highest estimated water column
concentrations was carried forward to the human health risk assessment (Use of lubricants and
functional fluids).
Table 3-6. Summary of High-End DIDP Concentrations in Various Environmental Media from
Environmental Releases
OES
Release
Media
Environmental Media
DIDP
Concentration
Environmental or
General Population
PVC plastics
compounding
Water
Total Water Column (7Q10)
7,460 ng/L
Environmental
Benthic Pore Water (7Q10)
4,760 ng/L
Environmental
Benthic Sediment (7Q10)
27,600 mg/kg
Environmental
Fugitive
Air
Soil (Air to Soil Deposition 100 m)
1,850 (xg/kg
General Population
Soil (Air to Soil Deposition 1,000 m)
13 (ig/kg
Environmental
Use of
lubricants and
functional fluids
Water
Surface Water (30Q5)
9,110 Mg/L
General Population
Surface Water (Harmonic Mean)
7,450 ng/L
General Population
"Table 3-1 provides the crosswalk of OES to COUs.
3.3.1 Weight of Scientific Evidence Conclusion
Detailed discussion of the strengths, limitations, and sources of uncertainty for modeled environmental
media concentration leading to a weight of scientific evidence conclusion can be found in EPA's Draft
Environmental Media and General Population Screening for Diisodecyl Phthalate (DIDP) (
20244). However, the weight of scientific evidence conclusion is summarized below for the modeled
concentrations for surface water and of soil from ambient air to soil deposition.
3.3.1.1 Surface Water
Due to the lack of release data for facilities discharging DIDP to surface waters, releases were modeled,
and the high-end estimate for each COU was applied for surface water modeling. Additionally, due to
site-specific release information, a generic distribution of hydrologic flows was developed from
facilities which had been classified under relevant NAICS codes, and which had NPDES permits citing
NHDPlus V2.1 reach codes for receiving waterbodies. From the distributions of flow statistics reported,
the median receiving waterbody represented a stream with minimal flow, dominated by the effluent
from the facility, while the lower end of the distribution represented a stream with essentially no flow
beyond the facility effluent, as described in EPA's Draft Environmental Media and General Population
Screening for Diisodecyl Phthalate (DIDP) ( ). As there was little variation between the
minimum and median stream conditions, the median flow rates selected from the generated distributions
represented conservative low flow rates from the distributions of 7Q10, 30Q5, and harmonic mean
flows. When coupled with high-end release scenarios, these low flow rates result in high modeled
instream concentrations. EPA has slight confidence in the modeled concentrations as being
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representative of actual releases, but for the purpose of a screening level assessment EPA has robust
confidence that no surface water release scenarios result in instream concentrations that exceed the
modeled concentrations presented in this evaluation. Other model inputs were derived from reasonably
available literature collected and evaluated through EPA's systematic review process for TSCA risk
evaluations. All monitoring and experimental data included in this analysis were from articles rated
"medium" or "high" quality from this process.
3.3.1.2 Ambient Air - Air to Soil Deposition
Similar to the surface water analysis, due to the lack of release data, releases were modeled using
generic scenarios and the high-end estimates for each COU was applied for ambient air modeling. With
moderate confidence in the release data detailed in Draft Release and Occupational Exposure
Assessment for Diisodecyl Phthalate ( Me) and conservative assumptions used for modeled
air dispersion and particle distribution inputs, EPA has slight confidence in the air and deposition
concentrations modeled based on EPA estimated releases being representative of actual releases, but for
the purposed of a risk screening level assessment EPA has robust confidence that it's modeled releases
used for estimating air to soil deposition is appropriately conservative for a screening level analysis.
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1099 4 HUMAN HEALTH RISK ASSESSMENT
DIDP - Human Health Risk Assessment (Section 4):
Key Points
EPA evaluated all reasonably available information to support human health risk characterization of
DIDP for workers, ONUs, consumers, bystanders, and the general population. Exposures to workers,
ONUs, consumers, bystanders, and the general population are described in Section 0. Human health
hazards are described in Section 4.2. Human health risk characterization is described in Section 4.3.
Exposure Key Points
• EPA assessed inhalation and dermal exposures for workers and ONUs, as appropriate, for each
condition of use (Section 4.1.1). However, the primary route of exposure was the inhalation route.
• EPA assessed inhalation, dermal, and oral exposures for consumers and bystanders, as appropriate,
for each condition of use (Section 4.1.2) in scenarios that represent a range of use patterns and
behaviors. The primary route of exposure was inhalation followed by ingestion.
• EPA assessed oral and dermal exposures for the general population, as appropriate, via surface
water, drinking water, soil, and fish (Sections 4.1.3 and 4.3.4).
Hazard Key Points
• EPA identified liver and developmental toxicity as the most sensitive and robust non-cancer
hazards associated with oral exposure to DIDP in experimental animal models (Section 4.2).
• A non-cancer POD of 9.0 mg/kg-day was selected to characterize non-cancer risks for acute,
intermediate, and chronic durations of exposure. The POD is from a two-generation study of rats in
which animals dosed with DIDP had litters where more infants died than was the case with the
litters of rodents that were not dosed with DIDP. A total uncertainty factor of 30 was selected for
use as the benchmark margin of exposure (Section 4.2).
• For purposes of assessing non-cancer risks, the selected POD is considered most applicable to
women of reproductive age, pregnant women, and infants. Use of this POD to assess risk for other
lifestages (e.g., toddlers, preschoolers, children of other ages, and adult males) is a conservative
approach.
• EPA reviewed the weight of evidence for the carcinogenicity of DIDP and determined that there is
Suggestive Evidence of Carcinogenic Potential of DIDP in rodents based on evidence of leukemia
in rats and liver tumors in mice. EPA did not conduct a dose-response assessment or further
evaluate DIDP for carcinogenic risk to humans.
Risk Assessment Key Points
• DIDP was evaluated for non-cancer risk.
• Inhalation exposures drive acute non-cancer risks to workers in occupational settings (Section
4.3.2).
• Inhalation exposures were found to drive acute non-cancer risks to consumers (Section 4.3.3).
• No potential non-cancer risk was identified for the general population.
• EPA considered combined exposure across all routes of exposure for each individual occupational
and consumer COU to calculate aggregate risks (Sections 4.3.2 and 4.3.3).
• EPA considered potentially exposed or susceptible subpopulation(s) (PESS) throughout the
exposure assessment and throughout the hazard identification and dose-response analysis
supporting this draft risk evaluation (Section 4.3.5).
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4.1 Summary of Human Exposures
4.1.1 Occupational Exposures
The following subsections briefly describe EPA's approach to assessing occupational exposures and
provide exposure assessment results for each OES. As stated in the Final Scope of the Risk Evaluation
for Diisodecyl phthalate (DIDP) (U.S. EPA. 2021b). EPA evaluated exposures to workers and ON Us
via the inhalation route, including incidental ingestion of inhaled dust, and exposures to workers via the
dermal route associated with the manufacturing, processing, use and disposal of DIDP. Also, EPA
analyzed dermal exposure for workers and ONUs to mists and dust that deposit on surfaces. The Draft
Environmental Release and Occupational Exposure Assessment for Diisodecyl Phthalate (DIDP) (U.S.
24e) provides additional details on the development of approaches and the exposure assessment
results.
4.1.1.1 Approach and Methodology
As described in the Final Scope of the Risk Evaluation for Diisodecyl Phthalate (DIDP) (U.S. EPA.
2 ), EPA distinguishes exposure levels among potentially exposed employees for workers and
ONUs. In general, the primary difference between workers and ONUs is that workers may handle DIDP
and have direct contact with the DIDP, while ONUs work in the general vicinity of DIDP but do not
handle DIDP. Where possible, for each condition of use, EPA identified job types and categories for
workers and ONUs.
As discussed in Section 3.1.1.1, EPA established OESs to assess the exposure scenarios more
specifically within each COU, and Table 3-1 provides a crosswalk between COUs and OESs. EPA
identified relevant inhalation exposure monitoring data for some of the OESs. EPA evaluated the quality
of this monitoring data using the data quality review evaluation metrics and the rating criteria described
in 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 (U.S.
21a). EPA assigned an overall quality level of high, medium, or low to the relevant data. In
addition, EPA established an overall confidence level for the data when integrated into the occupational
exposure assessment. EPA considered the assessment approach, the quality of the data and models, and
uncertainties in assessment results to assign an overall confidence level of robust, moderate, or slight.
Where monitoring data were reasonably available, EPA used these data to characterize central tendency
and high-end inhalation exposures. Where no inhalation monitoring data were available, but inhalation
exposure models were reasonably available, EPA estimated central tendency and high-end exposures
using only modeling approaches. If both inhalation monitoring data and exposure models were
reasonably available, EPA presented central tendency and high-end exposures using both. For inhalation
exposure to dust in occupational settings, EPA used the Generic Model for Central Tendency and High-
End Inhalation Exposure to Total andRespirable Particulates Not Otherwise Regulated (PNOR) (U.S.
2Id). In all cases of occupational dermal exposure to DIDP, EPA used a flux-limited dermal
absorption model to estimate high-end and central tendency dermal exposures for workers in each OES,
as described in the Draft Environmental Release and Occupational Exposure Assessment for Diisodecyl
Phthalate (DIDP) (U.S. EPA. 2024e).
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Figure 4-1. Approaches Used for Each Component of the Occupational Assessment for Each OES
CDR = Chemical Data Reporting; GS = Generic Scenario; ESD = Emission Scenario Document; BLS = Bureau
of Labor Statistics; NF/FF = near-field/far-field; PNOR = Particulates not Otherwise Regulated.
For inhalation and dermal exposure routes, 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. 1992). 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 99th 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. Table 4-1 provides a summary
of whether monitoring data were reasonably available for each OESs, and if data were available, the
number of data points and quality of the data. Table 4-1 also provides EPA's overall confidence rating
and whether EPA used modeling to estimate inhalation and dermal exposures for workers.
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Table 4-1. Summary of Exposure Monitoring and Modeling Data for Occupational Exposure Scenarios
Inhalation Exposure
Dermal Exposure
Monitoring
Modeling
Weight of Seientifie
Modeling
Weight of Seientifie
OES
Evidenee Conclusion
Evidenee Conelusion
Worker
# Data
Points
ONU
# Data
Points
Data
Quality
Worker
ONU
Worker
ONU
Worker
ONU
Worker
ONU
Ratings
Manufacturing
t/
2
t/
2
Medium
X
X
Moderate to
Robust
Moderate
X
Moderate
N/A
Import/
t/
2 a
t/
2a
Medium
X
X
Moderate
Moderate
X
Moderate
N/A
repackaging
Incorporation into
l/
2 a
l/
2a
High
X
X
Moderate
Moderate
l/
X
Moderate
N/A
adhesives and
sealants
Incorporation into
l/
2 a
l/
2a
High
X
X
Moderate
Moderate
l/
X
Moderate
N/A
paints and coatings
Incorporation into
l/
2 a
l/
2a
High
X
X
Moderate
Moderate
l/
X
Moderate
N/A
other formulations,
mixtures, and
reaction products
not covered
elsewhere
PVC plastics
l/1
lb
l/1
lb
High
t/
t/
Moderate
Moderate
v*
V*
Moderate
Moderate
compounding
PVC plastics
l/1
1
l/1
1
High
t/
t/
Moderate
Moderate
v*
V*
Moderate
Moderate
converting
Non-PVC material
l/1
lb
l/1
lb
High
t/
t/
Moderate
Moderate
v*
V*
Moderate
Moderate
compounding
Non-PVC material
l/
lb
1/
lb
High
l/
l/
Moderate
Moderate
l/"
i/"
Moderate
Moderate
converting
Application of
X
N/A
X
N/A
N/A
l/
Moderate
Moderate
l/
i/
Moderate
Moderate
adhesives and
sealants
Application of
X
N/A
X
N/A
N/A
l/
Moderate
Moderate
l/"
i/"
Moderate
Moderate
paints and coatings
Use of laboratory
2 a
2a
Medium
l/"
l/"
Moderate
Moderate
l/
i/
Moderate
Moderate
chemicals
Use of lubricants
2 a
2 a
Medium
X
X
Moderate
Moderate
l/
X
Moderate
N/A
and functional
fluids
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Inhalation Exposure
Dermal Exposure
Monitoring
Modeling
Weight of Scientific
Modeling
Weight of Scientific
OES
Evidence Conclusion
Evidence Conclusion
Worker
# Data
Points
ONU
# Data
Points
Data
Quality
Worker
ONU
Worker
ONU
Worker
ONU
Worker
ONU
Ratings
Use of penetrants
X
N/A
X
N/A
N/A
l/*
l/*
Moderate
Moderate
l/"
l/"
Moderate
Moderate
and inspection
fluids
Fabrication and
X
N/A
X
N/A
N/A
l/*
l/*
Moderate
Moderate
l/"
l/"
Moderate
Moderate
final use of
products or articles
Recycling and
X
N/A
X
N/A
N/A
%/
%/
Moderate
Moderate
l/"
l/"
Moderate
Moderate
disposal
" Inhalation monitoring data for exposure to vapors from the Manufacturing OES were used as surrogate data for OES where inhalation exposure comes from vapor
generating-activities only.
b Inhalation monitoring data for exposure to vapors from the PVC Plastics Converting OES were used as surrogate data for OES where inhalation exposure to vapor
occurs during the heating and cooling plastic and non-plastic polymer materials.
1166
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1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
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1183
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4.1.1.2 Summary of Number of Workers and ONUs
The Draft Environmental Release and Occupational Exposure Assessment for Diisodecyl Phthalate
(DIDP) (U .S. EPA. 2024e) provides a summary of the estimates for the total exposed workers and
ONUs for each OES. To prepare these estimates, EPA first attempted to identify relevant North
American Industrial Classification (NAICS) codes for each OES. For these NAICS codes, the Standard
Occupational Classification (SOC) codes from the Bureau of Labor Statistics (BLS) were used to
classify SOC codes as either workers or ONUs. EPA assumed that all other SOC codes represent
occupations where exposure is unlikely. EPA also estimated the total number facilities associated with
the relevant NAICS codes based on data from the U.S. Census Bureau. 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. Lastly, using estimates of the number of facilities using DIDP, the total
number of workers and ONUs potentially exposed to DIDP for each OES were estimated. The Draft
Environmental Release and Occupational Exposure Assessment for Diisodecyl Phthalate (DIDP) (U.S.
E Me) provides additional details on the approach and methodology for estimating the number of
facilities using DIDP and the number of potentially exposed workers and ONUs.
Table 4-2 summarizes the number of facilities and total number of exposed workers for all OES. For
scenarios in which the results are expressed as a range, the low end of the range represents the central
tendency result, and the upper end of the range represents the high-end result.
Table 4-2. Summary of Total Number of Workers and ONUs Potentially Exposed to DIDP for
Each OES"
OES
Total Exposed
Workers
Total Exposed
ONUs
Number of
Facilities
Notes
Manufacturing
155
71
4
Number of workers and ONU estimates based
on data from the BLS and the U.S. Census'
SUSB (U.S. BLS. 2016; U.S. Census Bureau.
2015)
Import/
Repackaging
151
41
11
Number of workers and ONU estimates based
on data from the BLS and the U.S. Census'
SUSB (U.S. BLS, 2016; U.S. Census Bureau,
2015)
Incorporation into
Adhesives and
Sealants
108 to 903
41 to 338
6 to 50
Number of workers and ONU estimates based
on data from the BLS and the U.S. Census'
SUSB (U.S. BLS, 2016; U.S. Census Bureau,
2015)
Incorporation into
Paints and
Coatings
91 to 576
27 to 170
6 to 38
Number of workers and ONU estimates based
on data from the BLS and the U.S. Census'
SUSB (U.S. BLS. 2016; U.S. Census Bureau.
2015)
Incorporation into
Other
Formulations,
Mixtures, and
Reaction Products
Not Covered
Elsewhere
51 to 102
24 to 48
1 to 2
Number of workers and ONU estimates based
on data from the BLS and the U.S. Census'
SUSB (U.S. BLS. 2016; U.S. Census Bureau.
2015)
PVC Plastics
Compounding
1,798 to 3,578
509 to 1,012
98 to 195
Number of workers and ONU estimates based
on data from the BLS and the U.S. Census'
SUSB (U.S. BLS, 2016; U.S. Census Bureau,
2015)
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OES
Total Exposed
Workers
Total Exposed
ONUs
Number of
Facilities
Notes
PVC Plastics
Converting
39,044 to
77,739
11,049 to
22,000
2,128 to
4,237
Number of workers and ONU estimates based
on data from the BLS and the U.S. Census'
SUSB (U.S. BLS, 2016; U.S. Census Bureau,
2015)
Non-PVC
Material
Compounding
90 to 203
24 to 54
4 to 9
Number of workers and ONU estimates based
on data from the BLS and the U.S. Census'
SUSB (U.S. BLS. 2016; U.S. Census Bureau.
2015)
Non-PVC
Material
Converting
4,016 to 4,783
1,068 to 1,272
178 to 212
Number of workers and ONU estimates based
on data from the BLS and the U.S. Census'
SUSB (U.S. BLS, 2016; U.S. Census Bureau,
2015)
Application of
Adhesives and
Sealants
4,523 to 56,857
1,433 to 18,012
84 to 1,056
Number of workers and ONU estimates based
on data from the BLS and the U.S. Census'
SUSB (U.S. BLS, 2016; U.S. Census Bureau,
2015)
Application of
Paints and
Coatings
2,615 to 14,631
1,140 to 6,375
222 to 1,242
Number of workers and ONU estimates based
on data from the BLS and the U.S. Census'
SUSB (U.S. BLS. 2016; U.S. Census Bureau.
2015)
Use of Laboratory
Chemicals
(Liquid)
223 to 2,075
1,964 to 18,290
225 to 2,095
Number of workers and ONU estimates based
on data from the BLS and the U.S. Census'
SUSB (U.S. BLS, 2016; U.S. Census Bureau,
2015)
Use of Laboratory
Chemicals
(Solid)
36,517
321,917
36,873
Number of workers and ONU estimates based
on data from the BLS and the U.S. Census'
SUSB (U.S. BLS, 2016; U.S. Census Bureau,
2015)
Use of Lubricants
and Functional
Fluids
228,779 to
1,620,403
56,176 to
397,887
2,596 to
18,387
Number of workers and ONU estimates based
on data from the BLS and the U.S. Census'
SUSB (U.S. BLS. 2016; U.S. Census Bureau.
2015)
Use of Penetrants
and Inspection
Fluids
203,772 to
291,282
85,651 to
122,433
15,315 to
21,892
Number of workers and ONU estimates based
on data from the BLS and the U.S. Census'
SUSB (U.S. BLS. 2016; U.S. Census Bureau.
2015)
Fabrication and
Final Use of
Products or
Articles
N/A
N/A
N/A
Number of workers and sites data were
unavailable for this OES.
Recycling and
Disposal
754
432
58
Number of workers and ONU estimates based
on data from the BLS and the U.S. Census'
SUSB (U.S. BLS. 2016; U.S. Census Bureau.
2015)
" EPA's approach and methodology for estimating the number of facilities using DIDP and the number of workers and
ONUs potentially exposed to DIDP can be found in Draft Environmental Release and Occupational Exposure Assessment
for Diisodecyl Phthalate (DIDP) (US. EPA. 2024s).
1189 4.1.1.3 Summary of Inhalation Exposure Assessment
1190 Table 4-3 presents a summary of inhalation exposure results based on monitoring data and exposure
1191 modeling for the various OESs. This tables provides a summary of the 8-hour time weighted average (8-
1192 hour TWA) inhalation exposure estimates, as well as the Acute Dose (AD), the Intermediate Average
1193 Daily Dose (IADD), and the Average Daily Dose (ADD). The Draft Environmental Release and
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Occupational Exposure Assessment for Diisodecyl Phthalate (DIDP) ( >24e) provides
exposure results for females of reproductive age and ONUs. The Draft Environmental Release and
Occupational Exposure Assessment for Diisodecyl Phthalate (DIDP) ( >24e) also provides
additional details regarding AD, IADD, and ADD calculations along with EPA's approach and
methodology for estimating inhalation exposures.
Table 4-3. Summary of Average Adult Worker Inhalation Exposure Results for Each PES
Inhalation Estimates (Average Adult Worker)
OES
Vapor/Mist 8-Hr
TWA (mjj/m3)
PNOR 8-hr
TWA (mjj/m3)
A
(m«/k
D
g/dav)
IADD (mj^/kji/tlay)
ADD
(mg/kjj/dav)
HE
CT
HE
CT
HE
CT
HE
CT
HE
CT
Manufacturing
7.2E-02
3.6E-02
N/A
N/A
9.0E-03
4.5E-03
6.6E-03
3.3E-03
4.4E-03
2.2E-03
Import/
Repackaging
7.2E-02
3.6E-02
N/A
N/A
9.0E-03
4.5E-03
6.6E-03
3.3E-03
6.2E-03
2.6E-03
Incorporation into
Adhesives and
3.0E-02
3.0E-02
N/A
N/A
3.8E-03
3.8E-03
2.8E-03
2.8E-03
2.6E-03
2.6E-03
Sealants
Incorporation into
Paints and
Coatings
3.0E-02
3.0E-02
N/A
N/A
3.8E-03
3.8E-03
2.8E-03
2.8E-03
2.6E-03
2.6E-03
Incorporation into
Other
Formulations,
Mixtures, and
Reaction Products
Not Covered
Elsewhere
3.0E-02
3.0E-02
N/A
N/A
3.8E-03
3.8E-03
2.8E-03
2.8E-03
2.6E-03
2.6E-03
PVC Plastics
Compounding
3.0E-02
3.0E-02
2.1
0.10
0.27
1.7E-02
0.20
1.2E-02
0.18
1.0E-02
PVC Plastics
Converting
3.0E-02
3.0E-02
2.1
0.10
0.27
1.7E-02
0.20
1.2E-02
0.18
1.0E-02
Non-PVC Material
Compounding
3.0E-02
3.0E-02
0.94
4.6E-02
0.12
9.5E-03
8.9E-02
7.0E-03
8.3E-02
6.10E-03
Non-PVC Material
Converting
3.0E-02
3.0E-02
0.94
4.6E-02
0.12
9.5E-03
8.9E-02
7.0E-03
8.3E-02
5.7E-03
Application of
Adhesives and
Sealants
22
0.14
N/A
N/A
2.8
1.7E-02
2.0
1.2E-02
1.9
1.1E-02
Application of
Paints and
Coatings
2.2
0.14
N/A
N/A
0.28
1.7E-02
0.20
1.2E-02
0.19
1.2E-02
Use of Laboratory
Chemicals - Liquid
7.2E-02
3.6E-02
N/A
N/A
9.0E-03
4.5E-03
6.6E-03
3.3E-03
6.2E-03
2.9E-03
Use of Laboratory
Chemicals - Solid
N/A
N/A
8.1E-0
2
5.7E-03
1.0E-02
7.1E-04
7.4E-03
5.2E-04
6.9E-03
4.9E-04
Use of Lubricants
and Functional
Fluids
7.2E-02
3.6E-02
N/A
N/A
9.0E-03
4.5E-03
1.2E-03
3.0E-04
9.9E-05
2.5E-05
Use of Penetrants
and Inspection
Fluids
5.6
1.5
N/A
N/A
0.70
0.19
0.51
0.14
0.47
0.13
Fabrication and
Final Use of
Products or
Articles
N/A
N/A
0.81
9.0E-02
0.10
1.1E-02
7.4E-02
8.3E-03
6.9E-02
7.7E-03
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OES
Inhalation Estimates (Average Adult Worker)
Vapor/Mist 8-Hr
TWA (mjj/m3)
PNOR 8-hr
TWA (mjj/m3)
AD
(m"/k"/d av)
IADD (m^/kjj/day)
ADD
(m"/k"/dav)
HE
CT
HE
CT
HE
CT
HE
CT
HE
CT
Recycling and
Disposal
N/A
N/A
1.6
0.11
0.20
1.4E-02
0.14
9.9E-03
0.13
8.2E-03
AD = acute dose; ADD = average daily dose; CT = central tendency; HE = high-end; IADD = intermediate average daily
dose; PNOR = Particulates Not Otherwise Regulated; TWA = time-weighted average
4.1.1.4 Summary of Dermal Exposure Assessment
Table 4-4 presents a summary of dermal exposure results, which are based on both empirical dermal
absorption data and dermal absorption modeling estimation efforts. This tables provides a summary of
the Acute Potential Dose Rate (APDR) for occupational dermal exposure estimates, as well as the Acute
Dose (AD), the Intermediate Average Daily Dose (IADD), and the Average Daily Dose (ADD). The
Draft Environmental Release and Occupational Exposure Assessment for Diisodecyl Phthalate (DIDP)
( ) provides exposure results for females of reproductive age and ONUs. The Draft
Environmental Release and Occupational Exposure Assessment for Diisodecyl Phthalate (DIDP) (U.S.
E Me) also provides additional details regarding AD, IADD, and ADD calculations along with
EPA's approach and methodology for estimating dermal exposures.
Table 4-4. Summary of Average Adult Worker Dermal Exposure Results for Each PES
OES
Dermal Estimates (Average Adult Worker)
Exposure
Tvpe
APDR
(mjj/dav)
AD
(m<;/k<;/d ay)
IADD
(mjj/kjj/day)
ADD (mjj/kg/day)
Liquid
Solid
HE
CT
HE
CT
HE
CT
HE
CT
Manufacturing
X
7.3
3.7
9.2E-02
4.6E-02
6.7E-02
3.4E-02
4.5E-02
2.3E-02
Import/
Repackaging
X
7.3
3.7
9.2E-02
4.6E-02
6.7E-02
3.4E-02
6.3E-02
2.6E-02
Incorporation into
Adhesives and Sealants
X
7.3
3.7
9.2E-02
4.6E-02
6.7E-02
3.4E-02
6.3E-02
3.1E-02
Incorporation into
Paints and Coatings
X
7.3
3.7
9.2E-02
4.6E-02
6.7E-02
3.4E-02
6.3E-02
3.1E-02
Incorporation into
Other Formulations,
Mixtures, and Reaction
Products Not Covered
Elsewhere
X
7.3
3.7
9.2E-02
4.6E-02
6.7E-02
3.4E-02
6.3E-02
3.1E-02
PVC Plastics
Compounding
X
X
7.3
3.7
9.2E-02
4.6E-02
6.7E-02
3.4E-02
6.3E-02
2.8E-02
PVC Plastics
Converting
X
7.7E-02
3.8E-02
9.6E-04
4.8E-04
7.1E-04
3.5E-04
6.6E-04
2.9E-04
Non-PVC Material
Compounding
X
X
7.3
3.7
9.2E-02
4.6E-02
6.7E-02
3.4E-02
6.3E-02
2.9E-02
Non-PVC Material
Converting
X
7.7E-02
3.8E-02
9.6E-04
4.8E-04
7.1E-04
3.5E-04
6.6E-04
2.9E-04
Application of
Adhesives and Sealants
X
7.3
3.7
9.2E-02
4.6E-02
6.7E-02
3.4E-02
6.3E-02
2.9E-02
Application of Paints
and Coatings
X
7.3
3.7
9.2E-02
4.6E-02
6.7E-02
3.4E-02
6.3E-02
3.1E-02
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OES
Dermal Estimates (Average Adult Worker)
Exposure
Type
APDR
(mjj/dav)
AD
(nig/kg/day)
IADD
(mjj/kjj/day)
ADD (mjj/kg/day)
Liquid
Solid
HE
CT
HE
CT
HE
CT
HE
CT
Use of Laboratory
Chemicals - Liquid
X
7.3
3.7
9.2E-02
4.6E-02
6.7E-02
3.4E-02
6.3E-02
3.0E-02
Use of Laboratory
Chemicals - Solid
X
7.7E-02
3.8E-02
9.6E-04
4.8E-04
7.1E-04
3.5E-04
6.6E-04
3.3E-04
Use of Lubricants and
Functional Fluids
X
7.3
3.7
9.2E-02
4.6E-02
1.2E-02
3.1E-03
1.0E-03
2.5E-04
Use of Penetrants and
Inspection Fluids
X
7.3
3.7
9.2E-02
4.6E-02
6.7E-02
3.4E-02
6.3E-02
3.1E-02
Fabrication and Final
Use of Products or
Articles
X
7.7E-02
3.8E-02
9.6E-04
4.8E-04
7.1E-04
3.5E-04
6.6E-04
3.3E-04
Recycling and Disposal
X
7.7E-02
3.8E-02
9.6E-04
4.8E-04
7.1E-04
3.5E-04
6.6E-04
2.9E-04
Abbreviations: AD = acute dose; ADD = average daily dose; APDR = Acute Potential Dose Rate; CT = central tendency;
HE = high-end; IADD = intermediate average daily dose
4.1.1.5 Weight of Scientific Evidence Conclusions for Occupational Exposure
Judgment on the weight of scientific evidence is based on the strengths, limitations, and uncertainties
associated with the release 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 relevance, 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 (U.S. EPA. 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 the 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
supporting TSCA risk evaluations for chemical substances, Version 1.0: A generic TSCA systematic
review protocol with chemical-specific methodologies ( ) for additional information on
weight of scientific evidence conclusions. Table 4-5 summarizes the overall weight of scientific
evidence conclusions for exposure assessments for each OES.
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1232 Table 4-5. Summary of Overall Confidence in Occupational Exposure Estimates by PES
OES
Weight of Scientific Evidence Conclusion in Occupational Exposures
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 is the use of
directly applicable monitoring data, which are preferrable to other assessment approaches such as modeling or the use of OELs. EPA used PBZ
air concentration data to assess inhalation exposures, with the data source having a high data quality rating from the systematic review process
(ExxonMobil 2022a). Data from these sources were DIDP-specific from a DIDP manufacturing facility, though it is uncertain whether the
measured concentrations accurately represent the entire industry. A further strength of the data is that it was compared against an EPA
developed Monte Carlo model and the data points from ExxonMobil were found to be more protective.
The primary limitations of these data include the uncertainty of the representativeness of these data toward the true distribution of inhalation
concentrations in this scenario, that the data come from one industry-source, and that 100% of the data for both workers and ONUs from the
source were reported as below the LOD. EPA also assumed 8 exposure hours per day and 180 exposure days per year based on a manufacturing
site reporting half-vear DIDP campaign runs (ExxonMobil 2022a); it is uncertain whether this captures actual worker schedules and exposures
at that and other manufacturing sites.
Based on these strengths and limitations, EPA has concluded that the weight of scientific evidence for this assessment is moderate to robust and
provides a plausible estimate of exposures.
Import and
Repackaging
EPA used surrogate manufacturing data to estimate worker inhalation exposures due to limited data. Import and repackaging inhalation
exposures were estimated using the manufacturing inhalation exposure as a surrogate. The primary strength is the use of monitoring data, which
are preferrable to other assessment approaches such as modeling or the use of OELs. EPA used PBZ air concentration data to assess inhalation
exposures, with the data source having a high data duality rating from the systematic review process (ExxonMobil 2022a). Data from these
sources were DIDP-specific from a DIDP manufacturing facility, 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 this OES and the true distribution of
inhalation concentrations in this scenario; that the data come from one industry-source; and that 100% of the data for both workers and ONUs
from the source were reported as below the LOD. The high-end exposures are based on 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 208 days per year as the exposure frequency based on the 50th percentile of operating days from the release
assessment. 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.
Based on these strengths and limitations, EPA has concluded that the weight of scientific evidence for this assessment is moderate and provides
a plausible estimate of exposures.
Incorporation
into Adhesives
and Sealants
EPA used surrogate data to estimate worker inhalation exposures due to limited data. Incorporation into adhesives and sealants exposures were
estimated using the PVC plastics converting OES inhalation exposure as a surrogate estimate. The primary strength is the use of monitoring
data, which are preferrable to other assessment approaches such as modeling or the use of OELs. EPA used both PBZ and stationary air
concentration data to assess inhalation exposures. The PBZ data are surrogate for an ONU exposed to DINP and the area sample is a DPHP
sample taken adjacent to two extruders in plastic cable manufacturing. Both data sources have a high data quality rating from the systematic
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review process (Irwin, lull: Porras ei al, zuiu). Data from these sources arc specific to a PVC clastic converting facilitv. 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 in this scenario, that the data come from one datapoint from each source, and that 100% of the data for both workers and ONUs
from the source were reported as below the LOD. EPA also assumed 8 exposure hours per day and 250 exposure days per year based on
continuous DIDP exposure each working day for a typical worker schedule; it is uncertain whether this captures actual worker schedules and
exposures.
Based on these strengths and limitations, EPA has concluded that the weight of scientific evidence for this assessment is moderate and provides
a plausible estimate of exposures.
Incorporation
into Paints and
Coatings
EPA used surrogate data to estimate worker inhalation exposures due to limited data. Incorporation into paints and coatings exposures were
estimated using the PVC plastics converting OES inhalation exposure as a surrogate estimate. The primary strength is the use of monitoring
data, which is preferrable to other assessment approaches such as modeling or the use of OELs. EPA used both PBZ and stationary air
concentration data to assess inhalation exposures. The PBZ data are surrogate for an ONU exposed to DINP and the area sample is a DPHP
sample taken adjacent to two extruders in plastic cable manufacturing. Both data sources have a high data quality rating from the systematic
review process (Irwin, 2022; Porras et aL, 2020). Data from these sources are specific to a PVC plastic converting facilitv. 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 in this scenario, that the data come from one datapoint from each source, and that 100% of the data for both workers and ONUs
from the source were reported as below the LOD. EPA also assumed 8 exposure hours per day and 250 exposure days per year based on
continuous DIDP exposure each working day for a typical worker schedule; it is uncertain whether this captures actual worker schedules and
exposures.
Based on these strengths and limitations, EPA has concluded that the weight of scientific evidence for this assessment is moderate and provides
a plausible estimate of exposures.
Incorporation
into Other
Formulations,
Mixtures, and
Reaction
Products Not
Covered
Elsewhere
EPA used surrogate data to estimate worker inhalation exposures due to limited data. Incorporation into other formulations, mixtures, and
reaction products not covered elsewhere exposures were estimated using the PVC plastics converting OES inhalation exposure as a surrogate
estimate. The primary strength is the use of monitoring data, which are preferrable to other assessment approaches such as modeling or the use
of OELs. EPA used both PBZ and stationary air concentration data to assess inhalation exposures. The PBZ data are surrogate for an ONU
exposed to DINP and the area sample is a DPHP sample taken adjacent to two extruders in plastic cable manufacturing. Both data sources have
a high data aualitv rating from the systematic review process (Irwin. 2022; Porras et al.. 2020). Data from these sources are specific to a PVC
plastic converting facility, 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 in this scenario, that the data come from one datapoint from each source, and that 100% of the data for both workers and ONUs
from the source were reported as below the LOD. EPA also assumed 8 exposure hours per day and 250 exposure days per year based on
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continuous DIDP exposure each working day for a typical worker schedule; it is uncertain whether this captures actual worker schedules and
exposures.
Based on these strengths and limitations, EPA has concluded that the weight of scientific evidence for this assessment is moderate and provides
a plausible estimate of exposures.
PVC Plastics
Compounding
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-hr TWA inhalation exposure estimates. EPA used surrogate data to estimate worker inhalation exposures due to
limited data. PVC plastics compounding exposures were estimated using the PVC plastics converting OES inhalation exposure as a surrogate
bounding estimate. The primary strength is the use of monitoring data, which are preferrable to other assessment approaches such as modeling
or the use of OELs. EPA used both PBZ and stationary air concentration data to assess inhalation exposures. The PBZ data are surrogate from
for an ONU exposed to DINP and the area sample is a DPHP sample taken adjacent to two extruders in plastic cable manufacturing. Both data
sources have a high data aualitv ratine from the systematic review process (Irwin. 2022; Porras et al. 2020). Data from these sources are
specific to a PVC plastic converting facility, though it is uncertain whether the measured concentrations accurately represent the entire industry.
Compounding activities are also expected to generate dust from the solid product; therefore, EPA incorporated the Generic Model for Central
Tendency and High-End Inhalation Exposure to Total and Respirable Particulates Not Otherwise Regulated (PNOR) into the assessment to
estimate worker inhalation exposure to solid particulate. The respirable PNOR range was refined using OSHA CEHD data sets, which the
systematic review process rated high for data aualitv (OSHA, 2020). EPA estimated the highest expected concentration of DIDP in plastic
using industry provided data on DIDP concentration in PVC, which were also rated high for data quality in the systematic review process.
The primary limitations of these data include the uncertainty of the representativeness of the monitoring data and PNOR model toward the true
distribution of inhalation concentrations in this scenario, that the monitoring data come from one datapoint from each source, that 100% of the
data for both workers and ONUs from the source were reported as below the LOD, and that the OSHA CEHD data are not specific to DIDP.
The high-end exposures are based on 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 223 days per
year as the exposure frequency based on the 50th percentile of operating days from the release assessment. 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.
Based on these strengths and limitations, EPA has concluded that the weight of scientific evidence for this assessment is moderate and provides
a plausible estimate of exposures.
PVC Plastics
Converting
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 PVC Plastics Converting OES. The primary strength is the use
of directly applicable monitoring data, which are preferrable to other assessment approaches such as modeling or the use of OELs. EPA used
both PBZ and stationary air concentration data to assess inhalation exposures. The PBZ data are surrogate from for an ONU exposed to DINP
and the area sample is a DPHP sample taken adjacent to two extruders in plastic cable manufacturing. Both data sources have a high data
quality ratine from the systematic review process (Irwin, 2022; Porras et al., 2020). Data from these sources are specific to a PVC plastic
converting facility, though it is uncertain whether the measured concentrations accurately represent the entire industry. Converting activities are
also expected to generate dust from the solid product; therefore, EPA incorporated the Generic Model for Central Tendency and High-End
Inhalation Exposure to Total and Respirable Particulates Not Otherwise Regulated (PNOR) into the assessment to estimate worker inhalation
exposure to solid particulate. The respirable PNOR range was refined using OSHA CEHD data sets, which the systematic review process rated
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high for data quality (usM, lulu). EPA estimated the highest expected concentration of D1DP in plastic using industry provided data on
DIDP concentration in PVC, which were also rated high for data quality in the systematic review process.
The primary limitations of these data include the uncertainty of the representativeness of the monitoring data and PNOR model toward the true
distribution of inhalation concentrations in this scenario, that the monitoring data come from one datapoint from each source, that 100% of the
data for both workers and ONUs from the source were reported as below the LOD, and that the OSHA CEHD data are not specific to DIDP.
The high-end exposures are based on 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 219 days per
year as the exposure frequency based on the 50th percentile of operating days from the release assessment. 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.
Based on these strengths and limitations, EPA has concluded that the weight of scientific evidence for this assessment is moderate and provides
a plausible estimate of exposures.
Non-PVC
Material
Compounding
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-hr TWA inhalation exposure estimates. EPA used surrogate data to estimate worker inhalation exposures due to
limited data. Non-PVC material compounding exposures were estimated using the PVC plastics converting OES inhalation exposure as a
surrogate bounding estimate. The primary strength is the use of monitoring data, which are preferrable to other assessment approaches such as
modeling or the use of OELs. EPA used both PBZ and stationary air concentration data to assess inhalation exposures. The PBZ data are
surrogate from for an ONU exposed to DINP and the area sample is a DPHP sample taken adjacent to two extruders in plastic cable
manufacturing. Both data sources have a high data aualitv rating from the systematic review process (Irwin, 2022; Porras et aL, 2020). Data
from these sources are specific to a PVC plastic converting facility, though it is uncertain whether the measured concentrations accurately
represent the entire industry. Compounding activities are also expected to generate dust from the solid product; therefore, EPA incorporated the
Generic Model for Central Tendency and High-End Inhalation Exposure to Total and Respirable Particulates Not Otherwise Regulated (PNOR)
into the assessment to estimate worker inhalation exposure to solid particulate. The respirable PNOR range was refined using OSHA CEHD
data sets, which the systematic review process rated high for data aualitv (OSHA. 2020). EPA estimated the highest expected concentration of
DIDP in plastic using industry provided data on DIDP concentration in PVC, which were also rated high for data quality in the systematic
review process.
The primary limitations of these data include the uncertainty of the representativeness of the monitoring data and PNOR model toward the true
distribution of inhalation concentrations in this scenario, that the monitoring data come from one datapoint from each source, that 100% of the
data for both workers and ONUs from the source were reported as below the LOD, and that the OSHA CEHD data are not specific to DIDP.
The high-end exposures are based on 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 234 days per
year as the exposure frequency based on the 50th percentile of operating days from the release assessment. 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.
Based on these strengths and limitations, EPA has concluded that the weight of scientific evidence for this assessment is moderate and provides
a plausible estimate of exposures.
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Non-PVC
Material
Converting
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-hr TWA inhalation exposure estimates. EPA used surrogate data to estimate worker inhalation exposures due to
limited data. Non-PVC material converting exposures were estimated using the PVC plastics converting OES inhalation exposure as a surrogate
bounding estimate. The primary strength is the use of monitoring data, which are preferrable to other assessment approaches such as modeling
or the use of OELs. EPA used both PBZ and stationary air concentration data to assess inhalation exposures. The PBZ data are surrogate from
for an ONU exposed to DINP and the area sample is a DPHP sample taken adjacent to two extruders in plastic cable manufacturing. Both data
sources have a high data quality ratine from the systematic review process (Irwin, 2022; Porras et aL, 2020). Data from these sources are
specific to a PVC plastic converting facility, though it is uncertain whether the measured concentrations accurately represent the entire industry.
Converting activities are also expected to generate dust from the solid product; therefore, EPA incorporated the Generic Model for Central
Tendency and High-End Inhalation Exposure to Total and Respirable Particulates Not Otherwise Regulated (PNOR) into the assessment to
estimate worker inhalation exposure to solid particulate. The respirable PNOR range was refined using OSHA CEHD data sets, which the
systematic review process rated high for data aualitv (OSHA. 2020). EPA estimated the highest expected concentration of DIDP in plastic
using industry provided data on DIDP concentration in PVC, which were also rated high for data quality in the systematic review process.
The primary limitations of these data include the uncertainty of the representativeness of the monitoring data and PNOR model toward the true
distribution of inhalation concentrations in this scenario, that the monitoring data come from one datapoint from each source, that 100% of the
data for both workers and ONUs from the source were reported as below the LOD, and that the OSHA CEHD data are not specific to DIDP.
The high-end exposures are based on 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 219 days per
year as the exposure frequency based on the 50th percentile of operating days from the release assessment. 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.
Based on these strengths and limitations, EPA has concluded that the weight of scientific evidence for this assessment is moderate and provides
a plausible estimate of exposures.
Application of
Adhesives and
Sealants
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-hr TWA inhalation exposure estimates. EPA used surrogate monitoring data from the ESD on Coating
Application via Spray-Painting in the Automotive Refinishing Industry, which the systematic review process rated high for data quality, to
estimate inhalation exposures (OE ). EPA used SDSs and product data sheets from identified DIDP-containing adhesives and sealant
products to identify product concentrations.
The primary limitation is the lack of DIDP-specific monitoring data, with the ESD serving as a surrogate source of monitoring data representing
the level of exposure that could be expected at a typical work site for the given spray application method. EPA assumes spray applications of
the adhesives and sealants, so the estimates may not be representative of exposure during other application methods. Additionally, it is
uncertain whether the substrates bonded, and products used to generate the surrogate data are representative of those associated with DIDP-
containing adhesives and sealants. EPA only assessed mist exposures to DIDP over a full 8-hour work shift to estimate the level of exposure,
though other activities may result in vapor exposures other than mist and application duration may be variable depending on the job site. The
high-end exposures are based on 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
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year as the exposure frequency based on the 50th percentile of operating days from the release assessment. 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.
Based on these strengths and limitations, EPA has concluded that the weight of scientific evidence for this assessment is moderate and provides
a plausible estimate of exposures.
Application of
Paints and
Coatings
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-hr TWA inhalation exposure estimates. EPA used surrogate monitoring data from the ESD on Coating
Application via Spray-Painting in the Automotive Refinishing Industry, which the systematic review process rated high for data quality, to
estimate inhalation exposures fOE ). EPA used SDSs and product data sheets from identified DIDP-containing products to identify
product concentrations.
The primary limitation is the lack of DIDP-specific monitoring data, with the ESD serving as a surrogate source of monitoring data representing
the level of exposure that could be expected at a typical work site for the given spray application method. EPA assumes spray applications of
the coatings, so the estimates may not be representative of exposure during other coating application methods. Additionally, it is uncertain
whether the substrates coated, and products used to generate the surrogate data are representative of those associated with DIDP-containing
coatings. EPA only assessed mist exposures to DIDP over a full 8-hour work shift to estimate the level of exposure, though other activities may
result in vapor exposures other than mist and application duration may be variable depending on the job site. EPA assessed 250 days of
exposure per year based on workers applying coatings on every working day, however, application sites may use DIDP-containing coatings at
much lower or variable frequencies.
Based on these strengths and limitations, EPA has concluded that the weight of scientific evidence for this assessment is moderate and provides
a plausible estimate of exposures.
Use of
Laboratory
Chemicals
EPA used surrogate data to estimate worker vapor inhalation exposures due to limited data. Use of laboratory chemicals inhalation exposures
were estimated using the manufacturing inhalation exposure as a surrogate bounding estimate. The primary strength is the use of monitoring
data, which are preferrable to other assessment approaches such as modeling or the use of OELs. EPA used PBZ air concentration data to assess
inhalation exposures, with the data source having a high data duality rating from the systematic review process (ExxonMobil 2022a). Data
from these sources were DIDP-specific from a DIDP manufacturing facility, 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 this OES and the true distribution of
inhalation concentrations in this scenario; that the data come from one industry-source; and that 100% of the data for both workers and ONUs
from the source were reported as below the LOD. The high-end and central tendency exposures to solid laboratory chemicals 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. The high-end and central tendency exposures to liquid laboratory chemicals use 235
days per year and 250 days per year, respectively, as the exposure frequencies. 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.
Based on these strengths and limitations, EPA has concluded that the weight of scientific evidence for this assessment is moderate and provides
a plausible estimate of exposures.
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Use of
Lubricants and
Functional
Fluids
EPA used surrogate data to estimate worker inhalation exposures due to limited data. Use of lubricants and functional fluids inhalation
exposures were estimated using the manufacturing inhalation exposure as a surrogate bounding estimate. The primary strength is the use of
monitoring data, which are preferrable to other assessment approaches such as modeling or the use of OELs. EPA used PBZ air concentration
data to assess inhalation exposures, with the data source having a high data quality ratine from the systematic review process (ExxonMobil
2022a). Data from these sources were DIDP-specific from a DIDP manufacturing facility, 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 this OES and the true distribution of
inhalation concentrations in this scenario; that the data come from one industry-source; and that 100% of the data for both workers and ONUs
from the source were reported as below the LOD. 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 2 days per year as the exposure frequency based
on the 50th percentile of operating days from the release assessment. 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.
Based on these strengths and limitations, EPA has concluded that the weight of scientific evidence for this assessment is moderate and provides
a plausible 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-hr TWA inhalation exposure estimates. EPA utilized a near-field/far-field approach ( I. 2009). 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 DIDP-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 DIDP-
containing penetrants and inspection fluids is not known. 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. 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.
Based on these strengths and limitations, EPA has concluded that the weight of scientific evidence for this assessment is moderate and provides
a plausible estimate of exposures.
Fabrication and
Final Use of
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-hr TWA inhalation exposure estimates. EPA utilized the Generic Model for Central Tendency and High-End
Inhalation Exposure to Total and Respirable Particulates Not Otherwise Regulated (PNOR) to estimate worker inhalation exposure to solid
particulate. The respirable PNOR range was refined using OSHA CEHD data sets, which the systematic review process rated high for data
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Products or
Articles
quality (usha, lulu). EPA estimated the highest expected concentration of D1DP in plastic using industry provided data on D1DP
concentration in PVC, which were also rated high for data quality in the systematic review process.
The primary limitation is the uncertainty in the representativeness of values toward the true distribution of potential inhalation exposures.
Additionally, the representativeness of the CEHD data set and the identified DIDP concentrations in plastics for this specific fabrication and
final use of products or articles is uncertain. EPA lacks facility and DIDP-containing product fabrication and use rates, methods, and operating
times and EPA assumed eight exposure hours per day and 250 exposure days per year based on continuous DIDP exposure each working day
for a typical worker schedule; it is uncertain whether this captures actual worker schedules and exposures.
Based on these strengths and limitations, EPA has concluded that the weight of scientific evidence for this assessment is moderate and provides
a plausible estimate of exposures.
Recycling 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 8-hr TWA inhalation exposure estimates. EPA utilized the Generic Model for Central Tendency and High-End
Inhalation Exposure to Total and Respirable Particulates Not Otherwise Regulated (PNOR) to estimate worker inhalation exposure to solid
particulate. The respirable PNOR range was refined using OSHA CEHD data sets, which the systematic review process rated high for data
duality (OSHA, 2020). EPA estimated the highest expected concentration of DIDP in plastic using industry provided data on DIDP
concentration in PVC, which were also rated high for data quality in the systematic review process.
The primary limitation is the uncertainty in the representativeness of values toward the true distribution of potential inhalation exposures.
Additionally, the representativeness of the CEHD data set and the identified DIDP concentrations in plastics for this specific recycling end-use
is uncertain. 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 number of working days. The central tendency exposures use 223
days per year as the exposure frequency based on the 50th percentile of operating days from the release assessment. 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.
Based on these strengths and limitations, EPA has concluded that the weight of scientific evidence for this assessment is moderate and provides
a plausible estimate of exposures.
Dermal -
Liquids
EPA used in vivo rat absorption data for neat DIDP (Elsisi et aL, 1989) to estimate occupational dermal exposures to workers since exposures to
the neat material or concentrated formulations are possible for occupational scenarios. Because rat skin generally has greater permeability than
human skin fScott et aL 1987). the use of in vivo rat absorption data is assumed to be a conservative assumption. Also, it is acknowledged that
variations in chemical concentration and co-formulant components affect the rate of dermal absorption. However, it is assumed that absorption
of the neat chemical serves as a reasonable upper bound across chemical compositions and the data received a medium rating through EPA's
systematic review process.
For occupational dermal exposure assessment, EPA assumed a standard 8-hour workday and that the chemical is contacted at least once per
day. Because DIDP has low volatility and low absorption, it is possible that the chemical remains on the surface of the skin after a dermal
contact until the skin is washed. Therefore, absorption of DIDP from occupational dermal contact with materials containing DIDP may extend
up to 8 hours per day CU.S. EPA, 19913). For average adult workers, the surface area of contact was assumed equal to the area of one hand (i.e..
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535 cm2), or two hands (i.e., 1.070cm2). for central tendency exposures, or high-end exposures, respectively (U.S. .tir/v, ). The standard
sources for exposure duration and area of contact received high ratings through EPA's systematic review process.
The occupational dermal exposure assessment for contact with liquid materials containing DIDP was based on dermal absorption data for the
neat material, as well as standard occupational inputs for exposure duration and area of contact, as described above. Based on the strengths and
limitations of these inputs, EPA has concluded that the weight of scientific evidence for this assessment is moderate and provides a plausible
estimate of occupational dermal exposures.
Dermal -
Solids
EPA used dermal modeling of aaueous materials CU.S. EPA. 2023a. 2004b) to estimate occupational dermal exposures of workers and ONUs to
solid materials as described in Appendix D.2.1.2 of the Draft Environmental Release and Occupational Exposure Assessment for Diisodecyl
Phthalate (DIDP) (U.S. EPA, 2024e). However, the modeling approach for determining the aaueous permeability coefficient was used outside
the range of applicability given the p-chem parameters of DIDP. Also, it is acknowledged that variations in chemical concentration and co-
formulant components affect the rate of dermal absorption. However, it is assumed that absorption of aqueous DIDP serves as a reasonable
upper bound for the dermal absorption of DIDP from solid matrices, and the modeling approach received a medium rating through EPA's
systematic review process.
For occupational dermal exposure assessment, EPA assumed a standard 8-hour workday and that the chemical is contacted at least once per
day. Because DIDP has low volatility and low absorption, it is possible that the chemical remains on the surface of the skin after a dermal
contact until the skin is washed. Therefore, absorption of DIDP from occupational dermal contact with materials containing DIDP may extend
up to 8 hours per day CU.S. EPA, 1991a). 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., 1.070cm2). for central tendency exposures, or high-end exposures, respectively CU.S. EPA, ). The standard
sources for exposure duration and area of contact received high ratings through EPA's systematic review process.
The occupational dermal exposure assessment for contact with solid materials containing DIDP was based on dermal absorption modeling of
aqueous DIDP, as well as standard occupational inputs for exposure duration and area of contact, as described above. Based on the strengths
and limitations of these inputs, EPA has concluded that the weight of scientific evidence for this assessment is moderate and provides a
plausible estimate of occupational dermal exposures.
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4.1.1.5.1 Strengths, Limitations, Assumptions, and Key Sources of Uncertainty for
the Occupational Exposure Assessment
EPA assigned overall confidence descriptions of robust, moderate, or slight to the exposure assessments
for each OES, based on the strength of the underlying scientific evidence. When the assessment is
supported by robust evidence, EPA's overall confidence in the exposure assessment is robust; when
supported by moderate evidence, EPA's overall confidence is moderate; when supported by slight
evidence, EPA's overall confidence is slight.
Strengths
The exposure scenarios and exposure factors underlying the inhalation and dermal assessment are
supported by moderate to robust evidence. Occupational inhalation exposure scenarios were informed
by the moderate or robust sources of surrogate monitoring data or GSs/ESDs used to model the
inhalation exposure concentration. Exposure factors for occupational inhalation exposure include
duration of exposure, body weight, and breathing rate, which were informed by moderate to robust data
sources.
A strength of the modeling assessment includes the consideration of variable model input parameters as
opposed to using a single static value. Parameter variation increases the likelihood that the true
occupational inhalation exposures fall within the range of modeled estimates. An additional strength is
that all data that EPA used to inform the modeling parameter distributions have overall data quality
ratings of either high or medium from EPA's systematic review process. Strengths associated with
dermal exposure assessment are described in Table 4-5.
Limitations
The principal limitation of the inhalation monitoring data is uncertainty in the representativeness of the
data, as there is limited exposure monitoring data in the literature for several scenarios. Differences in
work practices and engineering controls across sites can introduce variability and limit the
representativeness of the monitoring data. Age of the monitoring data can also introduce uncertainty,
due to differences in workplace practices and equipment used at the time the monitoring data were
collected compared those currently in use. A limitation of the modeling methodologies is that model
input data from GSs/ESDs are generic for the OESs and not specific to the use of DIDP within the
OESs. Limitations associated with dermal exposure assessment are described in Table 4-5.
Assumptions
To analyze the inhalation monitoring data, EPA categorized each data point as either "worker" or
"ONU." The categorizations are based on descriptions of worker job activity as provided in literature
and EPA's judgment. Exposures for ONUs can vary substantially and exposure levels for the "ONU"
category will have high variability depending on the specific work activity performed.
EPA calculated average daily concentration (ADC) values assuming that workers and ONUs are
regularly exposed during their entire working lifetime, which likely results in an overestimate.
Individuals may change jobs during the course of their career such that they are no longer exposed to
DIDP, and the actual ADC values become lower than the estimates presented. Assumptions associated
with dermal exposure assessment are described in Table 4-5.
Uncertainties
EPA addressed variability in inhalation models by identifying key model parameters to apply a
statistical distribution that mathematically defines the parameter's variability. EPA defined statistical
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distributions for parameters using documented statistical variations where available. Where the
statistical variation was unknown, assumptions were made to estimate the parameter distribution using
available literature data, such as GSs and ESDs. However, there is uncertainty as to the
representativeness of the parameter distributions because these data are often not specific to sites that
use DIDP. In general, the effects of these uncertainties on the exposure estimates are unknown, as the
uncertainties may result in either overestimation or underestimation of exposures depending on the
actual distributions of each of the model input parameters. Uncertainties associated with dermal
exposure assessment are described in Table 4-5.
There are several uncertainties surrounding the estimated number of workers potentially exposed to
DIDP. First, BLS's OES employment data for each industry/occupation combination are only available
at the 3-, 4-, or 5-digit NAICS level, rather than the full 6-digit NAICS level. This lack of granularity
could result in an overestimate of the number of exposed workers if some 6-digit NAICS are included in
the less granular BLS estimates but are not, in reality, likely to use DIDP for the assessed applications.
EPA addressed this issue by refining the OES estimates using total employment data from the U.S.
Census' Statistics of US Businesses (SUSB). However, this approach assumes that the distribution of
occupation types (SOC codes) in each 6-digit NAICS is equal to the distribution of occupation types at
the parent 5-digit NAICS level. If the distribution of workers in occupations with DIDP exposure differs
from the overall distribution of workers in each NAICS, then this approach will result in inaccuracy.
4.1,2 Consumer Exposures
The following subsections briefly describe EPA's approach to assessing consumer exposures and
provide exposure assessment results for each COU. The Draft Consumer and Indoor Dust Exposure
Assessment for Diisodecyl Phthalate ( 24a) provides additional details on the development
of approaches and the exposure assessment results. The consumer exposure assessment evaluated
exposures from individual COUs while the indoor dust assessment uses a subset of consumer articles
with large surface area and presence in indoor environments to garner COU specific contributions to the
total exposures from dust.
4.1.2.1 Consumer and Indoor Dust Exposure Scenarios and Modeling Approach and
Methodology
Consumer products or articles containing DIDP were matched with the identified consumer COUs.
Table 4-6 summarizes the consumer exposure scenarios by COU for each product example(s), the
exposure routes, which scenarios are also used in the indoor dust assessment, and whether the analysis
was done qualitatively or quantitatively. The indoor dust assessment uses consumer products
information for selected articles with the goal of recreating the indoor environment. The subset of
consumer articles used in the indoor dust assessment were selected for their potential to have large
surface area for dust collection.
When a quantitative analysis was conducted, exposure from the consumer COUs was estimated by
modeling. Exposure via inhalation and ingestion routes were modeled using EPA's CEM Version 3.2
((U.S. EPA. 2023a)) and dermal exposures were done using a computational framework implemented
within a spreadsheet environment. For each exposure route, EPA used the 10th percentile, average, and
95th percentile value of an input parameter (e.g., weight fraction, surface area and others) where
possible to characterize low, medium, and high exposure for a given condition of use. Should only a
range be reported as the minimum, average, and maximum EPA used these for the low, medium, and
high, respectively. See Draft Consumer and Indoor Dust Exposure Assessment for Diisodecyl Phthalate
( 2024a) for details about the consumer modeling approaches, sources of data, model
parameterization, and assumptions.
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Exposure via the inhalation route occurs from inhalation of DIDP gas-phase emissions or when DIDP
partitions to suspended particulate from direct use or application of products and articles. Exposure via
the dermal route can occur from direct contact with products and articles. Exposure via ingestion
depends on the product or article use patterns. It can occur via direct mouthing {i.e., directly putting
product in mouth) or ingestion of suspended dust when DIDP migrates from product to dust or partitions
from gas-phase to dust.
EPA made some adjustments to match CEM's lifestages to those listed in the Center for Disease Control
and Prevention (CDC) guidelines (CDC. 2021) and EPA's A Framework for Assessing Health Risks of
Exposures to Children (U.S. EPA. 2006). CEM lifestages are re-labeled from this point forward as
follows:
• Adult (>21 years) —~ Adult
• Youth 2 (16-20 years) —~ Teenager
• Youth 1 (11-15 years) —~ Young teen
• Child 2 (6-10 years) —~ Middle childhood
• Child 1 (3-5 years) —~ Preschooler
• Infant 2(1-2 years) —~ Toddler
• Infant 1 (<1 year) —~ Infant
EPA assessed acute, chronic, and intermediate exposures to DIDP from consumer COUs. For the acute
dose rate calculations, an averaging time of 1 day is used to represent the maximum time-integrated dose
over a 24-hour period during the exposure event. The chronic dose rate is calculated iteratively at a 30-
second interval during the first 24 hours and every hour after that for 60 days. Professional judgment and
product use descriptions were used to estimate events per day and per month for the calculation of the
intermediate dose.
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Table 4-6. Summary of Consumer CPUs, Exposure Scenarios, and Exposure Routes
Evaluated Routes
Ingestion
Consumer Use
Category
Consumer Use
Subcategory
Product/Article
Exposure Scenario and
Route
Inhalation
Dermal
Dust
(Air)
Dust
(Su rt'acc)
£/.
a
2
s
o
s
Qualitative/
Quantitative
/None
Automotive, fuel,
agriculture, outdoor
use products
Automotive products, other
than fluids
Products are like
synthetic leather fabrics
in furniture
See synthetic leather
furniture scenarios. Use
patterns are for dermal
exposure to automotive
synthetic leather fabric is
like the same
considerations for furniture
X
l/
X
X
X
Quantitative
Automotive, fuel,
agriculture, outdoor
use products
Lubricants
Auto transmission
conditioner
Direct contact during use;
inhalation of emissions
resulting from small spill
of product
l/
l/
X
X
X
Quantitative
Construction, paint,
electrical, and metal
products
Adhesives and sealants
(including plasticizers in
adhesives and sealants)
Construction Adhesive
for Small Scale Projects
Use of product in DIYC
small-scale home repair
and hobby activities. Direct
contact during use;
inhalation of emissions
during use
l/
l/
X
X
X
Quantitative
Construction, paint,
electrical, and metal
products
Adhesives and sealants
(including plasticizers in
adhesives and sealants)
Construction Sealant for
Large Scale Projects
Use of product in DIYC
small-scale home repair
and hobby activities. Direct
contact during use;
inhalation of emissions
during use
l/
l/
X
X
X
Quantitative
Construction, paint,
electrical, and metal
products
Adhesives and sealants
(including plasticizers in
adhesives and sealants)
Epoxy Floor Patch
Use of product in DIYC
home repair and hobby
activities. Direct contact
during use; inhalation of
emissions during use
l/
l/
X
X
X
Quantitative
Construction, paint,
electrical, and metal
products
Adhesives and sealants
(including plasticizers in
adhesives and sealants)
Lacquer Sealer (Non-
Spray)
Application of product in
house via roller or brush.
Direct contact during use;
inhalation of emissions
during use
l/
l/
X
X
X
Quantitative
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Evaluated Routes
Ingestion
Consumer Use
Category
Consumer Use
Subcategory
Product/Article
Exposure Scenario and
Route
Inhalation
Dermal
Dust
(Air)
Dust
(Su rt'acc)
©X
=
5
O
s
Qualitative/
Quantitative
/None
Construction, paint,
electrical, and metal
products
Adhesives and sealants
(including plasticizers in
adhesives and sealants)
Lacquer Sealer (Spray)
Application of product in
house via spray. Direct
contact during use;
inhalation of emissions
during use
l/
l/
X
X
X
Quantitative
Construction, paint,
electrical, and metal
products
Building/construction
materials covering large
surface areas including
stone, plaster, cement,
glass and ceramic articles
(wire or wiring systems;
joint treatment
Solid flooring
Direct contact, inhalation
of emissions / ingestion of
dust adsorbed chemical
%/ a
%/
•%/ a
•%/ a
X
Quantitative
Construction, paint,
electrical, and metal
products
Electrical and Electronic
Products
Wire Insulation
Direct contact, inhalation
of emissions / ingestion of
dust adsorbed chemical,
mouthing by children
V a
%/
V a
V a
Quantitative
Construction, paint,
electrical, and metal
products
Paints and coatings
Paint products/articles
were not identified. For
coatings, lacquers and
sealants were used as
their use patterns are
similar
See lacquers and sealants
See lacquers and sealants
Quantitative
Furnishing, cleaning,
treatment/care
products
Fabrics, textiles, and
apparel (as plasticizer)
See synthetic leather
furniture and clothing
See synthetic leather
furniture and clothing
See synthetic leather furniture and
clothing
Quantitative
Packaging, paper,
plastic, hobby
products
Arts, crafts, and hobby
materials (crafting paint
applied to craft)
Rubber Eraser
Direct contact during use;
rubber particles may be
inadvertently ingested
during use. Eraser may be
mouthed by children
Xi
%/
X
X
Quantitative
Packaging, paper,
plastic, hobby
products
Arts, crafts, and hobby
materials (crafting paint
applied to craft)
Crafting paint applied to
craft.
Current products were not
identified. Foreseeable
uses were matched with the
lacquers, and sealants
(small and large projects)
See lacquers and sealants (small and
large projects)
Quantitative
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Consumer Use
Category
Consumer Use
Subcategory
Product/Article
Exposure Scenario and
Route
Evaluated Routes
Inhalation
Dermal
Ingestion
Qualitative/
Quantitative
/None
Dust
(Air)
Dust
(Su rt'acc)
©X
=
5
O
s
because similar use
patterns are expected.
Packaging, paper,
plastic, hobby
products
Ink, toner, and colorant
products
No consumer products
identified
Current products were not
identified. Foreseeable
uses were matched with the
lacquers, and sealants
(small and large projects)
because similar use
patterns are expected.
See lacquers and sealants (small and
large projects)
Quantitative
Packaging, paper,
plastic, hobby
products
PVC film and sheet
Miscellaneous coated
textiles: truck awnings
Direct contact during use
Xi
%/
X
X
X
Quantitative
Packaging, paper,
plastic, hobby
products
Plastic and rubber products
(textiles, apparel, and
leather; vinyl tape; flexible
tubes; profiles; hoses
Shower Curtain
Direct contact during use;
inhalation of emissions /
ingestion of dust adsorbed
chemical while hanging in
place
V a
%/
V a
V a
X
Quantitative
Packaging, paper,
plastic, hobby
products
Plastic and rubber products
(textiles, apparel, and
leather; vinyl tape; flexible
tubes; profiles; hoses
Wallpaper
Direct contact during
installation (teenagers and
adults) and while in place;
inhalation of emissions /
ingestion of dust adsorbed
chemical
•%/ a
%/
•%/ a
•%/ a
X
Quantitative
Packaging, paper,
plastic, hobby
products
Plastic and rubber products
(textiles, apparel, and
leather; vinyl tape; flexible
tubes; profiles; hoses
Foam Flip Flops
Direct contact during use
Xb
%/
X
X
X
Quantitative
Packaging, paper,
plastic, hobby
products
Plastic and rubber products
(textiles, apparel, and
leather; vinyl tape; flexible
tubes; profiles; hoses
Synthetic Leather
Furniture
Direct contact during use;
inhalation of emissions /
ingestion of airborne
particulate; ingestion by
mouthing
V a
%/
V a
V a
Quantitative
Packaging, paper,
plastic, hobby
products
Plastic and rubber products
(textiles, apparel, and
leather; vinyl tape; flexible
tubes; profiles; hoses
Synthetic Leather
Clothing
Direct contact during use
Xb
%/
X
X
X
Quantitative
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Evaluated Routes
Ingestion
Consumer Use
Category
Consumer Use
Subcategory
Product/Article
Exposure Scenario and
Route
Inhalation
Dermal
Dust
(Air)
Dust
(Su rt'acc)
©X
=
5
O
s
Qualitative/
Quantitative
/None
Packaging, paper,
plastic, hobby
products
Plastic and rubber products
(textiles, apparel, and
leather; vinyl tape; flexible
tubes; profiles; hoses
Bags
Direct contact during use
X*
%/
X
X
X
Quantitative
Packaging, paper,
plastic, hobby
products
Toys, playgrounds, and
sporting equipment
Fitness Ball
Direct contact during use
X
%/
X
X
X
Quantitative
Packaging, paper,
plastic, hobby
products
Toys, Playground, and
Sporting Equipment
Children's Toys (new)
Collection of toys. Direct
contact during use;
inhalation of emissions /
ingestion of airborne PM;
ingestion by mouthing
%>' a
%/
V a
V a
%¦>'*
Quantitative
Packaging, paper,
plastic, hobby
products
Toys, Playground, and
Sporting Equipment
Children's Toys (legacy)
Collection of toys. Direct
contact during use;
inhalation of emissions /
ingestion of airborne
particulate; ingestion by
mouthing
%>' a
%/
V a
V a
%¦>'*
Quantitative
Other
Novelty Products
Adult Toys
Direct contact during use,
ingestion by mouthing
%b
%/
X
X
%¦>'*
Quantitative
Disposal
Disposal
Down the drain products
and articles
Down the drain and
releases to environmental
media
X
X
X
X
X
None
» Scenario is considered either qualitatively or quantitatively in this assessment.
" Scenario used in Indoor Dust Exposure Assessment in Section 4.1.2.3. These indoor dust articles scenarios consider the surface area from multiple articles such as
toys and wire insulation, while furniture, curtains, flooring, and wallpaper already have large surface areas in which dust can deposit and contribute to significantly
larger concentration of dust than single small articles and products.
* Scenario was deemed unlikely based low volatility and small surface area, likely negligible gas and particle phase concentration for inhalation, low possibility of
mouthing based on product use patterns and targeted population lifestages, and low possibility of dust on surface due to barriers or low surface area for dust ingestion.
** Scenario was deemed unlikely based low volatility and small surface area and likely negligible gas and suspended particle phase concentration.
DIYC - Do-it-Yourself
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Inhalation and Ingestion Exposure Routes Modeling Approaches
Key parameters for articles modeled in CEM 3.2 are summarized in detail in Section 2.1.2 in Draft
Consumer Exposure Analysis for Diisodecyl Phthalate (DIDP) ( )24v). Calculations,
sources, input parameters and results are also available in Draft Consumer and Indoor Dust Exposure
Assessment for Diisodecyl Phthalate ( 24a). Generally, and when possible, model
parameters were determined based on specific articles identified in this assessment and CEM defaults
were only used where specific information was not available. A list of some of the most important input
parameters for exposure from articles and products:
• Weight fraction (articles and products),
• Density (articles and products),
• duration of use (products),
• frequency of use for chronic, acute, and intermediate (products),
• product mass used (products),
• article surface area (articles),
• chemical migration rate to saliva (articles),
• area mouthed (articles), and
• use environment volume (articles and products).
Low, medium, and high scenarios correspond to the use of reported statistics, or single values usually an
average, or range of maximum and minimum or when different values are reported for low, medium,
and high, the corresponding statistics are maximum, calculated average from maximum and minimum,
and minimum. Each input in the list was parameterized according to the article data found via systematic
review, or provided by CEM if article specific parameters were not available, or an assumption based on
article use descriptions by manufactures always leaning on the health protective values. For example, the
chemical migration rate of DIDP was estimated based on data compiled in a review published by the
Denmark Environmental Protection Agency in 2016 (Danish EPA. 2016). DINP chemical migration
rates were used as surrogates since such data was not readily available for DIDP. The physical and
chemical characteristics of DIDP and DINP that affect chemical migration rates are similar, but the
larger size, higher molecular weight, and lower solubility of DIDP as compared to DINP can be
expected to result in a slower rate of migration through the polymer matrix of the article and less
partitioning to saliva for DIDP is expected in comparison to DINP. Thus, using chemical migration rates
for DINP to calculate the DIDP dose received during mouthing will provide a health protective estimate,
and it would still be a reasonable DIDP exposure estimate. For all scenarios, the near-field modeling
option was selected to account for a small personal breathing zone around the user during product use in
which concentrations are higher, rather than employing a single well-mixed room. A near-field volume
of 1 m3 was selected.
Dermal Exposure Routes Modeling Approaches
Dermal modeling was done outside of CEM. The use of the CEM model for dermal absorption, which
relies on total concentration rather than aqueous saturation concentration, would greatly overestimate
exposure to DIDP in liquid and solid products and articles. See Draft Consumer and Indoor Dust
Exposure Assessment for Diisodecyl Phthalate (U.S. EPA. 2024a) and ( 324v) for more
details. The dermal dose of DIDP associated with use of both liquid products and solid articles was
calculated in a spreadsheet outside of CEM. See Draft Consumer Exposure Analysis for Diisodecyl
Phthalate (DIDP) ( 2024v). For each product or article, high, medium, and low exposure
scenarios were developed. Values for duration or dermal contact and area of exposed skin were
determined based on reasonably expected use for each item. In addition, high, medium, and low
estimates for dermal flux (liquid products) or absorption (solid products) were calculated and applied in
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the corresponding scenario. Key parameters for the dermal model are shown in Section 2.2 in (U.S.
24a).
4.1.2.2 Modeling Dose Results by COU for Consumer and Indoor Dust
This section summarizes the dose estimates from inhalation, ingestion, and dermal exposure to DIDP in
consumer products and articles. Detailed tables of the dose results for acute, intermediate, and chronic
exposures are available in Section 4 of Draft Consumer and Indoor Dust Exposure Assessment for
Diisodecyl Phthalate (U.S. EPA. 2024a) and Draft Consumer Risk Calculator for Diisodecyl Phthalate
(DIDP) (\ > ii \ „o24wY
Acute, Intermediate, and Chronic Dose Rate Results, Conclusions, and Data Patterns
Figure 4-2 summarizes the high, medium, and low acute dose rate results from modeling in CEM and
outside of CEM (dermal only) for all exposure routes for infants, children, teenagers, and adults. The
chronic average daily dose (CADD) and intermediate figures resulted in the same data patterns as the
acute doses, see Section 4 in ( 2024a) figure narrative under each lifestage for data patterns
and discussion. Only four product examples under the Construction, paint, electrical, and metal
products Adhesives and Sealants and Paints and Coatings COUs were assessed for intermediate
exposure scenarios.
Some products and articles did not have dose results because the product or article was not targeted for
that lifestage or exposure route. Among the younger lifestages, there was no clear pattern which showed
a single exposure route most likely to drive exposure. However, for teens and adults, dermal contact was
a strong driver of exposure to DIDP, with the dose received being generally higher or similar (purple
bars in figures) than to the dose received from exposure via inhalation or ingestion.
In addition to assessing users of various lifestages EPA consider bystanders exposures to consumer
products and articles where applicable. Bystanders are people that are not in direct use or application of
the product but can be exposed to DIDP by proximity to the use of the product via inhalation of gas-
phase emissions or suspended dust. All bystander scenarios were assessed for children under 10 years
for products that are not targeted for the use of children under 10 and assessed as users for older than 11
years because the products can be used by children 11 and older. People older than 11 yrs can also be
bystanders, however the user scenarios utilize inputs that would result in larger exposure doses and thus
the bystander scenarios would have lower risk estimates. Bystander scenarios and COUs include: (1)
Automotive, fuel, agriculture, outdoor use products; lubricants; auto transmission conditioner; (2)
Construction, paint, electrical, and metal products; Adhesives and sealants (including plasticizers in
adhesives and sealants); Construction Adhesive for Small Scale Projects, Construction Sealant for Large
Scale Projects, and Epoxy Floor Patch; and (3) Construction, paint, electrical, and metal products;
Adhesives and sealants, and Paints and Coatings; spray and non-spray lacquer sealer.
For the assessment of indoor dust exposures and estimating contribution to dust from individual COUs,
EPA recreated plausible indoor environment using consumer products and articles commonly present in
indoor spaces inhalation exposure from toys, flooring, synthetic leather furniture, wallpaper, and wire
insulation include a consideration of dust collected on the surface of a relatively large area, like flooring,
furniture, and wallpaper, but also multiple toys and wires collecting dust with DIDP and subsequent
inhalation and ingestion. All lifestages assessed under the indoor dust exposure scenarios are considered
users of the articles being assessed.
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Solid Flooring
Shower Curtain
Wallpaper (in-place)
Children's Toys (new)
Children's Toys (legacy)
Synthetic Leather Furniture
Auto Transmission Conditioners
Construction Adhesive (Small ScaleVj
Lacquer Sealer (Non-Spray)
Epoxy Floor Patch..m
Construction Adhesive (Large Scale)«
Lacquer Sealer (Spray)
Wire Insulation
Solid Flooring
Shower Curtain
Wallpaper (in-place)
Children's Toys (new) -
*52
Children's Toys (legacy)
Synthetic Leather Furniture
Adult Toys
Rubber Eraser
Bags
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Foam Flip Flops
Miscelleneous Coated Textiles
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Auto Transmission Conditioner^^,
Construction Adhesive (Small Scale)
Lacquer Sealer (Non-Spray)
Epoxy Floor Patchr^^^
Construction Adhesive (Large Scale)^^^
Lacquer Sealer (Spray)
Wire Insulation
¦ Inhalation VHigh Exposure Scenario
Ingestion 0 Medium Exposure Scenario
=1 Dermal A Low Exposure Scenario
Auto Transmission Conditioner^
instruction Adhesive (Small Scale)-^H
Lacquer Sealer (Non-Spray)
Epoxy Floor Patch^^
instruction Adhesive (Large Scale)-^
Lacquer Sealer (Spray)
Wire Insulation
10s 104 103 10* 10' 1
ADR (lagfltg/day) in Infant Users and Bystanders
¦ Inhalation VHigh Exposure Scenario
Ingestion 0 Medium Exposure Scenario
~ Dermal A Low Exposure Scenario
Shower Curtain
Wallpaper (in-place)
Children's Toys (new)
V
Children's Toys (legacy)
Synthetic Leather Furniture
Rubber Eraser
Bags
Foam Flip Flops
Crafting Paints
10A-6 10A-5 10A-4 0.001 0.01
Auto Transmission Conditioner^
Construction Adhesive (Small ScaleY-—
Lacquer Sealer (Non-Spray)
¦ Inhalation VHigh Exposure Scenario
Ingestion 0 Medium Exposure Scenario
J Dermal ALow Exposure Scenario
Epoxy Floor Patchy
Construction Adhesive (Large Scale)gni
Lacquer Sealer (Spray)
Wire Insulation
Solid Flooring
Shower Curtain
Wallpaper (in-place)
Children's Toys (new) ^
3
Children's Toys (legacy)
Synthetic Leather Furniture
Adult Toys
Rubber Eraser
Bags
Fitness Ball
Foam Flip Flops
Miscelleneous Coated Textiles
Synthetic Leather Clothing
Wallpaper (application)
ADR (|igftg/day) in Teenager Users and Bystanders
10* 10-" 10"3 10* 101
ADR (Mg'kg'day) in Adult Users and Bystanders
Figure 4-2. Acute Dose Rate for DIDP from Ingestion, Inhalation, Dermal Exposure Routes in
Infant, Children, Teenagers and Young Adults, and Adults
Infants <1 year old (top left panel); children 6 to 10 years old (top right panel); teenagers and young adults 16 to
20 years old (bottom left panel); and adults older than 21 years old (bottom right panel)
In addition, for each lifestage and additional set of figures is provided which shows the contribution of
mouthing, suspended dust ingestion, and settled dust ingestion to the aggregated ingestion value. For all
articles modeled in all lifestages, DIDP doses from ingestion of settled dust were higher than those from
ingestion of suspended dust. This is likely because the overall ingestion rate of suspended dust is lower
than that of settled dust. CEM models intake of small (<10 pm) particles in air as inhalation exposure,
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while larger airborne particles are ingested. However, this larger size fraction will settle more quickly,
resulting in a higher density of ingestible dust on surfaces as compared to air. However, when mouthing
exposure was included for an article, the dose received was generally higher than or similar to the dose
received from ingestion of dust, indicating that mouthing may be a significant driver of exposure to
DIDP when this behavior is present and therefore a particular concern for young children. Mouthing
tendencies decrease significantly for older than 6 years lifestages; thus, most scenarios do not estimate
exposure via mouthing. Ingestion and inhalation of surface dust is an exposure route with similar dose
estimates as dermal for most of the articles used in the indoor dust assessment.
Wire Insulation
Solid Flooring
Shower Curtain
Wallpaper (in-place)
Dust (Suspended) V High Exposure Scenario
¦ Mouthing 0 Medium Exposure Scenario
¦Dust (Surface) A Low Exposure Scenario
Wire Insulation
Solid Flooring
Shower Curtain
Wallpaper (in-place)
Dust (Suspended) VHigh Exposure Scenario
¦Mouthing 0 Medium Exposure Scenario
¦Dust (Surface) A Low Exposure Scenario
Children's Toys (new) ^ A
Children's Toys (legacy)
Synthetic Leather Furniture
Children's Toys (new)^ A
Children's Toys (legacy)
Synthetic Leather Furniture
Wire Insulation
Solid Flooring
Shower Curtain
Wallpaper (in-place)
Children's Toys (new)
Children's Toys (legacy)
Synthetic Leather Furniture
10-5 10-1 10"3 102 10"1 1 10 1(
Ingestion ADR (pg/kg/day) in Infant Users and Bystanders
Dust (Suspended) V High Exposure Scenario
^¦Mouthing 0 Medium Exposure Scenario
^¦Dust (Surface) A Low Exposure Scenario
v 0 A
VQ a
vOa
Rubber Eraser
10"6
Wire Insulation
Solid Flooring
Shower Curtain
Wallpaper (in-place)
Children's Toys (new)
Children's Toys (legacy)
Synthetic Leather Furniture
10-5 104 10"3 102 101 1 10 102
Ingestion ADR (pg/kg/day) in Middle Childhood Users and Bystanders
Dust (Suspended) V High Exposure Scenario
Mouthing 0 Medium Exposure Scenario
^¦Dust (Surface) A Low Exposure Scenario
Adult Toys
10* 10"5 10^ 103 10z 10-1 1 10
Ingestion ADR (pg/kg/day) in Teenager Users and Bystanders
Adult Toys
10"6 10"5 10^ 10"3 10"2 10-1 1 10
Ingestion ADR (ng/kg/day) in Adult Users and Bystanders
Figure 4-3. Acute Dose Rate of DIDP from Ingestion of Airborne Dust, Surface Dust, and
Mouthing for Infants, Children, Teenagers and Young Adults, and Adults
Infants <1 year old (top left panel); children 6 to 10 years old (top right panel); teenagers and young adults 16 to
20 years old (bottom left panel); and adults older than 21 years old (bottom right panel)
The spread of values estimated for each product or article reflects the aggregate effects of variability and
uncertainty in key modeling parameters for each item; acute dose rate for some products/articles covers
a larger range than others primarily due to a wider distribution of DIDP weight fraction values, chemical
migration rates for mouthing exposures, and behavioral factors such as duration of use or contact time
and mass of product used as described in Section 4.1.2.1. Key differences in exposures among lifestages
include designation as product user or bystander; behavioral differences such as mouthing durations,
hand to mouth contact times, and time spent on the floor; and dermal contact expected from touching
specific articles which may not be appropriate for some lifestages.
For wallpaper, dust inhalation and ingestion contribute more to exposure than dermal contact. This is
likely because the wallpaper scenario only considers in-place exposure rather than the installation
process. Ingestion of dust on flooring is lower than inhalation likely due to particles in the inhalable size
fraction can remain suspended for long periods of time and inhalation exposure is continuous while
ingestion of dust from surfaces is not. Dermal contact with furniture is larger than any other dose,
followed by wallpaper and furniture inhalation.
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4.1.2.3 Monitoring Concentrations of DIDP in the Indoor Environment
For the indoor exposure assessment, EPA considered modeling and monitoring data. This section
describes indoor dust monitoring data exclusively while modeling data and approaches are summarized
in Sections 4.1.2.1 and 4.1.2.2. Modeling data used in indoor dust assessment originated from the
consumer exposure assessment, to reconstruct major indoor sources of DIDP into dust and obtain COU
and product specific exposure estimates for ingestion and inhalation.
Monitoring data are expected to represent aggregate exposure to DIDP in dust resulting from all sources
present in a home. While it is not a good indicator of individual contributions of specific COUs, it
provides a real-world indicator of total exposure through dust. The monitoring data considered are from
residential dust samples from studies conducted in countries with comparable standards of living to the
United States because no U.S. DIDP dust concentration data was identified. Measured DIDP
concentrations were compared to determine consistency among datasets, and data from Canada were
ultimately selected as the most representative of United States residential dust exposures. The Canadian
data were selected because the underlying study involved a large random sample from municipalities
across Canada and because Canadian consumer behavior was expected to be most similar to that of
consumers in the United States. The data on DIDP concentrations were used with body weight data
representative of the US population taken from the Exposure Factors Handbook ( ) and
estimated daily dust intake rates taken from Ozkavnak et al. (2022) to derive an estimate of daily DIDP
intake in residential dust per kilogram body weight. The monitoring studies and assumptions made to
estimate exposure are described in detail in Section 3.2 of the Draft Consumer and Indoor Dust
Exposure Assessment for Diisodecyl Phthalate ( 2024a).
Indoor Dust Monitoring Data
Because no U.S. indoor dust monitoring data for DIDP were identified, EPA evaluated non-US data.
The primary data source was the Canadian House Dust Study, as reported in the Canadian 2015 State of
the Science Report (EC/HC. 2015b). The Canadian assessment used Kubwabo et al. (2013) as the basis
for the estimated daily DIDP ingestion dose (intake rate) for dust. Kubwabo et al. (2013) reported DIDP
dust concentrations from 126 households, which were sampled as part of the Canadian House Dust
Study. EPA compared Kubwabo et al. (2013) reported concentrations to other non-U.S. DIDP household
dust concentrations to confirm that observed DIDP concentrations were reasonably similar to one
another (within one order of magnitude) and to identify similarities and differences in sampled
population and sampling methods. The non-U.S. data used to confirm the Canadian assessment were
from residential monitoring data from Canada, Belgium, Holland, Ireland, and Norway in two studies
(Giovamoulis et al.. 2017) and (Christia et al.. 2019).
These studies, representing samples from four European countries, showed median DIDP concentrations
in house dust that are well within an order of magnitude of the median total house dust value from
Kubwabo et al. (2013). The range within an order of magnitude of the median DIDP concentration from
Kubwabo et al. (2013) was 11.1 to 1110 |ig/g, and the range of median values was from 26 |ig/g in the
Belgian samples from Christia et al. (LP I"). to 140.2 |ig/g in the vacuum samples from Norway in
Giovanoulis et a I ^JP1 I The Dutch and Irish median values in Christia et al. (20 rst were 34 |ig/g and
72 jLig/g, respectively. Therefore, the concentrations from the Canadian House Dust Study are consistent
with results from residents in similar income countries during a similar time period. It is thus appropriate
to use this data as a surrogate for U.S. exposure assessment.
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Strengths, Limitations, Assumptions, and Key Sources of Uncertainty for the Indoor Dust Monitoring
Data
Indoor dust concentrations were derived from Kubwabo et al. (JO I <), which in turn sub sampled the
Canadian House Dust Study which was conducted from 2007-2010. That study sampled residential
house dust in approximately one thousand randomly selected households in 13 large Canadian
municipalities. It is possible that sampling biases were introduced by the choice of large municipalities
and by differences among households that chose to participate in the study. Differences in consumer
behaviors, housing type and quality, tidiness, and other variables that affect DIDP concentrations in
household dust are possible between participating households and the general population. Additionally,
because the underlying samples for Kubwabo et al. ( were taken between 2007-2010, uncertainty
is introduced due to the length of time that has elapsed.
There are several potential challenges in interpreting available indoor dust monitoring data. The
challenges are summarized in Table 4-7.
Table 4-7. Sources of Uncertainty in DIDP Dust Monitoring Data
Source of Uncertainty
Samples may have been collected at exposure times or for exposure durations not expected to be
consistent with a presumed hazard based on a specified exposure time or duration
Samples may have been collected at a time or location when there were multiple sources of DIDP
that included non-TSCA COUs
None of the identified monitoring data contained source apportionment information that could be
used to determine the fraction of DIDP in dust samples that resulted from a particular TSCA or non-
TSCA CPU
Activity patterns may differ according to demographic categories (e.g., stay at home/work from
home individual vs an office worker) which can affect exposures especially to articles that
continually emit a chemical of interest
Other considerations like specific household construction approaches, peoples' use and activity patterns,
and some indoor environments may have more ventilation than others, which may change across
seasons.
Weight of Scientific Evidence Conclusions for Indoor Dust Monitoring Data
The weight of scientific evidence conclusion for the indoor dust exposure assessment of DIDP from
monitored residential data is summarized in Table 4-8. Taken as a whole, with moderate confidence in
the DIDP concentration monitoring data in indoor residential dust from Kubwabo et al. (2013). robust
confidence in body weight data from the Exposure Factors Handbook I, and moderate
confidence in dust intake data from Ozkavnak et al. (2022). EPA has assigned moderate confidence to
our estimates of daily DIDP intake rates from ingestion of indoor dust in residences.
The exposure estimate for indoor dust is dependent on studies that include indoor residential dust
monitoring data. Based on the systematic review SOP, only studies that included indoor dust samples
taken from residences were included for data extraction. All studies that were included for data
extraction were rated "High" quality per the exposure systematic review criteria.
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Table 4-8. Weight of Scientific Evit
ence Conclusions for Indoor Dust Ingestion Exposure
Scenario
Confidence in
Data Used "
Confidence in Model Inputs
Weight of Scientific
Evidence Conclusion
Body
Weighth
Dust
Ingestion
Ratec
Indoor exposure
to residential dust
via ingestion
++
+++
++
++
+ - Slight; ++ - Moderate; +++ - Robust
a Kubwabo e 13); with Giovanoulis et al. (2017) and Christia et al. (2019) as comparators
b U.S. EPA (2011a)
c Ozkavnak et al. (2022)
Table 4-8 presents EPA's level of confidence in the data quality of the input datasets for estimating dust
ingestion from monitoring data, including the DIDP dust monitoring data themselves, the estimates of
U.S. body weights, and the estimates of dust ingestion rates, according to the following:
• Robust confidence (+++) means the supporting weight of scientific evidence outweighs the
uncertainties to the point that EPA has decided that it is unlikely that the uncertainties could have
a significant effect on the exposure estimate.
• Moderate confidence (++) means the supporting scientific evidence weighed against the
uncertainties is reasonably adequate to characterize exposure estimates, but uncertainties could
have an effect on the exposure estimate.
• Slight confidence (+) means EPA is making the best scientific assessment possible in the absence
of complete information. There may be significant uncertainty in the underlying data that need to
be considered.
Details on how the confidence conclusions for each of the data sources were reached can be found in
Section 5.2 of the Draft Consumer and Indoor Dust Exposure Assessment for Diisodecyl Phthalate
(DIDP) (U.S. EPA. 2024a). These confidence conclusions were derived from a combination of
systematic review {i.e., the quality determinations for individual studies) and the assessor's professional
judgment. It is important to note that these confidence conclusions refer to the assessor's confidence in
the data quality and numerical accuracy of the underlying data and the resulting model estimates. A
confidence evaluation of "moderate" or "slight" confidence in an individual data source or model
estimate does not indicate that the resulting risk characterization is not health protective.
4.1.2.4 Indoor Aggregate Dust Exposure Approach and Methodology
EPA considered the available modeling and monitoring data to estimate the aggregate exposures to
DIDP that may occur via dust in a typical indoor environment. Modeling data used in indoor dust
assessment originated from the consumer exposure assessment, Section 4.1.2.1, to reconstruct major
indoor sources of DIDP into dust and obtain COU and product specific exposure estimates for ingestion
and inhalation. The monitoring data considered, described in Section 4.1.2.3, are from residential dust
samples from studies conducted in countries with comparable standards of living to the United States.
Detailed descriptions of the indoor dust approaches and methodologies are available in Section 3 of the
Draft Consumer and Indoor Dust Exposure Assessment for Diisodecyl Phthalate (DIDP) (U.S. EPA.
2024a).
For the modeling indoor dust assessment EPA identified article specific information by COU to
construct relevant and representative exposure scenarios from the consumer assessment, Section 4.1.2.1.
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Exposure to DIDP via ingestion of dust was assessed for all articles expected to contribute significantly
to dust concentrations due to high surface area (> ~1 m2) for either a single article or collection of like
articles as appropriate, including:
• solid flooring;
• wallpaper;
• synthetic leather furniture;
• shower curtains;
• children's toys, legacy;
• children's toys, new; and
• wire insulation.
These exposure scenarios were modeled in CEM for inhalation, ingestion of suspended dust, and
ingestion dust from surfaces. See Section 4.1.2.1 for CEM parameterization, input values, and article
specific scenario assumptions and sources.
Indoor Dust Comparison between Monitoring and Modeling Ingestion Estimates
The exposure estimates for indoor dust from the CEM model are larger than those indicated by the
monitoring approach. Table 4-9 compares the sum of the chronic daily dose central tendency for indoor
dust ingestion from CEM outputs for all COUs to the central tendency predicted daily dose from the
monitoring approach.
Table 4-9 Comparison Between Modeled and Monitored Daily Dust Intake Estimates for DIDP
Daily DIDP Intake Estimate from
Daily DIDP Intake Estimate from
Lifestage
Dust, jig/kg-day,
Modeled Exposure"
Dust, jig/kg-day,
Monitoring Exposure''
Infant (<1 Year)
17.46
0.35c
Toddler (1-2 Years)
21.62
0.22
Preschooler (3-5 Years)
24.41
0.09
Middle Childhood (6-10
8.56
0.045
Years)
Young Teen (1-15 Years)
4.79
0.017
Teenager (16-20 Years)
3.80
0.0054
Adult (21+Years)
1.67
0.0048 d
a Sum of chronic daily doses for indoor dust ingestion for "medium" intake scenario for all seven dust COUs
modeled in CEM
h Central tendency estimate of daily dose for indoor dust ingestion from monitoring data
c Weighted average by month of monitored lifestages from birth to 12 months
d Weighted average by year of monitored lifestages from 21 to 80 years
The sum of DIDP intakes from dust in CEM modeled scenarios were, in all cases, considerably higher
than those predicted by the monitoring approach. These discrepancies partially stem from differences in
the exposure assumptions of the CEM model versus the assumptions made when estimating daily dust
intakes in Ozkavnak et al. (2022). Dust intakes in Ozkavnak et al. (2022) decline rapidly as a person
ages due to behavioral factors including walking upright instead of crawling, cessation of exploratory
mouthing behavior, and a decline in hand-to-mouth events. This age-mediated decline in dust intake,
which is more rapid for the Ozkavnak et al. (2022) study than in CEM, partially explains why the
margin between the modeled and monitoring results grows larger with age. Additional discussion of the
differences between modeled and monitored approaches for estimating DIDP exposure from indoor dust
ingestion can be found in Section 4.4 of the Draft Consumer and Indoor Dust Exposure Assessment for
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DiisodecylPhthalate (DIDP) ( 24a). Because the daily DIDP intake estimates from the
modeled exposure approach were, in all cases, higher than those predicted by the monitoring approach,
the higher modeled exposures were used in the derivation of risk estimates for aggregate indoor dust
exposure. Because the modeled DIDP dust risk estimates were higher than the monitored DIDP risk
estimates, EPA is confident that the resulting risk characterizations are health protective.
4.1.2.5 Weight of Scientific Evidence Conclusions for Consumer Exposure
Key sources of uncertainty for evaluating exposure to DIDP in consumer goods and strategies to address
those uncertainties are described in detail in Section 5.1 of Draft Consumer and Indoor Dust Exposure
Assessment for Diisodecyl Phthalate ( 24a). Generally, designation of robust confidence
suggests thorough understanding of the scientific evidence and uncertainties. The supporting weight of
scientific evidence outweighs the uncertainties to the point where it is unlikely that the uncertainties
could have a significant effect on the exposure estimate. The designation of moderate confidence
suggests some understanding of the scientific evidence and uncertainties. More specifically, the
supporting scientific evidence weighed against the uncertainties is reasonably adequate to characterize
exposure estimates. The designation of slight confidence is assigned when the weight of scientific
evidence may not be adequate to characterize the scenario, and when the assessor is making the best
scientific assessment possible in the absence of complete information and there are additional
uncertainties that may need to be considered. While the uncertainty for some of the scenarios and
parameters ranges from slight to robust the overall confidence to use the results for risk characterization
ranges from moderate to robust, depending on COU scenario. The basis for the moderate to robust
confidence in the overall exposure estimates is a balance between using parameters that will represent
various populations use patterns and lean on protective assumptions that are not excessive or
unreasonable.
4.1.2.5.1 Strength, Limitations, Assumptions, and Key Sources of Uncertainty for
the Consumer Exposure Assessment
The exposure assessment of chemicals from consumer products and articles has inherent challenges due
to many sources of uncertainty in the analysis, including variations in product formulation, patterns of
consumer use, frequency, duration, and application methods. Variability in environmental conditions
may also alter physical and/or chemical behavior of the product or article.
Product Formulation and Composition
Variability in the formulation of consumer products, including changes in ingredients, concentrations,
and chemical forms, can introduce uncertainty in exposure assessments. In addition, data were often
limited for weight fractions of DIDP in consumer goods. Where possible, EPA obtained multiple values
for weight fractions for similar products or articles. The lowest value was used in the low exposure
scenario, the highest value in the high exposure scenario, and the average of all values in the medium
exposure scenario. Weight fraction of DIDP in articles was sourced from the available literature and
database values. A confidence of robust was selected for products with multiple sources, moderate was
selected for products with limited sources but more current, and slight was selected for products with
limited and older sources. The uncertainty was improved by using ranges that included either a wide
range or higher values that are considered health protective, but not excessive. The low, medium, and
high exposure estimates capture a range of concentrations that is representative of past, present, and
future practices, encompassing lots of possible exposures.
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Product Use Patterns
Consumer use patterns like frequency of use, duration of use, and methods of application are expected to
differ. Use duration and frequency were primarily sourced from manufacturer use instructions, the
EPA's Exposure Factors Handbook, and by the judgment of the exposure assessor. A confidence rating
of robust was selected when the used values are well understood and represent a wide range of the
population. Moderate was selected for durations of use sourced from manufacturer use instructions that
had multiple types of products with different use instructions and variability is expected to increase with
numerous products available. The main limitation in this analysis and source of uncertainty in the
selected inputs is in the accuracy of the selected use pattern inputs, however EPA is confident that the
selected inputs include health protective inputs in the low, medium, and high exposure scenarios. The
high duration scenarios represent high intensity users, while the average expected use patterns are
captured in the medium scenarios, and low use patterns for occasional and incidental exposures.
Article Surface Area
The surface area of an article directly affects the potential for DIDP emissions to the indoor
environment. For each article modeled for inhalation exposure, low, medium, and high estimates for
surface area were calculated to represent multiple possibilities that capture upper and lower bounds. This
approach relied on manufacturer-provided dimensions where possible, or values from the EPA Exposure
Factors Handbook for floor and wall coverings. For small items which might be expected to be present
in a home in significant quantities, such as insulated wires and children's toys, aggregate values were
calculated for the cumulative surface area for each type of article in the indoor environment. Surface
area inputs are based on manufacturer use instructions, the EPA's Exposure Factors Handbook, and by
the judgment of the exposure assessor. Robust confidence rating was selected for commonly known
product dimensions and moderate for when the assessor made assumptions about the number of products
present in a room.
Human Behavior
CEM 3.2 has three different activity patterns: stay-at-home, part-time out-of-the home (daycare, school,
or work), and full-time out-of-the-home. The activity patterns were developed based on the
Consolidated Human Activity Database (CHAD). For all products and articles modeled, the stay-at-
home activity pattern was chosen as it is the most protective assumption.
Mouthing durations are a source of uncertainty in human behavior. There was considerable variability in
the data due to behavioral differences among children of the same lifestage and due to varying
experimental setup in the studies. EPA opted to use a range that represented the variability in the data so
various mouthing behavior could be captured in the low, medium, and high exposure duration scenarios.
The upper bound used for the high duration scenarios of the reported mouthing durations is likely to
provide a health protective estimate for mouthing of soft plastic items likely to contain DIDP. Mouthing
duration confidence designation of robust is given to scenarios about children toys because the
information used to derive these values is more comprehensive and specific about children toys and
children behaviors while other non-toy scenarios are less specific about mouthing durations and more
generalized, those were given a moderate confidence rating. In addition, mouthing area robust rating
was selected for scenarios in which the mouthing area is well defined by object boundaries, moderate
when object dimensions were based on generalizations and assumptions by the assessor from
manufacturer descriptions.
Modeling Parameters for DIDP Flux, Dermal Absorption, and Chemical Migration
DIDP is considered a data poor chemical with respect to dermal absorption, meaning chemical specific
empirical information is scarce. Data were lacking for key parameters, particularly the skin permeability
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coefficient and chemical migration rate from articles mouthed. To address this data gap, a scientifically
informed approach was adopted, wherein values from analogous chemicals sharing comparable physical
and chemical properties were leveraged as surrogates. These surrogate data, drawn from substances with
established empirical evidence and recognized similarity in relevant characteristics, facilitated the
estimation of needed parameters.
For liquid products EPA identified one set of experimental data related to the dermal absorption of neat
DIDP (El si si et ai. 1989) which was conducted in vivo using male rats. Results from in vitro dermal
absorption experiments ((Scott et al. 1987)) showed that rat skin was more permeable than human skin.
Though there is uncertainty regarding the magnitude of difference between dermal absorption through
rat skin versus human skin for DIDP, based on DIDP physical and chemical properties (solubility), EPA
is confident that the in vivo dermal absorption data using male F344 rats (El si si et al.. 1989) provides an
upper bound of dermal absorption of DIDP and therefore health protective.
There is uncertainty with respect to the modeling of dermal absorption of DIDP from solid matrices or
articles. Because there were no available data related to the dermal absorption of DIDP from solid
matrices or articles, EPA assumed that dermal absorption of DIDP from solid objects would be limited
by aqueous solubility of DIDP. Although this assumption introduces significant uncertainty in the
exposure dose, its use in the risk estimate is reasonable. The overall assumption that DIDP partitions to
liquid (sweat) on the skin and due to DIDP affinity to organic material the absorption through the skin is
likely to happen. The uncertainty stands in the accuracy of the amount of DIDP that is absorbed,
however, EPA is confident that the selected approach represents an upper bound of dermal absorption of
DIDP from solid articles.
For chemical migration rates to saliva, existing data were highly variable both within and between
studies. This high variability in chemical migration rate values adds on to the uncertainty from
differences among similar items due to variations in chemical makeup and polymer structure. As such,
an effort was made to choose DIDP migration rates likely to be representative of broad classes of items
that make up consumer COUs produced with different manufacturing processes and material
formulations. Based on available data for chemical migration rates of DIDP to saliva, the range of values
used in this assessment (1.6, 13.3, and 44.8 |aug/cm2/hr) are considered likely to capture the true value of
the parameter.
4,1.3 General Population Exposures
General population exposures occur when DIDP is released into the environment and the environmental
media is then a pathway for exposure. As described in the Draft Environmental Release and
Occupational Exposure Assessment for Diisodecyl Phthalate (DIDP) ( Me), releases of
DIDP are expected in air, water, and disposal to landfills. Figure 4-4 provides a graphic representation
of where and in which media DIDP is estimated to be found due to environmental releases and the
corresponding route of exposure for the general population.
EPA took a screening-level approach to assess DIDP exposure for the general population. Screening
level assessments are useful when there is little location- or scenario-specific information available. EPA
began its DIDP general population exposure assessment using a screening level approach because of
limited environmental monitoring data for DIDP and lack of location data for DIDP releases. A
screening-level analysis relies on conservative assumptions, including default input parameters for
modeling exposure, to assess exposures that would be expected to be on the high end of the expected
exposure distribution. Details on the use of screening-level analyses in exposure assessment can be
found in EPA's Guidelines for Human Exposure Assessment (U.S. EPA. 2019b)
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EPA evaluated the reasonably available information for releases of DIDP from facilities that use,
manufacture, or process DIDP under industrial and/or commercial COUs subject to TSCA regulations
detailed in the Draft Environmental Release and Occupational Exposure Assessment for Diisodecyl
Phthalate (DIDP) (U.S. EPA, 2024e). As described in Section 3.3, using the release data, EPA modeled
predicted concentrations of DIDP in surface water, sediment, drinking water, and soil from air to soil
deposition in the United States. Table 3-6 summarizes the high-end DIDP concentrations in
environmental media from environmental releases. The reasoning for assessing different pathways
qualitatively or quantitatively is discussed briefly in Section 3.3 and additional detail can be found in
Draft Environmental Media and General Population Screening for Diisodecyl Phthalate (DIDP) (U.S.
EPA. 2024d).
Ambient Air
Inhalation
Landfills
(Industrial or
Muncipal)
Water
Recreation
Oral. Derma!
Wastewater
Facility
Bathing
Water
Dermal.
Inhalation
| Surface Water |
Drinking
Water
Treatment
Drinking
Water
Oral
Figure 4-4. Potential Human Exposure Pathways to DIDP for the General Population
High-end estimates of DIDP concentration in the various environmental media presented in Table 3-6
and the Draft Environmental Media and General Population Exposure for Diisodecyl Phthalate (DIDP)
(U.S. EPA, 2024d) were used for screening-level purposes in the general population exposure
assessment. EPA's Guidelines for Human Exposure Assessment (U.S. EPA. 2019b) defines high-end
exposure estimates as a "plausible estimate of individual exposure for those individuals at the upper end
of an exposure distribution, the intent of which is to convey an estimate of exposure in the upper range
of the distribution while avoiding estimates that are beyond the true distribution." If risk is not found for
these individuals with high-end exposure, no risk is anticipated for central tendency exposures, which is
defined as "an estimate of individuals in the middle of the distribution." Plainly, if there is no risk for an
individual identified as having the potential for the highest exposure associated with a COU for a given
pathway of exposure, then that pathway was determined not to be a pathway of concern and not pursued
further. If any pathways were identified as a pathway of concern for the general population, further
exposure assessments for that pathway would be conducted to include higher tiers of modeling when
available, refinement of exposure estimates, and exposure estimates for additional subpopulations and
OES/COUs.
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Identifying individuals at the upper end of an exposure distribution included consideration of high-end
exposure scenarios defined as those associated with the industrial and commercial releases from a COU
and OES that resulted in the highest environmental media concentrations. As described in Section 3.3,
EPA focused on estimating high-end concentrations of DIDP from the largest estimated releases for the
purpose of its screening level assessment for environmental and general population exposures. This
means that EPA considered the environmental concentration of DIDP in a given environmental media
resulting from the OES that had the highest release compared to any other OES for the same releasing
media. Release estimates from OES resulting in lower environmental media concentrations were not
considered for this screening-level assessment. Additionally, individuals with the greatest intake rate of
DIDP per body weight were considered to be those at the upper end of the exposure.
Table 4-10 summarizes the high-end exposure scenarios that were considered in the screening level
analysis, including the lifestage assessed as the most potentially exposed population based on intake rate
and body weight. Table 4-10 also indicates which pathways were evaluated quantitatively or
qualitatively. Exposure was assessed quantitatively only when environmental media concentrations were
quantified for the appropriate exposure scenario. For example, exposure from soil or groundwater
resulting from DIDP release to the environment via biosolids or landfills was not quantitatively assessed
because DIDP concentrations to the environment from biosolids and landfills was not quantified. Due to
the high confidence in the biodegredation rates and physical and chemical data, there is robust
confidence that in soils receiving DIDP will not be mobile and will have low persistence potential and
there is robust confidence that DIDP is unlikely to be present in landfill leachates. However, exposure
was still assessed qualitatively for exposures potentially resulting from biosolids and landfills. Further
details on the screening level approach and exposure scenarios evaluated by EPA for the general
population are provided in the Draft Environmental Media and General Population Exposure for
DiisodecylPhthalate (DIDP) (U.S. EPA. 2024d). Selected OESs represent those resulting in the highest
modeled environmental media concentrations, for the purpose of a screening-level analysis.
Table 4-10. Exposure Scenarios Assessed in General Population Screening Level Analysis
OES"
Exposure
Pathway
Exposure
Route
Exposure Scenario
Lifestage
Analysis (Quantitative
or Qualitative)
All
Biosolids
No specific exposure scenarios were assessed for
qualitative assessments
Qualitative
All
Landfills
No specific exposure scenarios were assessed for
qualitative assessments
Qualitative
Use of
Lubricants and
Functional
Fluids
Surface
Water
Dermal
Dermal exposure to DIDP in
surface water during
swimming
Adults
Quantitative
Oral
Incidental ingestion of DIDP
in surface water during
swimming
Young
teenager and
teenager
Quantitative
Use of
Lubricants and
Functional
Fluids
Drinking
Water
Oral
Ingestion of drinking water
Infants
Quantitative
All
Fish
Ingestion
Oral
Ingestion of fish for general
population
Adult
Quantitative
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OES"
Exposure
Pathway
Exposure
Route
Exposure Scenario
Lifestage
Analysis (Quantitative
or Qualitative)
Ingestion of fish for
subsistence fishers
Adult
Quantitative
Ingestion of fish for tribal
populations
Adult
Quantitative
PVC Plastic
Compounding
Ambient Air
Oral
Ingestion of DIDP in soil
resulting from air to soil
deposition
Infant
through
middle
childhood
Quantitative
Dermal
Dermal exposure to DIDP in
soil resulting from air to soil
deposition
Infant
through
middle
childhood
Quantitative
"Table 3-1 provides the crosswalk of OES to COUs
EPA also considered biomonitoring data, specifically urinary biomonitoring data from the Centers for
Disease Control and Prevention's (CDC) National Health and Nutrition Examination Survey
(NHANES), to estimate exposure using reverse dosimetry (see Section 10.2 of EPA's Draft
Environmental Media and General Population Exposure for Diisodecyl Phthalate (1)1 DP) (U.S. EPA.
2024d)). Reverse dosimetry is a powerful tool for estimating exposure, but reverse dosimetry modeling
does not distinguish between routes or pathways of exposure and does not allow for source
apportionment {i.e., exposure from TSCA COUs cannot be isolated from uses that are not subject to
TSCA). Instead, reverse dosimetry provides an estimate of the total dose (or aggregate exposure)
responsible for the measured biomarker. Therefore, intake doses estimated using reverse dosimetry is
not directly comparable the exposure estimates from the various environmental media presented in this
document. However, the total intake dose estimated from reverse dosimetry can help contextualize the
exposure estimates from exposure pathways outlined in Table 4-10 as being potentially underestimated
or overestimated.
4.1.3.1 General Population Screening Level Exposure Assessment Results
Land Pathway
EPA evaluated general population exposures via the land pathway {i.e., application of biosolids,
landfills) qualitatively. Due to its water solubility (0.00017 mg/L) and affinity for sorption to soil and
organic constituents in soil (log Koc = 5.09), DIDP is unlikely to migrate to groundwater via runoff after
land application of biosolids. Additionally, the half-life of 28 to 52 days in aerobic soils (
2024f) indicates that DIDP will have low persistence potential in the aerobic environments associated
with freshly applied biosolids. Since the physical and chemical properties of DIDP indicate that it is
unlikely to migrate from land applied biosolids to groundwater via runoff, EPA did not model
groundwater concentrations resulting from land application of biosolids.
DIDP is expected to be present at low concentrations in landfill leachate. Further, due to its high affinity
for organic carbon and low water solubility, any DIDP that may present in landfill leachates will not be
mobile in receiving soils and sediments. Since the physical and chemical properties of DIDP indicate
that it is unlikely to be mobile in soils, modeling of groundwater contamination due to landfill leachate
containing DIDP was not performed.
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Surface Water Pathway - Incidental Ingestion and Dermal Contact from Swimming
EPA conducted modeling of releases to surface water at the point of release {i.e., in the immediate
receiving waterbody receiving the effluent) to assess the expected resulting environmental media
concentrations from TSCA COUs. EPA conducted modeling with the U.S. EPA's Variable Volume
Water Model with Point Source Calculator tool (VVWM-PSC), to estimate concentrations of DIDP
within surface water. Releases associated with the Use of Lubricants and Functional Fluids OES resulted
in the highest total water column concentrations, ranging from 7,540 to 9,110 |ig/L without wastewater
treatment and 452 to 547 |ig/L when run under an assumption of 94 percent wastewater treatment
removal efficiency (Table 4-11). Both treated and untreated scenarios were assessed due to uncertainty
about the prevalence of wastewater treatment from discharging facilities, and to demonstrate the
hypothetical disparity in exposures between treated and untreated effluent in the generic release
scenarios. COUs mapped to this OES are shown in Table 3-1. These water column concentrations were
used to estimate the ADR from dermal exposure and incidental ingestion of DIDP while swimming for
adults (21 and older), youth (11 to 15 years), and children (6 to 10 years). Exposure scenarios leading to
the highest modeled ADR are shown in Table 4-11.
For the purpose of a screening-level assessment, EPA used a margin of exposure (MOE) approach using
high-end exposure estimates to determine if exposure pathways were pathways of concern for potential
non-cancer risks. MOEs for general population exposure through dermal exposure and incidental
ingestion during swimming ranged from 190 to 286 for scenarios assuming no wastewater treatment and
from 3,070 to 6,830 for scenarios assuming 94 percent wastewater treatment removal efficiency
(compared to a benchmark of 30) (Table 4-11). Therefore, based on a screening-level assessment risk
for non-cancer health effects are not expected for the surface water pathway and the surface water
pathway is not considered to be a pathway of concern to DIDP for the general population.
Surface Water Pathway - Drinking Water
For the drinking water pathway, modeled surface water concentrations were used to estimate drinking
water exposures. For screening-level purposes, only the OES scenario resulting in the highest modeled
surface water concentrations, Use of Lubricants and Functional Fluids, was included in the drinking
water exposure analysis. COUs mapped to this OES are shown in Table 3-1. EPA evaluated drinking
water scenarios that assumed a wastewater treatment removal efficiency of 94 percent and no further
drinking water treatment, as well as a scenario that assumed a wastewater treatment removal efficiency
of 94 percent and a conservative drinking water treatment removal rate of 63 percent (Table 4-11). ADR
and ADD values from drinking water exposure to DIDP were calculated for adults (21 and older), youth
(11 to 15 years), and children (6 to 10 years). Exposure scenarios leading to the highest ADR and ADD
are shown in Table 4-11.
MOEs for general population exposure through drinking water exposure ranged from 117 to 316 across
the evaluated scenarios for the lifestage {i.e., infants) with the highest exposure (compared to a
benchmark of 30) (Table 4-11). Based on screening-level analysis, risk for non-cancer health effects are
not expected for the drinking water pathway and the drinking water pathway is not considered to be a
pathway of concern to DIDP for the general population.
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Table 4-11. General Population Surface Water and Drinking Water Exposure Summary
Occupational Exposure
Scenario"
Water Column
Concentrations
Incidental Dermal
Surface Water''
Incidental Ingestion
Su rface Water'
Drinking Water''
30Q5
(Hg/L)
Harmonic
Mean
(Hg/L)
ADRpot
(mg/kg-
day)
Acute
MOE
ADRpot
(mg/kg-
day)
Acute
MOE
ADRpot
(mg/kg-
day)
Acute
MOE
Use of Lubricants and
Functional Fluids without
Wastewater Treatment
9,110
7,540
4.73E-02
190
3.62E-02
286
Use of Lubricants and
Functional Fluids with
Wastewater Treatment
547
452
2.84E-03
3,170
2.92E-03
3,070
7.7E-02
117
Use of Lubricants and
Functional Fluids with
Wastewater and Drinking
Water Treatment
202
167
2.8E-02
316
" Table 3-1 provides crosswalk of COU to OES
h Most exposed lifestage: Adults (>21 years)
c Most exposed lifestage: Youth (11-15 years)
d Most exposed lifestage: Infant (birth to <1 year)
Note: ADRpot are derived from 30Q5 flow concentrations.
Fish Ingestion
EPA estimated fish tissue concentrations using monitored surface water concentrations and DIDP's
water solubility limit. The highest measured surface water concentration from untreated wastewater
exceeded the solubility limit of DIDP by up to two orders of magnitude (see Section 7 in the Draft
Environmental Media and General Population Exposure for Diisodecyl Phthalate (DIDP) (
2024d) for further details. DIDP within suspended solids found in wastewater could result in
concentrations greater than the water solubility limit. However, DIDP is not expected to be bioavailable
for uptake by aquatic organisms due to its strong sorption to organic matter and hydrophobicity. Use of
the measured DIDP concentrations in wastewater is already expected to overestimate fish tissue
concentrations for this reason. As a result, modeled surface water concentrations by COU/OES using
VVWM-PSC, which exceeded the estimates of the water solubility limit for DIDP by up to five orders
of magnitude, were not considered.
EPA evaluated exposure and potential risk to DIDP through fish ingestion for adults in the general
population, adult subsistence fishers, and adult tribal populations. Exposure estimates were the highest
for tribal populations because of their elevated fish ingestion rates compared to the general population
and subsistence fisher populations ( 324d). As such, tribal populations represent the sentinel
exposure scenario. Risk estimates calculated from the water solubility limit of DIDP as the input surface
water concentration were four-to-five orders of magnitude above its non-cancer risk benchmark using
both the current and heritage fish ingestion rate (Table 4-12). Using the highest monitored DIDP levels
as the input surface water concentration, risk estimates for tribal populations were still two orders of
magnitude above its corresponding benchmark for both fish ingestion rates. Exposure estimates based on
conservative values such as surface water concentration from untreated wastewater still resulted in risk
estimates that are above their benchmarks. Therefore, these results indicate that fish ingestion is not a
pathway of concern for DIDP for tribal members, subsistence fisher, and the general population.
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Table 4-12. Fish Ingestion for Adults in Tribal Populations Summary
Calculation Method
Current Mean Ingestion Rate
Heritage Ingestion Rate
ADR/ADD
(mg/kg-day)
MOE
ADR/ADD
(mg/kg-day)
MOE
Water solubility limit (1.7E-04 mg/L)
4.54E-06
1,980,000
2.62E-05
344,000
Monitored SWC from a WWTP's influent
(4.31E-02 mg/L)
1.15E-03
7,810
6.64E-03
1,360
Ambient Air Pathway - Air to Soil Deposition
EPA used the American Meteorological Society (AMS)/EPA Regulatory Model (AERMOD) to estimate
ambient air concentrations and air deposition of DIDP from EPA estimated releases. The highest
modelled 95th percentile annual ambient air and soil concentrations across all release scenarios were 4.7
x 102 |ig/m3 and 1.85 mg/kg at 100 m from the releasing facility for the PVC Plastic Compounding OES,
based on the high-end meteorology and rural land category scenario in AERMOD (Table 3-6). COUs
mapped to this OES are shown in Table 3-1. PVC Plastic Compounding was the only OES assessed for
the purpose of a screening-level assessment as it was the OES associated with the highest ambient air
concentration. Next, using conservative exposure assumptions for infants and children (ages 6 months to
less than 12 years), EPA estimated the acute dose rate (ADR) for soil ingestion and the dermal absorbed
dose (DAD) for soil dermal contact to be 0.0228 and 0.0617 mg/kg-day. EPA did not estimate inhalation
exposure to ambient air because it was not expected to be a pathway of concern (see Section 4 of (U.S.
24d) for more details).
Using the highest modelled 95th percentile air concentration, ADR, and DAD, MOEs for general
population exposure through a combined soil ingestion and dermal soil contact is 106.5 (Table 4-13
compared to a benchmark of 30). Based on risk screening results, risk for non-cancer health effects are
not expected for the ambient air pathway and the ambient air pathway is not considered to be a pathway
of concern to DIDP for the general population.
Table 4-13. General Population Ambient Air to Soil Deposition Exposure Summary
OES
Soil Ingestion
Dermal Soil Contact
Soil
Concentration"
(mg/kg)
ADD
(mg/kg-day)
MOE6
Soil
Concentration"
(mg/kg)
DAD
(mg/kg-day)
MOE6
PVC plastic
compounding
1.85
0.0228
106.5
1.85
0.0617
107
" Air and soil concentrations are 95th percentile at 100m from the emitting facility.
b MOE for soil ingestion and dermal contact based on combined exposure through soil ingestion and dermal soil contact.
Urinary Biomonitoring Data — NHANES
EPA analyzed urinary biomonitoring data from NHANES, which reports urinary concentrations for 15
phthalate metabolites specific to individual phthalate diesters. Specifically, EPA analyzed data for
mono-(carboxynonyl) phthalate (MCNP), a metabolite of DIDP, which has been reported in the 2005 to
2018 NHANES survey years. Urinary concentrations of MCNP were quantified for different lifestages
and, using reverse dosimetry, total daily intake values of DIDP were estimated for different life stages.
Detailed results of the NHANES analysis can be found in Section 10.2 of EPA's Draft Environmental
Media and General Population Exposure for Diisodecyl Phthalate (DIDP) (1 c< « i1 \ 2024d). The
highest daily intake value estimated was for female children (6-11 years old) and was 13.14 |ig/kg-bw-
day at the 95th exposure percentile. Median daily intake across all life stages assessed ranged from 0.97-
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1.59 |ig/kg-bw-day. As described earlier, reverse dosimetry modeling does not distinguish between
routes or pathways of exposure and does not allow for source apportionment {i.e., exposure from TSCA
COUs cannot be isolated from uses that are not subject to TSCA). Therefore, general population
exposure estimates from exposure to ambient air, surface water, and soil are not directly comparable.
However, in contrasting the general population exposures estimated for a screening level analysis with
the NHANES biomonitoring data, many of the acute dose rates or average daily doses from a single
exposure scenario exceed the total daily intake values estimated using NHANES. Taken together with
results from U.S. CPSC (2014) stating that DIDP exposure comes primarily from diet for women,
infants, toddlers, and children and that the outdoor environment did not contribute to DIDP exposures,
the exposures to the general population via surface water, drinking water, and soil from ambient air to
soil deposition quantified in this document are likely overestimates, as estimates from individual
pathways exceed the total intake values measured even at the 95th percentile of the U.S. population for
all ages.
4.1.3.2 Overall Confidence in General Population Screening Level Exposure
Assessment
The weight of scientific evidence supporting the general population exposure estimate is decided based
on the strengths, limitations, and uncertainties associated with the exposure estimates, which are
discussed in detail for ambient air, surface water, drinking water, and fish ingestion in the Draft
Environmental Media and General Population Exposure for Diisodecyl Phthalate (DIDP) (U.S. EPA.
2024d). EPA summarized its weight of scientific evidence using confidence descriptors: robust,
moderate, slight, or indeterminate. EPA used general considerations {i.e., relevance, data quality,
representativeness, consistency, variability, uncertainties) as well as chemical-specific considerations for
its weight of scientific evidence conclusions.
EPA determined robust confidence in its qualitative assessment of biosolids and landfills. For its
quantitative assessment, EPA modeled exposure due to various general population exposure scenarios
resulting from different pathways of exposure. Exposure estimates utilized high-end inputs for the
purpose of risk screening. When available, monitoring data was compared to modeled estimates to
evaluate overlap, magnitude, and trends. EPA has robust confidence that modeled releases used are
appropriately conservative for a screening level analysis. Therefore, EPA has robust confidence that no
exposure scenarios will lead to greater doses than presented in this evaluation. Despite slight and
moderate confidence in the estimated values themselves, confidence in exposure estimates capturing
high-end exposure scenarios was robust given that many of the modeled values exceeded those of
monitored values and exceeded total daily intake values calculated from NHANES biomonitoring data
(see Section 10 of ( 2024d) for more details regarding the NHANES analysis), adding to
confidence that exposure estimates captured high-end exposure scenarios.
4,1,4 Human Milk Exposures
Infants are a potentially susceptible lifestage because of their higher exposure per body weight,
immature metabolic systems, and the potential for chemical toxicants to disrupt sensitive developmental
processes, among other reasons. As discussed further in Section 4.2, DIDP is a developmental toxicant,
and developmental toxicity occurs following gestational exposure to DIDP. EPA considered exposure
and human health hazard information, as well as pharmacokinetic models, to determine how to evaluate
infant exposure to DIDP from human milk ingestion. Biomonitoring data, albeit limited, have not
demonstrated the presence of DIDP in human milk. Human health hazard values are based on
developmental toxicity following maternal exposure, and no studies have evaluated only lactational
exposure from quantified levels of DIDP in milk. Lastly, uncertainties in the toxic moiety for DIDP and
the limited half-life data of its metabolites in the human body that are both sensitive and specific
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precluded modeling human milk concentrations by COUs. Overall, EPA concluded that the most
scientifically supportable approach is to not model milk concentrations, but rather use human health
hazard values that are based on maternal exposure over two generations. It is thus expected to
incorporate potential risks to infants from exposure through milk. Further discussion of the human milk
pathway is provided in the Draft Environmental Media and General Population Exposure for Diisodecyl
Phthalate (DIDP) ( 2024d).
4,1.5 Aggregate and Sentinel Exposures
TSCA section 6(b)(4)(F)(ii) (15 USC 2605(b)(4)(F)(ii)) requires EPA, in conducting a risk evaluation,
to describe whether aggregate and sentinel exposures under the COUs were considered and the basis for
their consideration.
EPA defines aggregate exposure as "the combined exposures to an individual from a single chemical
substance across multiple routes and across multiple pathways (40 CFR § 702.33)." For the draft DIDP
risk evaluation, EPA considered aggregate risk across all routes of exposure for each individual
consumer and occupational COU evaluated for acute, intermediate, and chronic exposure durations.
EPA did not consider aggregate exposure for the general population. As described in Section 4.1.3, EPA
employed a risk screen approach for the general population exposure assessment. Based on results from
the risk screen, no pathways of concern {i.e., ambient air, surface water, drinking water, fish ingestion)
to DIDP exposure were identified for the generation population.
EPA did not consider aggregate exposure scenarios across COUs because EPA did not find any
evidence to support such an aggregate analysis, such as statistics of populations using certain products
represented across COUs, or workers performing tasks across COUs. However, EPA considered
combined exposure across all routes of exposure for each individual occupational and consumer COU to
calculate aggregate risks (Sections 4.3.2 and 4.3.3).
EPA defines sentinel exposure as "the exposure to a single chemical substance that represents the
plausible upper bound of exposure relative to all other exposures within a broad category of similar or
related exposures (40 CFR 702.33)." In terms of this draft risk evaluation, EPA considered sentinel
exposures by considering risks to populations who may have upper bound exposures; for example,
workers and ONUs who perform activities with higher exposure potential, or consumers who have
higher exposure potential or certain physical factors like body weight or skin surface area exposed. EPA
characterized high-end exposures in evaluating exposure using both monitoring data and modeling
approaches. Where statistical data are available, EPA typically uses the 95th percentile value of the
available dataset to characterize high-end exposure for a given condition of use. For general population
and consumer exposures, EPA occasionally characterized sentinel exposure through a "high-intensity
use" category based on elevated consumption rates, breathing rates, or user-specific factors.
4.2 Summary of Human Health Hazard
This section briefly summarizes the human health hazards of DIDP. Additional information on the
human health hazards of DIDP are provided in the Draft Human Health Hazard Assessment for
Diisodecyl Phthalate (DIDP) (U.S. EPA. 2024h).
A robust toxicological database is available for DIDP. Available studies include: one short-term
inhalation study of rats (General Motors. 1983); seven short-term oral exposure studies (5 of rats, 2 of
mice) (Chen et ai. 2019; Kwack et ai. 2010; Kwack et ai. 2009; Smith et ai. 2000; Lake et al. 1991;
\ * '0, 1986a); three subchronic dietary studies (2 of rats, 1 of beagles) ( ' 1 • l \ . iL. elton
Labs. 1968a. b); two chronic dietary studies (1 of each of rats and mice) (Cho et al.. JO I I; €ho et al..
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2010; Cho et al. 2008); two prenatal developmental studies of rats (Waterman et ai. 1999; Hell wis et
ai. 1997); one developmental/reproductive toxicity screening study of mice (Hazleton Labs. 1983); and
two two-generation dietary studies of rats (Hushka et al.. 2001; Exxon Biomedical. 2000. 1998). No
repeated dose studies investigating the systemic toxicity of DIDP are available for the dermal route of
exposure. Additionally, although the anti-androgenicity of DIDP is not discussed in detail in this
document (see U.S. EPA (2023b) for further discussion), several mechanistic studies have demonstrated
that gestational exposure during the critical window of development to DIDP does not induce
antiandrogenic effects on the developing male reproductive system (Furr et al.. 2014; Hannas et al..
2012). This conclusion was supported by the SACC (U.S. EPA. 2023d).
EPA identified liver and developmental toxicity as the most sensitive and robust non-cancer hazards
associated with oral exposure to DIDP in experimental animal models. Liver and developmental toxicity
were also identified as the most sensitive and robust non-cancer effects following oral exposure to DIDP
by the U.S. Consumer Product Safety Commission (I] S CPSC. 2014). Health Canada (ECCC/HC.
2020). European Chemicals Agency (ECHA. 2013). European Food Safety Authority (EFSA. 2019).
and the Australian National Industrial Chemicals Notification and Assessment Scheme (NIC.NAS.
2015). Consistent, dose-related effects on development were observed across available experimental
studies of rodent models. In two prenatal studies, increased incidences of skeletal and visceral variations
were observed in SD and Wistar rats at non-maternally toxic doses (Waterman et al.. 1999; Hell wis et
al.. 1997). No-observable-adverse-effect levels (NOAELs)/lowest-observable-adverse-effect level
(LOAELs) for developmental and maternal toxicity were 40/200 and 200/1000 mg/kg-day, respectively,
in the study by Hell wig et al. (1997). and 200/500 and 500/1000 mg/kg-day, respectively, in the study
by Waterman et al. (1999). The biological significance of the observed increases in skeletal and visceral
variations are difficult to assess. However, EPA's Guidelines for Developmental Toxicity Risk
Assessment ( ) states that, "if variations are significantly increased in a dose-related
manner, these should also be evaluated as a possible indication of developmental toxicity" and "Agents
that produce developmental toxicity at a dose that is not toxic to the maternal animal are especially of
concern." Therefore, EPA considered the increase in skeletal and visceral variations following
gestational exposure to DIDP to be treatment-related adverse effects. Effects on developing offspring
have also been observed consistently in two two-generation studies of reproduction of SD rats (Hushka
et al.. 2001; Exxon Biomedical. 2000. 1998). In the first two-generation study by Exxon Biomedical
( |), DIDP exposure reduced F1 offspring survival on postnatal day (PND) PND4, reduced F1 and F2
offspring body weight on PND0, and reduced F1 and F2 offspring body weight gain through PND 21 at
doses equal to 524 to 637 mg/kg-day DIDP, and reduced F2 offspring survival on PND1 and PND4 at
doses of 135 mg/kg-day and above. In the second two-generation study by Exxon Biomedical (2000).
which tested lower doses than the first study (high-dose group received 254 to 356 mg/kg-day DIDP),
reduced F2 offspring survival on PND1 and PND4 was observed at doses of 134 mg/kg-day and above.
To calculate non-cancer risks from oral exposure to DIDP for acute, intermediate, and chronic durations
of exposure in the draft risk evaluation of DIDP, EPA preliminarily selected a no-observed-adverse-
effect level (NOAEL) of 38 mg/kg-day from a two-generation study of reproduction of rats based on
reduced F2 offspring survival on PND 1 and PND4 (Hushka et al.. 2001; Exxon Biomedical. 2000). The
NOAEL of 38 was converted to a human equivalent dose (HED) of 9.0 mg/kg-day based on allometric
body weight scaling to the three-quarter power ( ). A total uncertainty factor of 30 was
selected for use as the benchmark margin of exposure (based on a interspecies uncertainty factor (UFa)
of 3 and a intraspecies uncertainty factor (UFh) of 10). The critical effect, reduced F2 offspring survival
on PND1 and PND4, is clearly adverse and is assumed to be human relevant. It is unclear whether
decreased pup survival was due to a single, acute exposure or from repeated exposures. It is plausible
that reduced offspring survival could result from a single exposure during gestation. However, it is also
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plausible that reduced offspring survival could result from repeated exposure during gestation or the
postnatal period. Since repeated dose studies were used to investigate these hazard endpoints and the
mode of action for DIDP is uncertain, and other studies did not provide a more sensitive or reliable
endpoint, EPA considered reduced F2 offspring survival relevant for all exposure durations (
1996. 1991b). Several additional acute, short-term and chronic duration studies of DIDP provide similar,
although slightly less-sensitive, candidate PODs, which further supports EPA's decision to use the
selected POD of 9.0 mg/kg-day to assess non-cancer risks for acute, intermediate, and chronic durations
of exposure.
EPA reviewed the weight of scientific evidence and has robust overall confidence in the selected POD
based on developmental outcomes for use in characterizing risk from exposure to DIDP for acute,
intermediate, and chronic exposure scenarios. This conclusion was based on several weight of scientific
evidence considerations. First, exposure to DIDP resulted in consistent, dose-related, developmental
toxicity in two prenatal developmental studies and two two-generation studies that adhered to relevant
EPA guidelines (i.e., OPPTS 870.3700 and OPPTS 870.3800). Further, developmental toxicity occurred
at doses lower that those that caused overt maternal and/or parental toxicity. Second, across available
studies, developmental toxicity was observed consistently at LOAELs ranging from 134 to 200 mg/kg-
day. Third, the selected POD (NOAEL of 38 mg/kg-day) for developmental toxicity was the most
sensitive and robust POD considered for acute, intermediate, and chronic exposures. Several additional
acute, short-term and chronic duration studies of DIDP provide similar, although slightly less-sensitive,
candidate PODs, which further supports EPA's decision to use the selected POD to assess non-cancer
risks for acute, intermediate, and chronic durations of exposure. Finally, other regulatory and
authoritative bodies have also concluded that DIDP is a developmental toxicant and that developmental
effects are relevant for estimating human risk (EFSA.. 2019; EC/HC. 2015b; NICNAS. 2015; ECHA.
2013; U.S. CPSC. 2010; EFSA. 2005; ECJRC. 2003a; NTP-CERHR. 20031
No data were available for the dermal or inhalation routes that were suitable for deriving route-specific
PODs. Therefore, EPA used the oral POD to evaluate risks from dermal exposure to DIDP. Differences
in absorption are accounted for in dermal exposure estimates in the draft risk evaluation for DIDP. For
the inhalation route, EPA extrapolated the oral HED to an inhalation human equivalent concentration
(HEC) using a human body weight and breathing rate relevant to a continuous exposure of an individual
at rest ( ;) The oral HED and inhalation HEC values selected by EPA to estimate non-
cancer risk from acute, intermediate and chronic exposure to DIDP in the draft risk evaluation of DIDP
are summarized in Table 4-14.
Available data indicate that DIDP is not genotoxic or mutagenic (see Section 4 of ( 024hV).
In a two-year dietary study of F344 rats (Cho et ai. 2010; Cho et al. 2008). increased incidence of
mononuclear cell leukemia (MNCL) was observed in high-dose male and female rats dosed with up to
479 to 620 mg/kg-day DIDP. In a 26-week study of male and female wild-type and rasH2 transgenic
mice (Cho et al.. 2011). increased incidence of hepatocellular adenomas were observed in high-dose
rasH2 males treated with 1500 mg/kg-day DIDP. No tumors were observed in any tissues in male or
female wild-type mice or female rasH2 mice treated with up to 1500 mg/kg-day.
Under the Guidelines for Carcinogen Risk Assessment ( )5), EPA reviewed the weight of
scientific evidence for the carcinogenicity of DIDP and determined that there is Suggestive Evidence of
Carcinogenic Potential of DIDP in rodents. EPA's determination is based on evidence of MNCL in
male and female F344 rats and hepatocellular adenomas in male CB6Fl-rasH2 transgenic mice.
According to the Guidelines for Carcinogen Risk Assessment ( 6), when there is
Suggestive Evidence "the Agency generally would not attempt a dose-response assessment, as the nature
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2167 of the data generally would not support one." Consistently, EPA is not conducting a dose-response
2168 assessment for DIDP or further evaluating DIDP for carcinogenic risk to humans.
2169
2170 Table 4-14. Non-cancer HECs and HEDs Used to Estimate Risks
Exposu re
Scenario
Target Organ
System
Species
Duration
POD
(mg/kg-
day)
Effect
HEC
(mg/m3)
[ppm|
HED
(mg/
kg-day)
Benchmark
MOE
Rcfcrcncc(s)
Acute,
intermed.,
chronic
Develop,
toxicity
Sprague-
Dawley
Approx. 35
weeks
NOAEL=
38
Reduced F2
offspring
survival on
PND1 and
PND4
49
[2.7]
9.0
UFa= 3"
UFh=10
Total UF=30
(Tliislika et al.
2001; Exxon
Biomedical,
2000)
HEC = human equivalent concentration; HED = human equivalent dose; MOE = margin of exposure; NOAEL = no-
observed-adverse-effect level; POD = point of departure; UF = uncertainty factor
" EPA used allometric body weight scaling to the three-quarters power to derive the HED. Consistent with EPA guidance
(TJ.S. EPA. 2011c). the UFa was reduced from 10 to 3.
2171 4.3 Human Health Risk Characterization
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4,3,1 Risk Assessment Approach
The exposure scenarios, populations of interest, and toxicological endpoints used for evaluating risks
from acute, short-term/intermediate, and chronic/lifetime exposures are summarized in Table 4-15.
Table 4-15. Exposure Scenarios, Populations of Interest, and Hazard Values
Population of Interest
and Exposure Seenario
Workers
Male and female adolescents and adults (>16 years old) and females of reproductive age
directly working with DIDP under light activity (breathing rate of 1.25 m3/hr)
Exposure Durations
• Acute - 8 hours for a single workday
• Intermediate - 8 hours per workday for 22 days per 30-day period
• Chronic - 8 hours per workday for 250 days per year for 31 or 40 working years
Exposure routes
• Inhalation and dermal
Occupational Non-users
Male and female adolescents and adults (>16 years old) indirectly exposed to DIDP within the
same work area as workers (breathing rate of 1.25 m3/hr)
Exposure Durations
• Acute, Intermediate, and Chronic - same as workers
Exposure routes
• Inhalation, dermal (mist and dust deposited on surfaces)
Consumers
Male and female infants (less than 1 year), toddlers (1 to 2 years), children (3 to 5 years and 6 to
10 years), young teens (11 to 15 years), teenagers (16 to 20 years) and adults (21 years and
above) exposed to DIDP through product or articles use
Exposure Durations
• Acute - 1 day exposure
• Intermediate - 30 days per year
• Chronic - 365 days per year
Exposure routes
• Inhalation, dermal, and oral
Bystanders
Male and female infants (less than 1 year), toddlers (1 to 2 years), and children (3 to 5 years and
6 to 10 years) incidentally exposed to DIDP through product use
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Exposure Durations
• Acute - 1 day exposure
• Intermediate - 30 days per year
• Chronic - 365 days per year
Exposure routes
• Inhalation
General Population
Male and female infants, children, youth, and adults exposed to DIDP through drinking
water, surface water, ambient air, soil, and fish ingestion
Exposure durations
• Acute - Exposed to DIDP continuously for a 24-hour period
• Chronic - Exposed to DIDP continuously up to 33 years
Exposure routes - Inhalation, dermal, and oral (depending on exposure scenario)
Health Effects,
Concentration and
Time Duration
Non-cancer Acute/Intermediate/Chronic Values
Sensitive health effect: Developmental toxicity
HEC Daily, continuous = 49 mg/m3 (2.7 ppm)
HED Daily = 9.0 mg/kg; dermal and oral
Total UF (benchmark MOE) = 30 (UFA = 3; UFH = 10)
4.3.1.1 Estimation of Non-cancer Risks
EPA used a margin of exposure (MOE) approach to identify potential non-cancer risks for individual
exposure routes {i.e., oral, dermal, inhalation). The MOE is the ratio of the non-cancer POD divided by a
human exposure dose. Acute, short-term, and chronic MOEs for non-cancer inhalation and dermal risks
were calculated using Equation 4-1.
Equation 4-1. Margin of Exposure Calculation
Non — cancer Hazard Value (POD)
M0E ~ Human Exposure
Where:
MOE = Margin of exposure for acute, short-term, or chronic
risk comparison (unitless)
Non-cancer Hazard Value (POD) = HEC (mg/m3) or HED (mg/kg-day)
Human Exposure = Exposure estimate (mg/m3 or mg/kg-day)
MOE risk estimates may be interpreted in relation to benchmark MOEs. Benchmark MOEs are typically
the total UF for each non-cancer POD. The MOE estimate is interpreted as a human health risk of
concern if the MOE estimate is less than the benchmark MOE {i.e., the total UF). On the other hand, if
the MOE estimate is equal to or exceeds the benchmark MOE, the risk is not considered to be of concern
and mitigation is not needed. Typically, the larger the MOE, the more unlikely it is that a non-cancer
adverse effect occurs relative to the benchmark. When determining whether a chemical substance
presents unreasonable risk to human health or the environment, calculated risk estimates are not "bright-
line" indicators of unreasonable risk, and EPA has the discretion to consider other risk-related factors in
addition to risks identified in the risk characterization.
4.3.1.2 Estimation of Non-cancer Aggregate Risks
As described in Section 4.1.5, EPA considered aggregate risk across all routes of exposure for each
individual consumer and occupational COU evaluated for acute, intermediate, and chronic exposure
durations. To identify potential non-cancer risks for aggregate exposure scenarios for workers (Section
4.3.2) and consumers (Section 4.3.3), EPA used the total MOE approach ( 31). For the total
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MOE approach, MOEs for each exposure route of interest in the aggregate scenario must first be
calculated. The total MOE for the aggregate scenario can then be calculated using Equation 4-2.
Equation 4-2. Total Margin of Exposure Calculation
Total MOE risk estimates may be interpreted in relation to benchmark MOEs, similarly as to described
above in Section 4.3.1.1.
4,3.2 Risk Estimates for Workers
Risk estimates for workers from inhalation and dermal exposures, as well as aggregated exposures, are
shown in Table 4-16. This section provides discussion and characterization of risk estimates for workers,
including females of reproductive age and ONUs, for the various OESs and COUs. In summary, it was
determined that the central tendency estimates of worker exposure and risk are most representative for
all manufacturing, processing, industrial and commercial COUs, with the exception of the Industrial
COU: "Adhesives and sealants" due to the potentially elevated inhalation exposures from pressurized
spray operations.
Application of Adhesives and Sealants
For the application of adhesives and sealants, inhalation exposure from mist generation is expected to be
the dominant route of exposure. In support of this, MOEs for high-end acute, intermediate, and chronic
inhalation exposure ranged from 2.9 to 4.8 for average adult workers and women of reproductive age,
while high-end dermal MOEs for the same populations and exposure scenarios ranged from 98 to 156
(Benchmark = 30). Aggregation of inhalation and dermal exposures led to negligible differences in
MOEs when compared to MOE estimates from inhalation exposure alone since the inhalation exposure
is the predominant source of worker exposure for this OES. Also, it is important to note that there were
large variations between the central tendency and high-end estimates of worker inhalation exposure
(central tendency inhalation MOEs ranged from 483 to 839 for acute, intermediate, and chronic
exposure scenarios for adult workers and women of reproductive age). Reasons for these variations are
described below.
EPA relied on mist monitoring data from the ESD on Coating Application via Spray-Painting in the
Automotive RefinishingIndustry (OECD, 2011a\ which showed that the central tendency {i.e., 50th
percentile) of 8-hour TWA mist concentrations from automotive refinishing was 3.38 mg/m3 and the
high-end {i.e., 95th percentile) was 22.1 mg/m3. These mist concentration data were derived from a
variety of industrial and commercial automotive refinishing scenarios {e.g., different gun types and
booth configurations), but all scenarios considered in the ESD commonly used the spray application of
auto refinishing coatings. The more highly pressurized spray guns led to higher exposure levels, and less
pressurized spray guns led to lower exposure levels. Therefore, the high-end inhalation exposure
estimates are more representative of high-pressure spray applications whereas the central tendency
1
Total MOE
Where
Total MOE
MOlUjrat
M() l^ljelinal
IMOElnhalation
Margin of exposure for aggregate scenario (unitless)
Margin of exposure for oral route (unitless)
Margin of exposure for dermal route (unitless)
Margin of exposure for inhalation route (unitless)
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estimates are more representative of low-pressure applications including non-spray methods such as
brush, roll, dip, bead application, and low-pressure spray guns. Regarding product concentrations, the
various commercial adhesive and sealant products considered are summarized in Appendix F of the
Draft Environmental Release and Occupational Exposure Assessment for Diisodecyl Phthalate (DIDP)
(U.S. EPA, 2024eY Though the concentrations are representative of commercial products, similar DIDP
concentrations are expected for industrial adhesives and sealants. The central tendency product
concentration was chosen as the mode of available product concentrations {i.e., 1 wt%) and the high-end
product concentration was chosen as 95th percentile of available product concentrations {i.e., 60 wt%).
Because there were significant differences between central tendency and high-end values for the mist
exposure concentration and the product concentration, which are both inputs to the inhalation exposure
distribution, there was a larger range of potential inhalation exposures for the application of adhesives
and sealants.
Since the mist exposure data is directly applicable to the spray application of coating, and the range of
DIDP concentrations in various commercial products is expected to be similar to industrial adhesive and
sealant products, the high-end inhalation exposure estimates are potentially reflective of industrial
operations where adhesives and sealants are applied using spray methods {i.e., Industrial COU:
Adhesives and sealants). However, it is unlikely that the application of adhesives and sealants through
low-pressure applications such as brush, roll, dip, bead application, and low-pressure spray guns would
reach the high-end inhalation levels estimated in Table 4-3, and the application of adhesives and sealants
through these non-spray methods are reflected by central tendency exposure and risk estimates. Non-
spray methods are generally used for the Industrial COU: Abrasives manufacturing and therefore
inhalation exposures are represented by the central tendency estimates. Also, the commercial adhesive
and sealant products that were identified through the risk evaluation process and summarized in
Appendix F of Draft Environmental Release and Occupational Exposure Assessment for Diisodecyl
Phthalate (DIDP) (U.S. EPA, 2024e) are not generally applied through highly pressurized spray
application, but rather bead, brush, or roll applications are used for the available commercial adhesive
and sealant products containing DIDP. Therefore, occupational exposures to DIDP from the Commercial
COUs: Adhesives and sealants (including plasticizers in adhesives and sealants) and "Lacquers, stains,
varnishes, and floor finishes (as plasticizer)" are represented by the central tendency levels of exposure.
Application of Paints and Coatings
For the application of paints and coatings, inhalation exposure from mist generation is expected to be the
dominant route of exposure. In support of this, MOEs for high-end acute, intermediate, and chronic
inhalation exposure ranged from 29 to 48 for average adult workers and women of reproductive age,
while high-end dermal MOEs for the same populations and exposure scenarios ranged from 98 to 156
(Benchmark = 30). Aggregation of inhalation and dermal exposures led to small differences in MOEs
when compared to MOE estimates from inhalation exposure alone. Also, it is important to note that
there were large variations between the central tendency and high-end estimates of worker inhalation
exposure (central tendency inhalation MOEs ranged from 483 to 779 for acute, intermediate, and
chronic exposure scenarios for adult workers and women of reproductive age). Reasons for these
variations are described below.
EPA relied on mist monitoring data from the ESD on Coating Application via Spray-Painting in the
Automotive RefinishingIndustry (OECD, 2011a\ which showed that the central tendency {i.e., 50th
percentile) of 8-hour TWA mist concentrations from automotive refinishing was 3.38 mg/m3 and the
high-end {i.e., 95th percentile) was 22.1 mg/m3. These mist concentration data were derived from a
variety of industrial and commercial automotive refinishing scenarios {e.g., different gun types and
booth configurations), but all scenarios considered in the ESD commonly used the spray application of
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auto refinishing coatings. The more highly pressurized spray guns led to higher exposure levels, and less
pressurized spray guns led to lower exposure levels. Therefore, the high-end inhalation exposure
estimates are more representative of high-pressure spray applications whereas the central tendency
estimates are more representative of low-pressure applications including non-spray methods such as
brush, roll, dip, and bead application. Regarding product concentrations, the various commercial paint
and coating products considered are summarized in Appendix F of the Draft Environmental Release and
Occupational Exposure Assessment for Diisodecyl Phthalate (1)11)P) (U.S. EPA, 2024el EPA used the
mode product concentration (i.e., 1 percent) to represent the central tendency product concentration and
the upper bound product concentration (i.e., 5 percent) to represent the high-end product concentration.
Due to the differences between central tendency and high-end values for the mist exposure concentration
and the product concentration, which are both inputs to the inhalation exposure distribution, there was a
larger range of potential inhalation exposures for the application of paints and coatings.
The commercial paint and coating products that were identified through the risk evaluation process and
summarized in Appendix F of Draft Environmental Release and Occupational Exposure Assessment for
Diisodecyl Phthalate (1)11)P) (U.S. EPA, 2024e) are not generally applied through highly pressurized
spray application, but rather low-pressure hand pump sprayers and buff coating applications are used for
the available commercial paint and coating products containing DIDP. Therefore, occupational
exposures to DIDP from the commercial COUs: "Paints and coatings (including surfactants in
paints and coatings)", "Lacquers, stains, varnishes, and floor finishes (as plasticizer)", and "Ink,
toner, and colorant products" are represented by the central tendency levels of exposure.
Use of Penetrants and Inspection Fluids
For the use of penetrants and inspection fluids, inhalation exposure from aerosol generation is expected
to be the dominant route of exposure. In support of this, MOEs for high-end acute, intermediate, and
chronic inhalation exposure ranged from 12 to 19 for average adult workers and women of reproductive
age, while high-end dermal MOEs for the same populations and exposure scenarios ranged from 98 to
157 (Benchmark = 30). Aggregation of inhalation and dermal exposures led to negligible differences in
MOEs when compared to MOE estimates from inhalation exposure alone. Also, it is important to note
that there were moderate variations between the central tendency and high-end estimates of worker
inhalation exposure (central tendency inhalation MOEs ranged from 43 to 69 for acute, intermediate,
and chronic exposure scenarios for adult workers and women of reproductive age). Reasons for these
variations are described below.
EPA based the central tendency and high-end exposure estimates on a near-field/far-field approach
( i009), and the product concentration was based on the range provided by the singular surrogate
product which contained DINP (i.e., 10 to 20 percent) rather than DIDP. As a result of the narrow range
of model inputs, calculated central tendency and high-end risk values were similar. It is important to
note that reliance on a single surrogate product for this OES adds uncertainty to the representativeness of
the modeled inhalation exposures. Further, although the surrogate product information indicates that the
product is aerosol and brush applied, EPA assessed only aerosol application due to limited data for this
OES. Aerosol application may overestimate inhalation exposures for brush application methods.
Therefore, the central tendency exposure levels are expected to be representative of the commercial
COU: "Inspection fluid/penetrant" due to uncertainties in both product concentration and method of
application.
PVC Plastics Compounding and Non-PVC Material Compounding
For PVC plastics compounding and non-PVC material compounding, inhalation exposure from dust
generation is expected to be the dominant route of exposure. In support of this, for PVC plastics
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compounding, MOEs for high-end acute, intermediate, and chronic inhalation exposure ranged from 30
to 49 for average adult workers and women of reproductive age, while high-end dermal MOEs for the
same populations and exposure scenarios ranged from 98 to 156 (Benchmark = 30). Similarly, for non-
PVC material compounding MOEs for high-end acute, intermediate, and chronic inhalation exposure
ranged from 67 to 108 for average adult workers and women of reproductive age, while high-end dermal
MOEs for the same populations and exposure scenarios ranged from 98 to 156. Aggregation of
inhalation and dermal exposures led to small differences in MOEs when compared to MOE estimates
from inhalation exposure alone (high-end MOEs based on aggregate exposure ranged from 24 to 37
(PVC plastics compounding) and 41 to 62 (non-PVC material compounding) for acute, intermediate,
and chronic duration exposures for average adult workers and women of reproductive age). Also, it is
important to note that there were large variations between the central tendency and high-end estimates of
worker inhalation exposure (central tendency inhalation MOEs ranged from 488 to 883 (PVC plastics
compounding) and 858 to 1,478 (non-PVC material compounding) for acute, intermediate, and chronic
exposure scenarios for adult workers and women of reproductive age). Reasons for these variations are
described below.
EPA estimated worker inhalation exposures using surrogate monitoring data for vapor exposures and the
Generic Model for Central Tendency and High-End Inhalation Exposure to Total and Respirable
Particulates Not Otherwise Regulated (PNOR) for dust exposures (U.S. EPA. 202Id). EPA did not have
sufficient data to define separate central tendency and high-end vapor exposures, and thus a singular
value was used to represent potential exposures from vapor. Regarding the dominant route of exposure,
inhalation exposure of PNOR, EPA determined the 50th and 95th percentiles of the surrogate dust
release data taken from facilities with NAICS codes starting with 326 (Plastics and Rubber
Manufacturing). EPA multiplied these dust concentrations by the industry provided DIDP concentration
range in PVC {i.e., 10 to 45 percent) and non-PVC {i.e., 10 to 20 percent) products, respectively, to
estimate DIDP particulate concentrations in the air. The differences in the central tendency and high-end
dust concentrations, as well as DIDP concentrations in the dust, led to significant differences between
the central tendency and high-end risk estimates.
Though the PNOR {i.e., dust) concentration data provides a reliable range of dust concentrations that a
worker may experience in the compounding industry, the composition of workplace dust is uncertain.
The exposure and risk estimates are based on the assumption that the concentration of DIDP in
workplace dust is the same as the concentration of DIDP in PVC plastics or non-PVC materials,
respectively. However, it is likely that workplace dust contains a variety of constituents and that the
concentration of DIDP in workplace dust is less than the concentration of DIDP in PVC or non-PVC
products. Therefore, central tendency values of exposure are expected to be more reflective of true
worker exposures within the COUs covered under the PVC plastics compounding and non-PVC material
compounding OESs {i.e., Industrial COUs: Plastic material and resin manufacturing, Plasticizers (rubber
manufacturing), and Other [part of the formulation for manufacturing synthetic leather]) due to the
uncertainty of DIDP concentration in workplace dust.
PVC Plastics Converting and Non-PVC Material Converting
For PVC plastics converting and non-PVC material converting, inhalation exposure from dust
generation is expected to be the dominant route of exposure. In support of this, for PVC plastics
converting, MOEs for high-end acute, intermediate, and chronic inhalation exposure ranged from 30 to
49 for average adult workers and women of reproductive age, while high-end dermal MOEs for the
same populations and exposure scenarios ranged from 9,356 to 14,867 (Benchmark = 30). Similarly, for
non-PVC material converting MOEs for high-end acute, intermediate, and chronic inhalation exposure
ranged from 67 to 108 for average adult workers and women of reproductive age, while high-end dermal
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MOEs for the same populations and exposure scenarios ranged from 9,356 to 14,867. Aggregation of
inhalation and dermal exposures led to negligible differences in MOEs when compared to MOE
estimates from inhalation exposure alone. Also, it is important to note that there were large variations
between the central tendency and high-end estimates of worker inhalation exposure (central tendency
inhalation MOEs ranged from 488 to 899 (PVC plastics converting) and 858 to 1,579 (non-PVC
material converting) for acute, intermediate, and chronic exposure scenarios for adult workers and
women of reproductive age). Reasons for these variations are described below.
EPA estimated worker inhalation exposures using surrogate monitoring data for vapor exposures and the
Generic Model for Central Tendency and High-End Inhalation Exposure to Total and Respirable
Particulates Not Otherwise Regulated (PNOR) for dust exposures (U.S. EPA. 202Id). EPA did not have
sufficient data to define separate central tendency and high-end vapor exposures, and thus a singular
value was used to represent potential exposures from vapor. Regarding the dominant route of exposure,
inhalation exposure of PNOR, EPA determined the 50th and 95th percentiles of the surrogate dust
release data taken from facilities with NAICS codes starting with 326 (Plastics and Rubber
Manufacturing). EPA multiplied these dust concentrations by the industry provided DIDP concentration
range in PVC {i.e., 10 to 45 percent) and non-PVC {i.e., 10 to 20 percent) products, respectively, to
estimate DIDP particulate concentrations in the air. The differences in the central tendency and high-end
dust concentrations, as well as DIDP concentrations in the dust, led to significant differences between
the central tendency and high-end risk estimates.
Though the PNOR {i.e., dust) concentration data provides a reliable range of dust concentrations that a
worker may experience in the converting industry, the composition of workplace dust is uncertain. The
exposure and risk estimates are based on the assumption that the concentration of DIDP in workplace
dust is the same as the concentration of DIDP in PVC plastics or non-PVC materials, respectively.
However, it is likely that workplace dust contains a variety of constituents and that the concentration of
DIDP in workplace dust is less than the concentration of DIDP in PVC or non-PVC products. Therefore,
central tendency values of exposure are expected to be more reflective of true worker exposures within
the COUs covered under the "PVC Plastics Converting" and the "Non-PVC Material Converting" OESs
{i.e., Industrial COUs: "Plasticizers (asphalt paving, roofing, and coating materials manufacturing;
construction; automotive products manufacturing, other than fluids; electrical equipment, appliance, and
component manufacturing; fabric, textile, and leather products manufacturing; floor coverings
manufacturing; furniture and related product manufacturing; plastics product manufacturing; rubber
product manufacturing; textiles, apparel, and leather manufacturing; transportation equipment
manufacturing; ink, toner, and colorant (including pigment) products manufacturing; photographic
supplies manufacturing; sporting equipment manufacturing") due to the uncertainty of DIDP
concentration in workplace dust.
Recycling and Disposal
For recycling and disposal of DIDP containing materials, inhalation exposure from dust generation is
expected to be the dominant route of exposure. In support of this, MOEs for high-end acute,
intermediate, and chronic inhalation exposure ranged from 41 to 67 for average adult workers and
women of reproductive age, while high-end dermal MOEs for the same populations and exposure
scenarios ranged from 9,356 to 14,867 (benchmark = 30). Aggregation of inhalation and dermal
exposures led to negligible differences in risk when compared to risk estimates from inhalation exposure
alone. Also, it is important to note that there were large variations between the central tendency and
high-end estimates of worker inhalation exposure (central tendency inhalation MOEs ranged from 604
to 1,091 for acute, intermediate, and chronic exposure scenarios for adult workers and women of
reproductive age). Reasons for these variations are described below.
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2465
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2467
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EPA estimated worker inhalation exposures using the Generic Model for Central Tendency and High-
End Inhalation Exposure to Total andRespirable Particulates Not Otherwise Regulated (PNOR) for
dust exposures (U.S. EPA. 202Id). Regarding the dominant route of exposure, inhalation exposure of
PNOR, EPA determined the 50th and 95th percentiles of the surrogate dust release data taken from
facilities with NAICS codes starting with 56 (Administrative and Support and Waste Management and
Remediation Services). EPA multiplied these dust concentrations by the industry provided maximum
DIDP concentration in PVC (i.e., 45 percent) to estimate DIDP particulate concentrations in the air.
Therefore, the differences in the central tendency and high-end dust concentrations led to significant
differences between the central tendency and high-end risk estimates.
Though the PNOR (i.e., dust) concentration data provides a reliable range of dust concentrations that a
worker may experience in the recycling and disposal industry, the composition of workplace dust is
uncertain. The exposure and risk estimates are based on the assumption that the concentration of DIDP
in workplace dust is the same as the maximum concentration of DIDP in PVC plastics. However, it is
likely that workplace dust contains a variety of constituents and that the concentration of DIDP in
workplace dust is less than the concentration of DIDP in recycled or disposed products or articles.
Therefore, central tendency values of exposure are expected to be more reflective of true worker
exposures within the COUs covered under the "Recycling" and the "Disposal" OESs (i.e., Industrial
COUs: "Recycling" and "Disposal") due to the uncertainty of DIDP concentration in workplace dust.
Fabrication and Final Use of Products or Articles
For fabrication and final use of products or articles, inhalation exposure from dust generation is expected
to be the dominant route of exposure. In support of this, MOEs for high-end acute, intermediate, and
chronic inhalation exposure ranged from 80 to 130 for average adult workers and women of
reproductive age, while high-end dermal MOEs for the same populations and exposure scenarios ranged
from 9,356 to 14,867 (Benchmark = 30). Aggregation of inhalation and dermal exposures led to
negligible differences in risk when compared to risk estimates from inhalation exposure alone. Also, it is
important to note that there were large variations between the central tendency and high-end estimates of
worker inhalation exposure (central tendency inhalation MOEs ranged from 724 to 1,168 for acute,
intermediate, and chronic exposure scenarios for adult workers and women of reproductive age).
Reasons for these variations are described below.
EPA estimated worker inhalation exposures using the Generic Model for Central Tendency and High-
End Inhalation Exposure to Total and Respirable Particulates Not Otherwise Regulated (PNOR) for
dust exposures (U.S. EPA. 202Id). Regarding the dominant route of exposure, inhalation exposure of
PNOR, EPA determined the 50th and 95th percentiles of the surrogate dust release data taken from
facilities with NAICS codes starting with 337 (Furniture and Related Product Manufacturing). EPA
multiplied these dust concentrations by the industry provided maximum DIDP concentration in PVC
(i.e., 45 percent) to estimate DIDP particulate concentrations in the air. Therefore, the differences in the
central tendency and high-end dust concentrations led to significant differences between the central
tendency and high-end risk estimates.
Though the PNOR (i.e., dust) concentration data provides a reliable range of dust concentrations that a
worker may experience in the end use and fabrication industry, the composition of workplace dust is
uncertain. The exposure and risk estimates are based on the assumption that the concentration of DIDP
in workplace dust is the same as the maximum concentration of DIDP in PVC plastics. However, it is
likely that workplace dust contains a variety of constituents and that the concentration of DIDP in
workplace dust is less than the concentration of DIDP in final products or articles. Therefore, central
tendency values of exposure are expected to be more reflective of true worker exposures within the
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2499
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2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
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COUs covered under the "Fabrication and final use of products and articles" OES (i.e., Industrial COU:
"Abrasives (surface conditioning and finishing discs; semi-finished and finished goods)" and
Commercial COUs: "Automotive products, other than fluids", "Building/construction materials (wire or
wiring systems; joint treatment, fire-proof insulation)", "Electrical and electronic products",
"Construction and building materials covering large surface areas including stone, plaster, cement, glass
and ceramic articles; fabrics, textiles, and apparel (as plasticizer) (Floor coverings (vinyl tiles, PVC-
backed carpeting, scraper mats))", "PVC film and sheet", "Furniture and furnishings", "Plastic and
rubber products (textiles, apparel, and leather; vinyl tape; flexible tubes; profiles; hoses)") due to the
uncertainty of DIDP concentration in workplace dust.
Distribution in Commerce
Distribution in commerce includes transporting DIDP or DIDP-containing products between work sites
or to final use sites as well as loading and unloading from transport vehicles. Individuals in occupations
that transport DIDP-containing products (e.g., truck drivers) or workers who load and unload transport
trucks may encounter DIDP or DIDP-containing products.
Worker activities associated with distribution in commerce (e.g., loading, unloading) are not expected to
generate mist or dust, similar to other COUs such as manufacturing and import. Therefore, inhalation
exposures to workers during distribution in commerce are expected to be from the vapor phase only.
Dermal contact with the neat material or concentrated formulations may occur during activities
associated with distribution in commerce, also similar to COUs such as manufacturing and import.
Though some worker activities associated with distribution in commerce are similar to COUs such as
manufacturing or import, it is expected that workers involved in distribution in commerce spend less
time exposed to DIDP than workers in manufacturing or import facilities since only part of the workday
is spent in an area with potential exposure. In conclusion, occupational exposures associated with the
distribution in commerce COU are expected to be less than other OESs/COUs without Dust or Mist
Generation, such as manufacturing or import, and the COU is captured in the subsection below.
OESs/COUs without Dust or Mist Generation
Due to the low vapor pressure of DIDP, inhalation exposures from vapor-generating activities, without
dust or mist generation, are shown to be quite low. Analysis of each OES relied on either direct or
surrogate vapor monitoring data, and resulting worker risk estimates were far above the benchmark
MOE of 30 (i.e., high-end inhalation MOEs for the OESs listed below were greater than or equal to 905
for all assessed populations and exposure duration). Also, due to the long alkyl chain length of DIDP,
the rate of dermal absorption of DIDP is quite slow which leads to low dermal exposure potential.
Therefore, any OES or COU where inhalation exposure to DIDP comes only from vapor-generating
activities is not expected to lead to significant worker exposures, and such uses are summarized below.
OESs where inhalation exposure comes from vapor-generating activities only:
• Manufacturing; Import and repackaging; Incorporation into adhesives and sealants;
Incorporation into paints and coatings; Incorporation into other formulations, mixtures, and
reaction products not covered elsewhere; Use of laboratory chemicals - liquids; Use of lubricants
and functional fluids; and Distribution in Commerce.
• Although there is dust generation expected during the OES for "Use of Laboratory chemicals -
solids," the industry provided maximum DIDP concentration is very low (i.e., 3 percent), which
leads to very low levels of potential worker inhalation exposure similar to that of vapor-
generating activities.
COUs where inhalation exposure comes from vapor-generating activities only:
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• Industrial: Domestic manufacturing; Import; repackaging; Adhesives and sealants
manufacturing; Surface modifier in paint and coating manufacturing; Plasticizers (paint and
coating manufacturing; colorants (including pigments)); Laboratory chemicals manufacturing;
Petroleum lubricating oil manufacturing; Lubricants and lubricant additives manufacturing;
Processing aids, specific to petroleum production (oil and gas drilling, extraction, and support
activities); Functional fluids (closed systems) (SCBA compressor oil); Lubricant and lubricant
additives; Solvents (for cleaning or degreasing)
• Commercial: Laboratory chemicals; Lubricants
• Distribution in Commerce
Table 4-16 summarizes the risk estimates discussed above for all OESs and COUs. Section 4.1.1
presents the occupational exposure assessment. The risk summary below is based on the most sensitive
non-cancer endpoints for each scenario {i.e., acute non-cancer, intermediate non-cancer, and chronic
non-cancer).
4.3.2.1 Overall Confidence in Worker Risks
As described in Section 4.1.1.5 and the Draft Environmental Release and Occupational Exposure
Assessment for Diisodecyl Phthalate (DIDP) ( )24e). EPA has moderate to robust
confidence in the assessed inhalation and dermal OESs (Table 4-5), and robust confidence in the non-
cancer POD selected to characterize risk from acute, intermediate, and chronic duration exposures to
DIDP (see Section 4.2 and ( !24h)). Overall, EPA has moderate to robust confidence in the
risk estimates calculated for worker and ONU inhalation and dermal exposure scenarios. Sources of
uncertainty associated with these occupational COUs are discussed above in Section 4.3.2.
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2569 Table 4-16. Occupational Risk Summary Table
Industrial/Commercial COUs
OES
Population
Exposure
Level
Inhalation Risk Estimates
(Benchmark MOE = 30)
Dermal Risk Estimates
(Benchmark MOE = 30)
Aggregate Risk Estimates
(Benchmark MOE = 30)
Life Cvcle
Stage/
Category
Subcategory
Acute
Intermed.
Chronic
Acute
Intermed.
Chronic
Acute
Intermed.
Chronic
Manufacturing
Domestic
Manufacturing
Manufacturing
Worker:
Average Adul
Worker
High-End
1,000
1,364
2,028
98
134
199
89
122
181
Central
Tendency
2,000
2,727
4,056
196
268
398
179
244
362
Worker:
Female of
Reproductive
Age
High-End
905
1,235
1,836
107
146
217
96
130
194
Central
Tendency
1,811
2,469
3,672
214
291
433
191
261
388
ONU
High-End
2,000
2,727
4,056
N/A
N/A
N/A
2,000
2,727
4,056
Central
Tendency
2,000
2,727
4,056
N/A
N/A
N/A
2,000
2,727
4,056
Manufacturing
Importing
Import and
Worker:
Average Adul
Worker
High-End
1,000
1,364
1,460
98
134
143
89
122
130
Central
Tendency
2,000
2,727
3,510
196
268
344
179
244
314
Worker:
Female of
Reproductive
Age
High-End
905
1,235
1,322
107
146
156
96
130
140
Processing
Repackaging
repackaging
Central
Tendency
1,811
2,469
3,177
214
291
375
191
261
335
ONU
High-End
2,000
2,727
2,920
N/A
N/A
N/A
2,000
2,727
2,920
Central
Tendency
2,000
2,727
3,510
N/A
N/A
N/A
2,000
2,727
3,510
Incorporation
into
formulation,
mixture, or
reaction
product
Adhesives and
sealants
manufacturing
Incorporation
into adhesives
and sealants
Worker:
Average Adul
Worker
High-End
2,400
3,273
3,504
98
134
143
94
129
138
Central
Tendency
2,400
3,273
3,504
196
268
287
181
247
265
Worker:
Female of
Reproductive
Age
High-End
2,173
2,963
3,172
107
146
156
102
139
149
Central
Tendency
2,173
2,963
3,172
214
291
312
195
265
284
ONU
High-End
120,000
163,636
175,200
N/A
N/A
N/A
120,000
163,636
175,200
Central
Tendency
240,000
327,273
350,400
N/A
N/A
N/A
240,000
327,273
350,400
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Industrial/Commercial COUs
OES
Population
Exposure
Level
Inhalation Risk Estimates
(Benchmark MOE = 30)
Dermal Risk Estimates
(Benchmark MOE = 30)
Aggregate Risk Estimates
(Benchmark MOE = 30)
Life Cvcle
Stage/
Category
Subcategory
Acute
Intermed.
Chronic
Acute
Intermed.
Chronic
Acute
Intermed.
Chronic
Incorporation
into
formulation,
mixture, or
reaction
product
Surface
modifier in
paint and
coating
manufacturing
Incorporation
into paints and
coatings
Worker:
Average Adul
Worker
High-End
2,400
3,273
3,504
98
134
143
94
129
138
Central
Tendency
2,400
3,273
3,504
196
268
287
181
247
265
Plasticizers
(paint and
coating
manufacturing;
colorants
(including
pigments))
Worker:
Female of
Reproductive
Age
High-End
2,173
2,963
3,172
107
146
156
102
139
149
Central
Tendency
2,173
2,963
3,172
214
291
312
195
265
284
ONU
High-End
120,000
163,636
175,200
N/A
N/A
N/A
120,000
163,636
175,200
Central
Tendency
240,000
327,273
350,400
N/A
N/A
N/A
240,000
327,273
350,400
Incorporation
into
formulation,
mixture, or
reaction
product
Laboratory
chemicals
manufacturing
Incorporation
into other
formulations,
mixtures, and
reaction
products not
covered
elsewhere
Worker:
Average Adul
Worker
High-End
2,400
3,273
3,504
98
134
143
94
129
138
Petroleum
lubricating oil
manufacturing;
Lubricants and
lubricant
additives
manufacturing
Central
Tendency
2,400
3,273
3,504
196
268
287
181
247
265
Worker:
Female of
Reproductive
Age
High-End
2,173
2,963
3,172
107
146
156
102
139
149
Central
Tendency
2,173
2,963
3,172
214
291
312
195
265
284
Processing aids,
specific to
petroleum
production (oil
and gas drilling,
extraction, and
support
activities)
ONU
High-End
120,000
163,636
175,200
N/A
N/A
N/A
120,000
163,636
175,200
Central
Tendency
240,000
327,273
350,400
N/A
N/A
N/A
240,000
327,273
350,400
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Industrial/Commercial COUs
OES
Population
Exposure
Level
Inhalation Risk Estimates
(Benchmark MOE = 30)
Dermal Risk Estimates
(Benchmark MOE = 30)
Aggregate Risk Estimates
(Benchmark MOE = 30)
Life Cvcle
Stage/
Category
Subcategory
Acute
Intermed.
Chronic
Acute
Intermed.
Chronic
Acute
Intermed.
Chronic
Incorporation
into
formulation,
mixture, or
reaction
product
Plastic material
and resin
manufacturing
PVC plastics
compounding
Worker:
Average Adul
Worker
High-End
34
46
49
98
134
143
25
34
37
Central
Tendency
539
735
883
196
268
321
144
196
236
Other (part of
the formulation
for
manufacturing
synthetic
leather)
Worker:
Female of
Reproductive
Age
High-End
30
41
44
107
146
156
24
32
35
Central
Tendency
488
666
799
214
291
350
149
203
243
ONU
High-End
692
943
1,010
18,711
25,515
27,318
667
910
974
Central
Tendency
694
946
1,135
18,711
25,515
30,626
669
912
1,095
Incorporation
into articles
Plasticizers "
PVC plastics
converting
Worker:
Average Adul
Worker
High-End
34
46
49
9,356
12,758
13,659
33
46
49
Central
Tendency
539
735
899
18,711
25,515
31,185
524
715
874
Worker:
Female of
Reproductive
Age
High-End
30
41
44
10,183
13,885
14,867
30
41
44
Central
Tendency
488
666
814
20,365
27,771
33,942
477
650
795
ONU
High-End
692
943
1,010
18,711
25,515
27,318
667
910
974
Central
Tendency
694
946
1,156
18,711
25,515
31,185
669
912
1,115
Incorporation
into
formulation,
mixture, or
reaction
product
Plastic material
and resin
manufacturing
Non-PVC
material
compounding
Worker:
Average Adul
Worker
High-End
74
101
108
98
134
143
42
58
62
Central
Tendency
947
1,292
1,478
196
268
306
163
222
254
Worker:
Female of
Reproductive
Age
High-End
67
92
98
107
146
156
41
56
60
Other (part of
the formulation
for
manufacturing
synthetic
leather)
Central
Tendency
858
1,170
1,338
214
291
333
171
233
267
Plasticizers
(rubber
manufacturing)
ONU
High-End
1,545
2,107
2,256
18,711
25,515
27,318
1,427
1,946
2,084
Central
Tendency
1,555
2,121
2,426
18,711
25,515
29,186
1,436
1,958
2,240
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Industrial/Commercial COUs
Exposure
Level
Inhalation Risk Estimates
(Benchmark MOE = 30)
Dermal Risk Estimates
(Benchmark MOE = 30)
Aggregate Risk Estimates
(Benchmark MOE = 30)
Life Cvcle
Stage/
Category
Subcategory
OES
Population
Acute
Intermed.
Chronic
Acute
Intermed.
Chronic
Acute
Intermed.
Chronic
Worker:
High-End
74
101
108
9,356
12,758
13,659
74
100
108
Average Adul
Worker
Central
Tendency
947
1,292
1,579
18,711
25,515
31,185
902
1,230
1,503
Incorporation
Plasticizers 4
Non-PVC
material
converting
Worker:
Female of
High-End
67
92
98
10,183
13,885
14,867
67
91
97
into articles
Reproductive
Age
Central
Tendency
858
1,170
1,429
20,365
27,771
33,942
823
1,122
1,372
ONU
High-End
1,545
2,107
2,256
18,711
25,515
27,318
1,427
1,946
2,084
Central
Tendency
1,555
2,121
2,592
18,711
25,515
31,185
1,436
1,958
2,393
Incorporation
into articles
Abrasives
manufacturing
Worker:
High-End
3.3
4.4
4.8
98
134
143
3.2
4.3
4.6
Industrial uses
Adhesives and
sealants7
Average Adul
- Adhesives
and sealants
Worker
Central
Tendency
533
727
839
196
268
309
143
196
226
Adhesives and
High-End
2.9
4.0
4.3
107
146
156
2.9
3.9
4.2
Commercial
uses -
Construction,
paint,
electrical, and
metal products
sealants
(including
plasticizers in
adhesives and
sealants)
Application of
adhesives and
sealants
Worker:
Female of
Reproductive
Age
Central
Tendency
483
658
760
214
291
336
148
202
233
Lacquers,
High-End
533
727
779
196
268
287
143
196
209
stains,
varnishes, and
floor finishes
(as plasticizer)
ONU
Central
Tendency
533
727
839
196
268
309
143
196
226
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Industrial/Commercial COUs
OES
Population
Exposure
Level
Inhalation Risk Estimates
(Benchmark MOE = 30)
Dermal Risk Estimates
(Benchmark MOE = 30)
Aggregate Risk Estimates
(Benchmark MOE = 30)
Life Cvcle
Stage/
Category
Subcategory
Acute
Intermed.
Chronic
Acute
Intermed.
Chronic
Acute
Intermed.
Chronic
Commercial
uses -
Construction,
paint,
electrical, and
metal products
Paints and
coatings
(including
surfactants in
paints and
coatings)
Application of
paints and
coatings
Worker:
Average Adul
Worker
High-End
33
44
48
98
134
143
24
33
36
Lacquers,
stains,
varnishes, and
floor finishes
(as plasticizer)
Central
Tendency
533
727
779
196
268
287
143
196
209
Worker:
Female of
Reproductive
Age
High-End
29
40
43
107
146
156
23
32
34
Commercial
uses -
Furnishing,
cleaning,
treatment/care
products
Ink, toner, and
colorant
products
Central
Tendency
483
658
705
214
291
312
148
202
216
ONU
High-End
533
727
779
196
268
287
143
196
209
Central
Tendency
533
727
779
196
268
287
143
196
209
Commercial
uses - Other
uses
Laboratory
chemicals
Use of
laboratory
chemicals -
liquids
Worker:
Average Adul
Worker
High-End
1,000
1,364
1,460
98
134
143
89
122
130
Central
Tendency
2,000
2,727
3,106
196
268
305
179
244
278
Worker:
Female of
Reproductive
Age
High-End
905
1,235
1,322
107
146
156
96
130
140
Central
Tendency
1,811
2,469
2,812
214
291
332
191
261
297
ONU
High-End
2,000
2,727
2,920
N/A
N/A
N/A
2,000
2,727
2,920
Central
Tendency
2,000
2,727
3,106
N/A
N/A
N/A
2,000
2,727
3,106
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Industrial/Commercial COUs
OES
Population
Exposure
Level
Inhalation Risk Estimates
(Benchmark MOE = 30)
Dermal Risk Estimates
(Benchmark MOE = 30)
Aggregate Risk Estimates
(Benchmark MOE = 30)
Life Cvcle
Stage/
Category
Subcategory
Acute
Intermed.
Chronic
Acute
Intermed.
Chronic
Acute
Intermed.
Chronic
Commercial
uses - Other
uses
Laboratory
chemicals
Use of
laboratory
chemicals -
solids
Worker:
Average Adul
Worker
High-End
889
1,212
1,298
9,356
12,758
13,659
812
1,107
1,185
Central
Tendency
12,632
17,225
18,442
18,711
25,515
27,318
7,541
10,283
11,010
Worker:
Female of
Reproductive
Age
High-End
805
1,097
1,175
10,183
13,885
14,867
746
1,017
1,089
Central
Tendency
11,436
15,594
16,696
20,365
27,771
29,733
7,323
9,986
10,692
ONU
High-End
12,632
17,225
18,442
18,711
25,515
27,318
7,541
10,283
11,010
Central
Tendency
12,632
17,225
18,442
18,711
25,515
27,318
7,541
10,283
11,010
Industrial uses
- Functional
fluids (closed
systems)
Functional
fluids (closed
systems)
(SCBA
compressor oil)
Use of
lubricants and
functional
fluids
Worker:
Average Adul
Worker
High-End
1,000
7,500
91,250
98
736
8,956
89
670
8,155
Central
Tendency
2,000
30,000
365,000
196
2,944
35,823
179
2,681
32,622
Industrial uses
- Lubricant anc
lubricant
additives
Lubricant and
lubricant
additives
Worker:
Female of
Reproductive
Age
High-End
905
6,790
82,610
107
801
9,748
96
717
8,719
Industrial uses
- Solvents (for
cleaning or
degreasing)
Solvents (for
cleaning or
degreasing)
Central
Tendency
1,811
27,159
330,439
214
3,205
38,990
191
2,866
34,875
ONU
High-End
2,000
15,000
182,500
N/A
N/A
N/A
2,000
15,000
182,500
Commercial
uses -
Automotive,
fuel,
agriculture,
outdoor use
products
Lubricants
Central
Tendency
2,000
30,000
365,000
N/A
N/A
N/A
2,000
30,000
365,000
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Industrial/Commercial COUs
Exposure
Level
Inhalation Risk Estimates
(Benchmark MOE = 30)
Dermal Risk Estimates
(Benchmark MOE = 30)
Aggregate Risk Estimates
(Benchmark MOE = 30)
Life Cvcle
Stage/
Category
Subcategory
OES
Population
Acute
Intermed.
Chronic
Acute
Intermed.
Chronic
Acute
Intermed.
Chronic
Worker:
High-End
13
18
19
98
134
144
11
16
17
Average Adul
Worker
Central
Tendency
47
64
69
196
268
290
38
52
56
Commercial
uses - Other
uses
Use of
Worker:
High-End
12
16
17
107
146
157
11
14
16
Inspection
fluid/penetrant
penetrants and
inspection
fluids
Female of
Reproductive
Age
Central
Tendency
43
60
64
214
291
316
36
50
53
High-End
190
259
280
196
268
288
97
132
142
ONU
Central
Tendency
1,413
1,927
2,088
196
268
290
172
235
255
Industrial uses
- Abrasives
Abrasives
(surface
conditioning
and finishing
discs; semi-
finished and
finished goods)
Worker:
Average Adul
Worker
High-End
89
121
130
9,356
12,758
13,659
88
120
129
Commercial
uses -
Automotive,
fuel,
agriculture,
outdoor use
products
Automotive
products, other
than fluids
Fabrication and
final use of
products or
articles
Central
Tendency
800
1,091
1,168
18,711
25,515
27,318
767
1,046
1,120
Commercial
uses -
Construction,
paint,
electrical, and
metal products
Building/
construction
materials (wire
or wiring
systems; joint
treatment, fire-
proof
insulation)
Worker:
Female of
Reproductive
Age
High-End
80
110
117
10,183
13,885
14,867
80
109
117
Electrical and
electronic
products
Central
Tendency
724
988
1,057
20,365
27,771
29,733
699
954
1,021
Commercial
uses -
Construction
and building c
ONU
High-End
800
1,091
1,168
18,711
25,515
27,318
767
1,046
1,120
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Industrial/Commercial COUs
Inhalation Risk Estimates
Dermal Risk Estimates
Aggregate Risk Estimates
Exposure
Level
(Benchmark MOE = 30)
(Benchmark MOE = 30)
(Benchmark MOE = 30)
Life Cvcle
Stage/
Subcategory
OES
Population
Acute
Intermed.
Chronic
Acute
Intermed.
Chronic
Acute
Intermed.
Chronic
Category
Furnishing,
cleaning,
PVC film and
sheet
treatment/care
products
Furniture and
furnishings
Plastic and
Central
Tendency
rubber products
(textiles,
apparel, and
leather; vinyl
tape; flexible
tubes; profiles;
hoses)
800
1,091
1,168
18,711
25,515
27,318
767
1,046
1,120
Worker:
Fligh-End
46
62
67
9,356
12,758
13,659
45
62
66
Recycling
Recycling
Average Adul
Worker
Central
Tendency
667
909
1,091
18,711
25,515
30,626
644
878
1,054
Worker:
Fligh-End
41
56
60
10,183
13,885
14,867
41
56
60
Recycling and
disposal
Female of
Reproductive
Age
Central
Tendency
604
823
988
20,365
27,771
33,333
586
799
959
Disposal
Disposal
Fligh-End
667
909
973
18,711
25,515
27,318
644
878
940
ONU
Central
Tendency
667
909
1,091
18,711
25,515
30,626
644
878
1,054
" Plasticizers (asphalt paving, roofing, and coating materials manufacturing; construction; automotive products manufacturing, other than fluids; electrical equipment, appliance,
and component manufacturing; fabric, textile, and leather products manufacturing; floor coverings manufacturing; furniture and related product manufacturing; plastics product
manufacturing; textiles, apparel, and leather manufacturing; transportation equipment manufacturing; ink, toner, and colorant (including pigment) products manufacturing;
photographic supplies manufacturing; sporting equipment manufacturing)
4 Plasticizers (asphalt paving, roofing, and coating materials manufacturing; construction; automotive products manufacturing, other than fluids; electrical equipment, appliance,
and component manufacturing; fabric, textile, and leather products manufacturing; floor coverings manufacturing; furniture and related product manufacturing; plastics product
manufacturing; rubber product manufacturing; textiles, apparel, and leather manufacturing; transportation equipment manufacturing; ink, toner, and colorant (including pigment)
products manufacturing; photographic supplies manufacturing; toys, playground, and sporting equipment manufacturing)
c Construction and building materials covering large surface areas including stone, plaster, cement, glass and ceramic articles; fabrics, textiles, and apparel (as plasticizer) (Floor
coverings (vinyl tiles, PVC-backed carpeting, scraper mats))
2570
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4,3.3 Risk Estimates for Consumers
Table 4-17 summarizes the dermal, inhalation, ingestion, and aggregate MOEs used to characterize non-
cancer risk for acute, intermediate, and chronic exposure to DIDP and presents these values for all
lifestages for each COU. A screening level assessment for consumers considers high-intensity exposure
scenarios risk estimates and it relies on conservative assumptions to assess exposures that would be
expected to be on the high end of the expected exposure distribution. Using the high-intensity risk
estimates will assist in developing health protective approaches. MOEs for high-intensity exposure
scenarios are shown for all consumer COUs, while MOEs for medium-intensity exposure scenarios are
shown only for COUs with high-intensity MOEs close to the benchmark of 30 {i.e., for Packaging,
paper, plastic, hobby products: Plastic and rubber products (textiles, apparel, and leather; vinyl tape;
flexible tubes; hoses)). Further, Table 4-17 provides MOEs for the modeling indoor exposure
assessment. The main objective in reconstructing the indoor environment using consumer products and
articles commonly present in indoor spaces is to calculate exposure and risk estimates by COU, and by
product and article from indoor dust ingestion and inhalation. EPA identified article-specific information
by COU to construct relevant and representative exposure scenarios. Exposure to DIDP via ingestion of
dust was assessed for all articles expected to contribute significantly to dust concentrations due to high
surface area (greater than approximately 1 m2) for either a single article or collection of like articles as
appropriate. Articles included in the indoor environment assessment included: solid flooring, wallpaper,
synthetic leather furniture, shower curtains, children's toys, both legacy and new, and wire insulation.
COUs associated with articles included in the indoor environment assessment are indicated with '**' in
Table 4-17.
Of note, the risk summary below is based on the most sensitive non-cancer endpoint for all relevant
duration scenarios. MOEs for all high-, medium- and low-intensity exposure scenarios for all COUs are
provided in the Draft Consumer Risk Calculator for Diisodecyl Phthalate (DIDP) ( *024w).
Consumer COUs Evaluated Quantitatively
COUs with MOEs for High-Intensity Exposure Scenarios Ranging from 60 to 11,221,891,082: All
consumer COUs and product/article examples, except for in-place wallpaper (discussed more below),
resulted in MOEs for high-intensity exposure scenarios ranging from 60 for acute aggregate exposure to
DIDP from synthetic leather furniture for infants (less than one) to 11,221,891,082 for chronic duration
ingestion of suspended dust from new children's toys for adults (21 years and older) (Table 4-17).
Variability in MOEs for these high-intensity exposure scenarios results from use of different exposure
factors for each COU and product/article example that led to different estimates of exposure to DIDP.
As described in the Draft Consumer and Indoor Dust Exposure Assessment for Diisodecyl Phthalate
( 2024a) and Draft Human Health Hazard Assessment for Diisodecyl Phthalate (U.S. EPA.
2024h), EPA has moderate to robust confidence in the exposure estimates and robust confidence in the
non-cancer hazard value used to estimate non-cancer risk for these COUs.
COUs with MOEs for High-Intensity Exposure Scenarios ranging from 27 to 30: For one COU, EPA
calculated MOEs for high-intensity exposures scenarios that range from 27 to 30 (Table 4-17). This
COU is discussed further below and in more detail in the Draft Consumer and Indoor Dust Exposure
Assessment for Diisodecyl Phthalate ( 24a).
• Packaging, paper, plastic, hobby products: Plastic and rubber products (textiles, apparel and
leather: vinyl tape: flexible tubes: profiles: hoses: In-place wallpaper - For in-place wallpaper,
EPA evaluated acute and chronic exposure to DIDP through dermal, inhalation, and oral routes
for infants (less than 1 year), toddlers (1 to 2 years), preschoolers (3 to 5 years), children (6 to 10
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2642
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2645
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2649
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years), teens (11 to 15 and 16 to 20 years), and adults (21 years and above). The acute MOE was
30 for the high-intensity acute inhalation exposure scenario for infants (less than 1) and ranged
from 31 to 39 for toddlers and preschoolers, and 56 to 115 for all other evaluated lifestages,
while high-intensity chronic MOEs ranged from 33 to 43 for infants, toddlers, and preschoolers,
and 62 to 128 for all other lifestages. Medium-intensity MOEs for the inhalation route ranged
from 63 to 272 for acute and chronic inhalation exposure scenarios for all evaluated lifestages.
EPA also considered aggregate exposure to DIDP for this COU. High-intensity aggregate MOEs
ranged from 27 to 34 and 31 to 38 for acute and chronic duration exposures, respectively, for
infants (less than 1 year), toddlers (1 to 2 years) and preschoolers (3 to 5 years). High-intensity
aggregate MOEs for other lifestages for this COU ranged from 52 to 125. For this COU, the
primary pathway is inhalation exposure to consumers in the indoor environment, while dermal
exposure and ingestion of suspended dust and dust on surfaces were comparatively minor
pathways.
Variability in high-intensity inhalation MOEs across lifestages result from use of different
lifestage-specific exposure factors such as body weight and inhalation rate. Differences in MOEs
between the high- and medium-intensity inhalation exposure scenarios result from use of
different exposure parameters in CEM. Key parameters that differed between high- and medium-
intensity scenarios include: weight fraction {i.e., 0.26 versus 0.245), article surface area (i.e., 200
versus 100 m2), and inhalation rates used per lifestage. Inhalation rates for lifestages range from
0.74 to 0.46 m3/hr for adults to infants respectively, with the largest difference between infants
and the next lifestage. Other CEM exposure factors were kept constant between high- and
medium-intensity inhalation scenarios (e.g., surface layer thickness, volume of use environment,
interzone ventilation rate). Overall, EPA has robust confidence in the inhalation exposure
estimates and robust confidence in the non-cancer hazard value used to estimate non-cancer risk
for this COU ( 024a, h).
The in-place wallpaper inhalation scenario in this assessment applies to stay-at-home infants to
adults. In this scenario DIDP in wallpaper is released into the gas-phase, the article inhalation
scenario tracks chemical transport between the source, air, airborne and settled particles, and
indoor sinks by accounting for emissions, mixing within the gas phase, transfer to particulates by
partitioning, removal due to ventilation, removal due to cleaning of settled particulates and dust
to which DIDP has partitioned, and sorption or desorption to/from interior surfaces. The
emissions from the wallpaper were modeled with a single exponential decay model. This means
that chronic and acute exposure duration scenario uses the same emissions/air concentration data
based on the weight fraction but have different averaging times for the air concentration used.
The acute data uses concentrations for a 24-hour period at the peak, while the chronic data was
averaged over the entire one-year period. Because air concentrations for most of the year are
significantly lower than the peak value, the air concentration used in chronic dose calculations is
lower than acute, resulting in a lower dose per day rate and risk estimate. The difference between
high and medium intensity scenarios risk estimates is driven by the weight fraction and article
surface area. For this specific article, the confidence in the data used for weight fraction is slight
because a surrogate chemical, DINP, concentration was used in the absence of DIDP specific
data. The confidence in the surface area is moderate because the source was the Exposure
Factors Handbook. EPA made a conservative assumption for the high-intensity exposure
scenario. The difference in risk estimates results among lifestages is driven by the inhalation rate
to body weight ratio.
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The aggregation across routes for a high-intensity exposure scenario for infants resulted in an
MOE value of 27. The inhalation and ingestion of surface dust are the main contributors to the
overall aggregate MOE value. The inhalation scenarios are explained above. The surface dust
ingestion scenario model estimates the DIDP concentration in settled dust on the wallpaper
surface, assuming primarily that DIDP partitions directly from the wallpaper to settled dust. The
model assumes exposure to occur through dust intake via incidental ingestion assuming a daily
stay-at-home dust ingestion rate per lifestage. The model, assuming instantaneous equilibrium is
achieved for partitioning, represents an upper bound scenario. There is no difference between
chronic and acute exposure, as both rely on the same upper end dust concentration.
4.3.3.1 Overall Confidence in Consumer Risks
As described in Section 4.1.2.5 and in more technical details in Section 5.1 in thq Draft Consumer and
Indoor Dust Exposure Assessment for Diisodecyl Phthalate (DIDP) ( ), EPA has
moderate to robust confidence in the assessed inhalation, ingestion, and dermal consumer exposure
scenarios, and robust confidence in the non-cancer POD selected to characterize risk from acute,
intermediate, and chronic duration exposures to DIDP (see Section 4.2 and ( J024h)). The
exposure doses used to estimate risk relied on conservative, health protective inputs and parameters that
are considered representative of a wide selection of use patterns. Further, the non-cancer POD selected
to characterize risk is based on reduced F2 offspring survival on PND1 and PND4 in rats. The
developmental effect that serves as the basis of the POD is considered most relevant for assessing risk to
women of reproductive age, pregnant women, and infants. Use of this POD to assess risk for other
lifestages (e.g., toddlers, preschoolers, and other children) is a conservative approach. Sources of
uncertainty associated with this consumer COUs are discussed above in Section 4.3.3. While the
conservative approaches used for consumer risks, in particular the in-place wallpaper use, constitute a
defensible screen to eliminate with confidence risk concerns, where benchmark exceedances are
indicated the conservative nature of the assumptions, as well as uncertainties in the assumptions, should
be considered when using these estimates to inform a risk determination.
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2693 Table 4-17. Consumer Risk Summary Table
Life Cycle Stage:
COU: Subcategory
Product /
Article
Duration
Exposure
Route
Exposure
Scenario
(H, M,
lr
Lifestage (years)
Overall
Exposure/
Hazard
Confidence'1
Infant
(<1)
Toddler
(1-2)
Preschooler
(3-5)
Middle
Childhood
(6-10)
Young
Teen
(11-15)
Teenagers
(16-20)
Adult
(>21)
Consumer Uses:
Other: Novelty
Products
Adult Toys
Acute
Dermal
H
-
-
-
-
-
122,178
114,331
M/R
Ingestion by
Mouthing
H
-
-
-
-
-
288
321
M/R
Aggregate
H
-
-
-
-
-
287
321
-
Intermediate
-
-
-
-
-
-
-
-
-
-
Chronic
Dermal
H
-
-
-
-
-
122,178
114,331
M/R
Ingestion by
Mouthing
H
-
-
-
-
-
288
321
M/R
Aggregate
H
-
-
-
-
-
287
321
-
Consumer Uses:
Automotive, fuel,
agriculture, outdoor
use products:
Lubricants
Auto
Transmission
Conditioner
(f " MOE for
bystander
scenario)
Acute
Dermal
H
-
-
-
-
13,256
14,495
13,564
M/R
Inhalation
H
f3,905,883
f4,146,245
f5,100,539
f7,325,032
9,624,741
11,245,617
14,001,320
R/R
Aggregate
H
-
-
-
-
13,237
14,476
13,551
-
Intermediate
-
-
-
-
-
-
-
-
-
-
Chronic
Dermal
H
-
-
-
-
4,838,273
5,290,655
4,950,860
M/R
Inhalation
H
f 12,323,061
f 13,081,404
f 16,092,203
f23,110,480
28,451,314
33,446,036
41,423,821
R/R
Aggregate
H
-
-
-
-
4,135,084
4,568,058
4,422,317
-
Consumer Uses:
Automotive, fuel,
agriculture, outdoor
use products:
Automotive products,
other than fluids
Products are
like synthetic
leather fabrics
in furniture
See synthetic leather furniture scenarios. Use patterns for dermal exposure to automotive synthetic leather fabric has same considerations than for
furniture.
Consumer Uses:
Packaging, paper,
plastic, hobby
products: Plastic and
rubber products
(textiles, apparel, and
leather; vinyl tape;
flexible tubes;
profiles; hoses
Bags
Acute
Dermal
H
-
-
71,198
88,311
111,731
122,178
114,331
M/R
Intermediate
-
-
-
-
-
-
-
-
-
-
Chronic
Dermal
H
71,198
88,311
111,731
122,178
114,331
M/R
Consumer Uses:
Packaging, paper,
plastic, hobby
products: Toys,
Playground, and
Sporting Equipment
Legacy
Children's
Toys
(** = Part of
indoor
Acute
Dermal
H
34,824
40,724
47,118
58,443
73,942
80,855
-
R/R
Ingestion
suspended
dust**
H
9,444,466
10,025,664
12,333,158
17,712,006
25,108,365
29,323,429
36,523,366
R/R
Ingestion
dust on
surface**
H
5,862
4,735
4,194
11,950
21,345
26,907
266,106
R/R
Page 133 of 223
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PUBLIC RELEASE DRAFT
May 2024
Exposure
Scenario
(H, M,
ly
Lifestage (years)
Overall
Lite Cycle Stage:
COU: Subcategory
Product /
Article
Duration
Exposure
Route
Infant
(<1)
Toddler
(1-2)
Preschooler
(3-5)
Middle
Childhood
(6-10)
Young
Teen
(11-15)
Teenagers
(16-20)
Adult
(>21)
Exposure/
Hazard
Confidence*
exposure
scenario)
Ingestion by
mouthing
H
240
917
1,796
-
-
-
-
R/R
Inhalation**
H
235
249
307
440
624
729
908
R/R
Aggregate
H
116
187
245
422
602
704
905
-
Intermediate
-
-
-
-
-
-
-
-
-
-
Dermal
H
34,824
40,724
47,118
58,443
73,942
80,855
-
R/R
Ingestion
H
11,160,902
11,847,727
14,574,585
20,930,985
29,671,556
34,652,666
43,161,119
R/R
suspended
dust**
Ingestion
H
6,665
5,383
4,768
13,586
24,268
30,591
68,359
R/R
Chronic
dust on
surface**
Ingestion by
mouthing
H
240
917
1,796
-
-
-
-
R/R
Inhalation**
H
263
279
343
492
698
815
1,015
R/R
Aggregate
H
123
205
270
471
672
786
1,000
-
Dermal
H
34,824
40,724
47,118
58,443
73,942
80,855
-
R/R
Ingestion
H
2,455,561,194
2,606,672,652
3,206,621,119
4,605,121,685
6,528,174,895
7,624,091,579
9,496,075,234
R/R
suspended
dust**
Ingestion
H
1,524,204
1,231,088
1,090,392
3,107,031
5,549,665
6,995,705
61,204,411
R/R
Acute
dust on
surface**
New
Ingestion by
mouthing
H
240
917
1,796
-
-
-
-
R/R
Consumer Uses:
Children's
Inhalation**
H
61,047
64,804
79,719
114,487
162,296
189,541
236,080
R/R
Packaging, paper,
plastic, hobby
products: Toys,
Playground, and
Sporting Equipment
Toys
Aggregate
H
238
884
1,691
38,215
50,337
56,222
235,167
-
(** = Part of
indoor
Intermediate
-
-
-
-
-
-
-
-
-
-
Dermal
H
34,824
40,724
47,118
58,443
73,942
80,855
—
R/R
exposure
scenario)
Ingestion
suspended
dust**
H
2,901,834,661
3,080,409,102
3,789,392,149
5,442,056,080
7,714,604,806
9,009,693,288
11,221,891,082
R/R
Ingestion
H
1,732,910
1,399,658
1,239,697
3,532,470
6,309,569
7,953,612
17,773,434
R/R
Chronic
dust on
surface**
Ingestion by
mouthing
H
240
917
1,796
-
-
-
-
R/R
Inhalation**
H
68,266
72,467
89,146
128,026
181,488
211,955
263,998
R/R
Aggregate
H
238
885
1,695
39,675
52,103
58,100
260,128
-
Page 134 of 223
-------
PUBLIC RELEASE DRAFT
May 2024
Lite Cycle Stage:
COU: Subcategory
Product /
Article
Duration
Exposure
Route
Exposure
Scenario
(H, M,
ly
Lifestage (years)
Overall
Exposure/
Hazard
Confidence*
Infant
(<1)
Toddler
(1-2)
Preschooler
(3-5)
Middle
Childhood
(6-10)
Young
Teen
(11-15)
Teenagers
(16-20)
Adult
(>21)
Consumer Uses:
Construction, paint,
electrical, and metal
products: Adhesives
and sealants
(including
plasticizers in
adhesives and
sealants)
Construction
Adhesive for
Small Scale
Projects
(f = MOE for
bystander
scenario)
Acute
Dermal
H
-
-
-
-
1,105
1,208
1,130
M/R
Inhalation
H
f41,580
¦f 44,139
f54,298
f77,979
99,614
117,533
145,107
R/R
Aggregate
H
-
-
-
-
1,093
1,196
1,122
-
Intermediate
Dermal
H
-
-
-
-
828
906
848
M/R
Inhalation
H
f31,185
f33,104
f40,723
f58,484
74,710
88,150
108,830
R/R
Aggregate
H
-
-
-
-
819
897
841
—
Chronic
Dermal
H
-
-
-
-
23,261
25,436
23,802
M/R
Inhalation
H
f7,982
f8,473
f 10,423
f 14,969
17,668
21,146
25,788
R/R
Aggregate
H
-
-
-
-
10,041
11,547
12,378
-
Consumer Uses:
Construction, paint,
electrical, and metal
products: Adhesives
and sealants
(including
plasticizers in
adhesives and
sealants)
Construction
Sealant for
Large Scale
Projects
(f = MOE for
bystander
scenario)
Acute
Dermal
H
-
-
-
-
828
906
848
M/R
Inhalation
H
f7,489
f7,950
f9,780
f 14,045
11,043
14,001
16,241
R/R
Aggregate
H
-
-
-
-
771
851
806
-
Intermediate
Dermal
H
-
-
-
-
3,681
302
283
M/R
Inhalation
H
f2,496
f2,650
f3,260
f4,682
276
4,667
5,414
R/R
Aggregate
H
-
-
-
-
257
284
269
-
Chronic
Dermal
H
-
-
-
-
100,797
110,222
103,143
M/R
Inhalation
H
f8,319
f8,831
f 10,864
f 15,602
13,080
16,462
19,220
R/R
Aggregate
H
-
-
-
-
11,578
14,323
16,201
-
Consumer Uses:
Construction, paint,
electrical, and metal
products: Adhesives
and sealants
(including
plasticizers in
adhesives and
sealants)
Epoxy Floor
Patch
(f = MOE for
bystander
scenario)
Acute
Dermal
H
-
-
-
-
13,256
14,495
13,564
R/R
Inhalation
H
f 13,041
f 13,844
f 17,030
f24,457
32,137
37,550
46,751
M/R
Aggregate
H
-
-
-
-
9,385
10,458
10,514
-
Intermediate
-
-
-
-
-
-
-
-
-
-
Chronic
Dermal
H
-
-
-
-
4,838,273
5,290,655
4,950,860
R/R
Inhalation
H
f 41,298
f43,839
f53,929
f77,449
95,348
112,086
138,822
M/R
Aggregate
H
-
-
-
-
93,505
109,761
135,036
-
Consumer Uses:
Packaging, paper,
plastic, hobby
products: Plastic and
rubber products
(textiles, apparel, and
leather; vinyl tape;
flexible tubes;
profiles; hoses
Fitness Ball
Acute
Dermal
H
-
-
-
-
111,731
122,178
114,331
M/R
Intermediate
-
-
-
-
-
-
-
-
-
-
Chronic
Dermal
H
111,731
122,178
114,331
M/R
Consumer Uses:
Packaging, paper,
plastic, hobby
Foam Flip
Flops
Acute
Dermal
H
-
-
25,172
31,223
39,503
43,196
40,422
M/R
Intermediate
-
-
-
-
-
-
-
-
-
-
Chronic
Dermal
H
-
-
25,172
31,223
39,503
43,196
40,422
M/R
Page 135 of 223
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PUBLIC RELEASE DRAFT
May 2024
Lite Cycle Stage:
COU: Subcategory
products: Plastic and
rubber products
(textiles, apparel, and
leather; vinyl tape;
flexible tubes;
profiles; hoses
Product /
Article
Duration
Exposure
Route
Exposure
Scenario
(H, M,
ly
Lifestage (years)
Overall
Exposure/
Hazard
Confidence*
Infant
(<1)
Toddler
(1-2)
Preschooler
(3-5)
Middle
Childhood
(6-10)
Young
Teen
(11-15)
Teenagers
(16-20)
Adult
(>21)
Consumer Uses:
Construction, paint,
electrical, and metal
products: Adhesives
and sealants
(including
plasticizers in
adhesives and
sealants); and Paints
and Coatings
Lacquer
Sealer (Non-
Spray)
(f = MOE for
bystander
scenario)
Acute
Dermal
H
-
-
-
-
414
453
424
M/R
Inhalation
H
f3,192
f3,388
f4,168
f5,178
6,778
8,656
9,978
M/R
Aggregate
H
-
-
-
-
390
430
407
-
Intermediate
Dermal
H
-
-
-
-
207
226
212
M/R
Inhalation
H
f 1,596
f 1,694
f2,084
f2,589
3,389
4,328
4,989
M/R
Aggregate
H
-
-
-
-
195
215
203
-
Chronic
Dermal
H
-
-
-
-
75,598
82,666
77,357
M/R
Inhalation
H
f5,724
f6,077
f7,475
f9,790
10,345
13,077
15,210
M/R
Aggregate
H
-
-
-
-
9,100
11,291
12,711
-
Consumer Uses:
Construction, paint,
electrical, and metal
products: Adhesives
and sealants
(including
plasticizers in
adhesives and
sealants); and Paints
and Coatings
Lacquer
Sealer (Spray)
(f = MOE for
bystander
scenario)
Acute
Dermal
H
-
-
-
-
1,036
1,132
1,060
M/R
Inhalation
H
f3,173
f3,368
f4,143
f5,143
6,659
8,514
9,804
M/R
Aggregate
H
-
-
-
-
896
999
956
-
Intermediate
Dermal
H
-
-
-
-
518
566
530
M/R
Inhalation
H
f 1,586
f 1,684
f2,072
f2,571
3,329
4,257
4,902
M/R
Aggregate
H
-
-
-
-
448
500
478
-
Chronic
Dermal
H
-
-
-
-
188,995
206,666
193,393
M/R
Inhalation
H
f5,724
f6,076
f7,475
f9,789
10,343
13,074
15,206
M/R
Aggregate
H
-
-
-
-
9,806
12,296
14,098
-
Consumer Uses:
Packaging, paper,
plastic, hobby
products: PVC film
and sheet
Miscellaneous
Coated
Textiles
(Truck
Awnings)
Acute
Dermal
H
-
-
-
-
111,731
122,178
114,331
M/R
Intermediate
-
-
-
-
-
-
-
-
-
-
Chronic
Dermal
H
—
—
—
—
111,731
122,178
114,331
M/R
Consumer Uses:
Packaging, paper,
plastic, hobby
products: Arts, crafts,
and hobby materials
(crafting paint
applied to craft)
Rubber Eraser
Acute
Dermal
H
-
-
177,996
220,778
279,328
305,445
285,828
R/R
Ingestion by
mouthing
H
-
-
1,027
1,755
-
-
-
R/R
Aggregate
H
-
-
1,021
1,741
-
-
-
-
Intermediate
-
-
-
-
-
-
-
-
-
-
Chronic
Dermal
H
-
-
177,996
220,778
279,328
305,445
285,828
R/R
Ingestion by
mouthing
H
-
-
1,027
1,755
-
-
-
R/R
Aggregate
H
-
-
1,021
1,741
-
-
-
-
Page 136 of 223
-------
PUBLIC RELEASE DRAFT
May 2024
Lite Cycle Stage:
COU: Subcategory
Product /
Article
Duration
Exposure
Route
Exposure
Scenario
(H, M,
ly
Lifestage (years)
Overall
Exposure/
Hazard
Confidence*
Infant
(<1)
Toddler
(1-2)
Preschooler
(3-5)
Middle
Childhood
(6-10)
Young
Teen
(11-15)
Teenagers
(16-20)
Adult
(>21)
Consumer Uses:
Packaging, paper,
plastic, hobby
products: Arts, crafts,
and hobby materials
(crafting paint
applied to craft)
Current products were not identified. Foreseeable uses were matched with the lacquers, and sealants (small and large projects) because similar use patterns are expected.
Consumer Uses:
Packaging, paper,
plastic, hobby
products: Ink, toner,
and colorant products
Current products were not identified. Foreseeable uses were matched with the lacquers, and sealants (small and large projects) because similar use patterns are expected.
Consumer Uses:
Packaging, paper,
plastic, hobby
products: Plastic and
rubber products
(textiles, apparel, and
leather; vinyl tape;
flexible tubes;
profiles; hoses
Shower
Curtain
(** = Part of
indoor
exposure
scenario)
Acute
Dermal
H
-
-
71,198
88,311
111,731
122,178
114,331
R/R
Ingestion
suspended
dust**
H
29,349,444
31,155,564
38,326,289
55,041,496
78,026,279
91,124,933
113,499,321
M/R
Ingestion
dust on
surface**
H
31,099
25,118
22,248
63,394
113,232
142,737
318,964
M/R
Inhalation**
H
914
970
1,194
1,714
2,430
2,838
3,535
R/R
Aggregate
H
888
934
1,115
1,638
2,330
2,721
3,393
-
Intermediate
-
-
-
-
-
-
-
-
-
-
Chronic
Dermal
H
-
-
71,198
88,311
111,731
122,178
114,331
R/R
Ingestion
suspended
dust**
H
33,861,044
35,944,801
44,217,811
63,502,482
90,020,489
105,132,669
130,946,451
M/R
Ingestion
dust on
surface**
H
35,360
28,560
25,296
72,080
128,747
162,294
362,668
M/R
Inhalation**
H
35,360
28,560
25,296
72,080
128,747
162,294
362,668
R/R
Aggregate
H
17,671
14,274
10,738
25,584
40,824
48,739
70,083
-
Consumer Uses:
Construction, paint,
electrical, and metal
products:
Building/construction
materials covering
large surface areas
including stone,
plaster, cement, glass
Solid Flooring
(** = Part of
indoor
exposure
scenario)
Acute
Dermal
H
37,209
43,513
50,345
62,445
79,006
86,393
80,844
M/R
Ingestion
suspended
dust**
H
38,746,871
41,131,294
50,598,021
72,665,287
103,009,591
120,302,315
149,840,781
R/R
Ingestion
dust on
surface**
H
4,861
3,926
3,478
9,909
17,700
22,312
49,859
R/R
Inhalation**
H
402
426
524
753
1,067
1,247
1,553
R/R
Aggregate
H
367
381
452
692
994
1,165
1,478
-
Page 137 of 223
-------
PUBLIC RELEASE DRAFT
May 2024
Exposure
Scenario
(H, M,
ly
Lifestage (years)
Overall
Lite Cycle Stage:
COU: Subcategory
Product /
Article
Duration
Exposure
Route
Infant
(<1)
Toddler
(1-2)
Preschooler
(3-5)
Middle
Childhood
(6-10)
Young
Teen
(11-15)
Teenagers
(16-20)
Adult
(>21)
Exposure/
Hazard
Confidence*
and ceramic articles
Intermediate
-
-
-
-
-
-
-
-
-
-
(wire or wiring
Dermal
H
37,209
43,513
50,345
62,445
79,006
86,393
80,844
M/R
systems; joint
treatment)
Ingestion
suspended
dust**
H
48,133,452
51,095,511
62,855,588
90,268,735
127,964,065
149,446,020
186,140,294
R/R
Chronic
Ingestion
dust on
surface**
H
5,525
4,463
3,953
11,263
20,117
25,359
56,669
R/R
Inhalation**
H
450
477
587
843
1,195
1,396
1,739
R/R
Aggregate
H
411
427
506
775
1,112
1,303
1,653
-
Consumer Uses:
Acute
Dermal
H
-
-
-
-
894
974
1,018
M/R
Furnishing, cleaning,
Synthetic
Leather
Clothing
Intermediate
-
-
-
-
-
-
-
-
-
M/R
treatment/care
products: Fabrics,
textiles, and apparel
Chronic
Dermal
H
—
—
—
894
974
1,018
M/R
(as plasticizer)
Dermal
H
491
553
613
894
974
1,018
R/R
Ingestion
H
4,860,228
5,159,319
6,346,781
9,114,796
12,921,045
15,090,164
18,795,332
M/R
suspended
dust**
Ingestion
H
1,949
1,574
1,394
3,973
7,097
8,946
19,991
M/R
Acute
dust on
surface**
Ingestion by
H
384
659
1,027
-
-
-
-
M/R
Synthetic
mouthing
Consumer Uses:
Leather
Inhalation**
H
86
91
112
161
229
267
333
R/R
Furnishing, cleaning,
treatment/care
products: Fabrics,
textiles, and apparel
(as plasticizer)
Furniture
Aggregate
H
60
67
82
128
178
205
248
-
(** = Part of
indoor
Intermediate
-
-
-
-
-
-
-
-
-
-
Dermal
H
491
553
613
737
894
974
1,018
R/R
exposure
scenario)
Ingestion
suspended
dust**
H
5,898,111
6,261,072
7,702,112
11,061,227
15,680,285
18,312,612
22,809,004
M/R
Ingestion
H
2,217
1,791
1,586
4,519
8,071
10,175
22,737
M/R
Chronic
dust on
surface**
Ingestion by
mouthing
H
384
659
1,027
-
-
-
-
M/R
Inhalation**
H
96
102
126
181
256
299
372
R/R
Aggregate
H
65
73
89
141
194
224
269
-
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Lite Cycle Stage:
COU: Subcategory
Product /
Article
Duration
Exposure
Route
Exposure
Scenario
(H, M,
ly
Lifestage (years)
Overall
Exposure/
Hazard
Confidence*
Infant
(<1)
Toddler
(1-2)
Preschooler
(3-5)
Middle
Childhood
(6-10)
Young
Teen
(11-15)
Teenagers
(16-20)
Adult
(>21)
Consumer Uses:
Packaging, paper,
plastic, hobby
products: Plastic and
rubber products
(textiles, apparel, and
leather; vinyl tape;
flexible tubes;
profiles; hoses)
Wallpaper
(application)
Acute
Dermal
H
-
-
-
-
27,933
30,545
28,583
M/R
Intermediate
-
-
-
-
-
-
-
-
-
-
Chronic
Dermal
H
10,195,466
11,148,750
10,432,715
M/R
Consumer Uses:
Packaging, paper,
plastic, hobby
products: Plastic and
rubber products
(textiles, apparel, and
leather; vinyl tape;
flexible tubes;
profiles; hoses)
Wallpaper (In
place)
(** = Part of
indoor
exposure
scenario)
Acute
Dermal
H
52,622
61,536
71,198
88,311
-
-
-
M/R
M
91,144
106,584
123,319
152,959
-
-
-
M/R
Ingestion
suspended
dust**
H
2,859,011
3,034,950
3,733,471
5,361,746
7,600,758
8,876,734
11,056,286
M/R
M
5,900,182
6,263,270
7,704,816
11,065,110
15,685,791
18,319,041
22,817,012
M/R
Ingestion
dust on
surface**
H
359
290
257
731
1,306
1,647
3,680
M/R
M
761
614
544
1,551
2,770
3,491
7,802
M/R
Inhalation**
H
30
31
39
56
79
92
115
M/R
M
63
67
82
118
167
195
243
M/R
Aggregate
H
27
28
34
52
74
87
111
-
M
58
60
71
110
158
185
236
-
Intermediate
-
-
-
-
-
-
-
-
-
-
Chronic
Dermal
H
52,622
61,536
71,198
88,311
-
-
-
M/R
M
91,144
106,584
123,319
152,959
-
-
-
M/R
Ingestion
suspended
dust**
H
3,551,514
3,770,069
4,637,783
6,660,455
9,441,796
11,026,836
13,734,314
M/R
M
7,308,222
7,757,959
9,543,520
13,705,727
19,429,102
22,690,761
28,262,144
M/R
Ingestion
dust on
surface**
H
408
329
292
831
1,485
1,872
4,183
M/R
M
865
698
618
1,762
3,148
3,968
8,867
M/R
Inhalation**
H
33
35
43
62
88
103
128
M/R
M
70
75
92
132
187
219
272
M/R
Aggregate
H
31
32
38
58
83
98
125
-
M
65
67
80
123
177
207
264
-
Consumer Uses:
Construction, paint,
electrical, and metal
products: Electrical
Wire
insulation
Acute
Dermal
H
52,622
61,536
71,198
88,311
111,731
122,178
114,331
M/R
Ingestion
suspended
dust**
H
82,715,538
87,805,725
108,014,979
155,123,448
219,901,463
256,817,398
319,875,137
M/R
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Exposure
Scenario
(H, M,
ly
Lifestage (years)
Overall
Lite Cycle Stage:
COU: Subcategory
Product /
Article
Duration
Exposure
Route
Infant
(<1)
Toddler
(1-2)
Preschooler
(3-5)
Middle
Childhood
(6-10)
Young
Teen
(11-15)
Teenagers
(16-20)
Adult
(>21)
Exposure/
Hazard
Confidence*
and Electronic
(** = Part of
Ingestion
H
10,095
8,154
7,222
20,579
36,757
46,335
103,542
M/R
Products
indoor
exposure
dust on
surface**
scenario)
Ingestion by
mouthing
H
384
659
1,027
-
-
-
-
M/R
Inhalation**
H
833
884
1,088
1,562
2,215
2,586
3,221
M/R
Aggregate
H
255
359
489
1,428
2,050
2,401
3,041
-
Intermediate
-
-
-
-
-
-
-
-
-
-
Chronic
Dermal
H
52,622
61,536
71,198
88,311
111,731
122,178
114,331
M/R
Ingestion
H
103,065,270
109,407,748
134,588,897
193,287,022
274,001,768
319,999,787
398,571,032
M/R
suspended
dust**
Ingestion
H
11,475
9,268
8,209
23,392
41,781
52,668
117,694
M/R
dust on
surface**
Ingestion by
mouthing
H
384
659
1,027
-
-
-
-
M/R
Inhalation**
H
933
990
1,218
1,749
2,480
2,896
3,607
M/R
Aggregate
H
264
377
518
1,598
2,293
2,685
3,396
-
"Exposure scenario intensities include high (H), medium (M), and low (L).
4 Overall exposure and hazard confidence judgments ranged from moderate (M) to robust (R).
2694
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4.3.4 Risk Estimates for General Population
As described in the Draft Environmental Media and General Population Exposure for Diisodecyl
Phthalate (DIDP) ( 2024d) and Section 4.1.3, EPA employed a screening-level approach for
general population exposures for DIDP releases associated with TCSA COUs. EPA evaluated surface
water, drinking water, fish ingestion, and ambient air pathways quantitatively, and land pathways {i.e.,
landfills and application of biosolids) qualitatively. For pathways assessed quantitatively, high-end
estimates of DIDP concentration in the various environmental media were used for screening-level
purposes. EPA used a margin of exposure (MOE) approach using high-end exposure estimates to
determine whether an exposure pathway had potential non-cancer risks. High-end exposure estimates
were defined as those associated with the industrial and commercial releases from a COU and OES that
resulted in the highest environmental media concentrations. Plainly, if there is no risk for an individual
identified as having the potential for the highest exposure, associated with a COU for a given pathway of
exposure, then that pathway was determined not to be a pathway of concern and not pursued further. If
any pathways were identified as a pathway of concern for the general population, further exposure
assessments for that pathway would be conducted to include higher tiers of modeling when available
and exposure estimates for additional subpopulations and COUs. However, using a screening-level
approach described in Section 4.1.3, no pathways of exposure were identified as pathways of concern
for the general population.
4.3.5 Potentially Exposed or Susceptible Subpopulations and Sentinel Exposures
EPA considered PESS throughout the exposure assessment and throughout the hazard identification and
dose-response analysis supporting the draft DIDP risk evaluation.
Some population group lifestages may be more susceptible to the health effects of DIDP exposure. As
discussed in Section 4.2 and in EPA's Draft Human Health Hazard Assessment for Diisodecyl Phthalate
(DIDP) ( ), exposure to DIDP causes developmental toxicity in experimental animal
models and therefore women of reproductive age, pregnant women, infants, children and adolescents are
considered to be susceptible subpopulations. These susceptible lifestages were considered throughout
the draft risk evaluation. For example, women of reproductive age were evaluated for occupational
exposures to DIDP for each COU (Section 4.3.2) and infants (less than 1 year), toddlers (1 to 2 years),
and middle school children (6 to 10 years) were evaluated for exposure to DIDP through consumer
products and articles (Section 4.3.3). The non-cancer POD for DIDP selected by EPA for use in risk
characterization is based on the most sensitive developmental effect {i.e., reduced F2 offspring survival
on PND1 and PND4) observed and is expected to be protective of susceptible subpopulations.
Additionally, EPA used a value of 10 for the UFh to account for human variability. The Risk
Assessment Forum, in A Review of the Reference Dose and Reference Concentration Processes,
discusses some of the evidence for choosing the default factor of 10 when data are lacking—including
toxicokinetic and toxicodynamic factors as well as greater susceptibility of children and elderly
populations (U.S. EPA. 20021
The available data suggest that some groups or lifestages have greater exposure to DIDP. This includes
people exposed to DIDP at work, those who frequently use consumer products and/or articles containing
high-concentrations of DIDP, those who may have greater intake of DIDP per body weight {e.g., infants,
children, adolescents), and those exposed to DIDP through certain age-specific behaviors {e.g.,
mouthing of toys, wires, and erasers by infants and children) leading to greater exposure. EPA
accounted for these populations with greater exposure in the draft DIDP risk evaluation as follows:
• EPA evaluated a range of OESs for workers and ONUs, including high-end exposure scenarios
for women of reproductive age (a susceptible subpopulation) and average adult workers.
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• EPA evaluated a range of consumer exposure scenarios, including high-intensity exposure
scenarios for infants and children (susceptible subpopulations). These populations had greater
intake per body weight and exposure due to age-specific behaviors (e.g., mouthing of toys, wires,
and erasers by infants and children).
• EPA evaluated a range of general population exposure scenarios, including high-end exposure
scenarios for infants and children (susceptible subpopulations). These populations had greater
intake per body weight.
• EPA evaluated exposure of children to DIDP through use of legacy and new toys.
• EPA evaluated exposure to DIDP through fish ingestion for subsistence fishers and tribal
populations.
• EPA aggregated occupational inhalation and dermal exposures for each COU for women of
reproductive age (a susceptible subpopulation) and average adult workers.
• EPA aggregated consumer inhalation, dermal, and oral exposures for each COU for infants and
children (susceptible subpopulations).
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2756 5 ENVIRONMENTAL RISK ASSESSMENT
DIDP - Environmental Risk Assessment (Section 5):
Key Points
EPA evaluated the reasonably available information for hazard and environmental exposures to
ecological receptors following releases of DIDP to surface water and air deposition of DIDP to soil
and surface waters. The key points of the environmental risk assessment are summarized below:
• EPA expects the main environmental exposure pathway for DIDP to be released to surface
water and subsequent deposition to sediment.
• The OES with the highest environmental media release to surface water or wastewater and
fugitive or stack air release was the PVC plastics compounding OES.
• Although the conservative nature of the VVWM-PSC and AERMOD outputs resulted in
reduced confidence for the environmental media concentrations in surface water, sediment,
and soil; there is robust confidence that the modeled environmental media concentrations do
not underestimate exposure to ecological receptors.
• A trophic transfer analysis indicates that DIDP exposure to terrestrial organisms occurs
primarily through diet via the sediment pathway for semi-aquatic terrestrial mammals
followed by the soil pathway for terrestrial mammals, with releases to surface water
representing the major source.
• Dietary exposure estimates from trophic transfer based on either biomonitoring literature
values or COU/OES-based calculated biota concentrations did not exceed the hazard value for
representative mammalian species, therefore EPA did not pursue further quantitative analysis
for these pathways.
• Hazard data for fish, aquatic invertebrates, and algae indicated no acute or chronic toxicity up
to and exceeding the limit of water solubility. No toxicity was observed from hazard studies
with bulk sediment or pore water exposure to sediment-dwelling organisms on an acute or
chronic exposure basis.
• Earthworm hazard data for DINP indicated no chronic toxicity and was used for read-across to
DIDP, which lacked soil invertebrate hazard data.
• Empirical toxicity data for rats were used to estimate a toxicity reference value (TRV) for
terrestrial mammals at 128 of mg/kg-bw/day.
• Qualitative risk characterization indicates that EPA does not expect risk for all pathways
assessed for exposure to ecological receptors. Expected lack of risk to aquatic and terrestrial
receptors was assigned moderated confidence except in cases where EPA lacked reasonably
available hazard data (e.g., avian and terrestrial plants) in which case, risk is indeterminate for
those receptors.
2757 5.1 Summary of Environmental Exposures
2758 EPA expects the main environmental exposure pathway for DIDP to be released to surface water and
2759 subsequent deposition to sediment. The ambient air exposure pathway was also assessed for its limited
2760 contribution via deposition to soil, water, and sediment since sediment represents an ecologically
2761 relevant exposure medium for environmental receptors. DIDP exposure to aquatic species via surface
2762 water and sediment were modeled to estimate concentrations from COU/OES with water releases.
2763 Concentrations of DIDP in representative organisms within the screening level trophic transfer analysis
2764 were calculated using modeled sediment concentrations from Variable Volume Water Model - Point
2765 Source Calculator (VVWM-PSC). Based on a solubility of 1.7xlCT4 mg/L and the predicted BCF of
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1.29 L/kg, the calculated concentration of DIDP in fish was 2,2/ 10 4 mg/kg, which was two orders of
magnitude lower than the highest DIDP measured concentrations reported in aquatic biota in the peer-
reviewed literature. Deposition of DIDP from air was modeled via AERMOD, then daily deposition
values were modeled with VVWM-PSC to represent surface water and sediment concentrations.
Exposure to terrestrial species through air deposition to soil was also assessed using data modeled using
American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD).
DIDP is not considered bioaccumulative, however, within the aquatic environment, relevant
environmental exposures are possible through incidental ingestion of sediment while feeding and/or
ingestion of food items that have become contaminated due to uptake from sediment. Exposure through
diet was assessed through a trophic transfer analysis with representative species, which estimated the
transfer of DIDP from soil through the terrestrial food web, from surface water and sediment through the
aquatic food web via releases to surface waters, and air deposition to surface water and sediment (Figure
5-1). The results of the trophic transfer analysis indicate that DIDP exposure to terrestrial organisms
occurs primarily through diet via the sediment pathway for semi-aquatic terrestrial mammals followed
by the soil pathway for terrestrial mammals, with releases to surface water representing the major
source.
The OES resulting in the highest environmental media concentrations from surface water or wastewater
release and fugitive or stack air release was the PVC plastics compounding OES. The PVC plastics
compounding OES is associated with the following COUs: Processing/incorporation into formulation,
mixture, or reaction product/plastic material and resin manufacturing; and Processing/incorporation into
formulation, mixture, or reaction product/other (part of the formulation for manufacturing synthetic
leather). The highest OES estimate (PVC plastics compounding) resulted in DIDP exposure
concentrations in a modeled terrestrial ecosystem of 0.05 mg DIDP/kg in the earthworm (Eisenia fetida)
consuming soil with an estimated dietary intake of 0.03 mg DIDP/kg-bw/day in shorttail shrews
(Blarina brevicauda). Within the aquatic modeled ecosystem the highest OES estimate (PVC Plastics
Compounding) resulted in a DIDP exposure concentration of 401 mg DIDP/kg in the blacktail redhorse
(Moxostomapoecilurum) consuming chironomids and resulted in an estimated dietary intake of 92.4 mg
DIDP/kg-bw/day in American mink (Mustela vison).
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BSAF = 0.6
Figure 5-1. Trophic Transfer of DIDP in Aquatic and Terrestrial Ecosystems
5.2 Summary of Environmental Hazards
Like most phthalates, DIDP would be expected to cause adverse effects on aquatic organisms through a
non-specific, narcotic mode of toxic action (Parkerton and Konkel. 2000); however, previous
assessments have found few to no effects of DIDP on organism survival and fitness ( EC/HC, 2015a;
ECJRC. 2003a). Hazard data for fish and aquatic invertebrates indicated no acute or chronic toxicity up
to and exceeding the limit of water solubility. No toxicity was observed from hazard studies with bulk
sediment or pore water exposure to sediment-dwelling organisms on an acute or chronic exposure basis.
Two studies were conducted to produce hazard data from an algal species (Selencistrum capricornutum)
and indicated no toxicity up to the highest tested concentrations (0.8 mg/L and 1.3 mg/L).
Terrestrial hazard data for DIDP were not available for birds or mammalian species, so studies in
laboratory rodents were used to derive hazard values for mammalian species. Specifically, five studies
conducted on different laboratory strains of Norway rat (Rattus norvegicus) were selected for containing
definitive data on DIDP for ecologically relevant endpoints (e.g., reproduction, growth, and survival)
(Cho et al.. 2008; Bushka et aL 2001; Waterman et al. 1999; Hellwig et al.. 1997; BIBRA. 1986b).
Empirical toxicity data for rats were used to estimate a toxicity reference value (TRV) for terrestrial
mammals at 128 of mg/kg-bw/day. Additionally, DINP was considered appropriate for use as an analog
for read-across to DIDP in the earthworm (Eisenici fetida) based on similarities in structure, physical,
chemical and environmental fate and transport properties, and hazard values in relevant taxa (benthic
and aquatic invertebrates).
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5.3 Environmental Risk Characterization
5,3,1 Risk Assessment Approach
EPA expects the main environmental exposure pathway for DIDP to be released to surface water and
subsequent deposition to sediment followed by limited dispersal from fugitive and stack air release. The
OES with the highest environmental media concentrations from surface water or wastewater releases
and fugitive or stack air release was the PVC plastics compounding OES associated with the following
COUs: Processing/ Incorporation into formulation, mixture, or reaction product/ Plastic material and
resin manufacturing; and Processing/ Incorporation into formulation, mixture, or reaction product/ Other
(part of the formulation for manufacturing synthetic leather). Modeled environmental media
concentrations resulting from the PVC plastics compounding OES environmental releases were assessed
as a worst-case (conservative) exposure to terrestrial receptors via aquatic and terrestrial trophic transfer
pathways. Hazard data for fish, aquatic invertebrates, and algae indicated no acute or chronic toxicity up
to and exceeding the limit of water solubility. No toxicity was observed from hazard studies with bulk
sediment or pore water exposure to sediment-dwelling organisms on an acute or chronic exposure basis.
Earthworm hazard data for DINP indicated no chronic toxicity and was used for read-across to DIDP
which lacked soil invertebrate hazard data. Empirical toxicity data for rats were used to estimate a
toxicity reference value (TRV) for terrestrial mammals at 128 of mg/kg-bw/day. In no circumstances did
exposure exceed the hazard threshold for terrestrial mammals. Qualitative risk characterization indicates
that EPA does not expect risk for all pathways assessed for exposure to ecological receptors. Expected
lack of risk to aquatic and terrestrial receptors was assigned moderated confidence except in cases where
EPA lacked reasonably available hazard data (e.g., avian species and terrestrial plants) in which case,
risk is indeterminate for those receptors. A summary of relevant exposure pathways to receptors and
resulting qualitative risk estimates are presented in Table 5-1.
Table 5-1. Relevant Exposure Pathway to Receptors and Corresponding Risk Assessment Type
Qualitative) for the DIDP Environmental Risk Characterization
Exposure Pathway
Receptor
Risk Assessment
Surface water, sediment
Aquatic species
Qualitative
Air deposition to surface water, sediment
Aquatic species
Qualitative
Landfill to surface water, sediment
Aquatic species
Qualitative
Surface water, sediment
Aquatic dependent mammal
Qualitative"
Air deposition to surface water, sediment
Aquatic dependent mammal
Qualitative"
Aggregate media of release (water, incineration, or
landfill)
Aquatic dependent mammal
Qualitative
Landfill to surface water, sediment
Aquatic dependent mammal
Qualitative
Air deposition to soil
Terrestrial mammal
Qualitative"
Biosolids
Terrestrial mammal
Qualitative
" Screening level trophic transfer analysis conducted by producing exposure estimates from the high-end exposure
scenarios defined as those associated with the industrial and commercial releases from a COU and OES that resulted in the
highest environmental media concentrations and presented within U.S. EPA (2024b).
A qualitative risk assessment for aquatic and terrestrial species was conducted based on a number of
factors such as hazard values not observed under environmental conditions (e.g., chemical doses in
toxicity studies far exceeding the solubility limit through use of a solvent), a lack of persistence of DIDP
in environmental media, and expected DIDP environmental exposures below the concentrations tested
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within hazard studies consistently indicating a lack of toxicity for this compound. For aquatic and
benthic species all the available high/medium hazard data indicates a consistent lack of toxicity. A
hazard threshold was determined for mammals and represented as a TRV evaluated within the screening
level trophic transfer analysis on aquatic mammals and terrestrial mammals within 1024b).
DIDP is expected to partition primarily to soil and sediment, regardless of the compartment of
environmental release (U.S. EPA. 2024f). DIDP is not expected to undergo long-range transport and is
expected to be found predominantly in sediments near point sources, with a decreasing trend in sediment
concentrations downstream. This is primarily due to DIDP's strong affinity and sorption potential for
organic carbon in soil and sediment. Transport of DIDP is further limited by its low water solubility (1.7
x 10"4 mg/L) which in combination with high sorption coefficients indicate that freely dissolved and
bioavailable concentrations would be reduced due to strong sorption to suspended solids (Mackintosh et
ai. 2006). Although DIDP is predicted to have an overall environmental half-life of 35 days, DIDP is
expected to have a low biodegradation potential within low oxygen conditions indicating longer
persistence within subsurface sediments and soils (ECJRC. 2003a; Ei lefts son et a 5).
Additional evidence indicates that DIDP is not persistent within other exposure pathways, added by
degradation related fate parameters. Within air, DIDP is expected to have an atmospheric half-life of 7.6
hours attributed to indirect photodegradation with an estimated 75 to 80 percent sorbed to airborne
particulates. The potential removal of DIDP via wastewater treatment was modeled using STPWIN™,
an EPI Suite™ module that estimates chemical removal in sewage treatment plants, predicting greater
than 93 percent removal of DIDP in wastewater by sorption to sludge ( ). These model
predictions were further supported by two studies with overall quality determinations of high, reporting
aerobic processes have the potential to help biodegrade DIDP from wastewater with 65.8 to 98.9 percent
removal of DIDP ( strong et ai. 2018; Trail et ai. 2014).
EPA assessed exposures based on the COU/OES which resulted in the highest environmental media
concentrations for a given pathway. If exposure did not exceed hazard from the concentrations
associated with that COU/OES then EPA did not proceed to evaluate environmental media
concentrations for the remaining COU/OESs detailed within the Draft Environmental Media and
General Population Exposure Technical Support Document ( )24d). DIDP concentrations
within surface water, sediment, and soil serve as exposure pathways and were used to determine
exposures to aquatic and terrestrial species. EPA assessed DIDP concentrations in surface water,
sediment, and soil via modeled concentrations (VVWM-PSC, AERMOD) representing COU-based
releases of DIDP. Using COU/OES-specific estimated days of release, high-end release distribution of
COU/OES-specific annual releases to surface water were assessed under conservative flow assumptions
in VVWM-PSC to generate conservative modeled environmental concentrations as described in U.S.
EPA. (2024d). As stated in U.S. EPA. (2024d). conservative estimates of DIDP within sediment from
VVWM-PSC modeling resulted in increased confidence that exposures were not underestimated. Air
deposition of DIDP to soil, sediment, and surface water were modeled to represent COU-based releases
to air using AERMOD with conservative estimates increasing confidence that exposures were not
underestimated.
The OES with the highest environmental media concentrations from surface water or wastewater and
fugitive or stack air release was the PVC plastics compounding OES and is associated with the
following COUs: Processing/ Incorporation into formulation, mixture, or reaction product/ Plastic
material and resin manufacturing; and Processing/ Incorporation into formulation, mixture, or reaction
product/ Other (part of the formulation for manufacturing synthetic leather). For COUs with water-based
releases, sediment concentrations modeled using VVWM-PSC resulted in the highest DIDP
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concentration for the P VC Plastics Compounding OES at 27,600 mg/kg ( 2024D. Deposition
of DIDP from air to soil and surface water was modeled via AERMOD, then daily deposition values
were modeled with VVWM-PSC to represent surface water and sediment concentrations. The highest
DIDP concentration in sediment from air deposition into water at 1,000 m from an annual fugitive
release (254 consecutive operating days of release) was from the PVC Plastics Compounding OES with
a modeled sediment concentration of 0.35 mg/kg. The highest DIDP concentration in soil from air
deposition at 1,000 m from a fugitive release was from the PVC Plastics Compounding OES with a
concentration of 0.05 mg/kg ( Z024d). EPA used a distance of 1,000 m from a fugitive/stack
release to represent an ecologically representative area to characterize risk to terrestrial receptors.
Maximum concentrations of DIDP in sediment within published literature originate from studies with
ambient monitoring at 3.4 and 3.7 mg/kg from urban sediments in Sweden and Taiwan, respectively
(Chen et ai. l , 1 < msins et al. 2007). Concentrations of DIDP within biosolids were reported in two
published studies as ranging from 3.8 to 8.0 and 4.3 to 24.9 mg/kg (Armstrong et al. 2018; ECJRC.
2003a).
DIDP is expected to have a low potential for bioaccumulation and biomagnification in aquatic
organisms (Blair et al.. 2009; McConnell. 2007; Mackintosh et al.. 2004). Monitored concentrations of
DIDP within differing aquatic taxa reflect dilution across trophic levels (McConnell. 2007; Mackintosh
et al.. 2004). DIDP exposure to terrestrial organisms occurs primarily through diet via the sediment
pathway for semi-aquatic terrestrial mammals followed by the soil pathway for soil invertebrates and
terrestrial mammals, with releases to surface water representing a major exposure pathway. Exposure
pathways to aquatic-dependant mammals and terrestrial mammals as receptors were not examined
further since, even with conservative assumptions, dietary DIDP exposures were not equal to or greater
than the identified hazard threshold ( ).
5.3.2 Qualitative Risk Assessment for Aquatic and Terrestrial Species
The landscape of hazard data for DIDP provides information for qualitative risk assessment connecting
relevant exposure pathways to aquatic and terrestrial organisms. DIDP demonstrated no aquatic toxicity
up to and beyond the limit of solubility under both acute and chronic exposure durations (
2024c). Two exceptions were observed under acute exposure conditions with durations of 72 and 96-
hours where two studies on zebrafish (D. rerio) identified acute mortality hazard values only by testing
six orders of magnitude greater than the limit of water solubility identified by EPA [1.7 x 10"4 mg/L,
(I if)] (Poopal et al.. 2020; Chen et al.. 2014). Therefore, these two studies were not
considered environmentally relevant for establishing hazard thresholds. Acute and chronic duration
hazard studies conducted on the aquatic invertebrate, Daphnia magna, consistently observed
undissolved DIDP on the water surface and attributed these concentrations (0.06 mg/L and 0.14 mg/L)
above solubility to mortality associated with entrapment of test organisms and not to the chemical
(Rhodes et al.. 1995). DIDP within sediment demonstrated no toxicity up to the highest concentrations
tested for chronic exposure durations. The highest measured concentration of DIDP tested within
sediment in a chronic duration study was 4,300 mg/kg with an exposure duration of 28 days for larval
midge (Chironomus ripari us) (Brown et al.. 1996). Similarly, effects on mortality within C. tentans
were not observed for 10-day exposures up to the highest measured DIDP concentration in sediment at
2,680 mg/kg (Call et al.. 2001). Studies on the algae (Selenastrum capricornatum) reported no effects up
to observed maximum concentrations of 1.3 mg/L (Adams et al.. 1995; Sprinebom Bionomics. 1984).
Empirical toxicity data for laboratory rats indicated ecologically-relevant hazard for reproductive,
growth, and mortality endpoints. These data were used to estimate a toxicity reference value (TRV) for
terrestrial mammals at 128 of mg/kg-bw/day. The TRV was used as a hazard threshold for representative
aquatic-dependent (mink) and terrestrial insectivorous (shrew) mammals for comparison to dietary
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exposure estimates generated by aquatic and terrestrial trophic transfer of DIDP from environmental
releases.
Water Releases to Surface Water and Sediment
Reasonably available published literature report DIDP concentrations within surface water and sediment
lower than the highest NOEC values reported within several hazard studies for aquatic invertebrates and
vertebrates in the water column, benthic invertebrates in the sediment, and aquatic plants and algae.
Eight studies within the pool of reasonably available information reported DIDP concentrations within
surface water. No U.S. studies were identified, however, primary studies were identified as reporting
DIDP in surface waters from Europe (Trail el A JO I I; Kjnrklund et at.. 2009) and China (Cheng et at..
2019; Wen et at.. 2018; Shi et at.. ). The highest concentrations of DIDP reported within these
studies (Trail et at.. 2014) includes mean values collected from the Fontenay-les-Briis WWTP influent
and effluent at 2.3 x 10~2 mg/L and 2,6/ 10 4 mg/L, respectively, the latter of which is the same order of
magnitude as the water solubility limit for DINP [1.7xl0~4 mg/L ( 2024f)l. The untreated
influent concentration represents DIDP concentrations above solubility likely due to suspended solids
and other particulate matter.
The Swedish National Screening Program for phthalates analyzed DIDP in sediments collecting from
areas within the country representing: (1) national background lakes, (2) a diffuse urban source, and (3)
a point source for phthalates (Cousins et at.. 2007). DIDP in urban sediments ranged from <0.1 to 3.4
mg/kg and sediments near a suspected point source landfill site were recorded at a maximum DIDP
concentration of 0.29 mg/kg. Mackintosh et at. (2006) sampled sediment from False Creek Harbor,
Vancouver, British Columbia, Canada, characterized by the authors as an urbanized marine ecosystem,
reported maximum DIDP concentration in the sediment from twelve samples at 0.58 mg/kg with a
geometric mean of 0.38 mg/kg. Chen reported a maximum concentration of DIDP within
sediments collected from Kaohsiung Harbor, Taiwan where DIDP was detected at all 20 collection sites
within the industrialized harbor with a maximum mean concentration of 3.7 ± 1.1 mg/kg.
The highest concentrations of DIDP in sediment modeled by VVWM-PSC were from the PVC plastics
compounding OES at 2.7x 104 mg/kg, four orders of magnitude higher than the highest sediment
concentrations reported within literature. This modeled sediment concentration was used in the trophic
transfer analysis for dietary exposure to an aquatic-dependant mammal and, as shown in U.S. EPA.
(2024b). The reasonably available literature monitoring DIDP within surface water and sediment
includes collections from suspected point sources, landfills, and urbanized areas, which builds
confidence in the role of monitored concentrations for this qualitative analysis. Therefore, DIDP within
surface water and sediment are not expected to produce hazardous effects within aquatic organisms and
represent lack of risk based on available hazard and monitoring data.
Based on the weight of scientific evidence for DIDP within the environment, lack of
bioaccumulation/biomagnification, and hazard value for an aquatic dependent mammal, qualitative
analysis indicates that reaching a daily rate of 128 mg/kg-day is highly unlikely and was not reached
even with conservative quantitative modeling and trophic transfer assumptions. The use of wildlife
exposure factors to calculate dietary exposure (mg DIDP/kg-day) within the conservative screening level
trophic transfer analysis presented within the Environmental Exposure Assessment Technical Support
Package ( 24b) allows for the ability to project the sediment concentration needed to
produce a risk quotient equal to or greater than one within a representative aquatic dependent mammal.
For example, a DIDP sediment concentration of 3.8x 104 mg/kg would be needed for a representative
mammal to ingest enough DIDP to exceed the TRY hazard threshold value of 128 mg/kg-bw/day. Based
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on the conservative VVWM-PSC outputs for surface water and sediment shown in ( 2024d),
the COU/OES based water releases of DIDP are not expected to produce environmental concentrations
leading to hazardous effects within aquatic dependent wildlife.
Air Deposition to Water, Sediment
Modeling results indicate a rapid decline in DIDP concentrations from air to surface water and sediment
at distances greater than 100 m from fugitive releases. Modeled values of DIDP in surface water and
sediment from air deposition were represented by modeling daily fugitive releases to annual
concentrations based the COU/OES with the highest daily release estimates (which was the PCV plastics
compounding OES). The surface water concentration modeled by VVWM-PSC at 100, 1,000, and 5,000
m from this fugitive release point were 3.5x 10 3, 9.5xl0~5, and 4.7xl0~6 mg/L, respectively, with the
100 m DIDP concentration one order of magnitude higher than the reported solubility of 1.7x10-4 mg/L
( 2Q24f). Sediment concentrations modeled by VVWM-PSC at 100, 1,000, and 5,000 m from
this fugitive release point were 13.1, 0.35, and 0.017 mg/kg, respectively. The limited contribution of
DIDP from air to sediment is likely due to its short atmospheric half-life driven by indirect
photodegradation [ti/2 = 7.6 hours; (Mackav et al. 2006a) 1 and sorption to airborne particles. Modeled
air concentrations of DIDP based on the COU/OES (PCV plastics compounding OES) are in alignment
with concentrations reported from monitored sites associated with plastics and former rubber production
facilities located within Gislaved and Stenungsund, Sweden as reported by the Sweden national
monitoring program, a co-operative program for the evaluation of long-range transmission of air
pollutants in Europe (EMEP) network (Cousins et al. 2007).
The concentrations of DIDP in sediment and surface water modeled from air deposition of the highest
releasing COU/OES are lower than the highest NOEC values reported within several hazard studies for
aquatic invertebrates and vertebrates in the water column, benthic invertebrates, and aquatic plants and
algae. For example, the effects on mortality and development within the benthic invertebrate, C. tentans,
were not observed from 10-day DIDP exposures up to the highest measured sediment concentrations
averaging 2,680 mg/kg (Call et al.. 2001). Therefore, COU/OES based fugitive and stack air releases of
DIDP and subsequent deposition to surface water and sediment are not expected to produce
environmental concentrations leading to hazardous effects within aquatic organisms.
Modeled daily deposition rates from 100 m and 5,000 m from a release source are 4 to 8 orders of
magnitude below the mammalian TRV value of 128 mg/kg-bw/day. Additionally, as described in U.S.
EPA. (2024b). dietary exposure estimates based on the highest modeled sediment concentration from air
deposition of DIDP at 1,000 m did not overlap with the hazard threshold (TRV) derived for aquatic-
dependant mammal nor did dietary exposure estimates of DIDP based on the available sediment
monitoring data. As a result, the COU/OES based fugitive and stack air releases of DIDP and
subsequent deposition to surface water and sediment are not expected to produce environmental
concentrations leading to hazardous effects within aquatic dependent mammals.
Air Deposition to Soil
Modeling results indicate a rapid decline in DIDP concentrations from air deposition to soil. The PVC
plastics compounding OES resulted in the highest fugitive release of DIDP with daily deposition rates to
soil at 100, 1,000, and 5,000 m of 1.8, 5.1xl0~2, and 2.4xl0~3 mg/kg, respectively. These modeled daily
deposition rates from 100 m and 5000 m from a release source are 2 to 5 orders of magnitude below the
mammalian TRV value of 128 mg/kg-bw/day. Comparatively, the highest reported soil concentration of
DIDP reported within the reasonably available literature is from Tran et al. (2015). indicate a DIDP
concentration of 1.3/1 0 2 and 4,Ox 10 2 mg/kg in rural and agricultural soils, respectively (Doue, Seine-
et-Marne, France; population 1,029). Although no hazard data for soil invertebrates was reasonably
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available for DIDP, read-across from a suitable analog (DINP) indicated a NOEC for DINP of 1,000
mg/kg which demonstrates no hazardous effects within this soil invertebrate even when testing DINP to
high concentrations. Therefore, COU/OES based fugitive and stack air releases of DIDP and subsequent
deposition to soil are not expected to produce environmental concentrations leading to hazardous effects
within soil invertebrates or terrestrial mammals.
Landfill (to Surface Water, Sediment)
Given the strong affinity of DIDP to adsorb to organic matter present in soils and sediments (log Koc
5.04 to 6.00, and Kd of 1.66 102 to 3.97 10s) ( .012; Mackav et al. 2006b: Williams et al.
1995). DIDP is expected to be immobile in soil and groundwater environments. Furthermore, due to the
insoluble nature of DIDP, migration of DIDP to groundwater is unlikely. In instances where DIDP could
reasonably be expected to be present in groundwater environments (proximal to landfills or agricultural
land with a history of land applied biosolids), limited persistence is expected based on rates of
biodegradation of DIDP in aerobic environments (half-life -14 to 26 days in water and -28 to 56 days in
soil) (ECJRC. 2003a). Measured concentrations of DIDP in landfill leachates collected from four
landfills in Sweden were below detection for all samples analyzed (n = 11) (Kalmykova ).
Sediments near a landfill in Sweden were found to have a DIDP concentration of 290 |ig/kg (Cousins et
al.. 2007). well below NOEC values for sediment-dwelling organisms with corresponding dietary
exposure estimate well below the TRV for terrestrial mammals (128 mg/kg-bw/day). DIDP is not likely
to be persistent in groundwater/subsurface environments unless anoxic conditions exist. As a result, the
evidence presented indicates that migration from landfills to surface water and sediment is limited and
not likely to result in hazardous effects within aquatic and terrestrial organisms.
Biosolids
EPA did not pursue using generic release scenarios to model potential DIDP concentrations in biosolids
because the high-end release scenarios were not considered to be applicable to the evaluation of land
application of biosolids. One monitoring report conducted in Sweden reported concentration of DIDP in
sludge from sewage treatment plants ranging 19.0 to 51.0 mg/kg (Cousins et al.. 2007). Two additional
studies reported DIDP concentrations in biosolids of 3.80 to 8.03 mg/kg and 4.3 to 24.9 mg/kg
( strong et al.. 2018; ECJRC. 2003a). The half-life of 28 to 52 days in aerobic soils (SRC. 1983)
indicates that DIDP is not persistent in the aerobic environments associated with freshly applied
biosolids. High-end releases from industrial facilities are unlikely to be released directly to municipal
wastewater treatment plants without pre-treatment or to be directly land-applied following on-site
treatment at the industrial facility itself. In comparison to hazard values, the highest reported DIDP
concentrations within biosolids from reasonably available literature are two orders of magnitude below
the read-across NOEC value within earthworms of 1,000 mg/kg from a 28-day exposure with
corresponding dietary exposure estimate less than the hazard threshold for mammals (128 mg/kg-day).
The combination of factors such as biodegradation (SRC. 1983) and the weight of evidence supporting a
lack of bioaccumulation and biomagnification (Mackintosh et al.. 2004; ECJRC. 2003a; Gob as et al..
2003) supports this qualitative assessment that potential DIDP concentrations in biosolids do not present
concentrations able to produce hazardous effects within soil invertebrates or terrestrial mammals.
Distribution in Commerce
EPA evaluated activities resulting in exposures associated with distribution in commerce (e.g., loading,
unloading) throughout the various life cycle stages and COUs (e.g., manufacturing, processing,
industrial use, commercial use, and disposal) rather than a single distribution scenario. EPA lacks data to
assess risks to the environment from environmental releases and exposures related to distribution of
DIDP in commerce as a single OES. However, most of the releases from this COU/OES are expected to
be captured within the releases of other COU/OES since most of the activities (loading, unloading)
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generating releases from distribution of commerce are release points of other COU/OESs. Because the
exposure estimates from these other COU/OESs did not exceed hazard to ecological receptors, EPA
expects that a similar release from distribution in commerce also would not result in exposure estimates
exceeding hazard to ecological receptors.
Aggregate Media of Release
Table 5-2 represents COU/OES with aggregated media of release, where the environmental release
assessment did not provide individual release estimates associated within singular release media.
Specifically, these COU/OESs detailed fugitive air and stack air releases in addition to water releases as
an aggregate of "wastewater, incineration, or landfill" rather than water or wastewater only. All
COU/OESs within Table 5-2 have annual release per site (kg/site-year) values lower than PVC plastic
compounding, the OES with the highest annual releases to water. As detailed within 24b)
the PVC plastic compounding OES Exposure pathways with aquatic-dependant mammals and terrestrial
mammals as receptors were not examined further since, even with conservative assumptions, exposure
concentrations from this analysis are not equal to or greater than the terrestrial mammal TRV of 128
mg/kg-day.
Table 5-2. Occupational Exposure Scenarios with Aggregate Met
ia of Release
COU (Life cycle stage"/ Category''/ Subcategory')
OES
Media of
Release
Processing/ Incorporation into formulation, mixture, or reaction product/
Adhesives and sealants manufacturing
Incorporation into
adhesives/sealants
Processing/
incorporation into
formulation, mixture,
or reaction product/
adhesives and
sealants
manufacturing
Water,
incineration, or
landfill
Processing/ Incorporation into formulation, mixture, or reaction product/
Plasticizers (construction materials other; paint and coating
manufacturing; pigments; all other chemical product and preparation
manufacturing)
Processing/ Incorporation into articles/ Plasticizers (asphalt paving,
roofing, and coating materials manufacturing; construction; miscellaneous
manufacturing)
Processing/ Incorporation into formulation, mixture, or reaction product/
surface modifier in paint and coating manufacturing
Incorporation into
paints and coatings
Water,
incineration, or
landfill
Processing/ Incorporation into formulation, mixture, or reaction product/
Plasticizers (construction materials other; paint and coating
manufacturing; pigments; all other chemical product and preparation
manufacturing)
Processing/ Incorporation into articles/ Plasticizers (asphalt paving,
roofing, and coating materials manufacturing; construction; furniture and
related product manufacturing; miscellaneous manufacturing; ink, toner,
and colorant products manufacturing; photographic supplies
manufacturing)
Processing/ Incorporation into formulation, mixture, or reaction product/
Laboratory chemicals manufacturing
Incorporation into
other formulations,
mixtures, or reaction
products
Water,
incineration, or
landfill
Processing/ Incorporation into formulation, mixture, or reaction product/
Lubricants and lubricant additives manufacturing
Processing/ Incorporation into formulation, mixture, or reaction product/
Petroleum lubricating oil manufacturing
Processing/ Incorporation into formulation, mixture, or reaction product/
Plasticizers
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COU (Life cycle stage"/ Category''/ Subcategory')
OES
Media of
Release
Processing/ Incorporation into formulation, mixture, or reaction product/
Processing aids, specific to petroleum production (oil and gas drilling,
extraction, and support activities)
Processing/ Incorporation into formulation, mixture, or reaction product /
Plasticizers (construction materials other; all other chemical product and
preparation manufacturing)
Processing/ Incorporation into articles/ Plasticizers (asphalt paving,
roofing, and coating materials manufacturing; construction; miscellaneous
manufacturing)
Processing/ Incorporation into articles/ Abrasives manufacturing
Application of
adhesives and
sealants
Water,
incineration, or
landfill
Industrial uses/ Adhesives and sealants/ Adhesives and sealants
Commercial uses/ Construction, paint, electrical, and metal products/
Adhesives and sealants (including plasticizers in adhesives and sealants)
Commercial uses/ Construction, paint, electrical, and metal products/
Lacquers, stains, varnishes, and floor finishes (as plasticizer)
Commercial uses/ Furnishing, cleaning, treatment & care products/
Furnisher and furnishings
Commercial uses/ Furnishing, cleaning, treatment & care products/
Construction and building materials covering large surface areas including
stone, plaster, cement, glass and ceramic articles; fabrics, textiles, and
apparel (as plasticizer)
Application of paints and coatings Commercial uses/ Construction, paint,
electrical, and metal products/ Paints and coatings (including surfactants
in paints and coatings)
Application of paints
and coatings
Water,
incineration, or
landfill
Commercial uses/ Construction, paint, electrical, and metal products/
Lacquers, stains, varnishes, and floor finishes (as plasticizer)
Commercial uses/ Furnishing, cleaning, treatment & care products/
Furnisher and furnishings
Commercial uses/ Furnishing, cleaning, treatment & care products/
Construction and building materials covering large surface areas including
stone, plaster, cement, glass and ceramic articles; fabrics, textiles, and
apparel (as plasticizer)
a Life Cycle Stage Use Definitions (40 CFR 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.
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.
h These categories of COUs appear in the Life Cycle Diagram, reflect CDR codes, and broadly represent COUs of
DIDP in industrial and/or commercial settings.
c These subcategories reflect more specific COUs of DIDP.
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5,3.3 Overall Confidence and Remaining Uncertainties Confidence in Environmental
Risk Characterization
Environmental risk characterization evaluated confidence from environmental exposures and
environmental hazards. The Draft Environmental Release and Occupational Exposure Assessment for
DIDP ( 024e) detailed moderate confidence in the release data, where daily releases were
estimated using information from (1) Chemical Data Reporting, (2) Generic Scenarios, and (3)
Engineering Scenario Documents (Figure 3-1). Exposure confidence is detailed within
(2 , the Technical Support Document for the Draft Environmental Media and General Population
Screening for DIDP, represented by modeled and monitored data. Trophic transfer confidence is
represented by evidence type as reported previously in 4b). Technical Support Package
for the Draft Environmental Exposure Assessment for DIDP. Hazard confidence was represented by
evidence type as reported previously in I v « « \ * J024c). Technical Support Document for the Draft
Environmental Hazard Assessment for DIDP. The following confidence determinations for risk
characterization inputs are: robust confidence for the aquatic evidence, and moderate confidence for
terrestrial evidence (Table 5-3).
Exposure
Conservative approaches within both environmental media modeling (e.g., AERMOD and VVWM-
PSC) and the screening level trophic transfer analysis likely overrepresent DIDP ability to transfer
among the trophic levels, however, this increases confidence that risks are not underestimated. Due to
the lack of release data for facilities discharging DIDP to surface waters, releases were modeled, and the
high-end estimate for each COU was applied for surface water modeling. Additionally, due to site-
specific release information, a generic distribution of hydrologic flows was developed from facilities
which had been classified under relevant NAICS codes, and which had NPDES permits. The median
flow rates selected from the generated distributions represented conservative low flow rates. When
coupled with high-end release scenarios, these low flow rates result in high modeled concentrations.
Although reported measured concentrations for ambient air found in the peer-reviewed and gray
literature from the systematic review, Cousins et al. (2007) are within range of the ambient air modeled
concentrations from AERMOD for some scenarios, the highest modeled concentrations of DIDP in
ambient air were many orders of magnitude higher than any monitored value.
Monitored DIDP concentrations within soil, surface water, and sediment were evaluated and used to
represent potential DIDP exposures within a screening level trophic transfer analysis concurrently with
the previously described modeled data for the same environmental media. All monitoring and
experimental data included in this analysis were from articles rated "medium" or "high" quality from
this process with an overall moderate confidence in evidence from monitored data from published
literature.
Aquatic Species
The overall confidence in the risk characterization for the aquatic assessment is robust. Studies used for
the aquatic environmental hazard assessment consisted of 11 studies with an overall quality
determination of high and two studies with an overall quality determination of medium. Consistently, no
effects were observed up to the highest DIDP concentration tested within all aquatic hazard studies. As
detailed within Section 5.3.2, monitoring data from published literature report DIDP concentrations
within surface water and sediment lower than the highest NOEC values presented among several hazard
studies for aquatic invertebrates and vertebrates in the water column, benthic invertebrates in the
sediment, and aquatic plants and algae.
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Terrestrial Species
There is moderate confidence in the risk characterization inputs for the terrestrial risk characterization.
For the terrestrial assessment for mammals, EPA assigned an overall quality determination of high or
medium to five acceptable toxicity studies used as surrogates for terrestrial mammals ("Cho et ai. 2008;
Hushka et ai. 2001; Waterman et al.. 1999; Hellwig et al.. 1997; BIBRA. 1986b). Moderate confidence
in hazard was assigned for terrestrial invertebrates due to the use of a single earthworm study with a
single test dose, however, the study found no deleterious effects of analog DINP at concentrations up to
1,000 mg/kg dw soil (ExxonMobil. 2010). DINP was considered appropriate for use as an analog for
read-across to DIDP based on similarities in structure, physical/chemical/environmental fate and
transport properties, and toxicity. The fate properties discussed in 40, soil and biosolid
monitoring presented within 024d). and the previous qualitative risk characterization for
terrestrial species (Section 5.3.2) increase confidence that DIDP concentrations at or above 1,000 mg/kg
in the soil are not environmentally relevant.
A hazard threshold was identified for mammals in the form of a TRV (128 mg/kg-day), permitting the
use of a screening level trophic transfer analysis to compare potential environmental concentrations and
dietary uptake of DIDP with a daily rate of oral uptake that produces hazard under experimental
conditions. Several conservative approaches incorporated within the screening level trophic transfer
analysis likely overrepresent DIDP ability to accumulate at higher trophic levels, however, this increases
confidence that risks are not underestimated. Exposure pathways with aquatic-dependant mammals and
terrestrial mammals as receptors were not examined further since, even with conservative assumptions,
dietary DIDP exposure concentrations from this analysis are not equal to or greater than the TRV. These
results align with previous studies indicating that DIDP is not bioaccumulative and will not biomagnify
as summarized within 202411. The utilization of both modeled and monitored data as a
comparative approach with similar results increases confidence that dietary exposure of DIDP does not
reach concentrations which would cause hazard within mammals.
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3185 Table 5-3. DIDP Evidence Table Summarizing Overall Confidence Derived for Environmental
3186 Risk Characterization
Types of Evidence
Exposure
Hazard
Trophic
Transfer
Risk
Characterization
Confidence
Aquatic
Acute aquatic assessment
+ PSC
+ AERMOD
+ + +
N/A
Robust
Chronic aquatic assessment
+++
N/A
Chronic benthic assessment
+ +
N/A
Algal assessment
+++
N/A
Tcnvsliial
Chronic a\ uui a^cssnvnl
\ A
\ A
\ A
Indck-rnunak-
Chronic mammalian assessment
+ PSC
+ AERMOD
+ +
+ +
Moderate
Terrestrial invertebrates
+ AERMOD
++
N/A
Moderate
Terrestrial plant assessment
N/A
N/A
N/A
Indeterminate
+ + + Robust confidence suggests thorough understanding of the scientific evidence and uncertainties. The supporting
weight of scientific evidence outweighs the uncertainties to the point where it is unlikely that the uncertainties could
have a significant effect on the risk estimate.
+ + Moderate confidence suggests some understanding of the scientific evidence and uncertainties. The supporting
scientific evidence weighed against the uncertainties is reasonably adequate to characterize risk estimates.
+ Slight confidence is assigned when the weight of scientific evidence may not be adequate to characterize the
scenario, and when the assessor is making the best scientific assessment possible in the absence of complete
information. There are additional uncertainties that may need to be considered.
N/A Indeterminant corresponds to entries in evidence tables where information is not available within a specific
evidence consideration.
3187
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6 UNREASONABLE RISK DETERMINATION
TSCA section 6(b)(4) requires EPA to conduct a risk evaluation to determine whether a chemical
substance presents an unreasonable risk of injury to health or the environment, without consideration of
costs or other non-risk factors, including an unreasonable risk to a potentially exposed or susceptible
subpopulation identified by EPA as relevant to the risk evaluation, under the TSCA COUs.
EPA is preliminarily determining that DIDP presents an unreasonable risk of injury to human health
under the COUs. Risk of injury to the environment does not contribute to EPA's preliminary
determination of unreasonable risk. This draft unreasonable risk determination is based on the
information in previous sections of this draft risk evaluation, the technical supplements that support this
draft risk evaluation and the appendices in accordance with TSCA section 6(b), as well as the best
available science (TSCA section 26(h)), the weight of scientific evidence standards (TSCA section
26(i)), and relevant implementing regulations in 40 CFR part 702.
As noted in the Executive Summary, DIDP is a clear, oily, viscous and transparent liquid used as a
plasticizer. DIDP is used or can be found in products used in industrial, commercial, and consumer
settings. DIDP is a high molecular weight phthalate characterized by its low volatility and insolubility in
water. DIDP is not considered bioaccumulative and is expected to biodegrade in the environment under
aerobic conditions (half-life on the order of days to weeks) but persists under anaerobic conditions.
DIDP may be released into the indoor environment through leaching from products and articles into
indoor air and adhere to dust leading to possible exposure through inhalation of vapors, indoor dust and
particles or ingestion of indoor dust and particles.
Importantly, human or environmental exposure to DIDP through non-TSCA uses (e.g., food, use in food
packaging materials, dental sealants and nail polish, fragrances, medical devices, and pharmaceuticals)
were not evaluated by EPA or taken into account in reaching its preliminary determination of
unreasonable risk to injury of human health, because these uses are explicitly not subject to TSCA.
Further, although the production volume of DIDP has increased over the past decade, it is unknown how
TSCA versus non-TSCA sources have contributed to this increase. Thus, while EPA is preliminarily
concluding in this draft risk evaluation that only one TSCA COU, Industrial use - adhesives and
sealants (due to high-pressure spray application), contributes to its draft unreasonable risk finding for
DIDP, this conclusion cannot be extrapolated to form conclusions about uses of DIDP that are not
subject to TSCA and that EPA did not evaluate.
As explained in Sections 4.1.3, 4.3.4, 5.3.1 and 5.3.2, EPA used a screening level approach in this draft
risk evaluation using conservative environmental release estimates for occupational COUs with the
highest releases to determine whether there is risk to the environment and the general population;
furthermore, hazard data for fish, aquatic invertebrates, and algae indicated no acute or chronic toxicity
up to and exceeding the limit of water solubility. Non-cancer health effects were evaluated in workers,
consumers, and the general population. EPA reviewed the weight of scientific evidence for the
carcinogenicity of DIDP and determined that there is Suggestive Evidence of Carcinogenic Potential of
DIDP and consistent with the Guidelines for Carcinogen Risk Assessment ( )05) EPA did
not conduct a dose-response assessment or further evaluate DIDP for carcinogenic risk to humans.
Whether EPA makes a determination of unreasonable risk for a particular chemical substance under
amended TSCA depends upon risk-related factors beyond exceedance of benchmarks, such as the
endpoint under consideration, the reversibility of effect, exposure-related considerations (e.g., duration,
magnitude, or frequency of exposure, or population exposed), and the confidence in the information
used to inform the hazard and exposure values.
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To determine if an occupational COU contributed to unreasonable risk, EPA compared the risk
estimates of the OES used to evaluate the COUs, and considered whether the risk from the COU was
best represented by the central tendency or high-end risk estimates. For DIDP exposures, whether risk
was best characterized by central tendency estimates as opposed to high end estimates for a given COU
was based on examination of the specific parameters used in the OES, including (1) the method of
application, (2) accuracy of the amount of DIDP found in the product(s) or in dust, and (3) accuracy of
the frequency of use for the product(s). The method of application is important for the determination of
the exposure level to DIDP, and the estimate of exposure for a particular COU. For example,
conventional spray guns use high pressures (typically 30 to 90 psig) that result in excessive spray mist
concentrations, whereas high-volume low-pressure (HVLP) spray guns use large quantities of low-
pressure air (typically less than 10 psig) which leads to higher transfer efficiency and lower levels of
overspray ("OECD. ^ ). The higher concentration of mist leads to higher inhalation exposure levels.
In comparison, the central tendency estimates are more representative of low-pressure spray applications
and non-spray methods such as brush, roll, dip, and bead applications. If the low-pressure applications
are used for a particular COU, risk for that COU is best represented by the central tendency estimates.
The accuracy of the frequency of use and/or amount of DIDP can also affect the exposure estimates. If
the frequency of use and/or the amount of DIDP is overestimated, this leads to a level of uncertainty in
the high-end estimates, and therefore the central tendency estimates were more representative of the
exposure for the COUs.
For the majority of COUs assessed for occupational exposures, the COUs were best represented by
central tendency estimates, and those estimates were used for the unreasonable risk determination.
However, high-pressure spray applications could be used in industrial settings for the application of
adhesives and sealants. Therefore, workers would be exposed to the potentially elevated inhalation
exposures from pressurized spray operations, and the high-end estimates best represent the Industrial use
- adhesives and sealants COU (see Table 4-16 of this draft risk evaluation for more details). Conversely,
the Processing - incorporation into a formulation, mixture, or reaction product - adhesives and sealants
manufacturing COU does not contribute to the unreasonable risk because—due to the low vapor
pressure of DIDP—inhalation exposures from vapor-generating activities (without dust or mist
generation) are quite low.
The consumer and bystander exposure scenarios described in this draft risk evaluation represent a wide
selection of consumer use patterns. High-intensity consumer exposure scenarios may use conservative
inputs representing sentinel exposures (e.g., 4 vs. 2 hours of exposure, but EPA still has moderate or
robust confidence in the majority of inputs used for modeling the high-intensity risk estimates. The high-
intensity consumer and bystander risk estimates represent an upper bound exposure scenario.
EPA is preliminarily determining the following COU, considered singularly or in combination with
other exposures, contributes to the unreasonable risk:
• Industrial use - adhesives and sealants due to high-pressure spray applications
EPA is preliminarily determining that the following COUs are not expected to contribute to the
unreasonable risk:
• Domestic manufacturing (including importing);
• Processing - repackaging;
• Processing - incorporation into a formulation, mixture, or reaction product - adhesives and
sealants manufacturing;
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• Processing - incorporation into a formulation, mixture, or reaction product - laboratory
chemicals manufacturing;
• Processing - incorporation into a formulation, mixture, or reaction product - petroleum
lubricating oil manufacturing; lubricants and lubricant additives manufacturing
• Processing - incorporation into a formulation, mixture, or reaction product - surface modifier in
paint and coating manufacturing;
• Processing - incorporation into a formulation, mixture, or reaction product - plastic material and
resin manufacturing;
• Processing - incorporation into a formulation, mixture, or reaction product - plasticizers (paint
and coating manufacturing; pigments; rubber manufacturing);
• Processing - incorporation into a formulation, mixture, or reaction product - processing aids,
specific to petroleum production (oil and gas drilling, extraction, and support activities);
• Processing - incorporation into a formulation, mixture, or reaction product - other; (part of the
formulation for manufacturing synthetic leather);
• Processing - incorporation into an article - abrasives manufacturing;
• Processing - incorporation into an article - plasticizers (asphalt paving, roofing, and coating
materials manufacturing; construction; automotive products manufacturing, other than fluids;
electrical equipment, appliance, and component manufacturing; fabric, textile, and leather
products manufacturing; floor coverings manufacturing; furniture and related product
manufacturing; plastics product manufacturing; rubber product manufacturing; textiles, apparel,
and leather manufacturing; transportation equipment manufacturing; ink, toner, and colorant
(including pigment) products manufacturing; photographic supplies manufacturing; toys,
playground, and sporting equipment manufacturing);
Processing - recycling;
Distribution in commerce
Industrial use - abrasives (surface conditioning and finish discs; semi-finished and finished
goods);
Industrial use - functional fluids (closed systems) (SBCA compressor oil);
Industrial use - lubricant and lubricant additives;
Industrial use - solvents (for cleaning and degreasing);
Commercial use - automotive, fuel, agriculture, outdoor use products - automotive products
other than fluid;
Commercial use - automotive, fuel, agriculture, outdoor use products - automotive, fuel,
agriculture, outdoor use products - lubricants;
Commercial use - construction, paint, electrical, and metal products - adhesives and sealants
(including plasticizers in adhesives and sealants);
Commercial use - construction, paint, electrical, and metal products - building/construction
materials (wire or wiring systems; joint treatment, fire-proof insulation);
Commercial use - construction, paint, electrical, and metal products - electrical and electronic
products;
Commercial use - construction, paint, electrical, and metal products - paints and coatings
(including surfactants in paints and coatings);
Commercial use - construction, paint, electrical, and metal products - lacquers, stains, varnishes,
and floor finishes (as plasticizer);
Commercial use - furnishing, cleaning, treatment/care products - furniture and furnishings;
Commercial use - furnishing, cleaning, treatment/care products - construction and building
materials covering large surface areas including stone, plaster, cement, glass and ceramic
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articles; fabrics, textiles, and apparel (as plasticizer) (floor coverings (vinyl tiles, PVC-backed
carpeting, scraper mats));
• Commercial use - furnishing, cleaning, treatment/care products - ink, toner, and colorant
products;
• Commercial use - furnishing, cleaning, treatment/care products - PVC film and sheet;
• Commercial use - furnishing, cleaning, treatment/care products - plastic and rubber products
(textiles, apparel, and leather; vinyl tape; flexible tubes; profiles; hoses)
• Commercial use - other uses - laboratory chemicals;
• Commercial use - other uses - inspection fluid/penetrant;
• Consumer use - automotive, fuel, agriculture, outdoor use products - automotive products other
than fluids;
• Consumer use - automotive, fuel, agriculture, outdoor use products - lubricants;
• Consumer use - construction, paint, electrical, and metal products - adhesives and sealants
(including plasticizers in adhesives and sealants);
• Consumer use - construction, paint, electrical, and metal products - building/construction
materials covering large surface areas including stone, plaster, cement, glass and ceramic articles
(wire or wiring systems; joint treatment)
• Consumer use - construction, paint, electrical, and metal products - electrical and electronic
products;
• Consumer use - construction, paint, electrical, and metal products - paints and coatings;
• Consumer use - Furnishing, cleaning, treatment/care products - fabrics, textiles, and apparel (as
plasticizer)
• Consumer use - packaging, paper, plastic, hobby products - arts, crafts, and hobby materials
(crafting paint applied to craft);
• Consumer use - packaging, paper, plastic, hobby products - ink, toner, and colorant products;
• Consumer use - packaging, paper, plastic, hobby products - PVC film and sheet;
• Consumer use - packaging, paper, plastic, hobby products - plastic and rubber products (textiles,
apparel, and leather; vinyl tape; flexible tubes; profiles; hoses)
• Consumer use - packaging, paper, plastic, hobby products - toys, playgrounds, and sporting
equipment;
• Consumer use - other - novelty products, and
• Disposal.
In this draft risk evaluation, the Agency describes the strength of the scientific evidence supporting the
human health and environmental assessments as robust, moderate, slight, or indeterminate. Robust
confidence suggests thorough understanding of the scientific evidence and uncertainties, and the
supporting weight of scientific evidence outweighs the uncertainties to the point where it is unlikely that
the uncertainties could have a significant effect on the exposure estimate. Moderate confidence suggests
some understanding of the scientific evidence and uncertainties, and the supporting scientific evidence
weighed against the uncertainties is reasonably adequate to characterize exposure estimates. Slight
confidence is assigned when the weight of scientific evidence may not be adequate to characterize the
scenario, and when the Agency is making the best scientific assessment possible in the absence of
complete information. The overall confidence in the human health exposure assessment as well as the
hazard assessment is described for each human population in the respective risk estimates section for
that population in Section 4. For the environment, Section 5.3.3 describes weighing the scientific
evidence for exposures and hazards to determine overall confidence in the environmental risk
assessment. The draft DIDP risk evaluation and the supporting technical supplements as well as scoping,
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assessments, and other documents and spreadsheets can be accessed in the docket EPA-HQ-OPPT-
2024-0073.
In general, the Agency makes an unreasonable risk determination based on risk estimates that have an
overall confidence rating of moderate or robust, since those confidence ratings indicate the scientific
evidence is adequate to characterize risk estimates despite uncertainties. If in the final TSCA risk
evaluation for DIDP, EPA determines that DIDP presents an unreasonable risk of injury to health or the
environment under the COUs, the Agency will initiate risk management rulemaking to mitigate
identified unreasonable risk associated with DIDP under the COUs by applying one or more of the
requirements under TSCA section 6(a) to the extent necessary so that DIDP no longer presents such risk.
EPA would also consider whether such risk may be prevented or reduced to a sufficient extent by action
taken under another federal law, such that referral to another agency under TSCA section 9(a) or use of
another EPA-administered authority to protect against such risk pursuant to TSCA section 9(b) may be
appropriate.
6.1 Unreasonable Risk to Human Health
This assessment provides a risk profile of DIDP by presenting a range of estimates (MOEs1) for
different health effects for different COUs. When characterizing the risk to human health from
occupational exposures during risk evaluation under TSCA, EPA conducts baseline assessments of risk
and makes its determination of unreasonable risk from a baseline scenario that does not assume use of
respiratory protection or other personal protective equipment (PPE). Making unreasonable risk
determinations based on the baseline scenario should not be viewed as an indication that EPA believes
there are no occupational safety protections in place at any location, or that there is widespread
noncompliance with existing regulations that may be applicable to. Rather, it reflects the Agency's
recognition that unreasonable risk may exist for subpopulations of workers that may be highly exposed
because they are not covered by Occupational Safety and Health Administration (OSHA) standards,
such as self-employed individuals and public sector workers who are not covered by a State Plan, or
because their employer is out of compliance with OSHA standards, or because EPA finds unreasonable
risk for purposes of TSCA notwithstanding existing OSHA requirements. In addition, the risk estimates
are based on exposure scenarios with monitoring data that likely reflects existing requirements, such as
those established by OSHA, or industry or sector best practices.
A calculated MOE that is less than the benchmark MOE is a starting point for informing a determination
of unreasonable risk of injury to health, based on non-cancer effects. It is important to emphasize that
these calculated risk estimates alone are not "bright-line" indicators of unreasonable risk. For example,
before determining whether a COU contributed to the unreasonable risk of DIDP due to occupational or
consumer exposure, EPA also examined the COU and the exposure scenario to determine the
uncertainties and which risk estimates best represented the contribution from that COU to the
unreasonable risk.
6.1.1 Populations and Exposures EPA Assessed to Determine Unreasonable Risk to
Human Health
EPA evaluated risk to workers, including ONUs; female workers of reproductive age; consumer users
and bystanders, including infants and children; and the general population, including infants and
children, using reasonably available monitoring and modeling data for inhalation and dermal exposures,
as applicable. With respect to health endpoints upon which EPA is basing this preliminary unreasonable
1 EPA derives non-cancer MOEs by dividing the non-cancer POD (HEC (mg/m3) or HED (mg/kg-day)) by the exposure
estimate ((mg/m3 or mg/kg-day). Section 4.3.1 has additional information on the risk assessment approach for human health.
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risk determination, the Agency has robust confidence in the non-cancer developmental toxicity POD.
The POD is based on an effect observed in an animal model, which may translate to miscarriages or
stillbirths in humans. EPA considers this developmental toxicity POD relevant for assessing risk from
acute exposures to DIDP. However, because the developmental toxicity POD is the most protective, it
was considered applicable to all durations evaluated in this risk evaluation (acute, intermediate, and
chronic). Liver toxicity was also identified as a robust and sensitive non-cancer hazard by the EPA, but
the POD for developmental toxicity is protective of the liver toxicity associated with the oral exposure to
DIDP in experimental animal models. EPA evaluated risk from inhalation and dermal exposure of DIDP
to workers, inhalation exposure to ONUs, and, for relevant COUs, dermal exposure to ONUs from
contact with mist or dust deposited on surfaces containing DIDP. The Agency evaluated risk from
inhalation, dermal, and oral exposure to consumer users and for relevant COUs, risk from inhalation
exposure to bystanders. The Agency evaluated risk from inhalation, dermal, and oral exposure to
consumer users and for relevant COUs, risk from inhalation exposure to bystanders. Finally, EPA also
evaluated risk from exposures from surface water, drinking water, fish ingestion, ambient air, and land
pathways {i.e., landfills and application of biosolids) to the general population.
Descriptions of the data used for human health exposure and human health hazards are provided in
Sections 0 and 4.2, respectively, in this draft risk evaluation. Uncertainties for overall exposures and
hazards are presented in this draft risk evaluation, the Draft Consumer and Indoor Exposure Assessment
for Diisodecyl Phthalate (DIDP) ( 24a). and the Draft Environmental Release and
Occupational Exposure and Environmental Release Assessment for Diisodecyl Phthalate (DIDP) (U.S.
24e) and are considered in this preliminary unreasonable risk determination.
6.1.2 Summary of Unreasonable Risks to Human Health
EPA is preliminarily determining that the unreasonable risks presented by DIDP are due to
• Non-cancer effects in workers from inhalation exposures.
Table 6-1 provides further detail regarding which COUs contribute to the above risks.
EPA's exposure and overall risk characterization confidence levels are summarized in Section 0, with
specific confidence levels present in Sections 4.3.2.1 (occupational exposure) and 4.3.3.1 (consumer
exposure). Additionally, health risk estimates for workers—including ONUs, consumers, bystanders,
and the general population—can be found in Sections 4.3.2 (workers and ONUs), 4.3.3 (consumers and
bystanders), and 4.3.4 (general population).
6.1.3 Basis for Unreasonable Risk to Human Health
In developing the exposure and hazard assessments for DIDP, EPA analyzed reasonably available
information to ascertain whether some human populations may have greater exposure and/or
susceptibility than the general population to the hazard posed by DIDP. The Agency identified as PESS
people who are expected to have greater exposure to DIDP—such as workers who use high-pressure
spray applications of DIDP, those who frequently use consumer products containing high concentrations
of DIDP, subsistence fishers and tribal populations whose diets include large amounts of fish ingestion,
individuals who have aggregated consumer exposures to DIDP, and infants and children using DIDP-
containing toys Additionally, EPA identified people who may have greater susceptibility to the health
effects of DIDP as PESS, including women of reproductive age, pregnant women, infants, and children.
A full PESS analysis is provided in Section 4.3.5 of this draft risk evaluation.
Risk estimates based on high-end exposure levels {e.g., 95th percentile) are generally intended to cover
individuals with sentinel exposure levels whereas risk estimates at the central tendency exposure are
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generally estimates of average or typical exposure. However, EPA was able to calculate risk estimates
for PESS groups in this assessment (e.g., female workers of reproductive age, and infants and children).
The use of either central-tendency or high-end risk estimates for female workers of reproductive age to
make a determination of unreasonable risk was based on assumptions about the COU based on
reasonably available information about a typical scenario and process within the COU (e.g., non-spray
application versus low- or high-pressure spray application). Risk estimates for consumers (e.g., infants
and children) were considered at the high-end exposure level, because parameters used for high-intensity
consumer scenarios were representative of an upper bound exposure scenario. For example, high-
intensity consumer indoor dust exposure scenarios assumed that people are in their homes for longer
periods than the medium- or lower- intensity scenarios. The parameters were varied between the high-,
medium-, and low- intensity scenarios, for example, weight fraction (i.e., 0.26 vs. 0.245 for high versus
medium, respectively), article surface area (i.e., 200 vs. 100 m2 for high versus medium, respectively).
Health parameters were also adjusted for each population such as, inhalation rates used per lifestage.
Additionally, EPA aggregated exposures across routes for workers, including ONUs, consumers, and
bystanders for COUs with quantitative risk estimates.
For workers, including ONUs, aggregation of inhalation and dermal exposures led to negligible
differences in risk estimates when compared to risk estimates from inhalation alone, since the inhalation
exposure is the predominant route of exposure. For consumers, dermal, oral, and inhalation routes were
aggregated. For one consumer COU, Packaging, paper, plastic, hobby products - plastic and rubber
products (textiles, apparel, and leather; vinyl tape; flexible tubes; profiles; hoses), acute, high-intensity
aggregate risk estimates were just below the benchmark of 30 for infants (MOE = 27) while individual
high-intensity risk estimates for this COU did not indicate risk. For all other consumer COUs, all
individual and aggregate risk estimates did not indicate risk. Therefore, EPA is preliminarily
determining that TSCA consumer uses do not contribute to unreasonable risk. However, EPA is not
taking into account consumer exposures through non-TSCA uses (e.g., food, use in food packaging
materials, dental sealants and nail polish, fragrances, medical devices, and pharmaceuticals) regulated by
other U.S. Federal Agencies to reach this conclusion. More detail about this preliminary determination
for consumer uses is in Section 6.1.5 of this preliminary unreasonable risk determination. The
uncertainty factor of 10 for human variability that EPA applied to MOEs accounts for increased
susceptibility of populations such as children and elderly populations. More information on how EPA
characterized sentinel and aggregate risks is provided in Section 0.
6,1.4 Unreasonable Risk in Occupational Settings
Based on the occupational risk estimates and related risk factors, EPA is preliminarily determining that
the non-cancer risks from worker acute, intermediate, and chronic inhalation exposure to DIDP in
occupational settings where high-pressure spray applications are used contribute to the unreasonable risk
presented by DIDP.
All occupational COUs were quantitatively assessed, and worker risks were evaluated using the central
tendency and high-end estimates to account for susceptible populations that may be exposed while
working (see Table 4-16 in this draft risk evaluation).
EPA analyzed vapor/mist and/or particulate concentration inhalation exposure in the occupational
scenarios using a time weighted average for a typical 8-hour shift. Separate estimates of central tendency
and high-end inhalation exposures were made for male and female adolescents and adults (>16 years
old) workers, female workers of reproductive age, and ONUs. Dermal exposure in the occupational
exposure scenarios was analyzed using the acute potential dose rate. Dermal exposure for ONUs was
assessed for COUs where exposure to DIDP is likely to occur via mist or dust deposited on surfaces. For
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the COUs assessed, dermal exposure for ONUs was evaluated using the central tendency estimates for
workers since the risk to ONUs are assumed to be equal to or less than risk to workers who handle
materials containing DIDP as a part of their job.
Non-cancer risk estimates were calculated from acute, intermediate, and chronic exposures. These terms
are in reference to the duration of exposure to DIDP. For most OESs, acute refers to an exposure time
frame of an 8-hour single workday, intermediate refers to an exposure time frame of 22 workdays, 8
hours per day, and chronic refers to an exposure time frame of 250 days per year for 31 to 40 years, 8
hours per day.
In order to make a preliminary risk determination, EPA analyzed the individual COUs to determine if
the COU was best represented by central tendency or high-end estimates for workers and ONUs based
on the description of the COU and the parameters and assumptions used in the occupational exposure
scenarios. Risk was not indicated at the high-end or central tendency estimates for dermal exposure to
workers and ONUs. There were COUs with MOEs below the benchmark of 30 at the high-end estimates
of inhalation exposure for worker populations. However, the high-end MOEs represent high-pressure
spray-application of coatings. For all COUs with high-end MOEs indicating risk, EPA does not expect
there to be high-pressure spray application since these COUs are in commercial settings where the most
likely methods of applications would be low-pressure applications (e.g., brush, roll, dip, bead
application, and low-pressure spray guns), except for the COU Industrial use - adhesives - adhesives
and sealants. The COUs were: Processing - incorporation into articles - abrasives manufacturing,
Industrial use -adhesives and sealants, Commercial use - construction, paint, electrical, and metal
products - adhesives and sealants (including plasticizers in adhesives and sealants), Commercial use -
construction, paint, electrical, and metal products - lacquers, stains, and floor finishes (as plasticizer),
Commercial use - construction, paint, electrical, and metal products - paints and coatings (including
surfactants and in paints and coatings, Commercial use - packaging, paper, plastic, hobby products -
ink, toner, and colorants, and Commercial use - other uses - inspection fluid/penetrants (Table 4-16).
Therefore, considering that only one COU is expected to have high-pressure spray application, EPA is
preliminarily concluding that the Industrial use - adhesives - adhesives and sealants is the only COU
that contributes to the unreasonable risk to human health based on the high-end acute, intermediate, and
chronic inhalation risk estimates for average male workers and females of reproductive age.
As discussed in Section 4.3.2 of this draft risk evaluation, the high end inhalation exposures are more
representative of high-pressure spray applications for the COUs associated with Processing -
incorporation into articles - abrasives manufacturing; Industrial use - adhesives and sealants;
Commercial use - construction, paint, electrical, and metal products - adhesives and sealants (including
plasticizers in adhesives and sealants); Commercial use - construction, paint, electrical, and metal
products - paints and coatings (including surfactants and in paints and coatings); Commercial use -
packaging, paper, plastic, hobby products - ink, toner, and colorants; and Commercial use -
construction, paint, electrical, and metal products - lacquers, stains, and floor finishes (as plasticizer).
EPA reviewed the percent of DIDP in products that were associated with each of these COUs,
uncertainties, and their method of application in processing, industrial, and commercial uses. The
primary limitation of the inhalation risk estimates for these COUs is the lack of DIDP-specific
monitoring data. EPA used surrogate monitoring data from the emission scenario document (ESD) on
Coating Application via Spray-Painting in the Automotive Refinishing Industry to Estimate Inhalation
Exposures ( ). The ESD served as a source of monitoring data representing the level of
exposure that could be expected at a typical work site for a given spray application method. EPA expects
that the percent of DIDP will not vary considerably between products used for processing, industrial and
commercial uses; only uses that have known pressurized spray applications associated with their use
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were represented by the high-end inhalation exposure estimates. EPA is preliminarily concluding that
Industrial uses adhesives - adhesives and sealants contributes to the unreasonable risk to human health
based on the high-end acute, intermediate, and chronic inhalation exposure estimates for average male
workers and females of reproductive age, even though the central tendency risk estimates do not indicate
that the COU contributes to the unreasonable risk. An additional uncertainty regarding the high-end
inhalation risk estimates for this COU is whether the automotive refinishing products in the surrogate
data used for estimating inhalation exposure are similar to DIDP-containing adhesives and sealants.
Lastly, the inhalation dose-response value used for the assessment is based on route-to-route
extrapolation from oral data, which is an additional source of uncertainty.
Further, EPA is not determining that other high end inhalation exposure COUs contribute to
unreasonable risk at this time The other COUs assessed are not generally applied using high-pressure
spray applications and high-end inhalation exposures would not occur. These COUs are in commercial
settings and/or where the most likely methods of applications would be low-pressure applications (e.g.,
brush, roll, dip, bead application, and low-pressure spray guns). Therefore, the best representation of
inhalation exposure for the Processing - incorporation into articles - abrasives manufacturing;
Commercial use - construction, paint, electrical, and metal products - adhesives and sealants (including
plasticizers in adhesives and sealants); Commercial use - construction, paint, electrical, and metal
products - paints and coatings (including surfactants and in paints and coatings); Commercial use -
packaging, paper, plastic, hobby products - ink, toner, and colorants; and Commercial use -
construction, paint, electrical, and metal products - lacquers, stains, and floor finishes (as plasticizer) are
the central tendency estimates. The Commercial use - other uses - inspection fluid/penetrant COU was
assessed using conservative estimates of the amount of aerosol exposure and DIDP contained in these
types of products. EPA based the range of the product concentration on a singular surrogate product
which contained DINP (i.e., 10 to 20 percent) rather than DIDP, and the product may be brush or aerosol
applied. Due to the uncertainty in the product concentration, the frequency of use, and the method of
application, EPA concluded that this COU is best represented by central tendency estimates of
inhalation and dermal exposure to workers and ONUs. Therefore, EPA determined that the Commercial
use - other uses - inspection fluid/penetrants COU does not contribute to the unreasonable risk to
human health at this time.
For the Processing - incorporation into formulation, mixture, or reaction product - plastic material and
resin manufacturing; Processing - incorporation into formulation, mixture, or reaction product - other
(part of the formulation for manufacturing synthetic leather); Processing - incorporation into
formulation, mixture, or reaction product - plasticizers (paint and coating manufacturing; pigments;
rubber manufacturing); Processing -incorporation into articles -plasticizers (asphalt paving, roofing, and
coating materials manufacturing; construction; automotive products manufacturing, other than fluids;
electrical equipment, appliance, and component manufacturing; fabric, textile, and leather products
manufacturing; floor coverings manufacturing; furniture and related product manufacturing; plastics
product manufacturing; rubber product manufacturing; textiles, apparel, and leather manufacturing;
transportation equipment manufacturing; ink, toner, and colorant (including pigment) products
manufacturing; photographic supplies manufacturing; and toys, playground, and sporting equipment
manufacturing) COUs, inhalation exposure estimates were based on inhaling dust containing DIDP for
both workers and ONUs, and dermal exposures were based on exposure to liquid DIDP or DIDP dust on
surfaces for workers or ONUs, respectively. As there was a high uncertainty in the amount of DIDP in
dust and the concentrations were likely overestimated, it was concluded that the central tendency
estimates are the best representation of inhalation exposure for these COUs.
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In the overall occupational assessment, EPA has moderate to robust confidence in the assessed
inhalation and dermal occupational exposure scenarios, and robust confidence in the non-cancer POD
selected to characterize risk from acute, intermediate, and chronic duration exposures to DIDP. Overall,
EPA has moderate to robust confidence in the risk estimates calculated for worker and ONU inhalation
and dermal exposure scenarios. More information on EPA's confidence in these risk estimates and the
uncertainties associated with them can be found in Section 4.3.2 in this draft risk evaluation.
6,1.5 Unreasonable Risk to Consumers
Based on the consumer risk estimates and related risk factors, EPA is preliminarily determining that
consumer uses covered by TSCA do not contribute to the unreasonable risk at this time. No COU had
MOEs below the benchmark of 30 due to acute, intermediate, or chronic inhalation, oral, or dermal
exposure. One COU had MOEs below the benchmark of 30 after aggregation of the oral, dermal, and
inhalation routes. No risk from acute, intermediate, or chronic inhalation exposure was found for
bystanders for the COUs assessed. Dermal and oral exposures were assessed for non-cancer risks for
consumers only since bystanders would not be expected to be exposed within any consumer COUs.
Non-cancer risk estimates for consumers and bystanders were calculated from acute, intermediate, and
chronic exposures. For a given consumer exposure scenario, acute exposure refers to the time frame of 1
day, intermediate refers to an exposure time frame of 30 days, and chronic refers to a time frame of 365
days. Professional judgment and product use descriptions were used to estimate the intermediate time
frame.
Consumer and bystander risks representing specific age groups were evaluated for consumer COUs.
Typically, consumers are adults since most products purchased are for adult use or application, while
bystanders would include other adults in the home, as well as children. However, for the assessment of
indoor dust exposures and estimating contribution to dust from individual COUs, EPA recreated
plausible indoor environment using consumer products and articles commonly present in indoor spaces.
All age groups assessed under the indoor dust exposure scenarios are considered users (consumers) of
the articles being assessed. Consumer and bystander populations assessed were infant (<1 year), toddler
(1-2 years), preschooler (3-5 years), middle childhood (6-10 years), young teen (11-15 years), teenager
(16-20), and adult (21+ years).
Dermal exposure was evaluated through direct contact with the product or article. Inhalation exposure
was evaluated assuming exposure occurred during the use through the emission of DIDP from the
product or article. When applicable, such as the assessment of the Packaging, paper, plastic, hobby
products - toys, playground, and sporting equipment COU, oral exposure to DIDP was evaluated
through the mouthing of articles during use. To evaluate the migration of DIDP from a children's toy
during the mouthing of toys, estimates were made for legacy toys (defined as toys that are not limited to
the weight fraction of 0.1 percent) and new toys (toys that may be limited to a weight fraction of 0.1
percent DIDP). EPA used weight fractions of 0.26, 0.23, and 0.2 for legacy toys in the high-, medium-,
and low- scenarios. For new toys, a weight fraction of 0.001 was assumed in all scenarios. The article's
surface area and the chemical migration rates of DIDP were varied between the scenarios; for example,
see Table 2-7 in the Draft Consumer and Indoor Dust Exposure Assessment for Diisodecyl Phthalate
(DIDP) (\ c. « ^ \ JO J U). The mouthing of articles did not indicate risk for the use of legacy or new
toys evaluated for any age group with MOEs of 240 to 1,1796 for infants, toddlers, and preschoolers
across all durations (see Table 4-17 in this draft risk evaluation for more information).
Due to the low volatility of DIDP, airborne DIDP particles released from household items are more
likely to be found on settled and suspended dust and then inhaled or ingested. EPA included the
ingestion and inhalation of dust for the assessment of the consumer COUs Construction, paint, electrical,
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and metal products - electrical and electronic products; packaging, paper, plastic, hobby products -
plastic and rubber products (textiles, apparel, and leather; vinyl tape; flexible tubes; profiles; hoses); and
Packaging, paper, plastic, hobby products - toys, playground, and sporting equipment by estimating the
amount of DIDP-containing dust that would be generated from indoor articles such as, toys, wallpaper,
and wire insulation. Dust on legacy toys and new toys was evaluated by varying the surface area and
number of toys for high, medium, and low-intensity scenarios (see Table 2-8 in the Consumer and
Indoor Exposure Assessment for Diisodecyl phthalate (DIDP) ( 24a)). Risks were not
indicated for any age group through the exposure routes assessed through the use of legacy or new toys
that contain DIDP, and EPA is preliminarily determining that the consumer COU Packaging, paper,
plastic, hobby products - toys, playground, and sporting equipment does not contribute to the
unreasonable risk to human health.
For the consumer COU, Packaging, paper, plastic, hobby products - plastic and rubber products
(textiles, apparel, and leather; vinyl tape; flexible tubes; profiles; hoses), the risk to infants and toddlers
is primarily driven by conservative estimates of acute inhalation of DIDP vapors and ingestion of DIDP
partitioned to surface dust from in-place wallpaper. The conservative high-intensity exposure scenario
represents an upper bound exposure scenario. The aggregation of exposures routes for the acute high-
intensity exposure scenario for infants resulted in an MOE value of 27. For infants, the MOEs for the
acute inhalation and ingestion of dust on surface was 30 and 359, respectively. The high-intensity model
conservatively assumes that a relatively large surface area of the house is covered with in-place
wallpaper (200 m2), a DIDP weight fraction of 0.26 percent (based on two wallpaper samples containing
both DINP and DIDP that was reported in 2001 study of four PVC wallpapers), and the infant stays at
home all day long. Further, the non-cancer POD selected to characterize risk is based on reduced F2
offspring survival on PND1 and PND4 in rats, which is applicable for infants exposed to in-place
wallpaper but is a conservative approach for estimating risks to toddlers. Even when all exposures
(inhalation, ingestion of surface dust, ingestion of suspended dust, and dermal) were aggregated, the
MOEs were just below the benchmark MOE of 30. Furthermore, for all other consumer COUs, all
individual and aggregate risk estimates did not indicate risk. As explained in this unreasonable risk
determination, benchmarks are not bright-line indicators of risk. While the conservative approaches used
for estimating risk to infants constitute a defensible screen to eliminate with confidence risk concerns,
EPA is taking into consideration the conservative nature of the assumptions, as well as uncertainties in
the assumptions (e.g., the small and relatively old age of the wallpaper samples used to derive an upper
bound weight fraction for the "high-intensity" consumer use) when making an unreasonable risk
determination. Therefore, EPA is preliminarily determining that consumer uses do not contribute to
unreasonable risk of DIDP.
The overall confidence in the exposure doses used to estimate risk ranges from moderate to robust. EPA
has robust confidence in the non-cancer POD selected to characterize risk from acute, intermediate, and
chronic duration exposures to DIDP. EPA has moderate to robust confidence in the assessed inhalation,
ingestion, and dermal consumer exposure scenarios (see Table 4-17 of this draft risk evaluation). More
information on EPA's confidence in these risk estimates and the uncertainties associated with them can
be found in this draft risk evaluation, Draft Consumer and Indoor Dust Exposure Assessment for
Diisodecyl Phthalate (DIDP) (U ,S. EPA. 2024a). and Draft Human Health Hazard Assessment for
Diisodecyl Phthalate (DIDP) (U.S. EPA. 2024h).
6,1,6 Unreasonable Risk to the General Population
Based on the risk estimates calculated using releases from manufacturing, processing, and industrial
uses of DIDP, and related risk factors, EPA is preliminarily determining that non-cancer risk effects do
not contribute to the unreasonable risk of DIDP to the general population.
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Due to DIDP's low water solubility and low persistence under most conditions, DIDP is unlikely to
migrate from land applied biosolids to groundwater via runoff and is unlikely to be present in landfill
leachate or be mobile in soils. For these reasons, biosolids and landfill were evaluated qualitatively. As
such, EPA does not expect general population exposure to DIDP to occur via the land pathway and
therefore, does not expect there to be risk to the general population from the land pathway. For further
information, see Section 4.1.3.1 of this draft risk evaluation.
EPA used the highest possible DIDP concentration in surface water due to facility release to
quantitatively evaluate the risk to the general population from exposure to DIDP from drinking water or
incidental ingestion and dermal contact during recreational swimming. It was concluded that risk for
non-cancer health effects is not expected for the surface water pathway for the general population.
Risk estimates for fish ingestion generated at concentrations of DIDP at the water solubility limit or at
highest measured concentrations in surface water did not indicate risk to tribal populations. As tribal
populations are considered to represent the sentinel exposure scenario, it can be extrapolated that, based
on these results, fish ingestion is also not a pathway of concern for subsistence fishers and the general
population.
EPA also considered concentrations of DIDP in ambient air and deposition of DIDP from air. Inhalation
exposure was not assessed because it is not expected to be a major pathway of exposure to DIDP for the
general population. EPA used the occupational exposure scenario that provided the highest modeled
95th percentile annual ambient air and air deposition concentrations for DIDP to calculate exposure due
to ingestion or contact with DIDP in soil from air to soil deposition. Risks were not indicated for non-
cancer health effects to the general population using these highly conservative estimates, which led to
the preliminary conclusion that the ambient air pathway is not considered to be a major pathway of
exposure to DIDP for the general population.
EPA has robust confidence in its qualitative assessment of biosolids and landfills. EPA had slight
confidence in the surface water exposure scenarios that were used to estimate incidental ingestion and
dermal contact, since the estimated environmental releases were overly conservative. EPA had moderate
confidence in the exposure scenarios used for fish ingestion and slight confidence in the exposure
scenarios used for the estimate of the ingestion and dermal contact with soil from air to soil deposition.
The moderate or slight confidence is based on the scenarios not presenting realistic scenarios of DIDP
exposure, but the exposure estimate capture high-end estimates. It is important to note that these
confidence conclusions refer to the confidence in the data quality and numerical accuracy of the
underlying data and the resulting model estimates. A confidence evaluation of "moderate" or "slight"
confidence in an individual data source or model estimate does not mean that the resulting risk
characterization is inaccurate. Further, EPA's overall confidence that the exposure estimates capture
high-end exposure scenarios is robust, and further refinement of the models is not warranted because
risks were not indicated for the pathways with the highest potential for exposure. More information on
EPA's confidence in these risk estimates and the uncertainties associated with them can be found in this
risk evaluation (Section 4.1.3.2) and the Draft Environmental Media and General Population Exposure
for Diisodecyl Phthalate (DIDP) (I v «« \ -°24d).
6.2 Unreasonable Risk to the Environment
Risk of injury to the environment does not contribute to EPA's preliminary determination of
unreasonable risk from DIDP. Calculated RQs can provide a risk profile by presenting a range of
estimates for different environmental hazard effects for different COUs. Although quantitative release
estimates were determined for some pathways, As described in Section 6.2.1 , RQs were not determined
because a qualitative environmental toxicity risk characterization was undertaken for DIDP. The
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qualitative approach involved using the COUs associated with the highest environmental releases and
comparing the estimates to the hazard values. Because of DIDP's low water solubility, the Agency did
not identify hazard effects for aquatic organisms. Additionally, even using the highest environmental
release estimates, the Agency did not find environmental risk.
6.2.1 Populations and Exposures EPA Assessed to Determine Unreasonable Risk to the
Environment
EPA quantitatively determined DIDP concentrations in surface water, sediment, and soil. However, EPA
did not quantitatively evaluate exposures to aquatic organisms and terrestrial species. The use of a
qualitative analysis of exposure for DIDP was chosen due to the fact that (1) DIDP does not persist in
environmental media, (2) hazard thresholds were not identified for some receptors, and (3) DIDP
environmental exposures were consistently below the concentrations tested within hazard studies
indicating a lack of environmental toxicity for this compound.
The Agency expects the main environmental exposure pathway for aquatic organisms to be releases to
surface water and subsequent deposition to sediment. Releases to ambient air and subsequent deposition
to water and sediment also have a limited contribution to environmental exposure for aquatic organisms.
As detailed within Section 5.3.2, monitoring data from published literature report DIDP concentrations
within surface water and sediment lower than the highest NOEC values presented among several hazard
studies for aquatic invertebrates and vertebrates in the water column, benthic invertebrates in the
sediment, and aquatic plants and algae.
EPA expects that DIDP has a low bioconcentration and biomagnification potential across trophic levels.
DIDP exposure to terrestrial organisms occurs primarily through diet via the sediment pathway for semi-
aquatic terrestrial mammals followed by the soil pathway for soil invertebrates and terrestrial mammals,
with releases to surface water representing a major exposure pathway. Direct exposure of DIDP to
terrestrial receptors via air was not assessed quantitatively because dietary exposure was determined to
be the driver of exposure to wildlife, however, air deposition of DIDP to soil, sediment, and surface
water were modeled to represent COU-based releases to air.
In general, EPA has an overall moderate confidence in environmental releases for acute and chronic
aquatic assessment, chronic benthic assessment, algal assessment, chronic mammalian assessment, and
terrestrial invertebrates. Although the conservative nature of model outputs resulted in slight confidence
for the environmental media concentrations in surface water, sediment, and soil, there is robust
confidence that the modeled environmental media concentrations do not underestimate exposure to
ecological receptors and the risk characterization is protective of the environment, as noted in Table 5-3
of this draft risk evaluation. EPA has also determined an indeterminate confidence in chronic avian and
terrestrial plant assessments as there is a lack of reasonably available hazard data. EPA determined that
DIDP is expected to have a low potential for bioaccumulation and biomagnification in aquatic
organisms.
6.2.2 Summary of Unreasonable Risks to the Environment
EPA qualitatively assessed risk via release to surface water and subsequent deposition to sediment; as
well as the ambient air exposure pathway for its limited contribution via deposition to soil, water, and
sediment; and is preliminarily identifying
• No acute or chronic toxicity risk to fish and aquatic invertebrates up to and exceeding the limit of
water solubility, and
• No acute or chronic toxicity risk to sediment-dwelling organisms.
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Terrestrial hazard data for DIDP were not available for birds or mammalian species, so studies in
laboratory rodents were used to derive hazard values for mammalian species. However, due to the lack
of bioaccumulation/biomagnification, and hazard value for an aquatic dependent mammal, qualitative
analysis indicates that reaching a daily rate of 128 mg/kg-day is highly unlikely and was not reached
even with conservative quantitative modeling and trophic transfer assumptions. EPA therefore did not
preliminarily identify any acute or chronic toxicity risk with mammalian species either.
6.2.3 Basis for Unreasonable Risk of Injury to the Environment
Based on the draft risk evaluation for DIDP—including the risk estimates, the environmental effects of
DIDP, the exposures, physical-chemical properties of DIDP, and consideration of uncertainties—EPA
did not identify risk of injury to the environment that would contribute to the unreasonable risk
determination for DIDP. For aquatic organisms, surface water and subsequent deposition to sediment
were determined to be the drivers of exposure, but EPA does not expect this pathway to contribute to
unreasonable risk to the environment. EPA does not expect exposure to DIDP via water, land, or dietary
pathways to contribute to unreasonable risk to the environment. The Agency's overall environmental
risk characterization confidence levels were varied and are summarized in thq Draft Environmental
Exposure Assessment for Diisodecyl Phthalate (DIDP) (U.S. EPA. 2024d).
6.3 Additional Information Regarding the Basis for the Unreasonable Risk
Table 6-1 summarizes the basis for this draft unreasonable risk determination of injury to human health
and the environment presented in this draft risk evaluation. In these tables, a checkmark (V) indicates
how the COU contributes to the unreasonable risk by identifying the type of effect (e.g., non-cancer for
human health) and the exposure route to the population or receptor that results in such contribution. As
explained in Section 6, for this draft unreasonable risk determination, EPA considered the effects of
DIDP to human health at the central tendency and high-end, as well as effects of DIDP to human health
from the exposures associated from the condition of use, risk estimates, and uncertainties in the analysis.
As explained in Section 6.1.3, checkmarks in Table 6-1 represent risk at the high-end exposure level for
one occupational COU. See Draft Human Health Risk Assessment for Diisodecyl phthalate (DIDP) for a
summary of risk estimates. In addition, certain exposure routes for some COUs were not assessed
because it was determined that there was no viable exposure pathway. These COUs and their respective
exposure routes are grayed-out in Table 6-1.
6.3.1 Additional Information about COUs Characterized Qualitatively
Two consumer COUs, Packaging, paper, and plastic, hobby products - ink, toner and colorant products
and Packaging, paper, and plastic, hobby products - arts, crafts, and hobby materials (crafting paint
applied to craft) were evaluated qualitatively, since current products were not identified. Foreseeable
uses for these two consumer COUs are likely similar to the consumer COUs evaluated quantitatively,
construction, paint, electrical, and metal products - paints and coatings and construction, paint,
electrical, and metal products - adhesives and sealants (including plasticizers in adhesives and sealants),
which had MOEs that did not indicate risk. Therefore, EPA is determining Ink, toner and colorant
products and arts, crafts, and hobby materials (crafting paint applied to craft) do not contribute to the
unreasonable risk of DIDP.
For the purposes of the unreasonable risk determination, distribution in commerce of DIDP consists of
the transportation associated with the moving of DIDP and DIDP containing products in commerce.
EPA evaluated the distribution in commerce COU qualitatively and did not calculate risk estimates for
the distribution in commerce COU. EPA evaluated activities resulting in exposures associated with
loading and unloading of the chemical throughout the various life cycle stages and conditions of use
(e.g., manufacturing, processing, industrial use, commercial use, and disposal). Most of the
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environmental releases (and subsequent general population and environmental receptor exposures) from
the DIDP COUs are expected to be captured in the COUs evaluated qualitatively, including the releases
to the environment from loading and unloading of DIDP and DIDP containing products. EPA expects
that environmental releases from distribution in commerce will be similar or less than the exposure
estimates from the COUs evaluated qualitatively, which did not exceed hazard to ecological receptors;
therefore, EPA expects that distribution in commerce also would not result in exposures that contribute
to the unreasonable risk of DIDP. Therefore, EPA is preliminarily determining that distribution in
commerce does not contribute to the unreasonable risk of DIDP to the risk of injury to the environment.
Similarly, EPA does not expect distribution in commerce to contribute to DIDP's unreasonable risk to
human health because distribution in commerce does not generate dust or mist, and DIDP's low vapor
pressure results in inhalation exposures that are quite low for workers. EPA expects that general
population inhalation exposures from distribution in commerce would be even lower than those for
workers. Therefore, EPA is preliminarily determining that distribution in commerce does not contribute
to the unreasonable risk of DIDP due to the injury to health.
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Table 6-1. Supporting Basis for the Draft Unreasonable Risk
determination for Human Healt
i (Occupational Conditions of Use)
Life Cycle
Stage
Category
Subcategory
Population
Exposure Route"
Human Health Effects6
Acute
Non-cancer
Intermediate
Non-cancer
Chronic Non-
cancer
Manufacturing
Domestic
Manufacturing
Domestic manufacturing
Worker: Average
Adult Worker
Dermal
Inhalation
Worker: Female of
Reproductive Age
Dermal
Inhalation
ONU
Dermal
Inhalation
Importing
Importing
Worker: Average
Adult Worker
Dermal
Inhalation
Worker: Female of
Reproductive Age
Dermal
ONU
Dermal
Inhalation
Processing
Incorporation
into
formulation,
mixture, or
reaction
product
Adhesives and sealants manufacturing
Worker: Average
Adult Worker
Dermal
Inhalation
Worker: Female of
Reproductive Age
Dermal
Inhalation
ONU
Dermal
Inhalation
Laboratory chemicals manufacturing
Worker: Average
Adult Worker
Dermal
Inhalation
Worker: Female of
Reproductive Age
Dermal
Inhalation
ONU
Dermal
Inhalation
Petroleum lubricating oil manufacturing;
Lubricants and lubricant additives
manufacturing
Worker: Average
Adult Worker
Dermal
Inhalation
Worker: Female of
Reproductive Age
Dermal
Inhalation
ONU
Dermal
Inhalation
Dermal
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Life Cycle
Stage
Processing
Category
Incorporation
into
formulation,
mixture, or
reaction
product
Subcategory
Surface modifier in paint and coating
manufacturing
Population
Worker: Average
Adult Worker
Exposure Route"
Human Health Effects6
Acute
Non-cancer
Intermediate
Non-cancer
Chronic Non-
cancer
Inhalation
Worker: Female of
Reproductive Age
Dermal
Inhalation
ONU
Dermal
Inhalation
Plastic material and resin manufacturing
Worker: Average
Adult Worker
Dermal
Inhalation
Worker: Female of
Reproductive Age
Dermal
Inhalation
ONU
Dermal''
Inhalation
Plasticizers (paint and coating
manufacturing; colorant (including
pigments); rubber manufacturing)
Worker: Average
Adult Worker
Dermal
Inhalation
Worker: Female of
Reproductive Age
Dermal
Inhalation
ONU
Dermal''
Inhalation
Processing aids, specific to petroleum
production (oil and gas drilling, extraction,
and support activities)
Worker: Average
Adult Worker
Dermal
Inhalation
Worker: Female of
Reproductive Age
Dermal
Inhalation
ONU
Dermal
Inhalation
Other (part of the formulation for
manufacturing synthetic leather)
Worker: Average
Adult Worker
Dermal
Inhalation
Worker: Female of
Reproductive Age
Dermal
Inhalation
ONU
Dermal''
Inhalation
Incorporation
into articles
Abrasives manufacturing
Worker: Average
Adult Worker
Dermal
Inhalation
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Life Cycle
Stage
Human Health Effects6
Category
Subcategory
Population
Exposure Route"
Acute
Intermediate
Chronic Non-
Non-cancer
Non-cancer
cancer
Worker: Female of
Dermal
Reproductive Age
Inhalation
ONU
Dermal®
Inhalation
Plasticizers (asphalt paving, roofing, and
Worker: Average
Dermal
coating materials manufacturing;
construction; automotive products
manufacturing, other than fluids; electrical
equipment, appliance, and component
Adult Worker
Inhalation
Worker: Female of
Dermal
Reproductive Age
Inhalation
manufacturing; fabric, textile, and leather
products manufacturing; floor coverings
manufacturing; furniture and related
product manufacturing; plastics product
manufacturing; rubber product
manufacturing; transportation equipment
manufacturing; ink, toner, and colorant
[including pigment] products
manufacturing; photographic supplies
manufacturing; sporting equipment
manufacturing)
Dermal''
Processing
ONU
Inhalation
Worker: Average
Dermal
Adult Worker
Inhalation
Repackaging
Repackaging
Worker: Female of
Dermal
Reproductive Age
Inhalation
ONU
Dermal
Inhalation
Recyling
Recycling
Worker: Average
Dermal
Adult Worker
Inhalation
Worker: Female of
Dermal
Reproductive Age
Inhalation
ONU
Dermal''
Inhalation
Distribution in
Distribution in
Distribution in commerce
Worker
Dermal
Commerce
Commerce
Inhalation
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Life Cycle
Stage
Human Health Effects6
Category
Subcategory
Population
Exposure Route"
Acute
Intermediate
Chronic Non-
Non-cancer
Non-cancer
cancer
ONU
Inhalation
General Population
Inhalation -
Ambient Air
Worker: Average
Dermal
Adult Worker
Inhalation
Abrasives
Abrasives (surface conditioning and
finishing discs; semi-finished and finished
goods)
Worker: Female of
Dermal
Reproductive Age
Inhalation
ONU
Dermald
Inhalation
Worker: Average
Dermal
Adult Worker
Inhalation
V
V
V
Adhesive and
Adhesive and sealants
Worker: Female of
Dermal
sealants
Reproductive Age
Inhalation
V
V
V
ONU
Dermal®
Inhalation
Worker: Average
Dermal
Adult Worker
Inhalation
Industrial Use
Functional
fluids (closed
systems)
Functional fluids (closed systems) (SCBA
Worker: Female of
Dermal
compressor oil)
Reproductive Age
Inhalation
ONU
Dermal
Inhalation
Worker: Average
Dermal
Adult Worker
Inhalation
Lubricant and
Worker: Female of
Dermal
lubricant
Lubricants and lubricant additives
Reproductive Age
Inhalation
additives
ONU
Dermal
Inhalation
Worker: Average
Dermal
Solvents (for
Adult Worker
Inhalation
cleaning or
degreasing)
Solvents (for cleaning or degreasing)
Worker: Female of
Dermal
Reproductive Age
Inhalation
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Life Cycle
Stage
Category
Subcategory
Population
Exposure Route"
Human Health Effects6
Acute
Non-cancer
Intermediate
Non-cancer
Chronic Non-
cancer
ONU
Dermal
Inhalation
Commercial
Use
Automotive,
fuel,
agriculture,
outdoor use
products
Automotive products, other than fluids
Worker: Average
Adult Worker
Dermal
Inhalation
Worker: Female of
Reproductive Age
Dermal
Inhalation
ONU
Dermal''
Inhalation
Lubricants
Worker: Average
Adult Worker
Dermal
Inhalation
Worker: Female of
Reproductive Age
Dermal
Inhalation
ONU
Dermal
Inhalation
Construction,
paint,
electrical, and
metal products
Adhesives and sealants (including
plasticizers in adhesives and sealants)
Worker: Average
Adult Worker
Dermal
Inhalation
Worker: Female of
Reproductive Age
Dermal
Inhalation
ONU
Dermal®
Inhalation
Building/construction materials (wire or
wiring systems; joint treatment, fire-proof
insulation)
Worker: Average
Adult Worker
Dermal
Inhalation
Worker: Female of
Reproductive Age
Dermal
Inhalation
ONU
Dermal''
Inhalation
Electrical and electronic products
Worker: Average
Adult Worker
Dermal
Inhalation
Worker: Female of
Reproductive Age
Dermal
Inhalation
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Life Cycle
Stage
Human Health Effects6
Category
Subcategory
Population
Exposure Route"
Acute
Non-cancer
Intermediate
Non-cancer
Chronic Non-
cancer
ONU
Dermal''
Inhalation
Worker: Average
Dermal
Adult Worker
Inhalation
Paints and coatings (including surfactants
Worker: Female of
Dermal
in paints and coatings)
Reproductive Age
Inhalation
ONU
Dermal®
Inhalation
Worker: Average
Dermal
Adult Worker
Inhalation
Lacquers, stains, varnishes, and floor
Worker: Female of
Dermal
finishes (as plasticizer)
Reproductive Age
Inhalation
Commercial
Use
ONU
Dermal®
Inhalation
Construction and building materials
covering large surface areas including
stone, plaster, cement, glass and ceramic
Worker: Average
Dermal
Adult Worker
Inhalation
Worker: Female of
Dermal
articles; fabrics, textiles, and apparel (as
Reproductive Age
Inhalation
plasticizer) (Floor coverings (vinyl tiles,
PVC-backed carpeting, scraper mats))
ONU
Dermal''
Inhalation
Furnishing,
cleaning,
treatment/care
Worker: Average
Dermal
Adult Worker
Inhalation
Furniture and furnishings
Worker: Female of
Dermal
products
Reproductive Age
Inhalation
ONU
Dermal
Inhalation
Worker: Average
Dermal
Adult Worker
Inhalation
Ink, toner, and colorant products
Worker: Female of
Dermal
Reproductive Age
Inhalation
ONU
Dermal®
Page 177 of 223
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PUBLIC RELEASE DRAFT
May 2024
Life Cycle
Stage
Human Health Effects6
Category
Subcategory
Population
Exposure Route"
Acute
Intermediate
Chronic Non-
Non-cancer
Non-cancer
cancer
Inhalation
Worker: Average
Dermal
Adult Worker
Inhalation
PVC film and sheet
Worker: Female of
Dermal
Furnishing,
cleaning,
treatment/care
products
Reproductive Age
Inhalation
ONU
Dermal''
Inhalation
Worker: Average
Dermal
Adult Worker
Inhalation
Plastic and rubber products (textiles,
apparel, and leather; vinyl tape; flexible
tubes; profiles; hoses)
Worker: Female of
Dermal
Commercial
Reproductive Age
Inhalation
Use
ONU
Dermal''
Inhalation
Worker: Average
Dermal
Adult Worker
Inhalation
Laboratory chemicals
Worker: Female of
Dermal
Reproductive Age
Inhalation
ONU
Dermal''
Other uses
Inhalation
Worker: Average
Dermal
Adult Worker
Inhalation
Inspection fluid/penetrant
Worker: Female of
Dermal
Reproductive Age
Inhalation
ONU
Dermal®
Inhalation
Worker: Average
Dermal
Adult Worker
Inhalation
Disposal
Disposal
Disposal
Worker: Female of
Dermal
Reproductive Age
Inhalation
ONU
Dermal''
Inhalation
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Life Cycle
Stage
Human Health Effects6
Category
Subcategory
Population
Exposure Route"
Acute
Non-cancer
Intermediate
Non-cancer
Chronic Non-
cancer
" Inhalation, dermal, and aggregate risk estimates were generated for each condition of use for workers (average adult and female of reproductive age) and ONUs if it was
determined that there was a viable exposure pathway.
b Grayed-out boxes indicate certain exposure routes that were not assessed because it was determined that there was no viable exposure pathway.
c Use of laboratory chemicals was assessed for liquids and solids containing DIDP. Dermal exposure to ONUs was assessed only for solids containing DIDP. No
unreasonable risk was found for each occupational exposure scenario.
d Dermal exposure to ONUs from contact with dust on surfaces was assessed.
e Dermal exposure to ONUs from contact with mist on the surfaces was assessed.
3862
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01 / docum ents/guidelin e s for human exposure assessment finaC If
U.S. EPA. (202 la). Draft systematic review protocol supporting TSCA risk evaluations for chemical
substances, Version 1.0: A generic TSCA systematic review protocol with chemical-specific
methodologies. (EPA Document #EPA-D-20-031). Washington, DC: Office of Chemical Safety
and Pollution Prevention. https://www.reeiilations.eov/dociiment/EPA-HQ-OPPT-2'
0005
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U.S. EPA. (202 lb). Final scope of the risk evaluation for di-isodecyl phthalate (DIDP) (1,2-
benzenedicarboxylic acid, 1,2-diisodecyl ester and 1,2-benzenedicarboxylic acid, di-C9-ll-
branched alkyl esters, ClO-rich); CASRN 26761-40-0 and 68515-49-1 [EPA Report], (EPA-740-
R-21-001). Washington, DC: Office of Chemical Safety and Pollution Prevention.
https://www.epa.eov/system/files/dociiments/2021-08/casn di-isodecvl-phthalate-
final~scope.pdf
U.S. EPA. (202 lc). Final Use Report for Di-isodecyl Phthalate (DIDP) (1,2-Benzenedicarboxylic acid,
1,2-diisodecyl ester and 1,2-Benzenedicarboxylic acid, di-C9-l 1-branched alkyl esters, ClO-rich)
(CASRN 26761-40-0 and 68515-49-1). Washington, DC.
U.S. EPA. (202 Id). Generic model for central tendency and high-end inhalation exposure to total and
respirable Particulates Not Otherwise Regulated (PNOR). Washington, DC: Office of Pollution
Prevention and Toxics, Chemical Engineering Branch.
U.S. EPA. (202 le). 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.
U.S. EPA. (202 If). 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.
U.S. EPA. (2022). Chemical repackaging - Generic scenario for estimating occupational exposures and
environmental releases (revised draft) [EPA Report], Washington, DC.
(2023a). Consumer Exposure Model (CEM) Version 3.2 User's Guide. Washington, DC.
https://www.epa.gov/tsca-screening-tools/consumer-exposure-model-cem-versio jters-
guide
U.S. EPA. (2023b). Draft Proposed Approach for Cumulative Risk Assessment of High-Priority
Phthalates and a Manufacturer-Requested Phthalate under the Toxic Substances Control Act.
(EPA-740-P-23-002). Washington, DC: U.S. Environmental Protection Agency, Office of
Chemical Safety and Pollution Prevention. https://www.regulations.gov/document/EPA-HQ-
QPPT-2022-0918-0009
U.S. EPA. (2023c). Methodology for estimating environmental releases from sampling waste (revised
draft). Washington, DC: Office of Pollution Prevention and Toxics, Chemical Engineering
Branch.
U.S. EPA. (2023d). Science Advisory Committee on Chemicals meeting minutes and final report. No.
2023-01 - A set of scientific issues being considered by the Environmental Protection Agency
regarding: Draft Proposed Principles of Cumulative Risk Assessment (CRA) under the Toxic
Substances Control Act and a Draft Proposed Approach for CRA of High-Priority Phthalates and
a Manufacturer-Requested Phthalate. (EPA-HQ-OPPT-2022-0918). Washington, DC: U.S.
Environmental Protection Agency, Office of Chemical Safety and Pollution Prevention.
https://www.regiilations.gov/dociiment/EPA-HQ-OPPT-2022-0918-0067
U.S. EPA. (2023e). 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.
U.S. EPA. (2024a). Draft Consumer and Indoor Dust Exposure Assessment for Diisodecyl Phthalate.
Washington, DC: Office of Pollution Prevention and Toxics.
(2024b). Draft Environmental Exposure Assessment for Diisodecyl Phthalate. Washington,
DC: Office of Pollution Prevention and Toxics.
(2024c). Draft Environmental Hazard Assessment for Diisodecyl Phthalate. Washington, DC:
Office of Pollution Prevention and Toxics.
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4387
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4389
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4391
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PUBLIC RELEASE DRAFT
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U.S. EPA. (2024d). Draft Environmental Media and General Population Exposure for Diisodecyl
Phthalate (DIDP) Washington, DC: Office of Pollution Prevention and Toxics.
(2024e). Draft Environmental Release and Occupational Exposure Assessment for Diisodecyl
Phthalate. Washington, DC: Office of Pollution Prevention and Toxics.
(2024f). Draft Fate Assessment for Diisodecyl Phthalate. Washington, DC: Office of
Pollution Prevention and Toxics.
(2024g). Draft Fish Ingestion Risk Calculator for Diisodecyl Phthalate (DIDP). Washington,
DC: Office of Pollution Prevention and Toxics.
(2024h). Draft Human Health Hazard Assessment for Diisodecyl Phthalate. Washington, DC:
Office of Pollution Prevention and Toxics.
(2024i). Draft Physical Chemistry Assessment for Diisodecyl Phthalate. Washington, DC:
Office of Pollution Prevention and Toxics.
(2024j). Draft Risk Evaluation for Diisodecyl Phthalate. Washington, DC: Office of Pollution
Prevention and Toxics.
(2024k). Draft Risk Evaluation for Diisodecyl Phthalate - Systematic Review Protocol.
Washington, DC: Office of Pollution Prevention and Toxics.
(20241). Draft Risk Evaluation for Diisodecyl Phthalate - Systematic Review Supplemental
File: Data Extraction Information for Environmental Hazard and Human Health Hazard Animal
Toxicology and Epidemiology. Washington, DC: Office of Pollution Prevention and Toxics.
U.S. EPA. (2024m). Draft Risk Evaluation for Diisodecyl Phthalate - Systematic Review Supplemental
File: Data Extraction Information for General Population, Consumer, and Environmental
Exposure. Washington, DC: Office of Pollution Prevention and Toxics.
U.S. EPA. (2024n). Draft Risk Evaluation for Diisodecyl Phthalate - Systematic Review Supplemental
File: Data Quality Evaluation and Data Extraction Information for Dermal Absorption.
Washington, DC: Office of Pollution Prevention and Toxics.
U.S. EPA. (2024o). Draft Risk Evaluation for Diisodecyl Phthalate - Systematic Review Supplemental
File: Data Quality Evaluation and Data Extraction Information for Environmental Fate and
Transport. Washington, DC: Office of Pollution Prevention and Toxics.
U.S. EPA. (2024p). Draft Risk Evaluation for Diisodecyl Phthalate - Systematic Review Supplemental
File: Data Quality Evaluation and Data Extraction Information for Environmental Release and
Occupational Exposure. Washington, DC: Office of Pollution Prevention and Toxics.
U.S. EPA. (2024q). Draft Risk Evaluation for Diisodecyl Phthalate - Systematic Review Supplemental
File: Data Quality Evaluation and Data Extraction Information for Physical and Chemical
Properties. Washington, DC: Office of Pollution Prevention and Toxics.
U.S. EPA. (2024r). Draft Risk Evaluation for Diisodecyl Phthalate - Systematic Review Supplemental
File: Data Quality Evaluation Information for Environmental Hazard. Washington, DC: Office of
Pollution Prevention and Toxics.
U.S. EPA. (2024s). Draft Risk Evaluation for Diisodecyl Phthalate - Systematic Review Supplemental
File: Data Quality Evaluation Information for General Population, Consumer, and Environmental
Exposure. Washington, DC: Office of Pollution Prevention and Toxics.
U.S. EPA. (2024t). Draft Risk Evaluation for Diisodecyl Phthalate - Systematic Review Supplemental
File: Data Quality Evaluation Information for Human Health Hazard Animal Toxicology.
Washington, DC: Office of Pollution Prevention and Toxics.
U.S. EPA. (2024u). Draft Risk Evaluation for Diisodecyl Phthalate - Systematic Review Supplemental
File: Data Quality Evaluation Information for Human Health Hazard Epidemiology. Washington,
DC: Office of Pollution Prevention and Toxics.
U.S. EPA. (2024v). Draft Risk Evaluation for Diisodecyl Phthalate (DIDP) - Supplemental Information
File: Consumer Exposure Analysis. Washington, DC: Office of Pollution Prevention and Toxics.
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U.S. EPA. (2024w). Draft Risk Evaluation for Diisodecyl Phthalate (DIDP) - Supplemental Information
File: Consumer Risk Calculator. Washington, DC: Office of Pollution Prevention and Toxics.
(2024x). Draft Risk Evaluation for Diisodecyl Phthalate (DIDP) - Supplemental Information
File: Risk Calculator for Occupational Exposures. Washington, DC: Office of Pollution
Prevention and Toxics.
U.S. EPA. (2024y). Draft Surface Water Human Exposure Risk Calculator for Diisodecyl Phthalate
(DIDP). Washington, DC: Office of Pollution Prevention and Toxics.
Waterman. SJ; Ambroso. JL; Keller. LH; Trimmer. GW; Mkiforoi [arris. SB. (1999).
Developmental toxicity of di-isodecyl and di-isononyl phthalates in rats. Reprod Toxicol 13:
131-136. http://dx.doi.org/i 0. i 0 i 6/80890-6238(99)0000:
Wen. ZD; Huanv \l 1 1 t Sham \ \ Uu. J; Zhao \ I I . Song. KS.
(2018). Phthalate esters in surface water of Songhua River watershed associated with land use
types, Northeast China. Environ Sci Pollut Res Int 25: 7688-7698.
http://dx.doi.orE
Williams. MP; Adams. WJ; Parkerton. TF; Biddinger. GR: Robillard. KA. (1995). Sediment sorption
coefficient measurements for four phthalate esters: Experimental results and model theory.
Environ Toxicol Chem 14: 1477-1486. http://dx.doi.ore/10.1002/etc.5620140906
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4422
4423
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4430
4431
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PUBLIC RELEASE DRAFT
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APPENDICES
Appendix A ABBREVIATIONS AND ACRONYMS
ADD
Average daily dose
ADC
Average daily concentration
AERMOD
American Meteorological Society/EPA Regulatory Model
BLS
Bureau of Labor Statistics
CASRN
Chemical Abstracts Service Registry Number
CBI
Confidential business information
CDR
Chemical Data Reporting
CEHD
Chemical Exposure Health Data
CEM
Consumer Exposure Model
CERCLA
Comprehensive Environmental Response, Compensation and Liability Act
CFR
Code of Federal Regulations
CPSC
Consumer Product Safety Commission
CWA
Clean Water Act
DEHP
Di ethyl hexyl phthalate
DIDP
Diisodecyl phthalate
DINP
Diisononyl phthalate
DIY
Do-it-yourself
DMR
Discharge Monitoring Report
EPA
Environmental Protection Agency
EPCRA
Emergency Planning and Community Right-to-Know Act
ESD
Emission Scenario Document
EU
European Union
FDA
Food and Drug Administration
FFDCA
Federal Food, Drug, and Cosmetic Act
GS
Generic Scenario
Koc
Soil organic carbon: water partitioning coefficient
Kow
Octanol: water partition coefficient
HEC
Human equivalent concentration
HED
Human equivalent dose
IADD
Intermediate average daily dose
IR
Ingestion rate
LCD
Life cycle diagram
LOD
Limit of detection
LOEC
Lowest-observed-effect concentration
Log Koc
Logarithmic organic carbon: water partition coefficient
Log Kow
Logarithmic octanol: water partition coefficient
MOE
Margin of exposure
NAICS
North American Industry Classification System
NHANES
National Health and Nutrition Examination Survey
NICNAS
National Industrial Chemicals Notification and Assessment Scheme
NOAEL
No-observed-adverse-effect level
NOEC
No-observed-effect-concentration
NPDES
National Pollutant Discharge Elimination System
NTP
National Toxicology Program
OCSPP
Office of Chemical Safety and Pollution Prevention
Page 192 of 223
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4462
4463
4464
4465
4466
4467
4468
4469
4470
4471
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
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OECD
Organisation for Economic Co-operation and Development
OEL
Occupational exposure limit
OES
Occupational exposure scenario
ONU
Occupational non-user
OPPT
Office of Pollution Prevention and Toxics
OSHA
Occupational Safety and Health Administration
PBZ
Personal breathing zone
PECO
Population, exposure, comparator, and outcome
PEL
Permissible exposure limit (OSHA)
PESS
Potentially exposed or susceptible subpopulations
PND
Postnatal Day
POD
Point of departure
POTW
Publicly owned treatment works
PVC
Polyvinyl chloride
REL
Recommended Exposure Limit
SACC
Science Advisory Committee on Chemicals
SDS
Safety data sheet
SOC
Standard Occupational Classification
SUSB
Statistics of U.S. Businesses (U.S. Census)
TRV
Toxicity reference value
TSCA
Toxic Substances Control Act
TWA
Time-weighted average
UF
Uncertainty factor
U.S.
United States
WWTP
Wastewater treatment plant
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4487 Appendix B REGULATORY AND ASSESSMENT HISTORY
4488 B.l Federal Laws and Regulations
4489
Table Apx B-l. Federa
Laws and Regulations
Statutes/Regulations
Description of Authority/Regulation
Description of Regulation
EPA statutes/regulations
Toxic Substances Control
Act (TSCA) - section 8(a)
The TSCA section 8(a) CDR Rule requires
manufacturers (including importers) to give
EPA basic exposure-related information on
the types, quantities and uses of chemical
substances produced domestically and
imported into the United States.
DIDP manufacturing (including importing),
processing and use information is reported
under the CDR rule (76 85 FR 5081620122.
April 9, 2020).
Toxic Substances Control
Act (TSCA) - section 8(b)
EPA must compile, keep current and publish
a list (the TSCA Inventory) of each chemical
substance manufactured (including imported)
or processed for commercial purposes in the
United States.
1,2-Benzenedicarboxylic acid, 1,2-diisodecyl
ester (CASRN 26761-40-0) and 1,2-
benzenedicarboxylic acid, di-C9-11-branched
alkyl esters, ClO-rich (CASRN 68515-49-1)
were on the initial TSCA Inventory and
therefore were not subject to EPA's new
chemicals review process under TSCA section 5
(60 FR 16309. March 29. 1995).
Toxic Substances Control
Act (TSCA) - section 8(e)
Manufacturers (including importers),
processors, and distributors must immediately
notify EPA if they obtain information that
supports the conclusion that a chemical
substance or mixture presents a substantial
risk of injury to health or the environment.
Two substantial risk reports were received for
CASRN 26761-40-0 and six substantial risk
reports were received for CASRN 68515-49-1
(1993-2009) (U.S. EPA, ChemView. Accessed
February 28, 2024).
Toxic Substances Control
Act (TSCA) - section 4
Provides EPA with authority to issue rules,
enforceable consent agreements and orders
requiring manufacturers (including importers)
and processors to test chemical substances
and mixtures.
One chemical data submission from test rules
was received for CASRN 26761-40-0 for
sorption to soil and sediments, and 17 chemical
data submissions from test rules were received
for CASRN 68515-49-1 (1983-1986) (U.S.
EPA, ChemView. Accessed February 28, 2024).
Federal Food, Drug, and
Cosmetic Act (FFDCA) -
section 408
FFDCA governs the allowable residues of
pesticides in food. Section 408 of the FFDCA
provides EPA with the authority to establish
tolerances (rules that establish maximum
allowable residue limits), or exemptions from
the requirement of a tolerance, for pesticide
residues (including inert ingredients) on food.
Prior to issuing a tolerance or exemption from
tolerance, EPA must determine that the
tolerance or exemption is "safe." Section
408(b) of the FFDCA defines "safe" to mean
a reasonable certainty that no harm will result
from aggregate exposures (which includes
dietary exposures from food and drinking
water as well as nonoccupational exposures)
to the pesticide. Pesticide tolerances or
exemptions from tolerance that do not meet
the FFDCA safety standard are subject to
revocation under FFDCA section 408(d) or
(e). In the absence of a tolerance or an
exemption from tolerance, or where pesticide
CASRN 26761-40-0 is approved for non-food
use (InertFinder, Accessed March 4, 2024).
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Statutes/Regulations
Description of Authority/Regulation
Description of Regulation
residues in food exceed an existing tolerance
limit, a food containing that pesticide residue
is considered adulterated and may not be
distributed in interstate commerce.
Clean Water Act (CWA) -
sections 301, 304, 306, 307,
and 402
Clean Water Act Section 307(a) established a
list of toxic pollutants or combination of
pollutants under the CWA. The statute
specifies a list of families of toxic pollutants
also listed in the Code of Federal Regulations
at 40 CFR 401.15. The "priority pollutants"
specified by those families are listed in 40
CFR part 423 Appendix A. These are
pollutants (along with non- conventional
pollutants) for which best available
technology effluent limitations must be
established on either a national basis through
rules (Sections 301(b), 304(b), 307(b), 306)or
on a case-by-case best professional judgement
basis in National Pollution Discharge
Elimination System (NPDES)permits, see
Section 402(a)(1)(B). EPA identifies the best
available technology that is economically
achievable for that industry after considering
statutorily prescribed factors and sets
regulatory requirements based on the
performance of that technology.
As a phthalate ester, DIDP is designated as a
toxic pollutant under section 307(a)(1) of the
CWA, and as such is subject to effluent
limitations (40 CFR 401.15).
Note - even if not specified as a toxic pollutant,
unless it is a conventional pollutant - it is also
subject to effluent limitations based on Best
Available Technology Economically
Achievable (BAT). All pollutants except
conventional pollutants are subject to BAT.
Comprehensive
Environmental Response,
Compensation and Liability
Act (CERCLA) - sections
102(a) and 103
Authorizes EPA to promulgate regulations
designating as hazardous substances, in
addition to those referred to in section
101(14) of CERCLA, those elements,
compounds, mixtures, solutions, and
substances which, when released into the
environment, may present substantial danger
to the public health or welfare or the
environment.
EPA must also promulgate regulations
establishing the quantity of any hazardous
substance the release of which must be
reported under Section 103.
Section 103 requires persons in charge of
vessels or facilities to report to the National
Response Center if they have knowledge of a
release of a hazardous substance above the
reportable quantity threshold. CERCLA
Hazardous substances listed under 40 CFR
Table 302.4 are subject to EPCRA Section
304 notification requirements.
As a phthalate ester, DIDP is designated as a
hazardous substance under CERCLA. No
reportable quantity is assigned to the generic or
broad class (40 CFR 302.4).
()llici" falcnl spumes icuuhikms
Federal Food, Drug, and
Cosmetic Act (FFDCA)
Provides the FDA with authority to oversee
the safety of food, drugs and cosmetics,
except residues of pesticides in food are
regulated by EPA under FFDCA section 408
(discussed above where applicable).
CASRN 26761-40-0 is listed as an Indirect
Additives used in Food Contact Substances (21
CFR 175.105; 21 CFR 175.300; 21 CFR
177.1210; 21 CFR 177.2600; 21 CFR
177.3910).
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Statutes/Regulations
Description of Authority/Regulation
Description of Regulation
Consumer Product Safety
Improvement Act of 2008
(CP SI A)
Under section 108 of the Consumer Product
Safety Improvement Act of 2008 (CPSIA),
CPSC prohibits the manufacture for sale,
offer for sale, distribution in commerce or
importation of eight phthalates in toys and
childcare articles at concentrations > 0.1%:
DEHP, DBP, BBP, DINP, DIBP, DPENP,
DHEXP and DCHP.
The interim prohibition on the use of DIDP in
childrens toys (15 U.S.C 2057©, August 14,
2008) was lifted in the final rule (16 CFR Dart
1307, October 27, 2017).
4491 B.2 State Laws and Regulations
4492
4493 Table Apx B-2. State Laws and Regulations
State Actions
Description of Action
State Right-to-Know Acts
Pennsylvania (P.L. 734, No. 159 and 34 Pa. Code § 323) includes phthalate esters on the
hazardous substance list as an environmental hazard.
Chemicals of High
Concern to Children
Several states have adopted reporting laws for chemicals in children's products containing DIDP,
including Maine (chemicals of concern) (38 MRSA Chapter 16-D), Minnesota (Toxic Free Kids
Act Minn. Stat. 116.9401 to 116.9407), Oregon (Toxic-Free Kids Act, Senate Bill 478, 2015),
Vermont (18 V.S.A § 1776), and Washington State (Wash. Admin. Code 173-334-130).
Other
California listed CASRN "68515-49-1/26761-40-0" on Proposition 65 in 2007 due to
developmental toxicity. (Cal Code Regs. Title 27, § 27001).
CASRN 26761-40-0 is listed as a Candidate Chemical under California's Safer Consumer
Products Program (Health and Safety Code § 25252 and 25253).
California issued a Health Hazard Alert for DIDP (Hazard Evaluation System and Information
Service, 2016).
California lists DIDP as a designated priority chemical for biomonitoring (California SB 1379).
4494 B.3 International Laws and Regulations
4495
4496 Table Apx B-3. International Laws and Regulations
Country/ Organization
Requirements and Restrictions
Canada
CASRNs 26761-40-0 and 68515-49-1 are on the Domestic Substances List (Government of
Canada. Managing substances in the environment. Substances search. Database accessed
March 6, 2024).
European Union
CASRN 26761-40-0 (EC/List no.: 247-977-1) and CASRN 68515-49-1 (EC/List no.: 271-
091-4) are registered for use in the EU. (European Chemicals Agency [ECHA] database.
Accessed February 28, 2024).
DIDP was added to the EC Inventory on the 2nd priority list, and a risk assessment was
conducted under the Existing Substances Regulation (ESR) in 2003 that found there was no
need for further information and/or testing and for risk reduction measures beyond those
which are already applied. (ECHA database. Accessed February 28, 2024).
httDs://echa.euroDa.eu/documents/l0162/b66cca3a-53()3-455b-8355-63bf741e263b
DIDP was added to the Annex III of REACH (Conditions of restriction) The list supports
registrants in identifying whether reduced minimum information requirements or a full
Annex VII information set is required. (ECHA database, accessed February 28, 2024).
In 2006, a restriction of sale and use of toys and childcare articles which can be placed in the
mouth by children containing 0.1% or more CASRN 26761-40-0 and CASRN 68515-49-1
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Country/ Organization
Requirements and Restrictions
was added to Annex XVII of regulation (EC) No 1907/2006 - REACH (Registration,
Evaluation, Authorization and Restriction of Chemicals). (European Chemicals Agency
|ECHA| database, accessed February 28, 2024).
Australia
CASRNs 26761-40-0 and 68515-49-1 were assessed under Human Health Tier I of the
Inventory Multi-Tiered Assessment and Prioritisation (IMAP). (NICNAS, 1,2-
Benzenedicarboxylic acid, diisodecyl ester: Human health tier I assessment. Accessed
February 28, 2024)
CASRNs 26761-40-0 and 68515-49-1 are listed on the Chemical Inventory and subject to
secondary notifications when importing or manufacturing the chemical in Australia.
(NICNAS database. Accessed February 28, 2024)
Japan
CASRNs 26761-40-0 and 68515-49-1 are regulated in Japan under the following legislation:
• Act on the Evaluation of Chemical Substances and Regulation of Their
Manufacture, etc. (Chemical Substances Control Law; CSCL)
• Food Sanitation Act
• Fire Service Act
(National Institute of Technology and Evaluation [NITE] Chemical Risk Information
Platform [CHIRP]. Accessed February 28, 2024).
Countries with
occupational exposure
limits
Occupational exposure limit for CASRN 26761-40-0 is:
• Austria: 3 mg/m3 (8-hour) and 5 mg/m3 (short-term);
• Ontario, Canada: 5 mg/m3 (8-hour);
• Denmark: 3 mg/m3 (8-hour) and 6 mg/m3 (short-term);
• Ireland: 5 mg/m3 (8-hour);
• New Zealand: 5 mg/m3 (8-hour);
• South Africa Mining: 5 mg/m3 (8-hour);
• Sweden: 3 mg/m3 (8-hour) and 5 mg/m3 (short-term); and
• United Kingdom: 5 mg/m3 (8-hour).
(GESTIS International limit values for chemical agents (Occupational exposure limits,
OELs) database. Accessed February, 28, 2024).
4497 B.4 Assessment History
4498
4499 Table Apx B-4. Assessment History of DIDP
Audiorin» ()r»ani/alion
Publication
LP A publications
None
Oilier I S.-based oiijani/alions
U.S. Consumer Product Safety Commission (U.S.
CPSC)
Chronic Hazard Panel on Phthalates and Phthalate
Alternatives Final Report (With Appendices) (2014)
Toxicity Review of DIDP (2010)
National Toxicology Program (NTP), Center for the
Evaluation of Risks to Human Reproduction (CERHR),
National Institute of Health (NIH)
NTP-CERHR Monograph on the Potential Human
Reproductive and Developmental Effects of Di-
Isodecvl Phthalate (DIDP) (2003)
Office of Environmental Health Hazard Assessment
(OEHHA), California Environmental Protection
Agency
Proposition 65 Maximum Allowable Dose Level
(MADL) for Reproductive Toxicity for Di-isodecvl
Phthalate (DIDP) (2010)
1 iilenuil ioikiI
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Authoring Organization
Publication
European Union. European Chemicals Agency (ECHA)
DiiNP and DlDP (2013)
European Union Risk Assessment Report: CAS Nos:
6^* 1 * -1° 1 X .V V1 -10 0 I benzenedicarboxvlic
acid, di-C9-l 1- branched alkvl esters tcli and di-
"isodecvl" phthalate (DIDP) (2003)
European Food Safety Authority (EFSA)
Update of the Risk Assessment of Di-butviphthalate
(DBF). Butvl-benzvl-phthalate (BBP). Bis(2-
ethvlhexvl)Dhthalate (DEHP), Di-isononvlphthalate
(DINP) and Diisodecvlphthalate (DIDP) for Use in
Food Contact Materials (2019)
Opinion of the Scientific Panel on Food Additives,
Flavourings. Processing Aids and Materials in Contact
with Food (AFC) on a Reouest from the Commission
Related to Di-isodecvlphthalate (DIDP) for Use in
Food Contact Materials (2005)
Government of Canada, Environment Canada, Health
Canada
Screening Assessment: Phthalate Substance Grouping
(2020)
State of the science report: Phthalates Substance
Grouping: Long-chain Phthalate Esters. 1.2-
Benzenedicarboxvlic Acid. Diisodecvl Ester
(Diisodecvl Phthalate; DIDP) and 1,2-
Benzenedicarboxvlic Acid. Diundecvl Ester
(Diundecvl Phthalate; DUP). Chemical Abstracts
Service Registry Numbei 68515-49-1;
3648-20-2 (2015)
National Industrial Chemicals Notification and
Assessment Scheme (NICNAS), Australian
Government
Priority Existing Chemical Assessment Report:
Diisodecvl Phthalate & Di-n-octvl Phthalate (2015)
Existing Chemical Hazard Assessment Report:
Diisodecvl Phthalate (2008)
4500
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Appendix C LIST OF TECHNICAL SUPPORT DOCUMENTS
Appendix C incudes a list and citations for all supplemental documents included in the Draft Risk
Evaluation for DIDP.
Associated Systematic Review Protocol and Data Quality Evaluation and Data Extraction
Documents - Provide additional detail and information on systematic review methodologies used as
well as the data quality evaluations and extractions criteria and results.
Draft Systematic Review Protocol for Diisodecyl Phthalate (DIDP) ( 1024k) - In lieu of
an update to the Draft Systematic Review Protocol Supporting TSCA Risk Evaluations for Chemical
Substances, also referred to as the "2021 Draft Systematic Review Protocol" ( 2la), this
systematic review protocol for the Draft Risk Evaluation for DIDP describes some clarifications and
different approaches that were implemented than those described in the 2021 Draft Systematic
Review Protocol in response to (1) SACC comments, (2) public comments, or (3) to reflect
chemical-specific risk evaluation needs. This supplemental file may also be referred to as the "DIDP
Systematic Review Protocol."
Data Quality Evaluation and Data Extraction Information for Physical and Chemical Properties for
Diisodecyl Phthalate (DIDP) ( 24q) - Provides a compilation of tables for the data
extraction and data quality evaluation information for DIDP. Each table shows the data point, set, or
information element that was extracted and evaluated from a data source that has information
relevant for the evaluation of physical and chemical properties. This supplemental file may also be
referred to as the "DIDP Data Quality Evaluation and Data Extraction Information for Physical and
Chemical Properties."
Data Quality Evaluation and Data Extraction Information for Environmental Fate and Transport for
Diisodecyl Phthalate (DIDP) ( Mo) - Provides a compilation of tables for the data
extraction and data quality evaluation information for DIDP. Each table shows the data point, set, or
information element that was extracted and evaluated from a data source that has information
relevant for the evaluation for Environmental Fate and Transport. This supplemental file may also be
referred to as the "DIDP Data Quality Evaluation and Data Extraction Information for
Environmental Fate and Transport."
Data Quality Evaluation and Data Extraction Information for Environmental Release and
Occupational Exposure for Diisodecyl Phthalate (DIDP) ( 2024p) - Provides a
compilation of tables for the data extraction and data quality evaluation information for DIDP. Each
table shows the data point, set, or information element that was extracted and evaluated from a data
source that has information relevant for the evaluation of environmental release and occupational
exposure. This supplemental file may also be referred to as the "DIDP Data Quality Evaluation and
Data Extraction Information for Environmental Release and Occupational Exposure."
Data Quality Evaluation and Data Extraction Information for Dermal Absorption for Diisodecyl
Phthalate (DIDP) ( ,4n) - Provides a compilation of tables for the data extraction and
data quality evaluation information for DIDP. Each table shows the data point, set, or information
element that was extracted and evaluated from a data source that has information relevant for the
evaluation for Dermal Absorption. This supplemental file may also be referred to as the "DIDP Data
Quality Evaluation and Data Extraction Information for Dermal Absorption."
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Data Extraction Information for General Population, Consumer, and Environmental Exposure for
Diisodecyl Phthalate (1)11)P) (U.S. EPA. 2024s) - Provides a compilation of tables for the data
quality evaluation information for DIDP. Each table shows the data point, set, or information
element that was evaluated from a data source that has information relevant for the evaluation of
general population, consumer, and environmental exposure. This supplemental file may also be
referred to as the "DIDP Data Quality Evaluation Information for General Population, Consumer,
and Environmental Exposure."
Data Quality Evaluation Information for General Population, Consumer, and Environmental
Exposure for Diisodecyl Phthalate (DIDP) (U.S. EPA. 2024m) - Provides a compilation of tables
for the data extraction for DIDP. Each table shows the data point, set, or information element that
was extracted from a data source that has information relevant for the evaluation of general
population, consumer, and environmental exposure. This supplemental file may also be referred to as
the "DIDP Data Extraction Information for General Population, Consumer, and Environmental
Exposure."
Data Quality Evaluation Information for Human Health Hazard Epidemiology for Diisodecyl
Phthalate (DIDP) ( 2024u) - Provides a compilation of tables for the data quality
evaluation information for DIDP. Each table shows the data point, set, or information element that
was evaluated from a data source that has information relevant for the evaluation of epidemiological
information. This supplemental file may also be referred to as the "DIDP Data Quality Evaluation
Information for Human Health Hazard Epidemiology."
Data Quality Evaluation Information for Human Health Hazard Animal Toxicology for Diisodecyl
Phthalate (DIDP) ( 2024t) - Provides a compilation of tables for the data quality
evaluation information for DIDP. Each table shows the data point, set, or information element that
was evaluated from a data source that has information relevant for the evaluation of human health
hazard animal toxicity information. This supplemental file may also be referred to as the "DIDP
Data Quality Evaluation Information for Human Health Hazard Animal Toxicology."
Data Quality Evaluation Information for Environmental Hazardfor Diisodecyl Phthalate (DIDP)
( 1024f) - Provides a compilation of tables for the data quality evaluation information for
DIDP. Each table shows the data point, set, or information element that was evaluated from a data
source that has information relevant for the evaluation of environmental hazard toxicity information.
This supplemental file may also be referred to as the "DIDP Data Quality Evaluation Information for
Environmental Hazard."
Data Extraction Information for Environmental Hazard and Human Health Hazard Animal
Toxicology and Epidemiology for Diisodecyl Phthalate (DIDP) (U.S. EPA. 20241) - Provides a
compilation of tables for the data extraction for DIDP. Each table shows the data point, set, or
information element that was extracted from a data source that has information relevant for the
evaluation of environmental hazard and human health hazard animal toxicology and epidemiology
information. This supplemental file may also be referred to as the "DIDP Data Extraction
Information for Environmental Hazard and Human Health Hazard Animal Toxicology and
Epidemiology."
Associated Technical Support and Supplemental Information Documents - Provide additional
details and information on exposure, hazard, and risk assessments.
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Draft Physical Chemistry Assessment for Diisodecyl Phthalate (1)11)P) ( 10241).
Draft Fate Assessment for Diisodecyl Phthalate (DIDP) ( 024f).
Draft Environmental Release and Occupational Exposure Assessment for Diisodecyl Phthalate
(DIDP) ( ).
Draft Environmental Media and General Population Exposure for Diisodecyl Phthalate (DIDP)
( >024cD.
Draft Consumer and Indoor Dust Exposure Assessment for Diisodecyl Phthalate (DIDP) (
2024a).
Draft Environmental Exposure Assessment for Diisodecyl Phthalate (DIDP) ( 24b).
Draft Environmental Hazard Assessment for Diisodecyl Phthalate (DIDP) ( ,024c).
Draft Human Health Hazard Assessment for Diisodecyl Phthalate (DIDP) ( 024h).
Draft Consumer Exposure Analysis for Diisodecyl Phthalate (DIDP) ( Z4v).
Draft Consumer Risk Calculator for Diisodecyl Phthalate (DIDP) ( >24 w).
Draft Risk Calculator for Occupational Exposures for Diisodecyl Phthalate (DIDP) (U.S. EPA.
2024x).
Draft Fish Ingestion Risk Calculator for Diisodecyl Phthalate (DIDP) ( 324e).
Draft Surface Water Human Exposure Risk Calculator for Diisodecyl Phthalate (DIDP) (
2024v).
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Appendix D UPDATES TO THE DIDP CONDITIONS OF USE
TABLE
D.l Additions and Name Changes to COUs Based on Updated 2020 CDR
Reported Data and Stakeholder Engagement
After the final scope ( ), EPA received updated submissions under the 2020 CDR
reported data. In addition to new submissions received under the 2020 CDR, the reporting name codes
changed for the 2020 CDR reporting cycle. Therefore, EPA is amending the description of certain DIDP
COUs based on those new submissions and new reporting name codes. Also, EPA received information
from stakeholders about other uses of DIDP. TableApx D-l summarizes the changes to the COUs
based on the new reporting codes in the 2020 CDR and any other new information since the publication
of the final scope.
Table Apx D-l. Additions and Name Changes to Categories and Subcategories of Conditions of
Use Based on CDR Reporting and Stakeholder Engagement
Life Cycle Stage and
Category
Original Subcategory in the
Final Scope Document
Occurred Change
Revised Subcategory in the
2024 Draft Risk Evaluation
Processing, Incorporation
into formulation,
mixture, or reaction
product
N/A
Added "Surface modifier
and plasticizer in paint
and coating
manufacturing"
Surface modifier in paint and
coating manufacturing
Processing, Incorporation
into formulation,
mixture, or reaction
product
N/A
Added "Other (part of
the formulation for
manufacturing synthetic
leather)"
Other (part of the
formulation for
manufacturing synthetic
leather)
Processing, Incorporation
into articles
Plasticizers (e.g., asphalt paving,
roofing, and coating materials
manufacturing; automotive care
products manufacturing; electrical
equipment, appliance, and
component manufacturing; fabric,
textile, and leather products not
covered elsewhere
manufacturing; floor coverings
manufacturing; plastics product
manufacturing; rubber product
manufacturing; textiles, apparel,
and leather manufacturing;
transportation equipment
manufacturing; miscellaneous
manufacturing; ink, toner, and
colorant products manufacturing;
photographic supplies
manufacturing; plastic material
and resin manufacturing; plastics
product manufacturing; rubber
product manufacturing; textiles,
apparel, and leather
manufacturing; toys, playgrounds,
and sporting equipment
manufacturing)
Added "construction"
Added "furniture and
related product
manufacturing"
Plasticizers (asphalt paving,
roofing, and coating
materials manufacturing;
construction; automotive care
products manufacturing;
electrical equipment,
appliance, and component
manufacturing; fabric,
textile, and leather products
manufacturing; floor
coverings manufacturing;
furniture and related product
manufacturing; plastics
product manufacturing;
rubber product
manufacturing; transportation
equipment manufacturing;
ink, toner, and colorant
products manufacturing;
photographic supplies
manufacturing; toys,
playgrounds, and sporting
equipment manufacturing)
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Life Cycle Stage and
Category
Original Subcategory in the
Final Scope Document
Occurred Change
Revised Subcategory in the
2024 Draft Risk Evaluation
Commercial uses,
Construction, paint,
electrical, and metal
products
Adhesives and sealants
Added "(including
plasticizers in adhesives
and sealants)"
Adhesives and sealants
(including plasticizers in
adhesives and sealants)
Commercial uses,
Construction, paint,
electrical, and metal
products
Paints and coatings
Added "(including
surfactants in paints and
coatings)"
Paints and coatings
(including surfactants in
paints and coatings)
Commercial uses,
Construction, paint,
electrical, and metal
products
N/A
Added "Lacquers, stains,
varnishes, and floor
finishes (as plasticizer)"
Lacquers, stains, varnishes,
and floor finishes (as
plasticizer)
Commercial uses,
Furnishing, cleaning,
treatment/care products
Floor coverings (vinyl tiles, PVC-
backed carpeting, scraper mats)
Name change based on
new industry code
Added, "(as plasticizer)"
Construction and building
materials covering large
surface areas including stone,
plaster, cement, glass and
ceramic articles; fabrics,
textiles, and apparel (as
plasticizer); (Floor coverings
(vinyl tiles, PVC-backed
carpeting, scraper mats))
Commercial uses,
Furnishing, cleaning,
treatment/care products
N/A
Added "PVC film and
sheet"
PVC film and sheet
Consumer uses,
Construction, paint,
electrical, and metal
products
Adhesives and sealants
Added "(including
plasticizers in adhesives
and sealants)"
Adhesives and sealants
(including plasticizers in
adhesives and sealants)
Consumer uses,
Construction, paint,
electrical, and metal
products
Building/construction materials
not covered elsewhere (e.g., wire
or wiring systems; joint
treatment
Name change based on
new industry code
Building/construction
materials covering large
surface areas including stone,
plaster, cement, glass and
ceramic articles (wire or
wiring systems; joint
treatment)
Consumer uses,
Furnishing, cleaning,
treatment/care products
N/A
Added category and
"Fabrics, textiles, and
apparel (as plasticizer)"
Fabrics, textiles, and apparel
(as plasticizer)
Consumer uses,
Packaging, paper, plastic,
hobby products
Arts, crafts, and hobby materials
Added "(crafting paint
applied to craft)"
Arts, crafts, and hobby
materials (crafting paint
applied to craft)
Consumer uses,
Packaging, paper, plastic,
hobby products
N/A
Added "PVC film and
sheet"
PVC film and sheet
Consumer uses, Other
N/A
Added category and
"Novelty Products"
Novelty Products
4642
4643 The changes based on CDR reporting, research, or stakeholder activity are:
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4647
4648
4649
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4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
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• Processing, incorporation into formulation, mixture, or reaction product, "other (part of the
formulation for manufacturing synthetic leather)" was added because it was a new reporting
sector in the 2020 CDR.
• Processing, incorporation into articles, "Plasticizers'" was updated to include the construction
and furniture and related product manufacturing industrial sector based on 2020 CDR reporting.
• For Commercial and Consumer uses, construction, paint, electrical and metal products,
"Adhesives and sealants (includingplasticizers in adhesives and sealants) ", the reference to
plasticizers was added after feedback from a stakeholder notifying the EPA that DIDP can be
used as a component in adhesives and sealants as a plasticizer.
• Commercial uses, Furnishing, cleaning, treatment/care products, "Construction and building
materials covering large surface areas including stone, plaster, cement, glass and ceramic
articles; fabrics, textiles, and apparel (plasticizer) floor coverings (vinyl tiles, PVC-backed
carpeting, scraper mats) was updated due to a change in the 2020 CDR reporting codes. The
2020 CDR code for floor coverings was changed to "construction and building materials
covering large surface areas including stone, plaster, cement, glass and ceramic articles; fabrics,
textiles, and apparel". The original subcategory of floor coverings and examples were combined
with the new reporting code in the subcategory. The term "as plasticizer" was added to specify
the use of DIDP in these floor coverings.
• Commercial uses, Paints and coatings, Paints and coatings was edited to include "(including
surfactants in paints and coatings) " because surfactants were referenced in 2020 CDR reporting
data.
• Commercial uses, Construction, paint, electrical, and metal products, "Lacquers, stains,
varnishes, andfloor finishes (as plasticizer) " was added because it was added as a reporting
category to the 2020 CDR.
• For Commercial and Consumer uses, Furnishing, cleaning, treatment/care products, "PVC film
and sheef was added after stakeholder notification that DIDP is used in the production of these
products.
• Consumer uses, Furnishing, cleaning, treatment/care products, "Fabrics, textiles and apparel
(asplasticizer) " was added after stakeholder notification that DIDP was used in these industries.
• Consumer uses, Construction, paint, electrical, and metal products, "Building/construction
materials covering large surface areas including stone, plaster, cement, glass and ceramic
articles (wire or wiring systems; joint treatment) " was changed based on the updated 2020 CDR
codes. The subcategory was updated to "Construction and building materials covering large
surface areas, including paper articles; metal articles; stone, plaster, cement, glass and ceramic
articles." The specific examples of "(wire or wiring systems; joint treatment)" were kept.
• Consumer uses, Packaging, paper, plastic, hobby products, Arts, crafts, and hobby materials
was edited to add "(craftingpaint applied to craft) " to reflect a use reported in the 2020 CDR.
• Consumer uses, Other, "Noveltyproducts" was added after EPA did further research and found
this use among the reasonably available information.
D.2 Consolidation and Other Changes to Conditions of Use Table
When developing this draft risk evaluation, EPA concluded that some subcategories of the COUs listed
in the final scope Qi.$ ) h) were redundant and consolidation was needed to avoid evaluation
of the same COU multiple times. EPA concluded that there were some instances where subcategory
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4687 information on the processing and uses of DIDP was misreported by CDR reporters based on outreach
4688 with stakeholders. For these instances, EPA recategorized the COU to fit the actual description of the
4689 COU. Finally, EPA determined that wording changes were needed to accurately describe COUs.
4690 Therefore, EPA has made changes to the COU for the risk evaluation. TableApx D-2 summarizes the
4691 changes to the COU subcategory descriptions.
4692
4693 Table Apx D-2. Subcategory Consolidations and Editing from the Final Scope Document to the
4694 Draft Risk Evaluation
Life Cycle Stage and
Category
Original Subcategory in
the Final Scope Document
Occurred Change
Revised Subcategory in
the 2024 Draft Risk
Evaluation
Processing, Incorporation
into formulation, mixture, or
reaction product
Intermediates (e.g., plastic
material and resin
manufacturing)
Removed
N/A
Processing, Incorporation
into formulation, mixture, or
reaction product
Plastic product manufacturing
Removed
N/A
Processing, Incorporation
into formulation, mixture, or
reaction product
Lubricants and lubricant
additives manufacturing
Removed "lubricants and
lubricant additives
manufacturing" as a
separate COU and
combined with
"petroleum lubricating
oil manufacturing"
subcategory
Petroleum lubricating oil
manufacturing; lubricant and
lubricant additives
manufacturing
Processing, Incorporation
into formulation, mixture, or
reaction product
Petroleum lubricating oil and
grease manufacturing
Removed "grease"
Added "lubricant and
lubricant additives
manufacturing"
Petroleum lubricating oil
manufacturing; lubricant and
lubricant additives
manufacturing
Processing, Incorporation
into formulation, mixture, or
reaction product
Plasticizers (e.g., adhesive and
sealant manufacturing; custom
compounding of purchased
resin; construction materials
other; ground injection
equipment; paint and coating
manufacturing; pigments;
plastic material and resin
manufacturing; rubber product
manufacturing)
Removed "(e.g., adhesive
and sealant
manufacturing; custom
compounding of
purchased resin;
construction materials
other; ground injection
equipment; plastic
material and resin
manufacturing)"
Removed "product" from
rubber product
manufacturing
Plasticizers (paint and
coating manufacturing;
pigments; rubber
manufacturing)
Processing, Incorporation
into articles
Plasticizers (e.g., asphalt
paving, roofing, and coating
materials manufacturing;
electrical equipment,
appliance, and component
manufacturing; fabric, textile,
and leather products not
covered elsewhere
manufacturing; floor
Removed "not covered
elsewhere from, fabric,
textile, and leather
products not covered
elsewhere
manufacturing,"
Removed "miscellaneous
manufacturing, plastic
Plasticizers (asphalt paving,
roofing, and coating
materials manufacturing;
construction; electrical
equipment, appliance, and
component manufacturing;
fabric, textile, and leather
products manufacturing;
floor coverings
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Life Cycle Stage and
Category
Original Subcategory in
the Final Scope Document
Occurred Change
Revised Subcategory in
the 2024 Draft Risk
Evaluation
coverings manufacturing;
plastics product
manufacturing; rubber product
manufacturing; textiles,
apparel, and leather
manufacturing; transportation
equipment manufacturing;
miscellaneous manufacturing;
ink, toner, and colorant
products manufacturing;
photographic supplies
manufacturing; plastic
material and resin
manufacturing; plastics
product manufacturing; rubber
product manufacturing;
textiles, apparel, and leather
manufacturing; toys,
playgrounds, and sporting
equipment manufacturing)
material and resin
manufacturing, and
automotive care
manufacturing"
Added "automotive
products manufacturing,
other than fluids."
Added "including
pigment"
Removed duplication of
"textiles, apparel and
leather manufacturing;
rubber product
manufacturing; and
plastic material and
plastics product
manufacturing."
manufacturing; furniture and
related product
manufacturing; plastics
product manufacturing;
rubber product
manufacturing;
transportation equipment
manufacturing; ink, toner,
and colorant products
(including pigment)
manufacturing; photographic
supplies manufacturing;;
toys, playgrounds, and
sporting equipment
manufacturing)
Industrial uses, Functional
fluids (open systems)
Functional fluids (open
systems) (e.g., ground
injection equipment)
Removed
N/A
Commercial uses,
Automotive, fuel,
agriculture, outdoor use
products
Automotive care products
Removed "care", added
"other than fluids"
Automotive products, other
than fluids
Commercial uses,
Automotive, fuel,
agriculture, outdoor use
products
Lubricants and greases
Removed "greases"
Lubricants
Commercial uses,
Construction, paint,
electrical, and metal
products
Building/construction
materials not covered
elsewhere (e.g., wire or wiring
systems; joint treatment, fire-
proof insulation)
Removed "not covered
elsewhere"
Building/construction
materials (wire or wiring
systems; joint treatment, fire-
proof insulation)
Commercial uses,
Furnishing, cleaning,
treatment/care products
Furniture and furnishings not
covered elsewhere
Removed "not covered
elsewhere"
Furniture and furnishings
Commercial uses,
Packaging, paper, plastic,
hobby products
Plastic and rubber products
not covered elsewhere (e.g.,
textiles, apparel, and leather;
vinyl tape; flexible tubes;
profiles; hoses)
Removed "not covered
elsewhere" and "e.g."
Plastic and rubber products
(textiles, apparel, and leather;
vinyl tape; flexible tubes;
profiles; hoses)
Consumer uses,
Automotive, fuel,
agriculture, outdoor use
products
Automotive care products
Removed "care," added
"other than fluids"
Automotive products, other
than fluids
Consumer uses,
Automotive, fuel,
Lubricants and greases
Removed "greases"
Lubricants
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4695
4696
4697
4698
4699
4700
4701
4702
4703
4704
4705
4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717
4718
4719
4720
4721
4722
4723
4724
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Life Cycle Stage and
Category
Original Subcategory in
the Final Scope Document
Occurred Change
Revised Subcategory in
the 2024 Draft Risk
Evaluation
agriculture, outdoor use
products
Consumer uses, Packaging,
paper, plastic, hobby
products
Photographic supplies (e.g.,
graphic films)
Removed
N/A
These changes were made from the scope of the risk evaluation for the following reasons:
• The CDR reporting convention, "not covered elsewhere," was removed from several COU
subcategories. These changes were made to cover all relevant uses under their respective
categories. Please see Table Apx D-2 for the specific changes to the affected COUs.
• References to "greases" throughout the COU table were removed when referring to lubricants
because of stakeholder clarification that DIDP is not used in greases.
• For processing and commercial uses pertaining to automotive products, the CDR automotive
care product category refers to lubricants and transmission conditioner that are already covered
under other categories, so the subcategory "automotive care products" was adjusted to
"automotive products, other than fluids" to reflect where DIDP is used in plastic
framing/molding of automobiles.
• For subcategories with lists of products or industries assessed, "e.g." was removed. The list of
items provided in these subcategories are the industrial sectors for the COU and not necessarily
examples so "e.g." was removed.
• Processing, incorporation into a formulation, mixture, or reaction product, "Intermediates
(plastic material and resin manufacturing) " was removed after further investigation determined
that the COU was redundant with the Processing, incorporation into a formulation, mixture, or
reaction product, "Plastic Material and Resin manufacturing" COU.
• Processing, incorporation into a formulation, mixture, or reaction product, "Plastic product
manufacturing" was removed after further investigation determined that it was a redundant COU
best evaluated under the Processing, incorporation into articles, "Plasticizers (plastic product
manufacturing) " COU.
• Processing, incorporation into a formulation, mixture, or reaction product, "Lubricants and
lubricant additives manufacturing" was combined with the petroleum lubricating oil
manufacturing COU after further investigation determined that lubricant and lubricant additives
manufacturing is not an industrial sector under CDR reporting but is a functional use of
petroleum lubricating oil manufacturing.
• Processing, incorporation into a formulation, mixture, or reaction product, "Plasticizers
(construction materials other; paint and coating manufacturing; pigments; rubber
manufacturing; all other chemical product and preparation manufacturing" was changed to
remove "adhesive and sealant manufacturing," "custom compounding of purchased resin,"
"plastic material and resin manufacturing," "ground injection equipment," "construction
materials other," and "all other chemical product and preparation manufacturing" because upon
further investigation,
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o The references to adhesive and sealant manufacturing, custom compounding of
purchased resin, and plastic material and resin manufacturing were removed because the
uses are assessed under other categories,
o Ground injection equipment was removed because it was already addressed under the
functional fluids COU. The functional fluids (open systems) COU category was also
removed (please see the explanation for removal of the "Industrial uses, Functional fluids
(open systems)" category for additional information,
o Construction materials other was removed because it is assessed under the processing,
incorporation into articles COU and was redundant,
o Product was removed from "rubber product manufacturing" to differentiate it from the
Processing, incorporation into article, "Plasticizer (rubber product manufacturing) "
COU.
• Processing, Incorporation into articles, plasticizers was updated for the following industries:
o Miscellaneous manufacturing - after stakeholder outreach, EPA concluded that this
industry was misreported under the CDR and was addressed under other COUs.
o Plastic material and resin manufacturing - EPA determined that this industry was
assessed under "plastics product manufacturing" within this COU.
o Automotive products manufacturing, other than fluids - this subcategory refers to the
plastic moldings in automobiles. Automobile-related fluids, such as transmission
conditioner, are addressed under the lubricants COU.
o Automotive care product manufacturing - after investigation it was determined that
DIDP is not incorporated into products associated with automotive care (e.g., waxes,
soaps, etc).
o Added "including pigment" to the ink, toner, and colorant manufacturing to indicate that
this COU describes the mixing of DIDP pigments into materials such as, polyurethane or
plastisol.
• Industrial uses, functional fluids (closed systems) COU, the reference to heat transfer fluid was
removed after review of notes from a stakeholder found that there was only discussion of SCBA
compressor fluid.
• Industrial uses, Functional fluids (open systems), Functional fluids (open systems) (e.g., ground
injection equipment) was removed; this COU is not included in CDR reporting, and upon further
investigation and outreach with the stakeholder, EPA was unable to confirm that the COU exists.
• Commercial uses, Packaging, paper, plastic, hobby products, Arts, crafts, and hobby materials
was removed after a stakeholder notified the EPA that DIDP is not used in this manner
commercially.
• Commercial and Consumer uses, Packaging, paper, plastic, hobby products, Photographic
supplies (e.g., graphic films) was removed because EPA confirmed with a stakeholder that DIDP
is not used in this manner.
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Appendix E CONDITIONS OF USE DESCRIPTIONS
E.l Manufacturing (Including Import)
Manufacturing means to manufacture or produce DIDP within the Unites States or import DIDP into the
customs territory of the Unites States. For purposes of the DIDP risk evaluation, this includes the
extraction of DIDP from a previously existing chemical substance or complex combination of chemical
substances. For the purposes of this risk evaluation, this COU includes loading and repackaging (but not
transport) associated with the manufacturing, production or import of DIDP.
E.l.l Domestic Manufacturing
The alkyl esters of DIDP are a mixture of branched hydrocarbon isomers in the C9 through CI 1 range,
comprising primarily C10 isomers of decyl esters. DIDP is manufactured through a reaction of phthalic
anhydride and isodecyl alcohol using an acid catalyst, resulting in a mixture of branched hydrocarbon
isomers in the C9 through CI 1 range, comprising primarily C10 isomers of decyl esters.
E.1.2 Import
In general, chemicals may be imported into the United States in bulk via water, air, land, and intermodal
shipments. These shipments take the form of oceangoing chemical tankers, railcars, tank trucks, and
intermodal tank containers CEPA-HQ-OPPT-2018-0435-0037). Imported DIDP is shipped in either dry
powder/crystal pellets/solid form or liquid form with concentrations ranging from 1 to 100 percent DIDP
( 3a).
E.2 Processing - Incorporation into a Formulation, Mixture, or Reaction
Product - Adhesive and Sealants
Processing to incorporate DIDP into a formulation, mixture, or reaction product refers to the preparation
of a chemical substance or mixture, i.e., adding DIDP to a product (or product mixture), after its
manufacture, for distribution in commerce, in this case as an adhesive and sealant. DIDP is blended with
other volatile and nonvolatile chemical components to produce adhesives and sealants ( 3 HPP.
2019a: OECD. 20091
The 2020, 2016, 2012 CDRs and the Final Use Report for Di-isodecyl Phthalate (DIDP) (1,2-
Benzenedicarboxylic acid, 1,2-diisodecyl ester and 1,2-Benzenedicarboxylic acid, di-C9-l 1-branched
alkyl esters, ClO-rich) (CASRN 26761-40-0 and 68515-49-1) report DIDPs use as a plasticizer for
processing (incorporation into formulation, mixture, or reaction product) in adhesive manufacturing
( >021c. 2020a).
E,3 Processing - Incorporation into a Formulation, Mixture, or Reaction
Product - Laboratory Chemicals
Processing to incorporate DIDP into a formulation, mixture, or reaction product refers to the preparation
of a chemical substance or mixture, i.e., adding DIDP to a product (or product mixture), after its
manufacture, for distribution in commerce, in this case into laboratory chemicals. Various companies
have reported DIDP use for chemical synthesis or as a reference standard alone or in a mixture CSupelco.
2024).
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4817
4818
4819
4820
4821
4822
4823
4824
4825
4826
4827
4828
4829
4830
4831
4832
4833
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4836
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E.4 Processing - Incorporation into a Formulation, Mixture, or Reaction
Product - Petroleum Lubricating Oil Manufacturing; Lubricants and
Lubricant Additive Manufacturing
Processing to incorporate DIDP into a formulation, mixture, or reaction product refers to the preparation
of a chemical substance or mixture, i.e., adding DIDP to a product (or product mixture), after its
manufacture, for distribution in commerce, in this case incorporating DIDP into petroleum lubricating
oil and greases. The 2016 and 2012 CDRs report this type of processing of DIDP as a lubricant and
lubricant additive (U.S. EPA. 2019a; Anderol. 2015). DIDP is used as lubricant additive in products
such as compressor fluids. The manufacture of DIDP for use in the industrial sector, "Petroleum
Lubricating Oil and Grease Manufacturing," was reported in the 2020 CDR ( 2020a).
E.5 Processing - Incorporation into a Formulation, Mixture, or Reaction
Product - Surface Modifier and Plasticizer in Paint and Coating
Manufacturing
Processing to incorporate DIDP into a formulation, mixture, or reaction product refers to the preparation
of a chemical substance or mixture, i.e., adding DIDP to a product (or product mixture), after its
manufacture, for distribution in commerce, in this case as a surface modifier and plasticizer in paint and
coating manufacturing. The term "surface modifier" encompasses DIDP's use as an inert ingredient that
is included in a coating as a plasticizer as well as other paint and coatings products used for downstream
industrial, commercial, and consumer uses. The 2020 CDR includes a report indicating that DIDP is
used as surface modifier in paint and coating manufacturing ( 020a).
E.6 Processing - Incorporation into a Formulation, Mixture, or Reaction
Product - Plastic Material and Resin Manufacturing
Processing to incorporate DIDP into a formulation, mixture, or reaction product refers to the preparation
of a chemical substance or mixture, i.e., adding DIDP to a product (or product mixture), after its
manufacture, for distribution in commerce, in this case describing the manufacture of plastic material
and resin through non-PVC and PVC compounding. Compounding involves the mixing of the polymer
with the plasticizer and other chemical such as, fillers and heat stabilizers. The plasticizer needs to be
absorbed into the particle to impart flexibility to the polymer. For PVC compounding, compounding
occurs through mixing of ingredients to produce a powder (dry blending) or a liquid (Plastisol blending).
The most common process for dry blending involves heating the ingredients in a high intensity mixer
and transfer to a cold mixer. The Plastisol blending is done at ambient temperature using specific mixers
that allow for the breakdown of the PVC agglomerates and the absorption of the plasticizer into the resin
particle. The 2012 and 2020 CDR report use of this chemical as a plasticizer in plastic material and resin
manufacturing ( :0a).
E.7 Processing - Incorporation into a Formulation, Mixture, or Reaction
Product - Plasticizers (Paint and Coating Manufacturing; Pigments;
Rubber Manufacturing)
Processing to incorporate DIDP into a formulation, mixture, or reaction product refers to the preparation
of a chemical substance or mixture, i.e., adding DIDP to a product (or product mixture), after its
manufacture, for distribution in commerce, in this case as a plasticizer in paint and coating
manufacturing, pigments and rubber manufacturing. This COU does not include the use as surface
modifier or resin manufacturing covered by other COUs. The 2020 CDR reported the import of DIDP
for use as a plasticize in rubber product manufacturing (U.S. EPA. 2020a). The 2016 and 2012 CDRs
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4850 report use of DIDP as a plasticizer for processing (incorporation into formulation, mixture, or reaction
4851 product) in paint and coating manufacturing ( :019a).
4852 E.8 Processing - Incorporation into a Formulation, Mixture, or Reaction
4853 Product - Processing Aids, Specific to Petroleum Production (Oil and
4854 Gas Drilling, Extraction, and Support Activities)
4855 Processing to incorporate DIDP into a formulation, mixture, or reaction product refers to the preparation
4856 of a chemical substance or mixture, i.e., adding DIDP to a product (or product mixture), after its
4857 manufacture, for distribution in commerce, in this case as a processing aid, specific to petroleum
4858 production (oil and gas drilling, extraction, and support activities). Data reported to the 2016 CDR
4859 indicates DIDP is used as a processing aid for petroleum production, such as oil and gas drilling
4860 activities (U.S. EPA. 2019a). This was not reported in 2020. In addition, DIDP is found in produced
4861 wastewaters from oil and gas drilling and extraction. (U.S. EPA. ). The use was also reported in the
4862 Manufacturer request for risk evaluation Di-isodecyl Phthalate (DIDP) (ACC HPP. 2019a).
4863 E.9 Processing - Incorporation into a Formulation, Mixture, or Reaction
4864 Product - Other (Part of the Formulation for Manufacturing
4865 Synthetic Leather)
4866 Processing to incorporate DIDP into a formulation, mixture, or reaction product refers to the preparation
4867 of a chemical substance or mixture, i.e., adding DIDP to a product (or product mixture), after its
4868 manufacture, for distribution in commerce, in this case as a plasticizer that is mixed with non-PVC
4869 (polyurethane) or PVC and other additives to make a liquid suspension that can be applied to paper in
4870 the manufacturing of synthetic leather ( .Q-QPPT-2018-043 5-00211. The 2020 CDR reported the
4871 use of DIDP as part of the formulation in the manufacturing of synthetic leather ( 020a).
4872 E.10 Processing - Incorporation into Articles - Abrasives Manufacturing
4873 Processing to incorporate DIDP into articles refers to the preparation of a chemical substance or mixture,
4874 i.e., DIDP becoming a component of an article, after its manufacture, for distribution in commerce, in
4875 this case as abrasives. Abrasives are manufactured by first applying adhesives and sealants to paper and
4876 then applying an abrasive to create a sandpaper type product. DIDP is a part of the adhesive and sealant
4877 product as a plasticizer, and it would be incorporated into the abrasive product. The use of DIDP was
4878 reported in the 2020 CDR as Processing—incorporation into formulation, mixture, or reaction product -
4879 Abrasive Manufacturing, but it was updated to Processing - Incorporation into Articles to reflect the
4880 description of the use more accurately ( 2020a).
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4893
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4897
4898
4899
4900
4901
4902
4903
4904
4905
4906
4907
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E.ll Processing - Incorporation into Articles - Plasticizers (Asphalt
Paving, Roofing, and Coating Materials Manufacturing; Construction;
Automotive Products Manufacturing, Other than Fluids; Electrical
Equipment, Appliance, and Component Manufacturing; Fabric,
Textile, and Leather Products Manufacturing; Floor Coverings
Manufacturing; Furniture and Related Product Manufacturing;
Plastics Product Manufacturing; Rubber Product Manufacturing;
Transportation Equipment Manufacturing; Ink, Toner, and Colorant
Products Manufacturing (Including Pigment); Photographic Supplies
Manufacturing; Toys, Playground, and Sporting Equipment
Manufacturing)
Processing to incorporate DIDP into articles refers to the preparation of a chemical substance or mixture,
i.e., DIDP becoming a component of an article, after its manufacture, for distribution in commerce. In
this case, DIDP is present in a raw material that contains a mixture of plasticizers and other additives.
This COU refers to the manufacturing of PVC articles using those raw materials that contain DIDP. The
manufacturing of PVC articles from the raw materials entails processes such as calendaring, extrusion,
injection molding, and plastisol spread coating (EPA-HQ-OPPT-2018-0435-0022). This COU includes
incorporating DIDP into other articles. For example, plastisol technology or film calendaring technology
is used in the production of plastic and rubber products such as textiles, apparel, and leather; vinyl tape;
flexible tubes; profiles; hoses (ACC HPP. 2023). The incorporation of DIDP-containing colorants into
material such as, polyurethane or plastisol. Plastisol mixed with DIDP-containing colorants are applied
through processes such as dipping, roto-molding, or slush molding to produce coated fabrics, vinyl
sealants, wall coverings, toys, and sporting goods (EPA-HQ-OPPT-2018-0435-0022). DIDP is also
present in colorants used to color two-part polyurethane, foam, and epoxy resin systems used for
production of prototypes, miniature models, and taxidermy ( Enterprises. 2023a. b, c, d; U.S. EPA.
20 J I h, ACC HPP. 2019a). Another activity that would be included in this COU is the gluing of the
synthetic leather to a fabric backing to create the final article. The 2020, 2016, and 2012 CDRs report
use of DIDP as an adhesive and sealant chemical or plasticizer for processing (incorporation into article)
in transportation equipment manufacturing ( v «« \ 2020a. 2019a). The 2016 and 2012 CDRs report
use of DIDP as a plasticizer for processing (incorporation into article) in electrical equipment, appliance,
and component manufacturing ( j). The 2016 and 2012 CDRs report use of DIDP as a
plasticizer for processing (incorporation into formulation, mixture, or reaction product) in paint and
coating manufacturing ( ). This COU describes the incorporation of DIDP-containing
paints and coatings into articles. The 2020, 2016, and 2012 CDR report use of DIDP as a plasticizer for
processing (incorporation into article) in plastic product manufacturing ( ,020a. 2019a).
E.12 Processing - Repackaging
Repackaging refers to preparation of DIDP for distribution into commerce in a different form, state, or
quantity than originally received or stored. Such activities include transferring DIDP from a bulk storage
container into smaller containers ( :0-0PPT-2Q 18-0435-0038).
E.13 Processing - Recycling
This COU refers to the process of treating generated waste streams {i.e., which would otherwise be
disposed of as waste) that are collected, either on-site or transported to a third-party site, for commercial
purpose. DIDP is primarily recycled industrially in the form of DIDP-containing PVC waste streams,
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4924 including roofing membranes, vinyl window frame profiles, and carpet squares. New PVC can be
4925 manufactured from recycled and virgin materials at the same facility.
4926 E.14 Distribution in Commerce - Distribution in Commerce
4927 For purposes of assessment in this risk evaluation, distribution in commerce consists of the
4928 transportation associated with the moving of DIDP or DIDP-containing products between sites
4929 manufacturing, processing or recycling DIDP or DIDP-containing products, or to final use sites, or for
4930 final disposal of DIDP or DIDP-containing products. More broadly under TSCA, "distribution in
4931 commerce" and "distribute in commerce" are defined under TSCA section 3(5).
4932 E.15 Industrial Use - Abrasives - Abrasives (Surface Conditioning and
4933 Finishing Discs; Semi-finished and Finished Goods)
4934 The COU refers to the use of finished, abrasive articles that contain DIDP to smooth surfaces. DIDP is
4935 present in products that are used for surface conditioning. Surface conditioning is needed for such tasks
4936 as smoothing a surface prior to the application of paints and coatings or blending parting lines on cast
4937 parts ( Q-QPPT-2018-0435-0037). DIDP is present at low concentrations (<1.5%) in the line of
4938 non-woven abrasives supplied by one company (I. c. « ^ \ AV I h). DIDP is also present in one
4939 company's abrasive products at concentrations ranging from 1 to 8 percent with applications as an
4940 abrasive system for semi-finished and finished goods CEPA-HQ-OPPT
4941 E.16 Industrial Use - Functional Fluids (closed systems) - Functional Fluids
4942 (Closed Systems) (SCBA Compressor Oil)
4943 The phthalates' generally low melting points and high boiling points make them useful as heat-transfer
4944 liquids and carriers, which includes the changing of liquids and carriers in the pipelines of the facility.
4945 DIDP is incorporated into these products at concentrations of 10-30% CDuratherm. 2019a. b). Examples
4946 of heat transfer fluids that use DIDP are listed in the Final Use Report for Di-isodecyl Phthalate (DIDP)
4947 (1,2-Benzenedicarboxylic acid, 1,2-diisodecyl ester and 1,2-Benzenedicarboxylic acid, di-C9-ll-
4948 branched a Iky I esters, ClO-rich) (CASRN 26761-40-0 and 68515-49-1) ( 21c).
4949 E.17 Industrial Use - Adhesives and Sealants - Adhesives and Sealants
4950 EPA understands that DIDP is used as a plasticizer in the manufacture of industrial adhesives and
4951 sealant end products; however, it is primarily used in commercial and consumer end products at
4952 concentrations ranging between 1 percent to less than 60 percent in products such as automotive
4953 interiors, undercoats, electrical products, and plastic products (I v << \ ). According to the
4954 manufacturer request for risk evaluation, less than five percent of DIDP is used in non-PVC applications
4955 such as those associated with adhesives and sealants ( ). Examples of applications for
4956 adhesive and sealant products include products that are used in marine environments, joint sealants in
4957 mechanical equipment, concrete and masonry, and wood/engineered wood flooring. Adhesives and
4958 sealants may be applied through automated or mechanical spraying in industrial applications i.e., in
4959 large manufacturing or processing facilities where exposure controls can be expected to be in place;
4960 however, products containing DIDP that are categorized as spray adhesives have not currently been
4961 identified by EPA ( )21c).
4962 E.18 Industrial Use - Lubricant and Lubricant Additives
4963 According to the manufacturer request for risk evaluation, DIDP is used in PVC and non-PVC
4964 applications in automotive products for consumer and industrial applications in synthetic lubricants and
4965 engine oils CACC HPP. 2019a). EPA understands that DIDP is used in the manufacture of various
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4966 lubricant additives that then are used in the manufacture of lubricating oils and greases (
4967 2021b). EPA has identified DIDP as a known chemical constituent of industrial/commercial hydraulic
4968 fracturing fluid produced water according to state sources (EPA-600-R-16-236Fb). DIDP is also used in
4969 commercial lubricants (and lubricating oils, compressor fluids for maintenance and repair, and
4970 transmission conditioner) at a concentration of at least 90 percent by weight ( 321c).
4971 E.19 Industrial Use - Solvents (for Cleaning or Degreasing)
4972 One company identifies DIDP as an ingredient in cleaners (sludge and carbon removal) for heat transfer
4973 systems. The company makes a variety of products for this purpose ( 21c). Additionally,
4974 another company identifies DIDP as an ingredient in one of its products, which is designed to be used as
4975 a degreasing fluid for its line of air compressors (Ouincv Compressor. 2022).
4976 E.20 Commercial Use - Automotive, Fuel, Agriculture, Outdoor Use
4977 Products - Automotive Products, Other than Fluids
4978 According to the Manufacturer request for risk evaluation Di-isodecyl Phthalate (DIDP), DIDP is
4979 primarily used as a plasticizer in automotive products such as upholstery and interior finishes (e.g.,
4980 synthetic leather for car interiors), interior PVC skins (dashboards and shift boot covers), window
4981 glazing (urethane glass bonding adhesives and PVC window encapsulate), body-side molding,
4982 automotive undercoating, molded interior applications, insulation for wire and cable and wire harnesses
4983 (3M. 2024; ACC HPP. 2019a). In addition, a product containing DIDP is applied as an undercover
4984 coating, most likely by spraying the coating on the underside of the vehicle.
4985 E.21 Commercial Use - Automotive, Fuel, Agriculture, Outdoor Use
4986 Products - Lubricants
4987 According to the Manufacturer request for risk evaluation Di-isodecyl Phthalate (DIDP), DIDP is used
4988 in PVC and non-PVC applications in automotive products for commercial applications including
4989 synthetic lubricants and engine oils (ACC HPP. 2019a). For the commercial use of these products, EPA
4990 expects them to be poured or applied by workers in auto repair and other maintenance shops. EPA
4991 understands that DIDP is used in the manufacture of various lubricant additives that then are used in the
4992 manufacture of commercial lubricants (and lubricating oils, compressor fluids for maintenance and
4993 repair, and transmission conditioner) at a concentration of at least 90 percent by weight (
4994 2021c). The commercial use of lubricants applies to the use of lubricants such as DIDP-containing auto
4995 transmission conditioner (BG Products. 2016).
4996 E.22 Commercial Use - Construction, Paint, Electrical, and Metal Products
4997 - Adhesives and Sealants (Including Plasticizers in Adhesives and
4998 Sealants)
4999 EPA understands that DIDP is primarily used as a plasticizer in the manufacture of commercial and
5000 consumer adhesive and sealant at concentrations ranging between 1 percent to less than 60 percent in
5001 commercial products such as electrical products, and plastic products (I v << \ i !¦). These
5002 adhesive and sealants are used in construction settings and commonly applied using a syringe, caulk gun
5003 or spread on the surface using a trowel. These adhesive and sealant products are used in marine
5004 environments, as joint sealants in mechanical equipment, concrete and masonry, and wood/engineered
5005 wood flooring (U.S. EPA. 2021c).
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5014
5015
5016
5017
5018
5019
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5022
5023
5024
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5028
5029
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E.23 Commercial Use - Construction, Paint, Electrical, and Metal Products
- Building/Construction Materials (Wire or Wiring Systems; Joint
Treatment, Fire-Proof Insulation)
The Manufacturer request for risk evaluation Di-isodecyl Phthalate (DIDP) reports the use of DIDP in
building wire and fire-proof building insulation (Campinc. . I, U "• . ''P, 2019a). and this COlI
covers the installation of such types of products.
E.24 Commercial Use - Construction, Paint, Electrical, and Metal Products
- Electrical and Electronic Products
The Manufacturer request for risk evaluation Di-isodecyl Phthalate (DIDP) states that DIDP is used as
a general-purpose plasticizer for PVC used in building construction, particularly wire associated with
electronic products (ACC HPP. 2019a). The 2020 CDR reports use of DIDP in machinery, mechanical
appliances, electrical and electronic articles (U.S. EPA. 2020a). This COU encompasses handling the
electric products, wiring, etc. and related insulation during installation and use of those products
containing DIDP.
E.25 Commercial Use - Construction, Paint, Electrical, and Metal Products
- Paints and Coatings (Including Surfactants in Paints and Coatings)
DIDP is used in a variety of paint and coating products, often used as a surfactant in paints and coatings.
The Manufacturer request for risk evaluation Di-isodecyl Phthalate (DIDP) and the 2020 CDR report
identify use of DIDP in commercial paints and coatings ( )20a; ACC HPP. 2019a). A
company identifies DIDP as a component in surface active agent manufacturing for paints and coatings
in a commercial setting in the 2020 CDR (U.S. EPA. 2020a). This COU encompasses the handling of
paint and coating products containing DIDP during the application of paints and coatings. The
application procedure depends on the type of paint or coating formulation and the type of substrate. 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. After application, the paint or coating is allowed
to dry or cure.
E.26 Commercial Use - Construction, Paint, Electrical, and Metal Products
- Lacquers, Stains, Varnishes, and Floor Finishes (as Plasticizer)
This COU consists of the application of lacquers, stains, varnishes, and floor finishers that have DIDP
already incorporated as a plasticizer. One company reported the use of DIDP in lacquers, stains,
varnishes, and floor finishes in the 2020 CDR (U.S. EPA. 2020a). Currently, EPA has been unable to
find any commercially available products containing DIDP that are on the market in the United States.
EPA expects the most common application methods for lacquers, stains, varnishes, and floor finishes
will involve brush or roll applications. EPA does not expect these products to be sprayed.
E.27 Commercial Use - Furnishing, Cleaning, Treatment/Care Products -
Furniture and Furnishings
This COU consists of handling furniture and furnishings that already have had DIDP incorporated in
them, as reported in the 2012 CDR and the Manufacturer request for risk evaluation Di-isodecyl
Phthalate (DIDP) ( 2021c; ACC HPP. 2019a). EPA has not identified products that have
DIDP and that are used in the manufacture of furniture, but the handling of synthetic leather furniture
falls under this COU.
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5048
5049
5050
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5052
5053
5054
5055
5056
5057
5058
5059
5060
5061
5062
5063
5064
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5070
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E.28 Commercial Use - Furnishing, Cleaning, Treatment/Care Products -
Construction and Building Materials Covering Large Surface Areas
Including Stone, Plaster, Cement, Glass and Ceramic Articles;
Fabrics, Textiles, and Apparel (as Plasticizer); Floor Coverings (Vinyl
Tiles, PVC-Backed Carpeting, Scraper Mats)
The Manufacturer request for risk evaluation Di-isodecyl Phthalate (DIDP) states that DIDP is used as
a general-purpose plasticizer for PVC used in building and construction materials such as vinyl tiles,
resilient flooring, PVC-backed carpeting, scraper mats, and wall coverings (ACC HPP. 2019a). This
COU encompasses handling the tiles, carpeting, etc that have DIDP incorporated into the products and
may involve cutting and shaping the products for installation. The use was reported in the 2020 CDR
(U.S. EPA. 2020a).
E.29 Commercial Use - Furnishing, Cleaning, Treatment/Care Products -
Ink, Toner, and Colorant Products
According to the Manufacturer request for risk evaluation Di-isodecyl Phthalate (DIDP) and
information received from stakeholders, this COU refers to the use of DIDP-containing PVC ink by
workers in a commercial setting (EPA-H.O-OPPT-2018-0435-C >PT-2018-043 5-0012).
DIDP can be used in formulation of screen-printing ink, typically referred to as plastisol. Plastisol
consists of PVC particles and a plasticizer that allows the PVC to retain a liquid form during use.
Plastisol can be used to produce finished goods such as t-shirts, sweatshirts, jackets, and tote bags
(Sharprint. 2019). However, according to public comments, DIDP likely is not used in practice to create
plastisol because less than 0.1 percent DIDP is allowed in textiles, per the OEKO-TEX standard (ACC
H O). EPA identified colorant products produced by a sealant manufacturing company that are
used to tint a polyurethane sealant ( )21c).
E.30 Commercial Use - Furnishing, Cleaning, Treatment/Care Products -
PVC Film and Sheet
DIDP is used in PVC film used in casting and masking fixtures
the uses of DIDP has been reported as a "plasticizer for polyvinyl chloride for calendered film, sheet"
(HSDB. 2024). The Manufacturer request for risk evaluation: Diisodecyl phthalate (DIDP) notes that
film and sheet applications include use in roofing, wall coverings, pool liners etc.(ACC HPP. 2019b).
The use covers other coated textiles such as truck awnings. This COU encompasses the commercial use
of PVC film and sheet, including the cutting and shaping of the final articles.
E.31 Commercial Use - Furnishing, Cleaning, Treatment/Care Products -
Plastic And Rubber Products (Textiles, Apparel, and Leather; Vinyl
Tape; Flexible Tubes; Profiles; Hoses)
DIDP is incorporated into synthetic leather furniture, and this COU refers to the final product
manufacture ( i). This COU also encompasses the assembly of the upholstery and
interior finishes (e.g., synthetic leather for car interiors) that contain DIDP in automobiles (ACC HPP.
2019a).
E.32 Commercial Use - Other Uses - Laboratory Chemicals
This COU refers to the use of DIDP as a laboratory chemical, such as in a chemical standard or
reference material during analyses. Two chemical companies identify use of DIDP as a certified
reference material and research chemical. One chemical company identifies DIDP as a dispersion
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5089 chemical (U.S. EPA. 2021c). Commercial use of laboratory chemicals may involve handling DIDP by
5090 hand-pouring or pipette and either adding to the appropriate labware in its pure form to be diluted later
5091 or added to dilute other chemicals already in the labware. EPA expects that laboratory DIDP products
5092 are pure DIDP in neat liquid form or DIDP present as an impurity in other products.
5093 E.33 Commercial Use - Other Uses - Inspection Fluid/Penetrant
5094 This COU refers to the use of DIDP in inspection fluid/penetrant (EPA-HQ-OPPT-2018-043 5-0023).
5095 Penetrant testing can be used to detect imperfections and flaws that are not detectable by the eye.
5096 Aircraft components are submerged in inspection fluid, and workers pull the component out of the fluid
5097 using their hands (Isbell. 2018).
5098 E.34 Consumer Use - Automotive, Fuel, Agriculture, Outdoor Use Products
5099 - Automotive Products, Other than Fluids
5100 According to the Manufacturer request for risk evaluation Di-isodecyl Phthalate (DIDP), DIDP is
5101 primarily used as a plasticizer in automotive products such as upholstery and interior finishes (e.g.,
5102 synthetic leather for car interiors), interior PVC skins (dashboards and shift boot covers), window
5103 glazing (urethane glass bonding adhesives and PVC window encapsulate), body-side molding,
5104 automotive undercoating, molded interior applications, insulation for wire and cable and wire harnesses
5 105 (ACC HPP. 2019a). This COU refers to consumer use of cars, i.e., driving, and consumer DIY-ers who
5106 may perform exterior or interior car maintenance involving automotive products containing DIDP other
5107 than fluids.
5108 E.35 Consumer Use - Automotive, Fuel, Agriculture, Outdoor Use Products
5109 - Lubricants
5110 According to the Manufacturer request for risk evaluation Di-isodecyl Phthalate (DIDP), DIDP is used
5111 in PVC and non-PVC applications in automotive products for consumer and industrial applications
5112 including synthetic lubricants and engine oils (ACC HPP. 2019a). EPA understands that DIDP is used in
5113 the manufacture of various lubricant additives in the manufacture of lubricating oils and greases. DIDP
5114 is also used in consumer lubricants and greases ( 321c). This COU encompasses consumer
5115 use of lubricants and greases used in automotive care.
5116 E.36 Consumer Use - Construction, Paint, Electrical, and Metal Products -
5117 Adhesives and Sealants (Including Plasticizers in Adhesives And
5U8 Sealants)
5119 According to the Manufacturer request for risk evaluation Di-isodecyl Phthalate (DIDP), less than five
5120 percent of DIDP is used in non-PVC applications such as those associated with adhesives and sealants
5121 (ACC HPP. 2019a). EPA understands that DIDP is primarily used as a plasticizer in the manufacture of
5122 commercial and consumer adhesive and sealant end products at concentrations ranging between 1
5123 percent to less than 60 percent in products such as automotive interiors, undercoats, electrical products,
5 124 and plastic products ( 2021b). One company supplied EPA with information on the use of
5125 DIDP in an adhesive product used to affix wall paneling inside of commercial vehicle interior
5 126 applications (3M. 2024). EPA considers that although this product is intended for commercial
5127 applications, this product and other similar products that contain DIDP, could be used in various
5128 consumer level applications as well.
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E.37 Consumer Use - Construction, Paint, Electrical, and Metal Products -
Building/Construction Materials Covering Large Surface Areas
Including Stone, Plaster, Cement, Glass and Ceramic Articles (Wire or
Wiring Systems; Joint Treatment)
The COU refers to the household use of solid flooring and other building materials. As reported in the
Manufacturer request for risk evaluation: Diisodecyl phthalate (DIDP), DIDP is used in PVC-backed
carpet, vinyl tiles and resilient flooring (ACC HPP. 2019a). In this draft risk evaluation, the weight
fraction used of DIDP was 1.9 percent in PVC flooring products, based on a European report (ECHA.
2012.).
E.38 Consumer Use - Construction, Paint, Electrical, and Metal Products -
Electrical and electronic products
The Manufacturer request for risk evaluation: Diisodecyl phthalate (DIDP) indicates that DIDP is used
as a general purpose plasticizer for PVC used in building construction, particularly wire associated with
electronic products (ACC HPP. 2019a). The 2020 CDR reports use of DIDP in machinery, mechanical
appliances, electrical and electronic articles (U.S. EPA. 2020a). This COU refers to consumer handling
of electric products, wiring, etc. and related insulation during installation and use that may have DIDP
incorporated into the products.
E.39 Consumer Use - Construction, Paint, Electrical, and Metal Products -
Paints and Coatings
DIDP is used in a variety of paint and coating products, often used as a surfactant in paints and coatings.
The Manufacturer request for risk evaluation Di-isodecyl Phthalate (DIDP) and the 2020 CDR report
use of DIDP in consumer paints and coatings ( 020a; ACC HPP. 2019a). This COU refers to
the consumer use of paint and coating products during the application of paints and coatings containing
DIDP. The application procedure depends on the type of paint or coating formulation and the type of
substrate. 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. After application, the paint or
coating is allowed to dry or cure.
E.40 Consumer Use - Furnishing, Cleaning, Treatment/Care Products -
Fabrics, Textiles, and Apparel (as Plasticizer)
This COU refers to household use of synthetic leather and vinyl fabrics where DIDP was used as a
plasticizer, which encompasses residential use of plastic furniture and vinyl textiles on cushions and
other upholstery, such as couches, synthetic leather clothing. The consumer use was reported in the 2020
CDR, with one manufacturer reporting use of DIDP as a plasticizer under Furniture and Related Product
Manufacturing, as well as information from a stakeholder provided in 2023 (ACC HPP. 2023; U.S.
20a).
E.41 Consumer Use - Packaging, Paper, Plastic, Hobby Products - Arts,
Crafts, and Hobby Materials (Crafting Paint Applied to Craft)
This COU refers to the consumer use of DIDP in crafting paint applied to paint, hobby materials such as
rubber erasers, and in a two-component urethane casting resin used in casting, prototyping, miniatures,
models, and taxidermy. The use of DIDP as a plasticizer in craft painting applied to craft was reported in
the 2020 CDR (U.S. EPA. 2020a). However, EPA has been unable to find a specific example of crafting
paint that contains DIDP. DIDP is present in one of the two components of a polyurethane casting resin
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in concentrations of 10 to 40 percent (Environmental. 2021). Weight fractions were reported in Europe
for erasing rubber made of PVC (ECIl \ JO I J). In one sample from a 2006 Danish investigation, the
combination of DINP and DIDP was reported as 32 percent.
E.42 Consumer Use - Packaging, Paper, Plastic, Hobby Products - Ink,
Toner, and Colorant Products
According to the Manufacturer request for risk evaluation Di-isodecyl Phthalate (DIDP) and
information received from stakeholders, this COU refers to the use of DIDP-containing PVC ink by
consumers in non-commercial settings (EPA-HQ-QPPT-2018-0435-0005; EPA-
0012). DIDP can be used in the formulation of screen-printing ink, typically referred to as plastisol.
Plastisol consists of PVC particles and a plasticizer that allows the PVC to retain a liquid form during
use. Plastisol can be used to produce finished goods such as t-shirts, sweatshirts, jackets, and tote bags
(Sharprint). However, according to public comments, DIDP likely is not used in practice to create
plastisol because less than 0.1 percent DIDP is allowed in textiles, per the OEKO-TEX standard (ACC
HPP. 2023). EPA identified colorant products produced by a sealant manufacturing company that are
used to tint a polyurethane sealant ( 321c).
E.43 Consumer Use - Packaging, Paper, Plastic, Hobby Products - PVC
Film and Sheet
This COU refers to the consumer use of PVC film and sheet. DIDP is used in PVC film used in casting
and masking fixtures (EP A-HQ-OPPT-2018-0435-0012). and as a "plasticizer for polyvinyl chloride for
calendered film, sheet" (HSDB. 2024). The Manufacturer request for risk evaluation: Diisodecyl
phthalate (DIDP) note that film and sheet applications include use in roofing, wall coverings, pool
liners, etc, (ACC HPP. ). The consumer use of PVC film and sheet includes household use of pool
liners, wall coverings, truck awnings, etc.
E.44 Consumer Use - Packaging, Paper, Plastic, Hobby Products - Plastic
and Rubber Products (Textiles, Apparel, and Leather; Vinyl Tape;
Flexible Tubes; Profiles; Hoses)
This COU refers to the consumer use of articles such as the wearing of synthetic leather bags and foam
flip-flops, and the household use of shower curtains and wallpaper. The COU also refers to the DIY
application of the wallpaper ( PP. 2023. 2019b). The weight fraction of DIDP varies based on the
article (approximately 0.047 to 0.35), although, EPA does not have information regarding DIDP weight
fraction for all articles identified.
E.45 Consumer Use - Packaging, Paper, Plastic, Hobby Products - Toys,
Playgrounds, and Sporting Equipment
This COU refers to the consumer use of toys, playgrounds, and sporting equipment that contain DIDP.
The use also refers to the do-it-yourself building of home playground equipment (ACC HPP. 2023.
2019b). A plastisol coating is commonly used on sporting equipment for household use, such as fitness
balls and hand weights. DIDP is used in these articles as a plasticizer to provide flexibility toys. The
Consumer Product Safety Improvement Act of 2008 placed an interim prohibition on DIDP that limited
the concentration of DIDP in children's toys to 0.1 percent. Upon the effective date of the final rule in
2018, the prohibition on DIDP was lifted (CFR:16 CFR 1307). For several articles, the weight fraction
of DIDP was reported as DINP plus DIDP. For example, concentrations of DINP plus DIDP in four
teether samples at 32 to 40 percent and in 2 of 3 doll samples at approximately 20 and 26 percent.
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E.46 Consumer Use - Other - Novelty Products
This COU refers to adult sex toys that are available for consumer use in the United States. Although the
U.S. Food and Drug Administration (FDA) classifies certain sex toys (such as vibrators) as obstetrical
and gynecological therapeutic medical devices, many manufacturers label these products "for novelty
use only" and they are not subject to the FDA regulations (Stabile. 2013). Reported tested weight
fractions of phthalates on sex toys ranges between 24 percent and 49 percent to create a softer, more
flexible plastic (Stabile. 2013).
E.47 Disposal
Each of the COUs of DIDP may generate waste streams of the chemical. For purposes of the DIDP risk
evaluation, this COU refers to the DIDP in a waste stream that is collected and transported to third-party
sites for disposal or treatment. This COU also encompasses DIDP contained in wastewater discharged to
publicly owned treatment works (POTW) or other, non-public treatment works for treatment, and other
wastes. DIDP is expected to be released to other environmental media, such as introductions of biosolids
to soil or migration to water sources, through waste disposal (e.g., disposal of formulations containing
DIDP, plastic and rubber products, textiles, and transport containers). Disposal may also include
destruction and removal by incineration ( 2021b). Recycling of DIDP and DIDP containing
products is considered a different COU. Environmental releases from industrial sites are assessed in
each condition of use.
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Appendix F DRAFT OCCUPATIONAL EXPOSURE VALUE
DERIVATION
EPA has calculated a draft 8-hour existing chemical occupational exposure value to summarize the
occupational exposure scenario and sensitive health endpoints into a single value. This calculated draft
value may be used to support risk management efforts for DIDP under TSCA section 6(a), 15 U.S.C.
§2605. EPA calculated the draft value rounded to 2.40 mg/m3 for inhalation exposures to DIDP as an 8-
hour time-weighted average (TWA) and for consideration in workplace settings (see Appendix F. 1)
based on the acute non-cancer human equivalent concentration (HEC) for developmental toxicity.
TSCA requires risk evaluations to be conducted without consideration of costs and other non-risk
factors, and thus this draft occupational exposure value represents a risk-only number. If risk
management for DIDP follows the final risk evaluation, EPA may consider costs and other non-risk
factors, such as technological feasibility, the availability of alternatives, and the potential for critical or
essential uses. Any existing chemical exposure limit used for occupational safety risk management
purposes could differ from the draft occupational exposure value presented in this appendix based on
additional consideration of exposures and non-risk factors consistent with TSCA section 6(c).
This calculated draft value for DIDP represents the exposure concentration below which workers and
ONUs are not expected to exhibit any appreciable risk of adverse toxicological outcomes, accounting for
potentially exposed and susceptible populations (PESS). It is derived based on the most sensitive human
health effect {i.e., developmental toxicity) relative to benchmarks and standard occupational scenario
assumptions of 8 hours per day, 5 days per week exposures for a total of 250 days exposure per year,
and a 40-year working life.
EPA expects that at the draft occupational exposure value of 0.131 ppm (2.40 mg/m3), a worker or ONU
also would be protected against liver toxicity from intermediate and chronic occupational exposures if
ambient exposures are kept below this draft occupational exposure value. EPA has not separately
calculated a draft short-term {i.e., 15-minute) occupational exposure value because EPA did not identify
hazards for DIDP associated with this very short duration.
EPA did not identify a government-validated method for analyzing DIDP in air.
The Occupational Safety and Health Administration (OSHA) has not set a permissible exposure limit
(PEL) as an 8-hour TWA for DIDP (https://www.osha.gov/annotated-pels). EPA located several
occupational exposure limits for DIDP in other countries (https://ilv.ifa.dgiiv.de/limitvalues/21303).
Identified 8-hour TWA values range from 3 mg/m3 in Austria, Denmark, and Sweden to 5 mg/m3 in
Ireland and South Africa. Additionally, EPA found that the province of Ontario. Canada. New Zealand.
and the United Kingdom all have an established occupational exposure limit of 5 mg/m3 (8-hour TWA)
in each country's code of regulation that is enforced by each country's worker safety and health agency.
F,1 Draft Occupational Exposure Value Calculations
This appendix presents the calculations used to estimate draft occupational exposure values using inputs
derived in this draft risk evaluation. Multiple values are presented below for hazard endpoints based on
different exposure durations. For DIDP, the most sensitive occupational exposure value is based on non-
cancer developmental effects and the resulting 8-hour TWA is rounded to 2.40 mg/m3.
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Draft Acute Non-cancer Occupational Exposure Value
The draft acute occupational exposure value (EVaCute) was calculated as the concentration at which the
acute MOE would equal the benchmark MOE for acute occupational exposures using EquationApx
F-l:
Equation Apx F-l.
HECacute ATHECacute IRresting
|7 Y — ^
Benchmark MOEacut:e ED I ^workers
24/i n£10rm3
2.68 ppm ~~rT 0-6125—-
* Sir * ¥- = 0-131 ppm
30 8h m3
d i"Zb hr
fv - EV ppm * MW - °-131PPm*446-7^ _ ? ,n mg
acute vm3 / Molar Volume 21 15 ^ ' m3
mol
Draft Intermediate Non-cancer Occupational Exposure Value
The draft intermediate occupational exposure value (EVintermediate) was calculated as the concentration at
which the intermediate MOE would equal the benchmark MOE for intermediate occupational exposures
using Equation Apx F-2:
Equation Apx F-2.
gy HECjntermefljate ^ AThec intermediate^ ^resting
intermediate Benchmark MOfjntermediate ED*EF IRworkers
24/i m3
2.68 ppm — *30d 0.6125-^ mg
= — * -77; * 5— = 0.179 ppm = 3.27 —7
30 22d 1.25^
a hr
Draft Chronic Non-cancer Exposure Value
The draft chronic occupational exposure value (EVchronic) was calculated as the concentration at which
the chronic MOE would equal the benchmark MOE for chronic occupational exposures using
EquationApx F-3:
Equation Apx F-3.
gy HECchronjc ^ AT^ec chronic ^ ^resting
chronic Benchmark MOEchronic ED*EF*WY IRworkers
24h 365d „_m3
9 ap i-\nm * *40 v*0.6125, m c
Z.00 ppm d y J hr ^ ^^ ^ r-^ m£
• * •
= 0.192 ppm = 3.50 --f
30 8,1 250d ^r-m ' ' m3
—* *40 v*1.25
d y J hr
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5321
5322
5323
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5328
5329
5330
5331
5332
5333
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5336
5337
5338
5339
5340
5341
5342
5343
5344
5345
5346
5347
5348
5349
Where:
ATh
'.ecate
A TnECintermediate
A TnECchronic
Benchmark MOEacute =
Benchmark MOEintermediate =
Benchmark MOEchronic =
EVacute
EVintermediate
E V chronic —
ED
EF
HEC
IR
Molar Volume =
MW
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PUBLIC RELEASE DRAFT
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Averaging time for the POD/HEC used for evaluating non-cancer
acute occupational risk based on study conditions and HEC
adjustments (24 hr/day).
Averaging time for the POD/HEC used for evaluating non-cancer
intermediate occupational risk based on study conditions and/or
any HEC adjustments (24 hr/day for 30 days).
Averaging time for the POD/HEC used for evaluating non-cancer
chronic occupational risk based on study conditions and/or HEC
adjustments (24 hr/day for 365 days/yr) and assuming the same
number of years as the high-end working years (WY, 40 years) for
a worker.
Acute non-cancer benchmark margin of exposure, based on the
total uncertainty factor of 30
Intermediate non-cancer benchmark margin of exposure, based on
the total uncertainty factor of 30
Chronic non-cancer benchmark margin of exposure, based on the
total uncertainty factor of 30
Occupational exposure value based on acute neurotoxicity
Occupational exposure value based on intermediate reproductive
toxicity
Occupational exposure value based on chronic reproductive
toxicity
Exposure duration (8 hr/day)
Exposure frequency (1 day for acute, 22 days for intermediate, and
250 days/yr for chronic and lifetime)
Human equivalent concentration for acute, intermediate, or chronic
non-cancer occupational exposure scenarios
Inhalation rate (default is 1.25 m3/hr for workers and 0.6125 m3/hr
assumed from "resting" animals from toxicity studies)
24.45 L/mol, the volume of a mole of gas at 1 atm and 25 °C
Molecular weight of DIDP (446.7 g/mole)
Working years per lifetime at the 95th percentile (40 years)
( )•
Unit conversion:
1 ppm = 18.3 mg/m (see equation associated with the EVacute calculation)
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