A EPA
EPA Document #EPA-740-R-24-015
December 2024
United States Office of Chemical Safety and
Environmental Protection Agency Pollution Prevention
Human Health Risk Assessment for Formaldehyde
CASRN 50-00-0
o
December 2024
-------
TABLE OF CONTENTS
ACKNOWLEDGEMENTS 8
EXECUTIVE SUMMARY 10
1 INTRODUCTION 18
1.1 Background 18
1.2 Risk Evaluation Scope 18
1.2.1 Life Cycle and Production Volume 20
1.2.2 Conditions of Use 22
1.2.3 Other Sources of Formaldehyde in Air 22
1.3 Changes made between Draft and the Revised Risk Evaluation 23
1.3.1 Occupational Exposure Assessment 23
1.3.2 Consumer Exposure Assessment 24
1.3.3 Indoor Air Exposure Assessment 24
1.3.4 Ambient Air Exposure Assessment 25
1.3.5 Human Health Hazard Assessment 25
1.4 Chemistry, Fate, and Transport Assessment Summary 26
1.5 Environmental Release Assessment 28
1.6 Human Health Risk Assessment Scope 30
1.6.1 Conceptual Exposure Models 30
1.6.1.1 Industrial and Commercial Activities and Uses 30
1.6.1.2 Consumer Exposure 32
1.6.1.3 Indoor Air Exposures 34
1.6.1.4 Ambient Air Exposures 36
1.6.2 Potentially Exposed or Susceptible Subpopulations 38
2 HUMAN EXPOSURE ASSESSMENT SUMMARY 40
2.1 Occupational Exposure Assessment 40
2.1.1 Inhalation Exposure Assessment 40
2.1.2 Dermal Exposure Summary 42
2.2 Consumer Exposure Assessment 42
2.2.1 Conditions of Use and Considerations for their Assessment 43
2.2.2 Summary of Consumer Exposure Assessment Results 44
2.3 Indoor Air Exposure Assessment 46
2.3.1 Conditions of Use and Considerations for their Assessment 47
2.3.2 Summary of Assessment Approach 47
2.3.3 Indoor Air Exposure Monitoring Results 47
2.3.4 Indoor Air CEM Exposure Modeling Results 51
2.3.5 Indoor Air IECCU Exposure Modeling Results 54
2.3.6 Aggregate Indoor Air Exposure 57
2.4 Ambient Air Exposure Assessment 58
2.4.1 Monitoring for Ambient Air Concentrations 58
2.4.2 Modeling Ambient Air Concentrations 61
2.4.2.1 Integrated Indoor/Outdoor Air Calculator Model (IIOAC) 61
Page 2 of 191
-------
2.4.2.1.1 Estimated Daily Average Formaldehyde Concentrations 62
2.4.2.1.2 Estimated Annual Average Formaldehyde Concentrations 67
2.4.2.2 AirToxScreen 69
2.4.2.3 Human Exposure Model (HEM) 71
2.4,3 Integrating Various Sources of Formaldehyde Data 74
2.5 Weight of Scientific Evidence and Overall Confidence in Exposure Assessment 75
2.5.1 Overall Confidence in Occupational Exposure Assessment 76
2.5.2 Overall Confidence in the Consumer Exposure Assessment 77
2.5.3 Overall Confidence in the Indoor Air Exposure Assessment 78
2.5.4 Overall Confidence in the Ambient Air Exposure Assessment 79
3 HUMAN HEALTH HAZARD SUMMARY 83
3.1 Summary of Hazard Values 83
3.2 Weight of Scientific Evidence and Overall Confidence in Hazard Assessment 86
3.2.1 Overall Confidence in the Acute Inhalation POD 86
3.2.2 Overall Confidence in the Chronic, Non-cancer Inhalation POD 86
3.2.3 Overall Confidence in the Chronic IUR 87
3.2.4 Overall Confidence in the Dermal POD 88
3.2.5 Overall Confidence in the Subchronic and Chronic Oral PODs 88
4 HUMAN HEALTH RISK CHARACTERIZATION 90
4.1 Risk Characterization Approach 90
4.1.1 Estimation of Non-cancer Risks 91
4.1.2 Estimation of Cancer Risks 92
4.2 Risk Estimates 92
4.2.1 Risk Estimates for Workers 92
4.2.1.1 Risk Estimates for Inhalation Exposures 93
4.2.1.1.1 Acute Inhalation Risks 93
4.2.1.1.2 Cancer Inhalation Risks 97
4.2.1.2 Risk Estimates for Dermal Exposures 101
4.2.2 Risk Estimates for Consumers 103
4.2.2.1 Risk Estimates for Inhalation Exposure to Formaldehyde in Consumer Products 103
4.2.2.2 Risk Estimates for Dermal Exposure to Formaldehyde in Consumer Products 106
4.2.3 Risk Estimates for Indoor Air 107
4.2.3.1 Risk Estimates Based on Indoor Air Monitoring Data 107
4.2.3.1.1 Monitoring Information in Consideration of Aggregate Risk Ill
4.2.3.2 CEM Indoor Air Modeling Risk Estimates Ill
4.2.3.3 IECCU Indoor Air Risk Estimates 114
4.2.3.4 IECCU Indoor Air Acute Risk Estimates 114
4.2.3.5 IECCU Indoor Air Intermediate Risk Estimates 115
4.2.3.6 IECCU Indoor Air Chronic Risk Estimates 116
4.2.4 Risk Estimates for Ambient Air 119
4.2.4.1 Risk Estimates Based on Ambient Air Monitoring 119
4.2.4.2 Risk Estimates Based on Modeled Concentrations near Releasing Facilities 122
4.2.4.3 Short-Term Risk Estimates for Ambient Air 122
4.2.4.4 Long-Term Risk Estimates for Ambient Air 129
4.2.4.5 Population Analysis for Cancer Risks using HEM 137
Page 3 of 191
-------
4.2.4.6 Integration of Modeling and Monitoring Information 139
4.2.4.7 Overall Confidence in Exposures, Risk Estimates, and Risk Characterizations for
Ambient Air 140
4.2.5 Comparison of Non-cancer Effect Levels and Air Concentrations 141
4.2.6 Potentially Exposed or Susceptible Subpopulations 142
4.3 Aggregate and Sentinel Exposures 147
REFERENCES 149
APPENDICES 158
Appendix A ABBREVIATIONS AND ACRONYMS 158
Appendix B LIST OF DOCUMENTS AND SUPPLEMENTAL FILES 160
Appendix C DETAILED EVALUATION OF POTENTIALLY EXPOSED AND
SUSCEPTIBLE SUBPOPULATIONS 162
C.l PESS Based on Greater Exposure 162
C.2 PESS Based on Greater Susceptibility 167
Appendix D AMBIENT AIR RISK ESTIMATES - COMMERCIAL USES 176
Appendix E OCCUPATIONAL EXPOSURE VALUE DERIVATION 178
E.l Occupational Exposure Value Calculations 179
E.2 Summary of Air Sampling Analytical Methods Identified 180
Appendix F ACUTE AND CHRONIC (NON-CANCER AND CANCER) OCCUPATIONAL
INHALATION EQUATIONS 182
Appendix G DERMAL EXPOSURE APPROACH 186
Appendix H ADDITIONAL OCCUPATIONAL RISK CHARACTERIZATION 187
H.l Chronic Non-cancer Risk Estimates 187
Appendix I ADDITIONAL CONSUMER RISK CHARACTERIZATION 190
T. I Consumer Chronic Risk Estimates 190
1.1.1 Risk Estimates for Inhalation Exposure to Formaldehyde in Consumer Products 190
LIST OF TABLES
Table 1-1. Physical and Chemical Properties of Formaldehyde and Select Transformation Products11... 26
Table 2-1. Indoor Air Monitoring Concentrations for Formaldehyde 48
Table 2-2. Formaldehyde Monitored in U.S. Commercial Buildings from 2000 to Present 49
Table 2-3. Estimated Chronic Average Daily Formaldehyde Indoor Air Concentrations (According to
CEM) 51
Table 2-4. Fifteen Minute Peak Formaldehyde Concentrations (|ig/m3) in Indoor Air for Single
Representative Article and Aggregate Model Scenarios 55
Table 2-5. Overall Monitored Concentrations of Formaldehyde from AMTIC archive Dataset 59
Table 2-6. Five Highest Exposure Concentrations Attributable to Combustion Based on IIOAC
Modeling of Maximum Release Value 65
Table 3-1. Hazard Values Identified for Formaldehyde 84
Table 4-1. Use Scenarios, Populations of Interest, and Toxicological Endpoints Used for Acute and
Chronic Exposures 90
Page 4 of 191
-------
Table 4-2. Top Five Acute Non-cancer Risk Estimates Indicating the Highest Risks Attributable to
TSCA COUs 124
Table 4-3. Top Five Acute Non-cancer Risk Estimates Indicating the Highest Risks Attributable to
Combustion 128
Table 4-4. Top Five Chronic Non-cancer Risk Estimates Indicating the Highest Risks Attributable to
TSCA COUs 131
Table 4-5. Top Five Cancer Risk Estimates Indicating the Highest Risks Attributable to TSCA COUs
135
Table 4-6. Population Summary for Cancer Risk Estimates Derived from HEM Modeling of TRI
Releases of Formaldehyde to Air 137
Table 4-7. Demographic Details of Population with Estimated Cancer Risk Higher than or Equal to 1 in
1 Million, Compared with National Proportions 138
Table 4-8. Summary of PESS Considerations Incorporated throughout the Analysis and Remaining
Sources of Uncertainty 144
LIST OF FIGURES
Figure 1-1. Risk Evaluation Document Summary Map 19
Figure 1-2. Lifecycle Diagram of Formaldehyde 21
Figure 1-3. Chemical Equilibria for Formaldehyde in Aqueous Solutions 27
Figure 1-4. Conceptual Model for Industrial and Commercial Activities and Uses: Potential Exposure
and Hazards 31
Figure 1-5. Formaldehyde Conceptual Model for Consumer Activities and Uses: Potential Exposures
and Hazards 33
Figure 1-6. Formaldehyde Conceptual Model for Indoor Air: Residential Exposures and Hazards from
Article Off-Gassing 35
Figure 1-7. Formaldehyde Conceptual Model for Environmental Releases and Wastes: General
Population Exposures and Hazards 37
Figure 1-8. Industrial Releases to the Environment and Pathways by Which Exposures to the People
May Occur 38
Figure 2-1. Summary of 15-Minute Peak Consumer Inhalation Concentrations (Based on CEM) 45
Figure 2-2. Summary of Acute Consumer Dermal Concentrations (Based on Thin Film Model) 46
Figure 2-3. Long-Term Average Daily Concentrations of Formaldehyde According to Air Monitoring
Data Source 50
Figure 2-4. Modeled Formaldehyde Average Daily Inhalation Concentrations in Indoor Air (According
to CEM) 53
Figure 2-5. Fifteen Minute Peak Concentrations (|ig/m3) of Formaldehyde in Indoor Air for TSCA COU
Representative Article and Aggregate Models 56
Figure 2-6. Formaldehyde Concentrations in Indoor Air (|ig/m3) for TSCA COU Representative Article
and Aggregate Models Over Time (10,000 hour simulation duration) 57
Figure 2-7. High-Resolution Monitoring Locations in Houston, Texas: 482010803 (N = 42,560),
482011015 (N = 70,126), and 482011035 (N = 71,621) 60
Figure 2-8. Houston area sites 5-minute concentration data aggregated by time of day 61
Figure 2-9. Daily Average Exposure Concentrations by TSCA COU using IIOAC non-site specific
analysis 63
Figure 2-10. Annual-Average Exposure Concentrations by TSCA COU 68
Figure 2-11. 2019 AirToxScreen Modeled Data for All Sources, Secondary Production Sources, Point
Sources, and Biogenic Sources for the Contiguous United States 70
Page 5 of 191
-------
Figure 2-12. 2020 AirToxScreen Modeled Data for All Sources, Secondary Production Sources, Point
Sources, and Biogenic Sources for the Contiguous United States 71
Figure 2-13. Map of Contiguous United States with HEM Model Results for TRI Releases Aggregated
and Summarized by Census Block 73
Figure 2-14. Median and Maximum Concentrations (Fugitive, Stack, and Total Emissions) across the 11
Discrete Distance Rings Modeled in HEM 74
Figure 2-15. Distributions of AMTIC Monitoring Data, IIOAC Modeled Data, and AirToxScreen
Modeled Data 75
Figure 4-1. Acute, Non-cancer Occupational Inhalation Risk by TSCA Manufacturing/ Processing
COUs 94
Figure 4-2. Acute, Non-cancer Occupational Inhalation Risk by TSCA Industrial/Commercial Use
COUs 95
Figure 4-3. Chronic Cancer Occupational Inhalation Risk by TSCA Manufacturing/Processing COUs 98
Figure 4-4. Cancer Risk for Manufacturing- Import and Processing - Repackaging 99
Figure 4-5. Chronic Cancer Occupational Inhalation Risk by TSCA Industrial/Commercial COUs .... 100
Figure 4-6. Acute Occupational Dermal Risks by TSCA COUs 102
Figure 4-7. Peak 15-Minute Inhalation Risk by COUs in Consumer Products 104
Figure 4-8. Acute Dermal Loading Risk by High-End Exposure Scenarios in Consumer Products 106
Figure 4-9. Chronic Non-Cancer Inhalation Risk by Indoor Air Monitoring Data Source 109
Figure 4-10. Cancer Inhalation Risk by Indoor Air Monitoring Data Source 110
Figure 4-11. Chronic Non-cancer Inhalation Risk Based on CEM-Modeled Air Concentrations for
Specific TSCA COUs 112
Figure 4-12. Cancer Inhalation Risk Based on CEM-Modeled Air Concentrations for Specific TSCA
COUs 113
Figure 4-13. Acute Inhalation Risk Based on IECCU Modeled Air Concentrations for Specific TSCA
COUs 114
Figure 4-14. Intermediate Non-cancer Inhalation Risk Based on IECCU-Modeled Air Concentrations for
Specific TSCA COUs 116
Figure 4-15. Chronic Non-cancer Inhalation Risk Based on IECCU-Modeled Air Concentrations for
Specific TSCA COUs 117
Figure 4-16. Cancer Inhalation Risk Based on IECCU-Modeled Air Concentrations for Specific TSCA
COUs 118
Figure 4-17. ADAF-Adjusted Cancer Risk for Monitoring and Modeling Ambient Air Data 121
Figure 4-18. Acute Risk Estimates based on Estimated Daily Concentrations by TSCA COU for the
Maximum Release Scenario and 95th Percentile Modeled Concentration at 100 m from
Industrial Facilities Releasing Formaldehyde 123
Figure 4-19. Chronic Non-cancer Risk based on Modeled Annual Average Air Concentrations
Attributable to TSCA COUs 130
Figure 4-20. Lifetime Risk Estimates for Cancer based on Modeled Annual Average Air Concentrations
Attributable to TSCA COUs 134
Figure 4-21. Comparison of Non-cancer Health Effect Levels Reported in People and Indoor and
Outdoor Air Concentrations 142
LIST OF APPENDIX TABLES
Table_Apx C-l. PESS Based on Greater Exposure 163
TableApx C-2. Susceptibility Category, Factors, and Evidence for PESS susceptibility 168
TableApx E-l. Limit of Detection (LOD) and Limit of Quantification (LOQ) Summary for Air
Sampling Analytical Methods Identified 180
Table_Apx F-l. Appendix F Formulae - Symbols, Values, and Units 183
Page 6 of 191
-------
TableApx F-2. Overview of Average Worker Tenure from U.S. Census SIPP (Age Group 50+)
TableApx F-3. Median Years of Tenure with Current Employer by Age Group
Page 7 of 191
-------
ACKNOWLEDGEMENTS
This report was 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
risk evaluation and associated technical support documents from OPPT, OPP, and OCSPP senior
managers and science advisors and assistance from EPA contractors SRC (Contract No.
68HERH19D0022) and ERG (Contract No. 68HERD20A0002). OPPT and OPP also gratefully
acknowledge systematic review work conducted by staff in the Data Gathering Management and Policy
Division. Special acknowledgement is given for the contributions of technical experts from EPA's
Office of Research and Development.
As part of an intra-agency review, the formaldehyde risk evaluation was provided to multiple EPA
Program Offices for review. Comments were submitted by the Office of Research and Development,
Office of Air and Radiation, and the Office of Children's Health Protection.
Docket
Supporting information can be found in public docket, Docket ID (EPA-HQ-OPPT-2Q18-0438).
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: Shawn Shifflett (Assessment Lead), Rochelle Bohaty (Management Lead and Branch
Supervisor), Bryan Groza, Grant Goedjen, Whitney Hollinshead, Giorvanni Merilis, and Susanna
Wegner
Contributors: John Allran, Edwin Arauz, Marcy Card, Ann Huang, and Myles Hodge
Technical Support: Mark Gibson and Hillary Hollinger.
This technical support document was reviewed and cleared for publication by OPPT, OPP, and
OCSPP leadership.
Page 8 of 191
-------
Formaldehyde - Human Health Risk Assessment - Key Points
Formaldehyde is a highly reactive gas that is ubiquitous in indoor and outdoor environments. It is
widely used in a range of industrial applications, consumer products, and building materials (e.g.,
composite wood products, plastics, rubber, various adhesives, and sealants). It also occurs as a product
of combustion, a product of normal metabolism in the human body, and is formed naturally through the
decomposition of organic matter (i.e., biogenic sources such as leaves).
Health effects of concern for formaldehyde include cancer, sensory irritation, and respiratory effects
such as increased asthma prevalence, reduced asthma control, and reduced lung function. People may
be exposed to formaldehyde at work, through indoor air, through use of consumer products, and
through outdoor air near sources of formaldehyde. People are often exposed to more than one source of
formaldehyde concurrently, some of which are regulated under the Toxic Substances Control Act
(TSCA), some of which are regulated under other laws, and some of which are not regulated at all
(e.g., the decomposition of leaves).
This human health risk assessment for formaldehyde evaluates the risks of formaldehyde exposures for
workers, consumers, and the general population resulting from TSCA conditions of use (COUs).
Risk estimates include inherent uncertainties and the overall confidence in specific risk estimates
varies. The analysis provides support for the Agency to make a determination about whether
formaldehyde poses an unreasonable risk to human health and to identify drivers of unreasonable risk
among exposures for people (1) with occupational exposure to formaldehyde, (2) with consumer
exposure to formaldehyde, (3) with exposure to formaldehyde in indoor air, and (4) who live or work
in proximity to locations where formaldehyde is released to air. Concurrent with this Human Health
Risk Assessment, EPA is releasing a risk determination for formaldehyde.
EPA considers the standard risk benchmarks associated with interpreting margins of exposure and
cancer risks. However, the Agency cannot solely rely on those risk values. If an estimate of risk for a
specific exposure scenario exceeds the benchmarks, then the decision of whether those risks are
unreasonable under TSCA must be both case-by-case and context driven in the case of formaldehyde.
EPA is taking the risk estimates of the human health risk assessment (HHRA), in combination with a
thoughtful consideration of other sources of formaldehyde, to interpret the risk estimates in the context
of making an unreasonable risk determination.
Page 9 of 191
-------
EXECUTIVE SUMMARY
Sixty-three conditions of use of formaldehyde were determined to be within the scope of TSC A and
were assessed by OPPT. These conditions of use were identified as part of the Final Scope for the Risk
Evaluation for Formaldehyde; 50-00-0 (U.S. EPA. 2020c) and recently updated to better reflect the
Agency's understanding of the sources of formaldehyde. Examples of the conditions of use considered
in the TSCA risk evaluation are listed below with a comprehensive list provided in the Conditions of
Use for the Formaldehyde Risk Evaluation (U.S. EPA. 2024c). These include
• manufacturing of formaldehyde,
• processing and manufacturing of articles and products,
• composite wood products,
• plastics used in toys,
• rubber materials, and
• various adhesives and sealants.
Reasonably available information indicates that formaldehyde is released to air, land, and water from
various TSCA conditions of use. Although the formaldehyde risk evaluation considered each of these
pathways of exposure, some of these releases result in negligible exposure based on the chemistry, fate,
and transport properties of formaldehyde. Formaldehyde exposures by those pathways were not assessed
further. These include
• sediment and water including drinking water, and
• soils, biosolids, and landfills.
Similarly, some conditions of use were considered for consumer scenarios and result in negligible
exposure based on the chemistry, fate, and transport properties of formaldehyde. Other conditions of use
could not be quantitatively assessed due to the limitation of available models and data. These conditions
of use are
• portable toilet cleaner and sanitizer,
• water treatment,
• laundry detergent, and
• lawn and garden products.
This Human Health Risk Assessment focuses on human exposure to formaldehyde from industrial,
occupational, and consumer activities via inhalation of indoor and outdoor air and dermal (skin) routes.
Exposure to workers, consumers and people within the general population have been assessed under
specific conditions of use. Not all conditions of use result in formaldehyde exposure for all populations.
Among the populations assessed are potentially exposed or susceptible subpopulations, which are people
who have higher exposures or are more susceptible so may be at greater risk of adverse health effects
from formaldehyde. Example populations (including PESS), routes of exposure, and conditions of use
include the following:
• worker inhalation and dermal exposure during manufacturing, processing, distribution, use and
disposal of formaldehyde;
• consumer (based on highest expected exposure among all ages) inhalation and dermal exposure
from use of paint, textile and leather finishing products, varnishes and floor finishes, rubber
mats, adhesives, caulks and sealants, liquid photographic processing solutions, and non-spray
lubricants that contain formaldehyde;
• general population (all ages) inhalation exposure to indoor air from articles used in new
construction of homes and mobile homes (e.g., wood materials, furniture seat covers); and
automobiles with articles that contain formaldehyde; and
Page 10 of 191
-------
• general population (all ages) inhalation exposure to outdoor air near industrial facilities that
release formaldehyde.
As mentioned, there are many formaldehyde sources. Not all sources are evaluated in the TSCA Risk
Evaluation, for instance because they occur naturally or because they are excluded from the TSCA
"chemical substance" definition under TSCA section 3(2)(B). These include
• biogenic sources (like trees and wood •
chips);
• forest fires; •
• embalming fluids and products used to
preserve animal specimens;
• other pesticides as defined in Federal
Insecticide, Fungicide, and Rodenticide •
Act;
• drugs for fisheries and hatcheries; •
• animal feed;
• pacifiers and baby bottles;
These other sources can produce substantial amounts of formaldehyde resulting in exposures in the
occupational, indoor, and outdoor environments. For example, biogenic concentrations can contribute
upwards of 25 percent of the total formaldehyde concentration and secondary formation can account for
as much as 80 percent in ambient air, depending on the circumstance.
plastic products used for food storage
and distribution;
other formaldehyde uses that meet the
definition of "food, food additive, drug,
cosmetic, or device" as defined in the
Federal Food, Drug, and Cosmetic Act;
tail-pipe emissions from cars, trucks, and
other vehicles; and
secondary formation.1
Hazard Values
Human health hazard data for this assessment were obtained through collaboration with ORD and OPP
as well as through the TSCA systematic review process. In addition, OSCPP is relying on the peer
reviews provided by the National Academies of Science, the TSCA Science Advisory Committee on
Chemicals, and the Human Studies Review Board on certain aspects of the human hazard assessment.
OPPT is using the inhalation unit risk for nasopharyngeal cancer as derived in the EPA IRIS
Toxicological Review of Formaldehyde-Inhalation. Although inhaled formaldehyde has been associated
with multiple types of cancer in humans including nasopharyngeal and myeloid leukemia, the myeloid
leukemia findings are not sufficient to develop quantitative estimates of cancer risk. While there may be
uncertainty on the extent to which other mechanisms contribute to the carcinogenicity of formaldehyde,
the IRIS assessment concluded that a mutagenic action contributes to risk of nasopharyngeal cancer
from inhaled formaldehyde. To account for the potential increased susceptibility that may be associated
with early life exposure to formaldehyde, OPPT used a cancer value adjusted with age dependent
adjustment factors for exposure scenarios that include early life.
Formaldehyde exposure is also associated with a range of respiratory and non-respiratory health effects
in humans including reduced pulmonary function, increased asthma prevalence, decreased asthma
control, allergy-related conditions, and sensory irritation (including eye irritation and respiratory
irritation). OPPT is using a chronic point of departure for pulmonary function in children derived from
the EPA IRIS Toxicol ogical Review of Formaldehyde-Inhalation. Sensory irritation (e.g., eye irritation)
1 Formaldehyde is also largely found in the environment
due to secondary formation of the chemical after
degradation of other compounds, for example when a
chemical undergoes chemical reactions in the air and
forms formaldehyde. Some secondary formation may be a
result of TSCA conditions of use, but these cannot be
distinguished from all other secondary formations because
they are so abundant.
Page 11 of 191
-------
observed in adults is the critical effect for non-cancer effects from acute exposure to formaldehyde in
air. Skin sensitization observed in adults is the critical effect for assessing formaldehyde exposure via
the dermal routes.
Oral hazard data are also available for formaldehyde but were not used in the risk assessment because
exposure was not expected.
Exposure for Workers and the General Population
Many data sources were used to evaluate exposures to humans (workers; consumers and general
population, both including children) from indoor and outdoor air as well as dermal exposures. These
include measured and model estimated concentrations data. There are many conditions of use and many
different exposure scenarios for each population assessed.
Workers: Worker exposure to formaldehyde via inhalation and dermal are expected to result in the
highest formaldehyde exposures among the assessed populations. Workplace concentrations of
formaldehyde vary based on activities performed {i.e., manufacturing, processing, industrial, and
commercial settings). Individuals in workplaces whose duties are not directly associated with
manufacturing, processing, or use of formaldehyde {i.e., occupational non-users [ONUs] such as
supervisors) which may be near or within the same workspace {i.e., breathing the same air) are also
expected to be exposed to formaldehyde at similar concentrations.
Inhalation exposures were estimated based largely on measured formaldehyde concentrations in
occupational settings. Monitoring data were available for many scenarios. However, monitoring data are
not available for four conditions of use in commercial settings and were thus modeled. These model
estimates broadly fell within the range of monitored workplace concentrations available for other
conditions of use. Across all conditions of use, full work shift (8-12 hours) inhalation exposure
estimates were between 0.0114 to 17,353.3 |ig/m3. Peak inhalation estimates for workers were between
2.5 to 209,815 |ig/m3 across all conditions of use. The highest inhalation exposure was based on
modeled estimates for use of formulations containing formaldehyde in automotive care products.
Occupational exposure concentrations, as expected, are generally higher than modeled and measured
outdoor and indoor formaldehyde air concentrations. EPA has an overall medium confidence in the
reported exposure estimates because most of the values are based on recent (1992-2020) real workplace
monitoring data from multiple sources and therefore are expected to be reflective of current industrial
practices. EPA does not have higher overall confidence in the reported exposure estimates because the
sources did not always provide supplemental information such as worker activities and associated
process conditions. Therefore, the Agency made assumptions in integrating monitoring data.
Short-term dermal exposures were estimated based on liquid contact with formulations containing
formaldehyde. Dermal exposure estimates ranged from 0.56 to 3,090 |ig/cm2. The highest dermal
exposure was estimated during spray application of products such as paints and automotive care
products. EPA has medium confidence in the dermal exposure estimates because the estimates were
derived using a standard peer-review model based on measured data on the retention of liquids on the
skin surface. The Agency does not have higher confidence in the reported values because EPA did not
have monitored formaldehyde dermal exposure data to ground truth these exposure estimates.
General Population - Consumer Exposures in Residential Settings: Frequent users of products
containing formaldehyde are anticipated to be the next highest population effected due to its use in
products and articles that are available to most people for purchase. Some examples of these consumer
products that contain formaldehyde include automotive care products; fabrics, textiles, and leather
Page 12 of 191
-------
products; and adhesives or sealants. Exposure estimates for these products varies due to the different
durations (or activity) of use along with formaldehyde amount acquired from safety data sheets. This
assessment considered concentrations of formaldehyde during and following use of consumer products
in residential settings. Specifically, peak (15-minute) inhalation exposures as well as short-term dermal
exposures were estimated.
Several conditions of use were evaluated for peak inhalation exposures. Fifteen-minute concentration
estimates ranged from 1.72 to 2,500 |ig/m3. The highest concentrations were for products like floor
covering, foam seating, bedding, etc. EPA has medium confidence in the inhalation exposure estimates
based on the number of monitoring data sources, use of the EPA's Exposure Factors Handbook and
survey data on consumer behavior and activities, and chemical amounts report on product-specific safety
data sheets. Monitoring data that can be tied to specific consumer conditions are not available.
Formaldehyde concentrations from consumer products are expected to be represented in the available
indoor air monitoring data as an aggregate concentration with other consumer and indoor air sources.
Dermal short-term exposures for consumers were estimated based on contact with products containing
formaldehyde. Dermal conditions of use were evaluated with estimated short-term formaldehyde dermal
loading rates ranging from 1.03 to 3,090 |ig/cm2. The highest concentrations were estimated to be for
exterior car waxes and polishes followed by photographic processing solutions. EPA has medium
confidence in these estimates because there are no monitoring data available to ground truth these
concentration estimates.
General Population - Indoor Air Exposures in Residential and Vehicular Settings: There are many
sources of formaldehyde within residences (homes and mobile homes) and vehicles. As mentioned,
these include both TSCA sources such as building materials, finishes such as wood flooring and paint,
and foam cushions on furniture, and other sources such as combustion sources like candles, fireplaces,
and stoves. Additionally, consumer products containing formaldehyde may also contribute to indoor
concentrations of formaldehyde.
The highest formaldehyde concentrations from TSCA sources are expected in newly constructed homes
and mobile homes. In these settings, multiple sources of formaldehyde contribute to total indoor air
concentrations especially during the peak product emission period when new formaldehyde containing
articles and products are introduced. These concentrations substantially diminish within the first two
years of the product life based on open literature data. The peak exposure to formaldehyde from these
products is expected to occur within one year of use or manufacture. Indoor air concentrations can also
be higher when new materials like hardwood floors or wallpaper are installed in homes. Similarly, fabric
in new furniture may also release formaldehyde in indoor environments after being introduced.
Therefore, formaldehyde concentrations in indoor environments are expected to vary over longer time
periods (e.g., an individual's lifetime) and are highly dependent on an individual's propensity to move to
new homes as well as their purchasing behaviors and the length of time between manufacturing and
installation.
Four conditions of use in both automobiles and homes were evaluated. The highest concentration comes
from construction and building materials that cover large surface areas like hardwood floors. These
modeled concentrations represent high-end estimates for each condition of use. Furthermore, many of
the products that fall within this condition of use are subject to the emission standards under TSCA Title
VI (15 U.S.C. §2697). which for laminated products, have only been fully implemented as of March
2024 (see 40 CFR part 770).
Page 13 of 191
-------
Monitoring data from the American Healthy Homes Survey II suggests that concentrations of
formaldehyde range from 0.27 to 124.2 |ig/m3 for all homes, with 95 percent of homes having
concentrations below 46 |ig/m3. Thus, indoor exposures to formaldehyde are in general agreement
across available data and sources of formaldehyde; but monitoring values represent all sources of
formaldehyde in indoor air (including sources that are not subject to TSCA) and cannot be attributed to a
single TSCA condition of use. Similarly, measured concentrations are not expected to reflect full
implementation of TSCA Title VI (15 U.S.C. §26971 which for laminated products has only been fully
implemented as of March 2024 (see 40 CFR part 770). Therefore, it is reasonable to expect that less
formaldehyde will be released from many wood products in the future than occurred in the past.
Overall, EPA has high confidence in the indoor air concentration estimates because the values are based
on article-specific emission rates and article-specific formulations of formaldehyde. In addition, EPA
integrated various indoor air monitoring data sources including the American Healthy Homes Survey II
(AHHS II), which is a robust nationally representative monitoring dataset representing multiple home
types and home characteristics for formaldehyde, monitoring data from outside the home to characterize
the spectrum of formaldehyde concentrations in the indoor environment, and two models which were
used to characterize expected concentrations in the indoor environment. Though, there were some
uncertainties in the precise indoor air concentration estimates because the models used were not able to
predict precise long-term concentrations due to model limitations (e.g., changes in emission rates over
time) and available monitoring data cannot be directly tied to specific articles (e.g., wood and fabric)
and associated conditions of use.
General Population - Outdoor Air Exposures: As previously mentioned, formaldehyde exposures in
outdoor air (ambient air) come from many sources including biogenic sources, secondary formation, and
TSCA COUs. Outdoor air exposure concentrations are mostly lower than those in other settings (indoor
air, occupational, consumer) under TSCA COUs, but can still substantially contribute to overall
exposures. The outdoor air exposure assessment evaluated daily average and annual average inhalation
exposures, focusing on a subset of the general population living within a half mile of releasing facilities.
Daily average exposures primarily attributable to TSCA COUs ranged from 0.0004 to 66.2 |ig/m3. The
highest modeled daily average exposures attributable to TSCA COUs came from wood product
manufacturing and paper manufacturing industry sectors.
Daily average exposures primarily attributable to combustion like airplanes, on-site vehicles, process
heaters, turbines and reciprocating internal combustion engines (RICE) ranged from 2 to 662 |ig/m3. The
highest modeled daily average concentrations came from the Wholesale and Retail Trade and Oil and
Gas drilling, extraction, and support activities industry sectors.
Annual average exposures primarily attributable to TSCA COUs ranged from 0.0001 to 5.75 |ig/m3. The
highest annual average exposures come from operations within nonmetallic mineral product
manufacturing and textile, apparel, and leather manufacturing industry sectors.
Monitoring data from Ambient Monitoring Technology Information Center archive, based on data
collected between 2015 to 2020, range from 0 to 60.1 |ig/m3 with a median of 1.6 |ig/m3 across more
than 300,000 monitored values from 214 sites. Monitoring data could not be linked to specific
conditions of use.
Because monitored concentrations represent total aggregated concentrations from all contributing
sources, while these values are not directly comparable to IIOAC modeled concentrations alone, by
Page 14 of 191
-------
considering multiple data sources (modeled concentrations, biogenic and secondary sources) EPA found
considering these three primary contributors together represent a large portion of the total monitored
concentrations and does not result in concentrations outside of or well above any monitored
concentration.
EPA has medium confidence in the IIOAC modeled results used to characterize exposures in this
ambient air assessment, due to uncertainties related to input parameters and spatial and temporal
differences seen across the multiple lines of evidence considered. This assessment is a conservative
assessment that is not site specific. Ambient air modeling for formaldehyde does not account
atmospheric degradation (i.e. photolysis) and how local weather patterns may affect the presence of
formaldehyde over time. Furthermore, the assumption that individuals reside in the same location for the
duration of their life (i.e. 78 years) is conservative. Similarly, the assessment was conducted independent
of the size of the facility footprint, the precise location of the release, and the relative location of
residences. Additional modeling with HEM results provides additional context on the spatial variability
of formaldehyde concentrations across the U.S. and an approximate understanding of populations
exposed.
Risk Characterization
People are regularly exposed to formaldehyde in their workplace, in their vehicles, and in their homes.
People may also be exposed to formaldehyde due to its natural formation in the environment and as a
natural part of human metabolism.
Worker Risk Characterization: Based on available occupational monitoring data and exposure modeling
estimates, worker exposure to formaldehyde is expected to be higher than exposures from naturally
occuring sources. This assessment does not assume personal protective equipment use to account for a
range of possible workplaces. Both high-end and central tendency exposure estimates were used with
the available hazard data to evaluate cancer and non-cancer risks. Sensory irritation is being used by
EPA to evaluate acute air exposure to formaldehyde. Sensory irritation is commonly used as a parameter
for setting occupational exposure limits. The Agency is using skin sensitization to evaluate risks from
dermal exposure to formaldehyde.
EPA recognizes that chronic inhalation exposure is likely for many workers and has calculated non-
cancer and cancer risk estimates for worker. However, the non-cancer chronic effects EPA used in its
calculations are based on effects observed in children, and some SACC peer reviewers indicated
concerns with determining risk to workers based on health effects observed in children.
At high-end exposure scenarios, results indicate workers may be at increased risk for acute sensory
irritation and nasopharyngeal cancer. Acute sensory irritation effects are based in controlled human
exposure studies. Cancer effects are based on human studies in occupational settings. The risk estimates
for occupational exposures reflect use of standard risk assessment approaches considering an abundance
of high-quality workplace monitoring data that clearly exceed concentrations of formaldehyde from
other sources including natural sources and human hazard data. Likewise, risk estimates are generally
consistent across central tendency and high-end exposure scenarios for workers. While there are some
uncertainties in the assessment, these uncertainties are not expected to change risk estimates enough to
shift the overall risk assessment conclusions but may be great enough to change risk estimates for
specific conditions of use.
Results indicate that effects to workers from dermal exposure that could lead to sensitization with
repeated exposure for all conditions of use except one. All exposure estimates were based on standard
Page 15 of 191
-------
modeling approaches including the assumption of the amount of liquid left on the skin after contact
which is not specific to formaldehyde. The hazard data for skin sensitization is based on controlled
human exposures in adult volunteers and is corroborated by animal and in vitro evidence. The dermal
sensitization data are based on controlled human exposures studies in adults.
Consumer Risk Characterization: Consumer risk estimates were calculated for acute inhalation effects
as well as dermal sensitization.
Consumers may experience acute sensory irritation when inhaling peak concentrations of formaldehyde
in their residences when using products that contain high amounts of formaldehyde for short durations.
These acute effects are based on a robust dataset of evidence for sensory irritation in humans, including
several high-quality controlled exposure studies with relevance for acute exposure scenarios. The risk
estimates reflect use of standard risk assessment approaches and best available data.
Consumers inhaling formaldehyde may also experience decreased pulmonary function and other chronic
effects when those products are used frequently. These effects are based on data from humans at
sensitive lifestages, but it is unclear whether exposure scenarios represent how all people use these
products and articles containing formaldehyde. EPA has substantial data on use patterns of these
products based on surveys conducted on consumer activities and behaviors. Similarly, EPA's Exposures
Factors Handbook was used to support consumer exposure analyses. Lastly, safety data sheets were
used to identify concentrations of formaldehyde in consumer products. It is worth noting that
conservative estimates from these data sources may not represent exposures to all consumers using
products and articles containing formaldehyde. The risk estimates reflect use of standard risk assessment
approaches considering best available data for consumers who frequently use products containing
formaldehyde; but understanding the commonness of these practices has some uncertainty because it is
unclear how older data from surveys represents current behaviors and uses.
At high-end exposure scenarios, results indicate consumers may have increased risk for developing
nasopharyngeal cancer, but this is expected to be rare in the general population. The data for cancer
effects are based on human studies that are corroborated in animal studies. EPA believes these risk
estimates are for consumers who frequently use products containing formaldehyde over the course of
many years. However, EPA does not have information on how common it is that consumers would use
these products for this length of time, and it is unclear how older data from surveys represents current
behaviors and uses.
Consumers using products containing formaldehyde may experience dermal sensitization after acute
exposures to their skin. The hazard data for skin sensitization is based on controlled human exposures in
adult volunteers and is corroborated by animal and in vitro evidence. Risk estimates for these dermal
exposures is based on estimated dermal loading from models. Monitoring data are not available to
determine how common these exposures may be for consumers. Thus, EPA has less certainty in how
common these exposures result in skin sensitization for consumers in the general population.
Indoor Air Risk Characterization: Indoor air risk estimates were calculated for acute, chronic non-
cancer, and cancer inhalation effects. People who are living in homes where high concentrations are
present may experience decreased pulmonary function and other chronic effects. These effects are based
on data from humans at sensitive lifestages. However, the exposure scenarios where these effects are
seen are mostly limited to homes where high surface area products like hardwood floors and wallpaper
may be introduced. Similarly, these effects may occur in new homes and mobile homes where all new
products may be contributing to high concentrations of formaldehyde in air. As previously mentioned,
Page 16 of 191
-------
the dissipation rate of formaldehyde from these TSCA conditions of use could not be fully characterized.
However, concentrations are anticipated to decrease with time and ventilation. Generally, new products
are expected to have substantially reduced formaldehyde emissions within two years.
In addition to TSCA sources, other sources of formaldehyde may contribute substantially to indoor air
concentrations of formaldehyde. Formaldehyde concentrations from candles, incense, cooking, wood
combustion, and air cleaning devices fall within the range of formaldehyde concentrations from TSCA
conditions of use. Furthermore, the range of concentrations estimated fall within the range of available
monitoring data.
Many of these other sources of formaldehyde represent temporary emission sources, which may affect
the overall impact on indoor air quality. Further, qualities such as the frequency and duration of use of
these temporary formaldehyde sources (e.g., burning candles or the use of a fireplace), age of the home
and formaldehyde-containing home finishes and furnishings, and ventilation rate will impact the total
concentration of formaldehyde in indoor air and the relative contribution of TSCA and other sources to
the indoor air. Combined, the many factors that may contribute to overall indoor air concentrations and
relative concentrations from TSCA and other uses introduce a significant source of uncertainty in the
indoor air exposure assessment.
EPA has high confidence in the conclusion of the inhalation risk assessment for indoor air. This is
because the assessment is based on product-specific emission rates, data, and standard methods. While
the monitoring data cannot be tied to individual conditions of use, it is expected to represent aggregate
exposure to formaldehyde resulting from multiple sources. As such, EPA has confidence it is not
underestimating formaldehyde exposure resulting from TSCA conditions of use or across all sources of
formaldehyde.
Ambient Air Risk Characterization: Based on modeling estimates, individuals of the general population
living within half mile of a releasing facility may be exposed to formaldehyde at high concentrations. In
some locations some individuals may be at increased risk for developing nasopharyngeal and other
cancer types. However, this is contingent on the assumption that an individual lives within a half mile of
a releasing facility their entire life.
EPA has medium confidence in the conclusion of the inhalation risk assessment for the general
population. EPA has this confidence because the assessment is based on a large amount for
formaldehyde reported release data, standard methods, and previously peer reviewed models.
Furthermore, the range of concentrations estimated fall within the range of available monitoring data.
While the monitoring data cannot be tied to individual conditions of use, it is expected to represent
aggregate exposure to formaldehyde resulting from multiple sources. However, this assessment is a
conservative assessment that is not site specific. Similarly, the assessment was conducted independent of
the size of the facility footprint, the precise location of the release, and the relative location of
residences. Therefore, EPA has high confidence it is not underestimating formaldehyde exposure
resulting from TSCA conditions of use or across all sources of formaldehyde due to conservatism but
medium confidence because of the uncertainties described above.
Page 17 of 191
-------
1 INTRODUCTION
1.1 Background
Formaldehyde is a high priority chemical undergoing the Toxic Substances Control Act (TSCA) risk
evaluation process after passage of the Frank R. Lautenberg Chemical Safety for the 21st Century Act in
2016. It is concurrently undergoing risk assessment under the Federal Insecticide, Fungicide, and
Rodenticide Act (FIFRA). This Raman Health Risk Assessment is a TSCA-specific assessment that will
serve to support risk management needs by the Office of Pollution Prevention and Toxics (OPPT) and is
one of many documents comprising the formaldehyde risk evaluation.
In April 2022, EPA's IRIS program released a draft Toxicological Review of Formaldehyde Inhalation
(U.S. EPA. 2022c) for public comment and peer review. In August 2023, the NASEM released its
Review of EPA's 2022 Draft Formaldehyde Assessment (NASEM. 2023). Subsequently, IRIS released
the final Toxicological Review of Formaldehyde - Inhalation in August of 2024 (U.S. EPA. 2024k)
(also referred to as the "IRIS assessment" or final IRIS assessment throughout this document). IRIS
provided responses to NASEM and public comments on the draft in Appendix F of the Supplemental
Information document (U.S. EPA. 2024k). EPA is relying on the IRIS assessment to identify relevant
chronic hazards to consider for inhalation exposure to formaldehyde under TSCA and FIFRA. OPPT
and Office of Pesticide Programs (OPP) have coordinated to evaluate additional information on
environmental fate and transport, human health hazard, and environmental hazard consistently across
programs.
A list of the regulatory history of formaldehyde can be found in Appendix D of the Final Scope for the
Risk Evaluation for Formaldehyde 50-00-0 (U.S. EPA. 2020c). which includes regulation under the
Clean Air Act, Clean Water Act, Resource Conservation and Recovery Act, and other EPA regulatory
programs and non-EPA programs.
Following publication of the final scope document, EPA considered and reviewed reasonably available
information in a systematic and fit-for-purpose approach to develop this formaldehyde risk evaluation,
leverage existing EPA assessment work, collaborate across offices, rely on best available science, and
base it on the weight of the scientific evidence as required by EPA's Risk Evaluation Rule under
TSCA. Reasonably available information was reviewed, and the quality evaluated in accordance with
EPA's Draft Systematic Review Protocol Supporting TSCA Risk Evaluations for Chemical Substances
(U.S. EPA. 2021c). which underwent external peer review by the Science Advisory Committee on
Chemicals (SACC) in July 2021.
In March 2024, EPA released the draft TSCA Risk Evaluation for Formaldehyde for public comment
and for peer review by the SACC. The SACC meeting was held May 20-23, 2024, with the minutes and
final report released on August 2, 2024 (U.S. EPA. 2024w). SACC and peer review input has been
incorporated, as appropriate, in this document.
1.2 Risk Evaluation Scope
The formaldehyde risk evaluation comprises a series of assessments spread across many documents. A
basic diagram showing the layout and relationships of these assessments is provided below in Figure
1-1. In some cases, these assessments were completed jointly under TSCA and Federal Insecticide,
Fungicide, and Rodenticide Act (FIFRA). These assessments are shown in dark gray. This human health
risk assessment is shaded blue. High level summaries of each relevant assessment are presented in this
Page 18 of 191
-------
risk assessment. Detailed information for each supporting assessment can be found in the corresponding
document.
Figure 1-1. Risk Evaluation Document Summary Map
These modules leveraged the data and information sources already identified in the Final Scope of the
Risk Evaluation for Formaldehyde CASRN 50-00-0 (U.S. EPA. 2020c). OPPT conducted a
comprehensive search for "reasonably available information" to identify relevant formaldehyde data for
use in the risk evaluation. In some modules, data utilized were also located in collaboration with other
EPA offices. As previously noted, OPPT is relying on the EPA's IRIS Toxicological Review of
Formaldehyde - Inhalation (U.S. EPA. 2024k) in the formaldehyde risk evaluation (shaded light gray in
Figure 1-1). The IRIS assessment is not part of the TSCA risk evaluation bundle. The approach used to
identify specific relevant risk assessment information was discipline-specific and is detailed in
Systematic Review Protocol for the Formaldehyde Risk Evaluation (U.S. EPA. 2024m). or as otherwise
noted in the relevant modules.
Page 19 of 191
-------
1.2.1 Life Cycle and Production Volume
The Life Cycle Diagram (LCD)—which depicts the conditions of use that are within the scope of the
risk evaluation during various life cycle stages, including manufacturing, processing, use (industrial,
commercial, consumer), distribution and disposal—is shown below in Figure 1-2. The LCD has been
updated since it was included in the Final Scope of the Risk Evaluation for Formaldehyde CASRN 50-
00-0 (U.S. EPA. 2020c). The commercial and consumer uses for agricultural use products (non-
pesticidal) have been included; it was inadvertently omitted under the industrial, commercial, and
consumer uses lifecycle stage in the diagram in the final scope document (U.S. EPA. 2020c).
Page 20 of 191
-------
MFG/IMPORT
PROCESSING
Manufacture
(Including
Import)
(453M-2.27B
kg/yr)
INDUSTRIAL, COMMERCIAL, CONSUMER USES RELEASES and DISPOSAL
I
Processing as Reactant
Adliesives and sealant chemicals (plastics and resin manufacturing;
wood product manufacturing; all other basic inorganic chemical
manufacturing); Intermediate (pesticide, fertilizer, and other
agricultural chemical manufacturing; petrochemical manufacturing;
soap, cleaning compound, and toilet preparation manufacturing)...
Incorporated into Formulation
Petrochemical manufacturing, petroleum, lubricating oil and grease
manufacturing (fuel and fuel additives, lubricant and lubricant
additives; all other basic organic chemical manufacturing); Asphalt,
paving, roofing, and coating materials manufacturing; Solvents which
become part of a product formulation or mixture (paint and coating
manufacturing); Processing aids, specific to petroleum production (oil
and gas drilling, extraction, and support activities)...
Incorporated into Article
Finishing agents (textiles, apparel, and leather manufacturing): Paint
additives and coating additives not described by other categories
(transportation equipment manufacturing including aerospace)....
Non-incorporative activities1
Furnishings, Cleaning, and
Treatment/Care Products1,2
Construction, Paint, Electrical,
and Metal Products1,2
Automotive and Fuel
Products1,2
Agricultural Use Products1-2
Outdoor Use Products1
Packaging, Paper, Plastic,
Hobby Products1,2
Other Use1
See Conceptual Model for
Environmental Releases and
Hastes
I ] Manufacture
' ' (Including Import)
~ Processing
J Uses.
1. Industrial and/or
commercial.
2. Consumer
Repackaging (Laboratory chemicals)
Recycling
Figure 1-2. Lifecycle Diagram of Formaldehyde
Page 21 of 191
-------
Based on data collected under the Chemical Data Reporting (CDR) Rule in 2019, domestic
formaldehyde production volume is between 453 million and 2.3 billion kg/year. CDR requires U.S.
manufacturers (including importers) to provide EPA with information on the chemicals they
manufacture or import into the United States every 4 years. Data collected for formaldehyde is further
detailed in the Use Report for Formaldehyde (CAS RN 50-00-0) (Docket: EPA-HQ-QPPT-2018-043 8).
1.2.2 Conditions of Use
As part of the TSCA risk evaluation, OPPT assessed formaldehyde COUs that were included in the
revised COU technical support document (U.S. EPA 2024c) including industrial, commercial, and
consumer applications such as textiles, foam bedding/seating, semiconductors, resins, glues, composite
wood products, paints, coatings, plastics, rubber, resins, construction materials (including insulation and
roofing), furniture, toys, and various adhesives and sealants. The COUs were evaluated using the
corresponding environmental exposure scenarios for aquatic and terrestrial organisms. A description of
COUs is available in the Conditions of Use for the Formaldehyde Risk Evaluation (U.S. EPA. 2024c).
1.2.3 Other Sources of Formaldehyde in Air
Formaldehyde is ubiquitous in both indoor and outdoor (ambient) air because it is formed naturally in
the environment and from numerous anthropogenic sources, which include both TSCA (Section 0) and
other activities. As a result, people are routinely exposed to formaldehyde in indoor and outdoor air,
with indoor air generally having higher concentrations than outdoor air. Robust monitoring data are
available to estimate the concentrations of formaldehyde across common outdoor and indoor
environments. However, attributing measured concentrations to TSCA COUs versus other sources is
complex. This section will provide an overview of these data sources and seeks to differentiate between
sources when possible. This section is not intended to be a comprehensive review of the scientific
literature on this topic but instead provides context for understanding and interpreting the exposures of
formaldehyde from a variety of sources as part of risk characterization and risk determination of COUs
under TSCA.
Formaldehyde has been measured in outdoor air across the country. EPA's Ambient Monitoring
Technology Information Center (AMTIC) archive maintains a database of spatially and temporally
diverse air quality monitoring data that meet specified collection and quality assurance criteria. The
Agency used monitoring data extracted from EPA's AMTIC archive (U.S. EPA 2022a) from 2015
through 2021 to contextualize modeled values as well as characterize total aggregate exposures to
formaldehyde from all possible contributing sources—including sources associated with TSCA COUs
and other sources out of scope for this assessment and not associated with TSCA COUs (e.g., biogenic
sources). These data are described in detail in Sections 2.4.1 and 3.3.2 of the Ambient Air Exposure
Assessment for Formaldehyde (U.S. EPA. 2024a). In addition, satellite data have measured
formaldehyde concentrations across the United States, providing insights on temporal and geographic
trends that help to characterize ambient formaldehyde concentrations (Wang et al.. 2022; Harkev et al..
2021: Zhuetal.. 2017V
Comprehensive modeling efforts were undertaken to characterize formaldehyde concentrations that vary
across the county. EPA's AirToxScreen is one example that uses release data with chemical transport
and dispersion models to estimate average annual outdoor ambient air concentrations of air toxics across
the U.S. and is validated against available monitoring data. For formaldehyde, this model estimates
concentrations from different sources contributing to ambient air concentrations including biogenic
sources, secondary formation, and point sources. Other sources of formaldehyde are included but may
not be relevant to the scope of this risk evaluation for formaldehyde. Accordingly, the 2019
AirToxScreen estimates that secondary formation of formaldehyde accounts for up to 80 percent of
Page 22 of 191
-------
formaldehyde in ambient air and direct biogenic sources contribute up to 15 percent. Based on the 2019
AirToxScreen estimates, the calculated ninety-fifth percentile biogenic concentration of formaldehyde in
ambient air was 0.28 |ig/m3.
Much like outdoor air, many efforts have been made to characterize formaldehyde in the indoor
environment. Data from a recent national survey provides a representative sample of formaldehyde
concentrations in indoor air, showing average residential levels an order of magnitude higher than
outdoor concentrations. The American Healthy Homes Survey II (AHHS II), sponsored by the U.S.
Department of Housing and Urban Development (HUD) along with EPA, was conducted from March
2018 through June 2019 and measured indoor air concentrations of formaldehyde in U.S. homes of
various ages, types, conditions, and climates (OuanTech. 2021). Across all housing, the weighted-mean
concentration is 23.2 |ig/m3 (95% confidence interval 21.6-25.2 |ig/m3) with 10 percent of homes higher
than 41.8 |ig/m3. Formaldehyde is introduced into residential indoor air from numerous TSCA sources
(e.g., building materials, finishes such as flooring and paint, and furniture) and other sources (e.g.,
fireplaces, gas stoves, candles, photocatalytic air purifiers, and tobacco use). The TSCA sources are
expected to consistently release formaldehyde over long periods of time, with release rates decreasing
over time as the materials age. In contrast, many of the other sources are temporary emission sources
and contribute formaldehyde to the indoor air intermittently. Overall, due to differences in the ages of
building materials, home finishes, and furnishings and differences in presence and use patterns of other
formaldehyde sources in the residence, the relative contributions of formaldehyde from TSCA and other
sources to residential indoor air varies both among homes and over time within a single home. Thus,
despite the availability of quality monitoring data, it remains difficult to discern source apportionment
for the residential environment and there are uncertainties related to assessing exposures tied to specific
TSCA COUs based on this monitoring data. OPPT solicited comment from the SACC and the public on
additional sources of information that could inform the attribution of other sources of formaldehyde to
support risk characterization. No data was identified from this solicitation to inform source attribution in
indoor air.
1.3 Changes made between Draft and the Revised Risk Evaluation
1.3.1 Occupational Exposure Assessment
Substantial updates have been incorporated into this assessment. A full description of the changes is
included in the Occupational Exposure Assessment for Formaldehyde. The key changes were:
EPA expanded the acute exposure analysis by including multiple short-term estimates categorized by
sample durations. In the draft risk evaluation, the Agency only extracted full-shift estimates and 15-
minute samples from the OSHA database. In the revised assessment, EPA provides the central tendency
and high-end estimates based on 15-minute samples, as well as samples taken for more than 15-minutes
but less than the cut-off for full-shift estimates (330 minutes). Based on public comments, the Agency
also provides the estimates for samples taken between 15-minutes and 60-minutes.
EPA received additional information on the use of fertilizers containing formaldehyde. EPA revised the
approach for the Commercial Use- Lawn and garden products COU to incorporate submitted
information on the maximum concentration expected, container sizes, and types of fertilizers developed
using formaldehyde. In addition, EPA revised the approach to estimate a use rate based on generic
information on fertilizer use for agricultural and landscape applications. EPA employed a probabilistic
approach that addressed variation in the expected exposure frequencies and durations.
EPA initially relied on monitoring data to support Industrial Use- Non-incorporative activities- Process
aid in: oil and gas drilling, extraction, and support activities; process aid specific to petroleum
Page 23 of 191
-------
production, hydraulic fracturing COU. However, there were uncertainties noted in sites monitored and a
lack of data for acute risk characterization. EPA has modeled the exposures for this COU using the ESD
on Chemicals Used in Hydraulic Fracturing (U.S. EPA. 2022b) and formaldehyde-specific information
reported in FracFocus 3.0 database (GWPC and IOGCC. 2022).
EPA also incorporated directly or indirectly submitted monitoring data submitted during the public
comment period as well as modified assignment of OSHA data as needed.
1.3.2 Consumer Exposure Assessment
No substantive changes were made to the analytical approach for the consumer exposure assessment.
However, some COUs published in the Draft Consumer Exposure Assessment have been removed as
formaldehyde appears to have been removed from their formulation based on reasonably available
information. These COUs and a rationale for why they have been removed are provided below.
For the Draft Consumer Exposure Assessment, EPA identified a safety data sheet (SDS) published in
2017 for a portable toilet cleaner and sanitizer (Port-o-Loo) with a formaldehyde weight fraction of 10
percent that was relevant to a drain and toilet cleaner exposure scenario. As of 2023, this product no
longer contained formaldehyde in its formulation and no similar products could be identified. As a
result, this use is not reasonably foreseen to occur now or in the future. Therefore, it has been removed
for the Revised Consumer Exposure Assessment.
Also for the Draft Consumer Exposure Assessment, EPA identified a safety data sheet (SDS) published
in 2018 for a laundry and dish washing products (WOOLITE® Darks Laundry Detergent), with a
formaldehyde concentration of less than 0.01%. As of June 1, 2021, this product has been discontinued
and no similar products could be identified. As a result, this use is not reasonably foreseen to occur now
or in the future. Therefore, it has been removed for the Revised Consumer Exposure Assessment.
Lastly, EPA assumed consumer uses of products containing formaldehyde were chronic and continuous
(i.e., 24 hours per day, 7 days per week) in the Draft Consumer Exposure Assessment. For the revised
assessment, the Agency assumes that uses are less frequent for consumer products and focuses on peak
exposures. In addition, Revised Consumer Exposure Assessment presents the 1-year average estimated
consumer formaldehyde concentrations in Appendix C (U.S. EPA 2024d).
1.3.3 Indoor Air Exposure Assessment
Substantial updates have been incorporated into this assessment. The most substantial change is the use
of a second EPA model to better characterize indoor air concentrations of formaldehyde. The Draft Risk
Evaluation for Formaldehyde relied on the CEM to estimate 365-day average formaldehyde
concentrations from articles that may be contributing to long-term indoor air concentrations. This model
is commonly used by EPA to estimate exposure to chemicals in consumer products and articles for
TSCA conditions of use.
In this revised assessment, EPA maintains the CEM assessment. In addition, EPA used the Simulation
Program for Estimating Chemical Emissions from Sources and Related Changes to Indoor
Environmental Concentrations in Buildings with Conditioned and Unconditioned Zones or IECCU to
estimate short-term (15-minute peak), intermediate (3-month), and long term (1-year) concentrations.
This model is better parameterized for volatile organic chemicals like formaldehyde. It provides
exposure decay curves allowing for better characterization of exposure concentrations over time (i.e.,
after an article is introduced to the home). However, available data suggest IECCU may underestimate
long-term exposure concentrations. As such, modeled concentrations for both CEM and IECCU are
Page 24 of 191
-------
presented in the results of this assessment to characterize the potential range of formaldehyde
concentrations in indoor air.
In addition to this updated modeling, this technical support document further characterizes
formaldehyde concentrations in trailer homes, athletic fields with tire crumb surfaces, and government
buildings. Furthermore, feedback and resources from data submissions to the docket (Docket ID: EPA-
HQ-QPPT-2023-0613) were incorporated throughout this assessment.
1.3.4 Ambient Air Exposure Assessment
The ambient air exposure assessment for formaldehyde developed to support this human health risk
assessment has been updated to reflect SACC and public comments. A full description of revisions are
included in the Ambient Air Exposure Assessment for Formaldehyde (U.S. EPA. 2024a). Relevant
revisions impacting this human health risk assessment include:
Daily average modeled formaldehyde concentrations are used to derive acute risk estimates and are
summarized in Section 2.4.2.1.1. Daily average modeled formaldehyde exposures and associated risk
estimates are further characterized by separately presenting exposures and risk estimates attributed to
TSCA COUs and attributed to other sources like airplanes, on-site vehicles, process heaters, turbines,
and reciprocating internal combustion engines in Section 2.4.2.1.1 (exposures) and Section 4.2.4.3 (risk
estimates).
Annual average modeled formaldehyde exposure estimates are used to derive chronic non-cancer and
cancer risk estimates which are now summarized in Section 4.2.4.4 (risk estimates). In addition, data
from both the Toxics Release Inventory and the National Emissions Inventory have been incorporated
(see Section 4.2.4). Lastly, high frequency monitoring data from Texas are included to understand
variation in daily concentrations.
In addition to these changes, EPA lowered the overall confidence in the Ambient Air Exposures
Assessment to medium after reviewing uncertainties in the approach. These include uncertainties related
to input parameters and spatial and temporal differences seen across the multiple lines of evidence. This
assessment was conservative and not site specific. Similarly, the assessment was conducted independent
of the size of the facility footprint, the precise location of the release, and the relative location of
residences. Additional modeling with HEM results provide context on the spatial variability of
formaldehyde concentrations across the U.S. and an approximate understanding of populations exposed.
1.3.5 Human Health Hazard Assessment
The human health hazard assessment has been updated to reflect SACC and public comments as well as
revisions made to the final IRIS assessment (U.S. EPA. 2024k) published August 2024. Specific
revisions include:
The narrative around the cancer IUR and cancer mode of action has been revised to acknowledge SACC
comments and point to sections of the IRIS assessment that are responsive to these comments.
The acute inhalation POD remains the same, but the narrative explaining the selection and interpretation
of that POD has been revised for clarity. The uncertainty factor applied for sensory irritation has been
revised from 10 to 3 and the rationale for the selected uncertainty factor has been expanded.
Page 25 of 191
-------
The chronic inhalation POD and uncertainty factor remain the same, but the narrative has been updated
to reflect changes made in the final IRIS assessment, acknowledge SACC comments, and point to
sections of the IRIS assessment that are responsive to these comments.
The dermal POD and UF remain the same. The narrative has been updated to provide a more robust
explanation for the selection and interpretation of that POD.
The oral PODs and UFs remain the same. The narrative has been revised throughout for clarity and
transparency.
1.4 Chemistry, Fate, and Transport Assessment Summary
EPA considered reasonably available information identified by the Agency through its systematic
review process under TSCA and submissions under FIFRA to characterize the physical and chemical
properties as well as the environmental fate and transport of formaldehyde. This was done as a joint
effort with the OPP. Physical and chemical properties of formaldehyde, as well as some known
environmental transformation products (methylene glycol, paraformaldehyde), are provided in Table
1-1. Formaldehyde is expected to be a gas under most environmental conditions. Due to the reactivity of
formaldehyde, it is not expected to be present in most environmental media but may be abundant in air
due to continual release from multiple sources including from TSCA releases, biogenic sources, and
formation from secondary sources.
Table 1-1. Physical and Chemical Properties of Formaldehyde and Select Transformation
Products11
Chemical Properties
Formaldehyde
Methylene Glycol
Paraformaldehyde
Molecular formula
CH20
CH2(OH)2
HO(CH20)„H
(n = 8-100)
CASRN
50-00-0
463-57-0
30525-89-4
Molecular weight
30.026 g/mol
48.02 g/mol
(30.03)n g/mol (Varies)
Physical form
Colorless gas
Colorless liquid
White crystalline solid
Melting point
-92.0 to-118.3 °C
-43.8 °C
120 to 170 °C
Boiling point
-19.5 °C
131.6 °C
None identified
Density
0.815 g/cm3 at 20 °C
1.20 g/cm3
1.46 g/cm3 at 15 °C
Vapor pressure
3,890 mmHg at 25 °C
3.11 mmHg at 25°C
1.45 mmHg @25 °C
Vapor density
1.067 (air = 1)
None identified
1.03 (air = 1)
Water solubility
<55%; 400 to 550 g/L
Miscible
Insoluble
Octanol/water partition
coefficient (log Kow)
0.35
-0.79
N/A
Henry's Law constant
3.37E-07 atm/m3mol at
25 °C
1.65E-07
atm/m3mol at 25 °C
N/A
11 Physical and chemical properties for formaldehyde, methylene glycol, and paraformaldehyde are considered
best estimates. Because the chemical substance often exists in a mixture at varying concentrations, these
properties can vary based on the equilibration with other chemical substances present.
Page 26 of 191
-------
In water, formaldehyde quickly hydrates to form methylene glycol, which can polymerize to form
oligomers of various chain lengths and paraformaldehyde (U.S. EPA. 2024b)—all structurally different
compounds when compared to formaldehyde (Figure 1-3). Formaldehyde is not expected to be found in
aquatic systems (U.S. EPA. 2024e).
N"
0 n HO OH Urt.
hXh . H' -H — „X ' '«=2-7
ormaldehyde W!ito' methylene glycol mutliPle
I
ho'Ko}1"1
1 Jn=8-100
paraformaldehyde
Figure 1-3. Chemical Equilibria for Formaldehyde in Aqueous Solutions
Adapted from (Bover et al.. 2013).
In soil, formaldehyde is also expected to quickly transform to products that are structurally dissimilar to
parent formaldehyde; thus, formaldehyde is not expected to be found in soil (U.S. EPA. 2024b).
Formaldehyde can be formed in the early stages of plant residue decomposition in soil and is reportedly
degraded by bacteria in the soil (U.S. EPA. 2024b). Formaldehyde is expected to undergo abiotic
(hydration and nucleophilic addition) chemical reactions in soils to form other compounds.
In air, formaldehyde is susceptible to direct and indirect photolysis; however, it may be present in air
environments with low or no sunlight (e.g., nighttime, indoor). As such, the primary exposure route for
formaldehyde is expected to be the air pathway (U.S. EPA. 2024e). More specifically, the half-life of
formaldehyde in air depends on the intensity and duration of sunlight and ambient conditions such as
temperature and humidity. Under direct sunlight, formaldehyde will undergo photolysis with a half-life
up to 4 hours yielding mainly hydroperoxyl radical (HO2), carbon monoxide (CO), and hydrogen (Fh).
In the absence of sunlight, formaldehyde can persist with a half-life up to 114 days.
Due to the physical and chemical properties of formaldehyde including a log Kow (0.35),
bioconcentration and bioaccumulation are not expected (U.S. EPA. 2024b). Therefore, human exposure
to formaldehyde via consumption of fish was not expected and therefore not assessed.
EPA has high confidence in the overall fate and transport profile of formaldehyde and
paraformaldehyde; however, EPA is less confident in the overall fate and transport of the transformation
products methylene glycol and poly(oxy)methylene glycol. Key sources of uncertainty for this
assessment are related to formaldehyde equilibrium in various media and subsequent transformation. In
cases where there are little fate and transport data, EPA relied on physical and chemical properties to
describe the expected fate and transport of the respective chemical. As such, although EPA has some
uncertainty in the precision of a specific parameter value, it has confidence in the overall fate and
Page 27 of 191
-------
transport profile of formaldehyde. Additional details can be found in the Chemistry, Fate, and Transport
Assessment for Formaldehyde (U.S. EPA. 2024b).
1.5 Environmental Release Assessment
Formaldehyde is directly released to all three environmental media (air, land, and water) from TSCA
COUs (U.S. EPA 2024g). It is also released to the environment during other uses (e.g., use as a
pesticide as defined in FIFRA, or use as a food, food additive, drug, cosmetic, or device as defined in the
Federal Food, Drug, and Cosmetic Act), as a transformation product of different parent chemicals, and
from combustion sources.
EPA used release data from TRI (data from 2016 to 2021), Discharge Monitoring Report (DMR; data
from 2016 to 2021), and the 2017 National Emissions Inventory (NEI) to identify releases to the
environment that are relevant to the formaldehyde TSCA COUs. In addition, total releases reported in
2022 were incorporated into the Environmental Release Assessment for Formaldehyde (U.S. EPA.
2024g). Based on a review of these databases, waste streams containing formaldehyde are directly
discharged to surface water, indirectly discharged to publicly owned treatment works (POTW) or other
wastewater treatment (WWT) plants, disposed of via different land disposal methods (e.g., landfills,
underground injection), sent to incineration, and emitted via fugitive and stack releases.
Based on TRI and DMR reporting from 2016 to 2021, less than 150,000 kg each year of formaldehyde
are directly discharged to surface water for TSCA-related activities based on reporting from 168
facilities. Approximately 2 million kg each year are transferred to POTW/WWT plants for treatment
based on reporting from 168 facilities (U.S. EPA. 2024g). For these wastewater streams transferred to
POTW or WWT plants, biological wastewater treatment systems have shown a mean removal efficiency
of 99.9 percent for formaldehyde based on literature and 92 percent removal of methylene glycol
through biodegredation based on EPISuite™ estimates (U.S. EPA. 2024b). These disposal methods
provide additional time for formaldehyde and methylene glycol to further transform to chemically
dissimilar products in the presence of water and chemical, biological, and physical treatment processes
prior to being discharged to surface water.
Based on TRI reporting from 2016 to 2021, most waste of formaldehyde is disposed of via land disposal
methods. The most significant method of land disposal of formaldehyde is via underground injection
with 22 sites disposing of more than 5 million kg of formaldehyde annually. The amount of waste
reported to be disposed of in RCRA Subtitle C landfills and other landfills varies across the reporting
years from 200 facilities reporting a total of 423,517 kg/year in 2016 to 127,348 kg/year in 2021. Other
land disposal methods (e.g., surface impoundments, solidification/ stabilization) are also reported at
lower levels. Formaldehyde is not expected to persist in water or soils; thus, EPA determined that
additional analyses of releases to water or land were not needed and targeted its review of release
information to fugitive and stack emissions of formaldehyde from TSCA COUs.
EPA identified more than 150,000-point source emission data (includes unit-level estimates) for
formaldehyde across the two EPA databases (TRI data from 2016 to 202land 2017 NEI). To
characterize this amount of data, EPA utilized the self-reported NAICS codes to assign sites into CDR
industrial sectors (IS). These industrial sectors can be directly correlated with the TSCA COUs, as
further discussed in the Environmental Release Assessment for Formaldehyde (U.S. EPA. 2024g). Most
TSCA COUs indicate one or more industrial sectors, and in some cases an industrial sector can appear in
more than one TSCA COU. Therefore, an industrial sector may be associated with multiple
formaldehyde TSCA COUs.
Page 28 of 191
-------
For this fit-for-purpose TSCA risk assessment, EPA targeted its review of environmental releases to
point sources, and did not review the road, nonroad, and other automotive exhaust information
identified, as formaldehyde produced from combustion sources is not assessed as an independent COU
subcategory in this risk evaluation. EPA focused its environmental release assessment on total facility
emissions which can include emission from both uses of formaldehyde and combustion sources at the
same facility or, potentially, only combustion sources from that facility.
EPA categorizes the facilities and corresponding release information by industrial sectors that can be
directly correlated to the TSCA industrial COUs. For commercial TSCA COUs, EPA used professional
judgement to assign the industrial sector to commercial TSCA COUs, where applicable. For a few
TSCA COUs (Commercial use - chemical substances in treatment/care products - laundry and
dishwashing products; Commercial use - chemical substances in treatment products - water treatment
products; Commercial use - chemical substances in outdoor use products - explosive materials; and
Commercial use - chemical substances in products not described by other codes - other: laboratory
chemicals), releases were only qualitatively assessed due to limited use information. Additional details
are provided in the Environmental Release Assessment for Formaldehyde (U.S. EPA. 2024g).
In the Environmental Release Assessment for Formaldehyde (U.S. EPA. 2024a), EPA identified
approximately 800 TRI facilities between 2016 and 2021 and approximately 50,000 NEI facilities in
2017 with reported air releases of formaldehyde (U.S. EPA. 2024g). From these facilities, EPA
identified the maximum release reported through TRI was 10,161 kg/year-site (IS: Paper
Manufacturing) for a fugitive release reported in 2019 and 158,757 kg/year-site (IS: Wood Product
Manufacturing) for a stack release reported in 2017. The NEI program identified sites reporting as high
as 138,205 kg/year-site (IS: Wholesale and Retail Trade) for fugitive releases and 1,412,023 kg/year-site
(IS: Oil and gas drilling, extraction, and support activities) for stack releases reporting in 2017, in which
the higher releases are associated with sectors not required to report to TRI. The high release sites in
NEI program were associated with natural gas compressor stations and airport operations, which EPA
expects is due to formaldehyde produced from combustion sources. EPA analyzed the release
information by the industrial sector, providing the minimum, median, 95th percentile, and maximum
releases across the entire distribution of reported releases within each industrial sector, as further
discussed in the Environmental Release Assessment for Formaldehyde (U.S. EPA. 2024g)
In general, EPA has medium to high confidence in environmental releases for industrial TSCA COUs2
and low to medium confidence in commercial TSCA COUs.3 EPA has high data quality ratings for TRI
and NEI, which are supported by numerous facility-reported estimates. Some sites that emit
formaldehyde may not be included in these databases if the release does not meet the reporting criteria
for the respective program. EPA used total emissions per site, which may combine formaldehyde
emissions from multiple TSCA COUs if the site's formaldehyde-generating processes are applicable to
more than one TSCA COU. For example, a facility may manufacture formaldehyde as well as process
formaldehyde as a reactant. In some cases, the formaldehyde-generating process may also fall outside of
scope of the risk evaluation.
EPA categorizes the facilities and corresponding release information by industrial sectors that can be
directly correlated to the TSCA industrial COUs. EPA developed this approach to streamline analysis
using the facility's primary NAICS code. This approach does not use the TRI use codes or NEI SCC
codes, which EPA views as a higher tier characterization. There is some uncertainty if a site's primary
2 TSCA COUs that are included under the life cycle stage of manufacturing, processing, and industrial use.
3 TSCA COUs that are included under the life cycle stage of commercial uses.
Page 29 of 191
-------
NAICS code will assign it to the appropriate COU. For commercial COUs, EPA used professional
judgement to assign the industrial sector to commercial COUs, where applicable. For a few COUs
(Commercial use - chemical substances in treatment/care products - laundry and dishwashing products;
Commercial use - chemical substances in treatment products - water treatment products; Commercial
use - chemical substances in outdoor use products - explosive materials; and Commercial use -
chemical substances in products not described by other codes - other: laboratory chemicals), releases
were only qualitatively assessed due to limited use information. For distribution in commerce,
formaldehyde released accidently during transit has occurred based on available information, but it was
not quantified due to uncertainties in the frequency or volume that may occur in the future. Additional
details are provided in the Environmental Release Assessment for Formaldehyde (U.S. EPA. 2024g).
1.6 Human Health Risk Assessment Scope
Generally, EPA expects inhalation4 to be a major route of exposure for occupational, consumer, indoor
air, and ambient air. Dermal sensitization from formaldehyde exposure is a rapid effect. Thus, for
occupational and consumer COUs where dermal contact to formaldehyde may occur, EPA expects the
dermal route to be another significant route of exposure to formaldehyde.
A quantitative assessment of the water pathway was not conducted in this risk assessment given the
relatively limited release of formaldehyde directly to surface water, and due to the rapid transformation
of formaldehyde in water based on the physical and chemical properties governing the environmental
fate of formaldehyde in water. Water monitoring data, while limited, demonstrate formaldehyde is rarely
detected in water as described in more detail in the environmental exposure assessment (U.S. EPA
2024e). Based on these lines of evidence, EPA does not expect human exposure to formaldehyde will
occur via surface water. In addition, formaldehyde is not expected to persist in land or leach to
groundwater that may be sourced for drinking water based on the physical and chemical properties
governing the environmental fate of formaldehyde in land. Therefore, EPA does not expect human
exposure to formaldehyde will occur via soil, land, or groundwater.
1.6.1 Conceptual Exposure Models
1.6.1.1 Industrial and Commercial Activities and Uses
The conceptual model in Figure 1-4 presents the exposure pathways, exposure routes and hazards to
people from industrial and commercial activities and uses of formaldehyde. EPA evaluated exposures to
workers and occupational non-users (ONU) via inhalation routes and exposures to workers via dermal
routes as shown in Figure 1-4. Oral exposure may occur through products that can generate particulates
such as wood or textile dust that deposit in the upper respiratory tract that is then ingested; however,
formaldehyde will continue to evaporate and there is uncertainty on the amount inhaled that is ingested.
For this risk evaluation, these exposures were evaluated as an inhalation exposure.
4 In this formaldehyde risk evaluation, references to "acute inhalation" exposure, hazard and risk are intended to refer broadly
to air concentrations of formaldehyde that may cause sensory irritation from both eye exposure and from inhalation
(breathing in air).
Page 30 of 191
-------
INDUSTRIAL AND COMMERCIAL
ACTIVITIES / USES
EXPOSURE PATHWAY
EXPOSURE ROUTE
RECEPTORS
HAZARDS
Manufacturing
Processing
-As a reactant intermediate
-Incorporation into an article
-Incorporation into formulation, mixture, or reaction
product
Xon-Incorporative Activities
Adhesives and Sealants
Arts, Craft and Hobby
Materials
Automotive Care
Products
Building/Construction
Materials- wood and
engineered wood
products and other
products
Laboratorv Chemicals
Laundry and
dishwashing products
Lawn Products
Cleaning and Furniture
Care Products
Electrical Products
Metal Products
Packaging
Explosive Products
Fabric, Textile, and
leather products not
elsewhere
Paints and Coatings
Floor Coverings
Foam Setting and
Bedding Products
Paper Products
Photographic Supplies
Fuel and related
products
Toys, playground and
sporting equipment
Water Treatment
Products
Recycling
~Q
Waste Handling, Treatment, and
Disposal
Furniture and
Furnishings not covered
elsewhere
Ink, toner, and colorant
products
Lubricants and greases
Personal Care Products
Hazards potentially
associated with acute
and'or chronic
exposures
Wastewater, Liquid wastes, and Solid Wasters
(See Environmental Release Conceptual Model)
Figure 1-4. Conceptual Model for Industrial and Commercial Activities and Uses: Potential Exposure and Hazards
Page 31 of 191
-------
Note that fugitive air emissions, as described in Figure 1-4, are those that are not stack emissions and
include fugitive equipment leaks from valves, pump seals, flanges, compressors, sampling connections
and open-ended lines; evaporative losses from surface impoundment and spills; and releases from
building ventilation systems.
1.6.1.2 Consumer Exposure
Formaldehyde is found in consumer products and articles that are readily available for public purchase
at common retailers and through online shopping venues. Formaldehyde may be either a chemical
ingredient in a consumer product or a component in material(s) utilized in the manufacturing of
consumer products or articles (adhesives, resins, glues, etc.) or both. Use of such product is expected to
result in exposures to both consumers who use a product (consumer user) and bystanders (individuals
who are not directly using a product but are exposed while the product is being used by someone else).
Figure 1-5 presents the conceptual model for consumer activities and uses that are in scope for the
TSCA formaldehyde risk evaluation. Formaldehyde-containing consumer products include textiles,
foam bedding/seating, semiconductors, resins, glues, composite wood products, paints, coatings,
plastics, rubber, resins, construction materials (including roofing), furniture, toys, and various adhesives
and sealants. EPA identified these formaldehyde COUs from information reported to EPA through CDR
and TRI reporting, published literature, and consultation with stakeholders for products currently in
production or not discontinued.
Page 32 of 191
-------
CONSUMER ACTIVITIES &
USES
EXPOSURE
PATHWAY
EXPOSURE
ROUTE
EXPOSED
GROUP
HAZARDS
Arts, crafts, and hobby
materials
Floor coverings: Foam
seating and bedding
products: Furniture &
furnishings: Cleaning
and furniture care
products; Textile
fimshins. etc.
Construction and
buildins materials
covering larse surface
areas, including wood,
metal, paper articles,
etc.
Machinery; mechanical
appliances, electrical
electronic articles, etc.
Ink, toner, and colorant
products: Photographic
supplies
Automotive care
products; Lubricants and
greases; Fuels and
related products
—I-*
Fabric, textile, and
leather products not
covered elsewhere
(clothing)
Adhesires and Sealants.
Paint and coatines
Paper products; Plastic
and rubber products:
Toys, and playground
equipment
^Lujuid^
Vlist
Dermal
Consumer Handling of
Disposal and Waste
Consumers
Vapor, Mist
>r
Inhalation
Hazards Potentially
Associated with Acute
and oi Chrome
Exposures
Wastewater, Liquid Wastes and
Solid Wastes (See Environmental
Releases Conceptual Models)
Figure 1-5. Formaldehyde Conceptual Model for Consumer Activities and Uses: Potential Exposures and Hazards
Page 33 of 191
-------
Some consumer products assessed may also have commercial applications. Inhalation is the primary
expected route of exposure for formaldehyde resulting from consumer activities, however, dermal
exposures are also expected. EPA considered potential oral exposure pathways associated with TSCA
COUs, including lawn and garden products and oral mouthing behaviors in infants and young children.
However, because EPA lacks sufficient data to quantify exposures and risks for any of these pathways,
oral exposures were qualitatively assessed for relevant COUs (e.g., lawn and garden products). Section
2.2 of the Consumer Exposure Module for Formaldehyde (U.S. EPA. 2024d) provides more detail about
the COUs within the scope of this risk evaluation.
1.6.1.3 Indoor Air Exposures
People are exposed to formaldehyde regularly indoors due to off-gassing of formaldehyde from various
sources. Some of these exposures may be caused by the offgassing from TSCA COUs while others are
from other sources of formaldehyde like wood burning in a fireplace. The conceptual model in Figure
1-6 presents the exposure pathways, exposure routes and hazards to people from assessed TSCA COUs.
Page 34 of 191
-------
CONSUMER ACTIVITIES &
USES
EXPOSURE
PATHWAY
Floor coverings; Foam seating
and bedding products; Furniture
& furnishings; Cleaning and
furniture carc products; Textile
finishing, etc.
Fabric, textile, and leather products
not covered elsewhere (clothing)
Construction and building
materials covering large surface
areas, including wood, metal,
paper articles, etc.
Paper products; Plastic and
rubber products; Toys, and
playground equipment
Consumer Handling of
Disposal and Waste
Indoor Air/Vapor
Solid Wastes (See
Environmental Releases
Conceptual Models)
EXPOSURE
ROUTE
EXPOSED
GROUP
HAZARDS
Inhalation
-------
1.6.1.4 Ambient Air Exposures
Ambient air formaldehyde concentrations are highly variable based on location, releases, weather
conditions, and other sources of formaldehyde. Communities - particularly those near releasing facilities
and especially some facilities with releases attributed to combustion - were considered in this human
health risk assessment.
While formaldehyde is susceptible to direct and indirect photolysis, it is expected to be present in the
ambient air for at least several hours in direct sunlight (and many more hours in no sunlight) based on
the chemical, fate, and transport properties of formaldehyde as described in the Chemistry, Fate, and
Transport Assessment for Formaldehyde (U.S. EPA. 2024b) and Section 1.2.3. Formaldehyde is
consistently present in ambient air based on monitoring and testing programs implemented under the
Clean Air Act and other EPA programs and statutes. This can be due to TSCA sources of formaldehyde
as well as other sources formed through biological activity (biogenic) or through the breakdown of other
chemicals (secondar formation). Data from the Air Tox Screening Assessment demonstrate the potential
contribution of some of these sources. Considering these lines of evidence, EPA quantitatively assessed
the ambient air pathway in this risk assessment.
Figure 1-7 provides a detailed conceptual model of all pathways and all routes considered for this
assessment. While environmental releases are reported to all three environmental media, formaldehyde
is not expected to be present in water or land based on the chemical, fate, and transport properties of
formaldehyde as described in the Chemistry, Fate, and Transport Assessment for Formaldehyde (U.S.
EPA. 2024b) and discussed in Section 1.2.3. As such, EPA does not expect general population exposure
to formaldehyde to occur via either the water or land media and therefore did not quantitatively assess
exposures via these media in this risk assessment. This is depicted in Figure 1-7 by the dashed lines.
Page 36 of 191
-------
RELEASE S AMI WASIES FROM INDUSTRIAL EXPOSURE PATHWAYS
C OMMERCXAL t CO PIER USES EXPOSURE ROUTE S REC EPTOR S
Figure 1-7. Formaldehyde Conceptual Model for Environmental Releases and Wastes: General Population Exposures and Hazards
Page 37 of 191
-------
Figure 1-8 provides a simplified visual representation of how industrial releases to ambient air can lead
exposure for communities located near industrial releases. In general, formaldehyde is released from
industrial facilities as either uncontrolled fugitive releases (e.g., process equipment leaks, process vents,
building windows, building doors, roof vents) or stack releases that may be either uncontrolled (e.g.,
direct releases out a stack) or controlled with some pollution control device prior to release to the
ambient air (e.g., baghouse, scrubber, thermal oxidizer). Once released, formaldehyde will mix with air
in the atmosphere, move into the surrounding areas, and may be subsequently inhaled if communities
are located nearby. Thus, EPA assessed exposures for individuals living near industrial facilities
associated with TSCA COUs that are releasing formaldehyde.
Movement of chemicals
between source(s) and media
Emissions
from
Source
Communities
near Release
Sites
Breathing Zone
Inhalation
Figure 1-8. Industrial Releases to the Environment and Pathways by Which Exposures to the
People May Occur
1.6,2 Potentially Exposed or Susceptible Subpopulations
This assessment considers potentially exposed or susceptible subpopulation (PESS), 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. There are many factors that may contribute to
increased exposure or biological susceptibility to a chemical, including life stage (e.g., infants, children,
pregnant women, elderly), pre-existing disease, lifestyle activities (e.g., smoking, physical activity),
occupational and consumer exposures (including workers and ONUs, consumers and bystanders),
geographic factors (living in proximity to a large industrial source of formaldehyde), socio-demographic
factors, unique activities (e.g., subsistence fishing), aggregate exposures, and other chemical and non-
chemical stressors.
Page 38 of 191
-------
Considerations related to PESS may influence the selection of relevant exposure pathways, the
sensitivity of derived hazard values, the inclusion of populations, and/or the discussion of uncertainties
throughout the assessment.
Page 39 of 191
-------
2 HUMAN EXPOSURE ASSESSMENT SUMMARY
This section summarizes the formaldehyde exposures to occupational workers, ONUs, consumers,
bystanders, and general population from both indoor air and ambient air. Detailed information
supporting each subsection are available in the associated technical support documents included as
supplemental files to this human health risk assessment for formaldehyde.
Each exposure assessment considers peak and long-term inhalation exposures. When available, the
highest 15-minute average concentrations are used to represent peak exposures while annual average
concentrations or 8-hour time-weighted averages (TWA) are used to represent longer-term exposure
durations. The long-term exposure duration depends on the exposure scenario being assessed.
Specifically, exposure durations for cancer assessments are based on 31 (central tendency) and 40 (high-
end) working years for occupational exposure. Exposure durations for cancer assessment are based on
12- or 57-year residency time and 78-year lifetime exposure for consumer and general population. Acute
dermal exposures were estimated for workers and consumers and are based on short-term durations, see
Appendix G for additional information on the dermal approaches.
Each exposure assessment integrates modeling methodologies previously peer reviewed as well as
monitoring data to assess exposures to the respective populations. The exposure assessment also
integrates information from the Chemistry, Fate, and Transport Assessment for Formaldehyde (U.S.
EPA. 2024b) and the Environmental Release Assessment for Formaldehyde (U.S. EPA. 2024g).
2.1 Occupational Exposure Assessment
EPA identified 50 TSCA COUs under manufacturing, processing, industrial/commercial uses, and
disposal. In the Occupational Exposure Assessment for /' Ormaldeh yde (U.S. EPA. 20241). EPA evaluated
occupational exposure scenarios (OESs) based on the COUs with expected worker activities, inhalation
exposure estimates, and dermal exposure estimates for each OES (U.S. EPA. 20241). Several of the
TSCA COU categories and subcategories were grouped and assessed together into a single OES due to
similarities in the processes or lack of data to differentiate between them. This grouping minimized
repetitive assessments. In other cases, TSCA COU subcategories were further delineated into multiple
OESs based on expected differences in processes and associated releases/exposure potentials between
facilities. This resulted in assessing 35 OESs for inhalation and dermal exposure. For additional details
on the approaches and results, please refer to Occupational Exposure Assessment for Formaldehyde
(U.S. EPA. 20241V
2.1.1 Inhalation Exposure Assessment
To assess inhalation exposures from formaldehyde, EPA reviewed workplace inhalation monitoring data
from government agencies such as Occupational Safety and Health Administration (OSHA), inhalation
monitoring data found in peer-reviewed literature, and other inhalation monitoring data submitted to
EPA. Where monitoring data were reasonably available, EPA used these data to characterize central
tendency and high-end short-term and full shift inhalation exposures for each scenario (OES) to workers
and ONUs. The quality of the monitoring data was evaluated using the data quality review evaluation
metrics and the categorical ranking criteria described in the Draft Systematic Review Protocol
Supporting TSCA Risk Evaluation for Chemical Substances (U.S. EPA. 2021c). Relevant data were
assigned an overall quality determination of high, medium, low, or uninformative. For evidence
integration, preference was given to discrete monitoring data sampled in the United States, and after the
latest update of the OSHA permissible exposure limit (PEL) of formaldehyde in 1992 to 937 |ig/m3
(0.75 ppm) and short-term exposure limit (STEL) to 2,498 |ig/m3 (2.0 ppm). This reduces uncertainties
Page 40 of 191
-------
with relying on data that may not reflect the conditions in the U.S. and the current regulatory
requirements for TSCA COUs.
For many cases, EPA did not have monitoring data to estimate inhalation exposure for ONUs. In such
cases for full-shift exposures, EPA used the central tendency of worker exposure estimates. However,
EPA did not quantify short exposures for ONUs. In general, EPA expects ONU exposures to be similar
or less than worker exposures.
For some of the OESs, inhalation monitoring data were not identified. For these cases, EPA utilized
models including using a Monte Carlo simulation and Latin Hypercube sampling method to estimate
inhalation exposures. Where available, the EPA used generic scenarios or emission scenario documents
for relevant exposure points and model input parameters.
Monitoring data were available to support exposure estimates for all COUs except for four COUs that
relied on modeled estimates:
• Industrial use - Non-incorporative activities - Process aid in: oil and gas drilling, extraction, and
support activities; process aid specific to petroleum production, hydraulic fracturing
• Commercial use - chemical substances in automotive and fuel products - automotive care
products; lubricants and greases; fuels and related products;
• Commercial use - chemical substances in agriculture use products - lawn and garden products;
and
• Commercial use - chemical substances in treatment products - water treatment products.
Across TSCA COUs for short-term exposure estimates, the central tendency of air concentration
estimates up to 2,002 |ig/m3 (1.6 ppm) and high-end of air concentration estimates up to 209,815 |ig/m3
(171 ppm). The TSCA COU of Manufacturing showed formaldehyde concentrations above other
scenarios, with high-end and central tendency of air concentration results of 209,815 |ig/m3 and 736
|ig/m3, respectively. The underlying scenario was based on monitoring data from manufacturing sites
within the United States, which included tasks where the workers wore respiratory protection.
Across TSCA COUs for full-shift estimates, the central tendency of air concentration estimates ranged
from 0.0114 to 540 |ig/m3 (9.34E-06 to 0.44 ppm) and high-end of air concentration estimates ranged
from 8.59 to 17,353 |ig/m3 (0.007 to 14 ppm). The TSCA COU of Commercial use - chemical
substances in automotive and fuel products - automotive care products; lubricants and greases; fuels and
related products showed formaldehyde concentrations above other scenarios. The underlying scenario
was modeled using a Monte Carlo simulation and assumed that no engineering controls were present.
The first modeling approach resulted in a high-end and central tendency of air concentrations results of
17,353.3 |ig/m3 and 499.3 |ig/m3, respectively and assumes that formaldehyde within the automotive
care product is completely evaporated during duration of application. This results in a very conservative
high-end estimate, well above the current OSHA PEL. EPA also used a second modeling approach using
monitoring data on total volatile organic compounds to estimate 1,874 |ig/m3 and 371 |ig/m3.
EPA uses short-term exposure air concentration estimates to calculate acute exposure concentrations
(AECs), which is used to estimate acute, non-cancer risks. Full-shift exposure estimates can also be used
for acute, non-cancer risks. The full-shift (8- or 12-hour TWA concentrations) are used to calculate
average daily concentrations (ADCs) and lifetime average daily concentrations (LADCs). The ADC is
used to estimate chronic, non-cancer risks and the LADC is used to estimate chronic, cancer risks. These
calculations required additional parameter inputs, such as years of exposure (31 or 40 year worker
Page 41 of 191
-------
tenure), exposure duration and frequency (167 or 250 days), and lifetime years (78 years). See Appendix
F for more information about parameters and equations used to calculate acute and chronic exposures.
2.1.2 Dermal Exposure Summary
Dermal exposure data were not reasonably available for any of the formaldehyde OESs. Therefore, the
EPA modeled dermal exposure to workers using a modified version of the EPA Dermal Exposure to
Liquids Model. As the health effect of concern for formaldehyde is the result of exposure at the point of
contact, as opposed to the chemical absorbing into the skin, the absorption factor, body weight, and
surface area were not necessary for the calculation of dermal exposure. The calculation reduces to an
assumed amount of liquid on the skin during one contact event per day adjusted by the weight fraction
of formaldehyde in the liquid to which the worker is exposed.
EPA only evaluated dermal exposures for workers since ONUs are not assumed to directly handle
formaldehyde. EPA did not quantify dermal exposure for two COUs: Distribution in commerce and
Commercial use - chemical substances in packaging, paper, plastic, hobby products - paper products;
plastic and rubber products; toys, playground, and sporting equipment as dermal contact was expected
with solid articles that contain low residual formaldehyde concentrations.
EPA used the maximum formaldehyde concentrations, which is the highest concentration level of
formaldehyde that a worker handles throughout the process. EPA used concentration data from
published literature and CDR to develop high-end and central tendency dermal exposure estimates.
The dermal exposure estimates ranged from 0.56 to 1140 |ig/cm2 for central tendency exposures, and
0.84 to 3,090 |ig/cm2for high-end exposures. The high-end dermal retained dose for four COUs had a
value of 3,090 |ig/cm2, which is well above the other dermal exposure estimates:
• Commercial use - chemical substances in automotive and fuel products - automotive care
products; lubricants and greases; fuels and related products and
• Processing - incorporation into an article - paint additives and coating additives not described by
other categories in transportation equipment manufacturing [including aerospace];
• Industrial use - paints and coatings; adhesives and sealants; lubricants; and
• Commercial use - chemical substances in construction, paint, electrical, and metal products -
adhesives and sealants; paint and coatings.
For manual spray applications, EPA expects dermal exposures to be higher. Spray applications are
expected for the use of automotive care products and coatings, paints, adhesives, or sealants. In addition,
during the use of automotive care products, workers may use immerse rags in the detailing products,
which could lead to higher dermal loading. For both OESs, EPA assumed an immersive dermal loading
(HE: On of 10.3 mg/cm2) on the skin during the exposure scenario. For other OESs, EPA calculated
dermal exposures assuming lower dermal loadings based on expected worker activities (HE: On of 2.1
mg/cm2).
2.2 Consumer Exposure Assessment
This Consumer Exposure Assessment focuses on users of consumer products and articles and those that
may be exposed as a result. EPA identified 24 exposure scenarios (from 12 formaldehyde TSCA COUs)
that may lead to consumer or bystander exposures. EPA's Consumer Exposure Model (CEM) Version
3.0 was used to estimate the 15-minute peak and 1 year-average daily concentrations for inhalation
exposures to consumer users and bystanders, and the dermal loading during relevant product and article
use. For the inhalation route, 15-minute peak exposures were emphasized for risk characterization, as
presented below, but all results from modeled exposure durations (e.g., 15-minute, 1 year) are included
Page 42 of 191
-------
in the risk calculator (U.S. EPA. 2024i)5. The key conclusions of the consumer exposure assessment are
summarized in the Consumer Exposure Assessment (U.S. EPA. 2024cT) and below.
2.2.1 Conditions of Use and Considerations for their Assessment
EPA quantified exposures exposure pathways, routes, and timespans of exposure and exposure scenarios
for which EPA had at least a medium confidence. As presented in Table 1-1 of the Consumer Exposure
Assessment for Formaldehyde (U.S. EPA. 2024d). EPA quantified exposures for all relevant COUs for
at least one route of exposure where appropriate.
Each TSCA COU may comprise multiple exposure scenarios and multiple scenarios may be applicable
to multiple COUs. To simplify, representative scenarios were identified for each TSCA COU per
relevant exposure assessment. Representative scenarios were identified according to the highest
estimated exposure estimate per assessment. Refer to Appendix B of the Consumer Exposure
Assessment for Formaldehyde (U.S. EPA. 2024d) for a list of representative consumer exposure
scenarios according to TSCA COUs.
EPA did not quantify exposures for COUs in which EPA had a low exposure assessment confidence.
For example, no dermal loading estimate was generated for machinery, mechanical appliances, and
electrical/electronic articles because the best available tools and data could not support an effective
assessment. In addition, EPA is not quantitatively assessing the following COUs:
• Water treatment products: No supporting products could be identified to assess formaldehyde
from residential water treatment.
• Laundry and dish washing products: No supporting products could be identified to assess
formaldehyde from laundry and dish washing products.
Furthermore, EPA qualitatively assessed Lawn and garden products: The non-pesticidal exposure
scenario for this TSCA COU is unclear because when mixed in water, formaldehyde is highly reactive.
In addition, EPA's CEM assumes no inhalation exposure from such products. This is likely due to the
default assumption that such activities typically occur outdoors where the chemical would be diluted in
the ambient air during and after use.
In 1982, the U.S. Consumer Product Safety Commission (CPSC) banned the sale of urea formaldehyde
foam insulation (UFFI) for use in residences and schools, as a result of associated health concerns (47
FR 1662, January 13, 1982). However, this ban was reversed in 1983 (see GulfS. Insulation v. United
States Consumer Prod. Safety Com., 701 F.2d 1137 (5th Cir. 1983)). Furniture articles have been
reported to contain formaldehyde. During the public comment period for the draft scope of
formaldehyde, the North American Insulation Manufacturers Association submitted a comment that
stated, "For those insulation products in which formaldehyde is a component of the binder, the products
are cured at high temperatures during the manufacturing process after the binder has been applied,
virtually eliminating the free formaldehyde content. Any free formaldehyde released from the binder
during heat cure is destroyed either during the cure process or by emissions control equipment required
by the [Maximum Achievable Control Technology] MACT standard.... Therefore, formaldehyde off-
gassing from the majority of finished products is highly unlikely" (Docket ID EPA-HQ-QPPT-2019-
0131-0029). Given this information, formaldehyde consumer exposures to foam insulation may be
negligible. However, formaldehyde offgassing has been reported from such materials in the literature
5 The risk calculator for both the Consumer and Indoor Air inhalation exposure assessments are embedded within the
supplemental file titled "21. Acute and Chronic Inhalation Risk Calculator for Consumer and Indoor Air for Formaldehyde
Supplement C.xlsx"
Page 43 of 191
-------
(Maddalena et al.. 2009). Therefore, EPA considered the quantification of such exposures from
upholstery that are used by consumers and in indoor air.
Lastly, for electronic products, surrogate information from adhesives and sealants was used to estimate
inhalation exposure. The Agency believes this is an appropriate substitution because adhesives and
sealants are used in the binding of internal components, especially at the seams.
2.2.2 Summary of Consumer Exposure Assessment Results
A detailed analysis for consumer exposures can be found in Consumer Exposure Assessment for
Formaldehyde (U.S. EPA. 2024d). Modeled formaldehyde concentrations depended upon the room of
use, amount of the chemical in the product, and consumer use patterns (e.g., amounts used). Peak
inhalation results are shown in Figure 2-1. Users of consumer products and articles (Near Field) had
higher peak and long-term inhalation exposures when compared to bystanders who are in the same room
(Far Field). Similarly, users of consumer products and articles and bystanders in the same room (Zone
1) were estimated to have higher exposures than individuals in the same house (Zone 2). Across all
relevant age groups and exposure scenarios, the highest estimated 15-minute peak formaldehyde air
exposure was for consumer users of adhesives and sealants; paints and coatings, while the lowest 15-
minute peak exposure was for individuals using textiles or clothing that emit formaldehyde (Figure 2-1).
Dermal exposures are shown in Figure 2-2. The highest acute dermal loading for consumer users
resulted from use of automotive care products. The lowest acute dermal loading resulted from use of
arts, crafts, and hobby materials .
Page 44 of 191
-------
Adhesives and Sealants; Paint and coatings
Paper products; Plastic and rubber products; Toys,
playground, and sporting equipment
Floor coverings; Foam seating and bedding
products; Cleaning and furniture care products;
Furniture & furnishings including stone, plaster,
cement, glass and ceramic articles; metal
articles; or rubber articles
3
o
o
Ink, toner, and colorant products; Photographic
supplies
Construction and building materials covering
large surface areas, including wood articles;
Construction and building materials covering
large surface areas, including paper articles;
metal articles; stone, plaster, cement, glass and
ceramic articles
Automotive care products; Lubricants and greases;
Fuels and related products
Arts Crafts and Hobby Materials
Fabric, textile, and leather products not covered
elsewhere (clothing)
+
+
Zone
• Far Field
A Near Field
¦ Zone 1
+ Zone 2
_j i i i
I
i i i i
10 1tf
Peak 15-min Concentration (ng/m3)
Figure 2-1. Summary of 15-Minute Peak Consumer Inhalation Concentrations (Based on CEM)
For some products, air concentrations were modeled for near-field and far-field (generally describing differences in exposure within the same room), while
for other products, concentrations were modeled for zones 1 and 2 (generally describing different rooms). Risks from near-field and zone 1 exposures
generally represent risks from direct exposures to consumer users while far-field and zone 2 tend to represent risks to consumer bystanders. The x-axis
presents the 15-minute peak inhalation non-cancer concentration, and the y-axis presents the modeled TSCA COU.
Page 45 of 191
-------
Polish and wax - (Exterior Car Wax and.
Polish)
Photographic Supplies - (Liquid photographic.
processing solutions)
ro
c
a)
o
C/D
TD
a)
a)
TD
O
Adhesives and Sealants - (Glues and
Adhesives, small or large scale)
Cleaning and Furnishing Care Products -
(Textile & Leather Finishing (stain remover,
waterproofing, tanning))
Building / Construction Materials
(Liquid-based concrete, cement, plaster-
(prior to hardening))
Arts, Crafts, and Hobby Materials - (Crafting.
Paint (direct and incidental contact))
,,
Modeled
Exposure Level
¦ High
.
101 10' 1(T
Acute Dermal Loading Concentration (jjg/cm2)
Figure 2-2. Summary of Acute Consumer Dermal Concentrations (Based on Thin Film Model)
The x-axis presents dermal loading concentration, and the y-axis presents the modeled TSCA COUs. The term
"High" in the figure refers to high-end scenarios as described above.
2.3 Indoor Air Exposure Assessment
A detailed analysis for indoor air can be found in the Indoor Air Exposure Assessment for Formaldehyde
(U.S. EPA. 20240. The separation of the Consumer Exposure Assessment and the Indoor Air Exposure
assessment is intentional. As mentioned in section 2.2, the Consumer Exposure Assessment focuses on
users of consumer products and articles and those that may be exposed as a result. The Indoor Air
Assessment focuses on scenarios where an article may be newly introduced to a home and subsequently
off gasses formaldehyde. In the draft Risk Evaluation for Formaldehyde, indoor air exposures were
expected to be primarily driven by long-term and continuous exposure scenarios, primarily focusing on
Page 46 of 191
-------
persistent and/or significant article emissions of formaldehyde after being installed in a home. These
exposures were assessed with CEM. For the revised Risk Evaluation, EPA additionally assessed short-
term (i.e., 15-minute peak), intermediate (i.e., 3-month), and long-term (i.e., 1-year) formaldehyde
indoor air inhalation exposures from articles (e.g., wood, wallpaper, seat covers, etc.). These exposures
were assessed using IECCU.
2.3.1 Conditions of Use and Considerations for their Assessment
EPA assessed four conditions of use for the Indoor Air Exposure Assessment. The CEM assessment
conducted for the draft Risk Evaluation and maintained in the revised assessment includes six exposure
scenarios. The revised Indoor Air Exposure Assessment additional uses IECCU to assess the same
conditions of use for four representative scenarios and two aggregate scenarios. Both approaches have
been included to bolster confidence in this overall assessment.
2.3.2 Summary of Assessment Approach
EPA considered both monitoring data and models to estimate indoor air concentrations of formaldehyde.
Measured formaldehyde concentrations were collected for residential, commercial, and automobile
environments. Two modeling tools were used to estimate formaldehyde concentrations from TSCA
COUs. EPA used CEM to estimate 1-year average indoor air concentrations from articles. In addition,
EPA used IECCU to estimate 15-minute, 3-month, and 1-year concentrations of formaldehyde for
indoor air. For more information on the differences between these two models, see thq Indoor Air
Exposure Assessment for Formaldehyde (U.S. EPA. 2024i).
As mentioned, EPA used monitoring data to characterize measured indoor air concentrations of
formaldehyde. The monitoring data for this assessment is robust and nationally representative. EPA used
information collected through the systematic review process and leveraged monitoring data collected
through the American Health Homes Survey II. These monitoring data do not differentiate between
TSCA COUs assessed in this evaluation and other sources of formaldehyde like gas stoves. Monitoring
data are presented and discussed further in Section 2.3.3.
EPA used CEM as a screening tool and IECCU to refine its assessment of formaldehyde in residential
indoor air. IECCU is specifically designed to assess indoor air exposures. Using both models provides
the potential range of formaldehyde concentrations in indoor air given the uncertainties of both models.
CEM is expected to provide the highest concentrations while IECCU is expected to provide the lowest
concentrations for TSCA COUs. Where CEM was used to estimate concentrations of formaldehyde in
vehicular air, IECCU was not as this is a limitation of that model. Thus, CEM modeling results are the
only estimates provided for the associated TSCA COUs and are considered the best available. CEM's
results are presented and discussed further in Section 2.3.4 and IECCU's results are presented in Section
2.3.5.
2.3.3 Indoor Air Exposure Monitoring Results
EPA identified over 800 monitoring studies, -290 of which are specific to the indoor air environment
and associated with the 12 TSCA COUs subject to this risk evaluation (see Appendix A of the Indoor-
Air Exposure Assessment for Formaldehyde (U.S. EPA. 2024iV). As was presented in Section 3.2.2 of
the 2016 Formaldehyde Exposure Assessment Report TSCA Title VI Final Rule (U.S. EPA. 2016b). EPA
presents a supplemental summary of formaldehyde concentrations identified from several well-
established residential (Table 2-1, Figure 2-3) and commercial (Table 2-2) indoor air monitoring studies
to provide additional context to the TSCA formaldehyde indoor air exposure assessment. From a
comparison of residential (Table 2-1) and commercial (Table 2-2) indoor air monitoring, residential
indoor air exposures to formaldehyde are generally expected to be higher compared to commercial
Page 47 of 191
-------
buildings due to expected lower room volumes and air exchange rates in residences relative to
commercial buildings.
Table 2-1. Indoor Air Monitoring Concentrations for Formaldehyde
Reference
Monitoring Study Description
Formaldehyde Concentrations (jig/m3)
Central Value
Range/Percentiles
(ATSDR. 2007)
96 unoccupied FEMA trailers
assessed during the summer of
2006
Mean: 1,280
Range: 12.28-4,500
American Healthy
Home Survey
(OuanTech, 2021)
Nationally representative
sample of 689 U.S. homes of
various ages, types, conditions,
and climates
Mean: 23.2
Range (lower/upper 95%
tiles of mean): 21.4-24.9
(California Air
Resources Board,
2004)
Portable and traditional
classrooms in
67 California schools (Phase II
study)
Arithmetic Mean:
18.42 (portable)
14.74 (traditional)
95th Percentile:
31.93 (portable)
27.02 (traditional)
(Gilbert et al., 2005)
59 homes in Prince Edward
Island, Canada
Geometric Mean: 33.16
Range: 5.53-87.33
(Gilbert et al., 2006)
96 homes in Quebec City,
Canada
Geometric Mean: 29.48
Range: 9.58-89.91
(Hodsson et al.,
2004)
4 new relocatable classrooms
Unspecified Mean:
9.83 (indoor-outdoor)
Range: 4.91-14.74
(indoor-outdoor)
(Hodsson et al.,
2000)
New homes in eastern/SE U.S.:
4 new manufactured homes
7 new site-built homes
Geometric Mean:
41.76
44.22
Range:
25.79-57.73
17.2-71.24
(Liu et al., 2006)
234 homes in Los Angeles
County, CA; Elizabeth, NJ; and
Houston, TX
Median: 20.02
Range:
12.53-32.43
(5th-95th percentiles)
(LBNL. 2008)
4 FEMA camper trailers
Unspecified Mean:
568.67
Range: 330.39-924.85
(Murohv et al., 2013)
Sample:
All structures (519)
Travel trailers (360)
Park models (90)
Mobile homes (69)
Geometric Mean:
94.57
99.49
54.04
70.01
Range:
3.68-724.65
3.68-724.65
3.68-196.52
13.51-393.03
(Offermann et al.,
2008)
108 new SF homes in CA
Median: 38.2
Range: 4.67-143.33
(Sax et al., 2004)
Inner-city homes:
NY City (46) - winter (W),
summer (S)
Median:
12.28 (W), 18.42 (S)
Range:
4.91-22.11 (W), 6.14-
50.36 (S)
Los Angeles (41) - winter (W),
fall (F)
18.42 (W), 14.74 (F)
7.37-55.27 (W), 7.37-
31.93 (F)
Page 48 of 191
-------
Table 2-2. Formaldehyde Monitored in U.S. Commercial Buildings from 2000 to Present
Reference
Monitoring Study Description
Formaldehyde
Concentrations
(iug/m3)
Descriptor
(Ceballos and
Burr. 2012)
Office space indoor air monitoring for
formaldehyde in a commercial building
24.56
Average
(U.S. EPA. 2023)
Indoor air monitoring across 100
randomly selected U.S. commercial
buildings
3.68
5th percentile
14.74
50th percentile
30.71
95th percentile
(Pase and Couch,
2014)
Indoor air U.S. government offices
<61.41
Maximum
(Lukcso et al„
2014)
12.28
Geometric mean
56.50
Maximum
(Dodson et al.,
2007)
Classrooms in school buildings in the
United States
17.69
Median
Page 49 of 191
-------
CD
O
i_
13
O
CO
ro
15
Q
O)
o
"c
o
100
96 unoccupied FEMA tra lers
4 FEMA camper tra lers
All structures (519)
Travel trailers (360)
Mobi e homes (69)
Park models (90)
108 new SF homes in CA
Inner-city homes
Various
96 homes in Quebec City, Canada
Canada
7 new site-built homes
U.S. government offices (A)
4 new manufactured homes
U.S. government offices (B)
Los Angeles (41) - Winter
NY City (46) - Summer
New homes in eastern/SE U.S.
59 homes in Prince Edward Island
Elizabeth, NJ; and Houston, IX
Los Angeles (41) - Fall
Portable Classroom
randomly selected U.S. commercial buildings
Traditional Classroom
Office space in commercial building
NY City (46)-Winter
234 homes in Los Angeles County CA
Classrooms in U.S. school buildings
4 new relocatab e classrooms
Metric
Range
Reported
Central
Tendency
_l I I I '''' I I L
t
I i 1111
_i i i i i 111 i i i i i
10" 101 102 10J
Indoor Air Concentration (|jg/m3)
Figure 2-3. Long-Term Average Daily Concentrations of Formaldehyde According to Air Monitoring Data Source
Page 50 of 191
-------
Monitoring data from the American Healthy Homes Survey II suggests that concentrations of
formaldehyde may range from 0.27 to 124.2 |ig/m3 for all homes (including new homes at the time of
survey), with 95 percent of homes having concentrations below 47 |ig/m3 (QuanTech. 2021). Those data
include formaldehyde produced from both TSCA sources (Figure 1-2 of the Indoor Air Exposure
Assessment for Formaldehyde (U.S. EPA. 2024i) and other sources of formaldehyde such as tobacco
smoke or the use of fireplaces, gas-burning appliances, candles, and air purifiers (QuanTech. 2021).
These other sources do not contain formaldehyde but rather lead to the formation of formaldehyde
during use.
An important consideration in these data is how formaldehyde may dissipate in homes. The most
prominent cause is home ventilation either through mechanical systems or through open windows. Due
to improved insulation in American homes built after 1990, formaldehyde may persist longer in newer
homes compared to older homes as a result of reduced indoor-outdoor air exchange (see Appendix C of
Indoor Air Exposure Assessment for Formaldehyde (U.S. EPA. 2024i)). Sorption is not expected to be a
key source of dissipation for homes. Also, the available monitoring data may not reflect future
concentrations as energy efficiency and building materials change over time. These factors are not
readily presented in the monitoring data but do play an important role in understanding why some homes
may have higher formaldehyde concentrations than others.
Unlike residential settings, most commercial settings are not expected to have sources of formaldehyde
attributable to combustion. A comparison of formaldehyde indoor air concentrations from both general
settings and residential settings (Table 2-1 and Table 2-2) suggest similar concentrations of
formaldehyde. It also suggests that, while combustion sources may be notable contributors in some
settings, combustion is not a substantial contributor to typical indoor air concentrations that Americans
may be exposed.
2.3.4 Indoor Air CEM Exposure Modeling Results
Through a review of key products expected to be significant and persistent emitters of formaldehyde,
EPA identified four TSCA COUs as potential significant contributors to residential indoor air
environment. EPA used CEM to estimate indoor air concentrations in homes and vehicles based on
article specific emission rates for these four TSCA COUs. Central tendency 1-year average daily indoor
air exposures estimates were generated (Table 2-3 and Figure 2-4) as discussed in Section 2.1.1.1.3 of
the Indoor Air Exposure Assessment (U.S. EPA. 2024i) for comparability with AHHS II monitoring data
and to estimate common indoor air concentrations for most American households.
Table 2-3. Estimated Chronic Average Daily Formaldehyde Indoor Air Concentrations
According to CEM)
COU Subcategory
Scenario8
Environment
CEM Calculated One-Year
Average Daily Concentration
(jig/m3)
Construction and building materials
covering large surface areas, including
wood articles; Construction and
building materials covering large
surface areas, including paper articles;
metal articles; stone, plaster, cement,
glass and ceramic articles
Building /
Construction
Materials - Wood
Articles:
Hardwood Floors
(Residential)3
Living Room
423.47
Page 51 of 191
-------
COU Subcategory
Scenario8
Environment
CEM Calculated One-Year
Average Daily Concentration
(jig/m3)
Fabric, textile, and leather products not
covered elsewhere
Seat Covers
(Automobile)
Automobile
7.10
Fabric, textile, and leather products not
covered elsewhere
Furniture Seat
Covers
(Residential)
Living Room
4.01
Fabric, textile, and leather products not
covered elsewhere
Fabrics: Clothing
(Residential)
Bedroom
5.19
Floor coverings; Foam seating and
bedding products; Cleaning and
furniture care products; Furniture &
furnishings including stone, plaster,
cement, glass and ceramic articles;
metal articles; or rubber articles
Furniture &
Furnishings -
Wood Articles:
Furniture
(Residential)
Living Room
108.62
Paper products; Plastic and rubber
products; Toys, playground, and
sporting equipment
Paper-Based
Wallpaper
Living Room
18.05
a The bolded text are representative scenarios for the COU subcategory as it yielded the highest concentrations compared to
other modeled scenarios within the relevant COU subcategory.
Page 52 of 191
-------
Building / Construction Materials - Wood Articles:
Hardwood Floors (residential)
Furniture & Furnishings -Wood Articles: Furniture _
(residential)
o
**_
CO
G
CD
O
05
Paper-Based Wallpaper -
Fabrics: Clothing (residential) -
Figure 2-4. Modeled Formaldehyde Average Daily Inhalation Concentrations in Indoor Air (According to CEM)
The x-axis presents the average daily concentration, and the y-axis presents the modeled TSCA COUs.
Average Daily Indoor Air Concentration (ug/m3)
Page 53 of 191
-------
While not directly comparable due to potential differences in individual COU vs total monitoring indoor
air estimates, differences in rooms of use, and building configurations among others, modeled
concentrations of formaldehyde were within the same order of magnitude as reported in monitoring
studies, including the American Healthy Homes Survey II (see Section 2.1 of the Indoor Air Exposure
Assessment (U.S. EPA. 2024i)). The estimated formaldehyde indoor air exposures likely represent
exposures from new articles added to a residence (e.g., wood products).
Over the span of a year, the highest TSCA COU contributor to the residential indoor air environment
was building wood products. In additional, several of the modeled COUs may occur simultaneously.
Therefore, in consideration of simultaneous exposures in residential indoor air, EPA aggregated
exposures to representative TSCA COUs (bolded text in Table 2-3). These included hardwood floors,
clothing, wood furniture, and paper-based wallpaper. Aggregating the COUs resulted in a total CEM-
modeled formaldehyde residential concentration of approximately 555 |ig/m3. While several of the
modeled COUs may occur simultaneously, aggregating exposures for all four of these articles may not
be reflective of actual exposure scenarios encountered over a lifetime because the combination of these
TSCA COUs likely differ from home to home and over time.
2.3.5 Indoor Air IECCU Exposure Modeling Results
EPA used IECCU to model indoor air concentrations in American homes based on TSCA COU-specific
emission fluxes and article surface areas, providing an estimate of TSCA COU-specific contributions to
formaldehyde in indoor air. Modeled indoor air results are presented in detail in Section 2.3 of the
Indoor Air Exposure Assessment (U.S. EPA. 2024i) for potential comparability with monitoring studies
such as the AHHS II.
Modeled 15-minute peak, indoor air concentrations for both single item and aggregate scenarios are
shown in Table 2-4 and Figure 2-5. For the TSCA COU covering building materials with large surface
areas, models were generated for both pressed wood cabinets and laminate flooring. The high-end air
peak air concentrations were 51 |ig/m3 for pressed wood cabinets and 142 |ig/m3 for laminate flooring.
As such, model results for laminate flooring are reported as the representative article for this COU;
model results for pressed wood cabinets are not reported in Table 2-4 or shown in Figure 2-5. However,
pressed wood cabinets are included in the modeled results for the new construction aggregate scenario.
Zone 1 in Figure 2-5 indicates the primary location or room for articles that were assumed to be placed,
while the corresponding zone 2 represents the articles' air contributions to the rest of the home through
interzonal (room-to-room) air flow. Also, note that for items modeled in a whole home, a single zone
model was used, and Zone 2 concentrations are therefore recorded as N/A.
Page 54 of 191
-------
Table 2-4. Fifteen Minute Peak Formaldehyde Concentrations (jig/m3) in Indoor Air for Single Representative Article and Aggregate
Model Scenarios
15-Minute
15-Minute
3-Month
cou
Representative
Scenario
Level
Peak Air
Concentration
Peak Air
Concentration
Average Air
Concentration
1-Year Average Air
Concentration Zone
Zone 1
(jig/m3)
Zone 2
(jig/m3)
Zone 1
(jig/m3)
1 (^g/m3)
High
142
N/A
27.5
6.1
Construction and building materials covering
large surface areas, including wood articles;
Construction and building materials covering
Laminate
Flooring
Med
22
N/A
4.3
1
Low
1
N/A
0.2
0.05
large surface areas, including paper articles;
metal articles; stone, plaster, cement, glass
and ceramic articles
New
High
160
N/A
31.1
6.87
Construction
Med
64
N/A
12.3
2.72
Aggregate
Low
21
N/A
4.1
0.9
Fabric, textile, and leather products not
covered elsewhere
Textile
High
18
0.3
3.5
0.8
Furniture
Med
2
0.03
0.4
0.1
Covers
Low
0.007
0.00009
0.001
0.0003
Pressed Wood
Furniture
High
26
0.4
5
1.1
Floor coverings; Foam seating and bedding
Med
7
0.1
1.4
0.3
products; Cleaning and furniture care
products; Furniture & furnishings including
stone, plaster, cement, glass and ceramic
articles; metal articles; or rubber articles
Low
2
0.03
0.3
0.1
Living Room
High
68
0.9
12.9
2.9
Decor Change
Med
16
0.2
3.1
0.7
Aggregate
Low
3
0.04
0.5
0.1
Paper products; Plastic and rubber products;
Tovs, playground, and sporting equipment
Wallpaper
-
12
N/A
2.3
0.5
Page 55 of 191
-------
I Single Item V Low Exposure Scenario
Aggregate 0 Medium Exposure Scenario
A High Exposure Scenario
Construction and building materials covering large surface areas,
including wood articles; Construction and building materials
covering large surface areas, including paper articles; metal
articles; stone, plaster, cement, glass and ceramic articles
Fabric, textile, and leather products not covered elsewhere
V
0
A
Floor coverings; Foam seating and bedding products; Cleaning
and furniture care products; Furniture & furnishings including
stone, plaster, cement, glass and ceramic articles; metal articles;
or rubber articles
Paper products; Plastic and rubber products; Toys, playground,
and sporting equipment
0 25 50 75 100 125 150 175
Figure 2-5. Fifteen Minute Peak Concentrations (jtig/m3) of Formaldehyde in Indoor Air for TSCA COU Representative Article and
Aggregate Models
v 0
A
Page 56 of 191
-------
Except for wallpaper, modeled air concentrations for each representative scenario (Section 2.2.2 of the
Indoor Air Exposure Assessment (U.S. EPA. 2024iV) showed a significant range in values. This was
driven largely by variability in emissions factors and estimated surface areas. However, these parameters
likely exhibit significant variability due to differences in materials, manufacturing practices, and
purchasing preferences. As such, EPA considers it reasonable that the range of estimated concentrations
reflects real-world conditions for each COU assessed.
Figure 2-6 shows air concentrations over the full duration of modeling (10,000 hours) for the high-end
models and for each representative scenario. The modeled concentrations of formaldehyde in air peaked
on the first day the article was installed in the home. Then, the concentrations in indoor air declined
rapidly, approaching zero |ig/m3 after a period of approximately three months (U.S. EPA. 2024i).
— Aggregate-Decor Change — Fabric Furniture Covers — Pressed Wood Furniture
— Aggregate-New Build — Laminate Flooring — Wallpaper
150
CO
z£_
<
c
c
o
'•*—>
03
i_
C
CD
O
C
o
0
CD
"O
_£=
CD
T3
CD
E
1
o
100
50
1 2 3 4 5 6 7 8 9 10 11 12
Time after Installation in Home (Months)
Figure 2-6. Formaldehyde Concentrations in Indoor Air (jig/m3) for TSCA COU Representative
Article and Aggregate Models Over Time (10,000 hour simulation duration)
2.3.6 Aggregate Indoor Air Exposure
EPA defines aggregate exposure as "the combined exposures from a chemical substance across multiple
routes and across multiple pathways" (40 CFR § 702.33). The reported formaldehyde concentrations
from the monitoring data may represent aggregate formaldehyde indoor air concentrations, as presented
in the AHHS II study across U.S. households (OuanTech. 2021). assuming either at least a 3-hour TWA,
or the typical indoor air concentration of formaldehyde in residential environments. An aggregate
exposure to formaldehyde via the COUs assessed may occur in the home in which an individual resides.
Page 57 of 191
-------
An individual may be exposed to formaldehyde via residential indoor air, with an estimated COU-
specific aggregate indoor air concentration as high as 160 [j,g/m3 for a new construction scenario and 68
[j,g/m3 for living room decor change scenario. Furthermore, using the AHHS II measured average
concentration of formaldehyde (-23 (J,g/m3) as a typical residential concentration, and considering the
addition of new laminate flooring yielding concentrations as high as 142 (J,g/m3, a resident's aggregate
exposure may be as high as 165 [j,g/m3.
2.4 Ambient Air Exposure Assessment
EPA assessed 43 COUs for the Ambient Air Exposure Assessment. Like the indoor air assessment, this
assessment integrates both monitoring data and models to estimate and characterize how people may be
exposed to formaldehyde when outside. This assessment used a nationally representative monitoring
dataset provided by EPA's Ambient Monitoring Technology Information Center (AMTIC) archive as
discussed in Section 2.4.1. Several models were used to a) quantitatively evaluate exposures from
industrial releases of formaldehyde to ambient air that are associated with TSCA COUs; b) characterize
some of the other sources of formaldehyde in ambient air; and, c) spatially represent modeled
formaldehyde concentrations from TSCA COUs relative to biogenic or natural sources. These
assessments are summarized and discussed in Section 2.4.2. A detailed summary of all the analyses
conducted, methodologies used, and all exposure concentration results for formaldehyde are provided in
the Ambient Air Exposure Assessment for Formaldehyde (U.S. EPA. 2024a) and associated
supplemental files.
2.4.1 Monitoring for Ambient Air Concentrations
EPA identified and summarized monitoring data for formaldehyde from EPA's Ambient Monitoring
Technology Information Center (AMTIC) archive (U.S. EPA 2022a). These results are presented in the
Ambient Air Exposure Assessment for Formaldehyde (U.S. EPA. 2024a). These data are based on all
potential sources of formaldehyde and do not distinguish between biogenic production, secondary
production, or point sources. Furthermore, these data are not specific to TSCA COUs. They are,
however, useful in understanding spatial and temporal differences in ambient air concentrations in the
contiguous United States.
The AMTIC dataset for formaldehyde includes 195 monitoring sites from 36 different states. Data were
extracted across 6 years (2015 through 2020). Due to the time it takes for AMTIC to accept submissions,
clear, classify, and process the monitored data, the 2020 data was the latest available. The full dataset
considered for this risk assessment includes a total of 306,529 observations (untouched/unprocessed raw
data). Post processing of the raw dataset by EPA included filtering out error codes, missing/incomplete
data files, brought the raw dataset entries down to 233,961. This processed dataset includes monitoring
data from 20 air monitoring programs covering 32 states within the contiguous United States.
EPA calculated summary statistics for all 233,961 samples, samples by state, samples by census tract,
samples by monitoring site, samples by monitoring site and year, and samples by monitoring site and
year and quarter. For purposes of this ambient air exposure assessment, EPA used the overall statistics
across all samples to characterize exposures and characterize exposures to the general population (Table
2-5). Monitoring locations and annual summary statistics are provided in thq Ambient Air Exposure
Assessment for Formaldehyde (U.S. EPA. 2024a).
Table 2-5 presents results for all 233,961 samples and includes the following adjustments (where
applicable): Any entries with missing key data were omitted from the analysis (e.g., concentrations,
concentration units, method detection limits, methodology used). All concentration and method
detection limit (MDL) values were converted to micrograms per cubic meter (|ig/m3) for unit uniformity
Page 58 of 191
-------
between submitting programs. Method detection limits were provided along with sample concentrations
on a submission-by-submission basis by submitting agencies, from 0.000011 to 1.2 |ig/m3, and varied by
sample based on the sampling and analysis methodology. Entries with reported concentrations below the
method detection limit were substituted with a value of 0 |ig/m3. Concentrations of formaldehyde ranged
from below the method detection limit to 60.1 |ig/m3 and a median value of 1.6 |ig/m3. A summary of
the statistics extracted from the overall dataset are provided in Table 2-5.
Table 2-5. Overall Monitored Concentrations of Formaldehyde from AMTIC archive Dataset
Monitored Concentrations (jig/m3)
Aggregation
Count
Minimum
Minimum
(non-zero)
Median
Mean
Maximum
All Entries
233,961
0
0.002
1.6
2.1 ±2.2
60
Daily Mean
3,843
0
0.011
2.5
3.0 ± 2.0
18.4
Annual Mean
64
1.4
1.4
2.9
3.0 ± 1.1
6.5
The individual site data collected by AMTIC represents various sampling techniques and differing
sample collection durations ranging from 5 minutes to 24 hours. When using these data for comparison
to the presented formaldehyde models, the concentrations were converted to daily and annual averages.
AMTIC concentration values were used to calculate daily or annual average only when there was greater
than 75 percent sample coverage over the averaged timeframe when converting from sub-hour samples
to hourly averages and again for hourly samples to daily averages. Each annual quarter required a
minimum of seven valid daily averages and each annual mean required a minimum of three valid
quarterly averages per year per site. The high standards for coverage resulted in a drastic reduction in the
data available for conversion to daily and annual averages. Of the original 233,961 complete entries,
there were 64 site-years and 3,843 site-days with sufficient coverage to calculate daily and annual
average statistics (Table 2-5).
Three AMTIC high-frequency sampling locations in Houston, Texas located around the Buffalo Bayou
area were isolated from AMTIC data for a more in-depth analysis of ambient formaldehyde
concentrations in mixed-use regions. Each of the three sites collected continuous five-minute composite
samples seven days a week over approximately one year using a FluxSense sampling system. The sites
were located around the Port of Houston in mixed industrial regions with known NEI releasing facilities
intertwined with residential neighborhoods (Figure 2-7). Additional details on this case study are
included in the Ambient Air Exposure Assessment for Formaldehyde (U.S. EPA. 2024a).
Page 59 of 191
-------
Symbol Size Guide for Emissions (Tons)
O >0-0.10
O >0.10 - 1.0
O >1.0-5.0
O >5.0 -10
(3 *10-19.3
_ >0-0.10
_ >0.10 - 1.0
_ >1.0 - 5.0
A >5.0 -10
>10-19.3
~ >0-0.10
~ >0.10 -1.0
~ >1.0-5.0
>5.0 -10
] >10-19.3
u >0-0.10
\J >0.10-1.0
\_j >1.0-5.0
\J >5.0 - 10
O >10-19.3
•A'
u
482010803
* G
°o
<82011015
¦_
482011035
C©
C * C
- O
• o
•<
%
o
• ft c
(
tt •
9
NEI Reported FacilityTvoe
AMTIC Monilofino Site
•
Airport
~
Fabricated Metal Products Plant
¦
Hot Mix Asphalt Plant
•
Plastic, Resin. Rubber or Syn Ffoer Manuf Plant
Monitoring Locations
c
Bakeries
*
Electricity Generation via Combustion
~
Institutional (school, hospital, prison, etc.)
#
Rail Yard
o
& ewer ies "D s ti leri es W ineries
-
Fertilizer Plant
~
Landfil
U
ShipYards
o
Chemical Plant
~
Food Products Processing Plant
~
Oflor Gas Facility (On-shore)
•
Steam/Heatng Facility
0 5 1 2
•
Chlor-akali Plant
~
Foundries. Iron and Steel
¦
Petroleum Refinery
#
Unspecified "
•
Compressor Station
~
Glass Plant
¦
Petroleum Storage Facility
#
Wastewater Treatment Facility
i i l i ¦ i l
Miles
Figure 2-7. High-Resolution Monitoring Locations in Houston, Texas: 482010803 (N = 42,560), 482011015 (N = 70,126), and
482011035 (N = 71,621).
Page 60 of 191
-------
Approximately 0.5 to 18 percent of measurements fell below the reported 0.159 |ig/m3 method detection
limit. Median values ranged from 1.0 to 2.2 ug/iri: with slightly higher mean 5-minute concentration of
1.3 to 2.9 (ig/m3 with a slight positive skew meaning there is a higher quantity of higher-concentration
samples than would be expected in a standard normal distribution (Figure 2-8). Ambient formaldehyde
concentrations appear to be stable throughout the monitoring period indicating that formaldehyde in
ambient air is generally representative of an ongoing concentration to which the general population may
be routinely exposed in day-to-day life (Figure 2-8). There were, however, notable daily trends in
formaldehyde concentration that aligned with the working day. Concentration of formaldehyde peaked
in the afternoon and evening between the hours of 12:00 PM and 7:00 PM during the day and the lowest
concentrations of formaldehyde were typically in the early morning between 12:00 AM and 8:00 AM
(Figure 2-8).
482010803
50-
10-
5-
1-
°!
50-
10-
5-
482011015
CR
=L
C.
.2
V-j
ca
L,
C
8
c
o
O
1-
°i
50-
10-
5-
iliii||
Hff
MMU,
482011035
0
04:00
Legend
p "-Maximum
Range 0—Mean
L , Minimum
10:00
16:00
Time of Day
Figure 2-8. Houston area sites 5-ininute concentration data aggregated by time of day.
2.4.2 Modeling Ambient Air Concentrations
EPA used three different models to estimate formaldehyde concentration in outdoor air. These included
EPA's Integrated Indoor-Outdoor Air Calculator (IIOAC) Model, the Air Toxics Screening Tool
(AirToxScreen), and EPA's Human Exposure Model (HEM). Each model's use served a different
purpose in this assessment as described in detail in the Ambient- Air Exposure Assessment for
Formaldehyde (U.S. EPA. 2024a).
2.4.2.1 Integrated Indoor/Outdoor Air Calculator Model (IIOAC)
EPA used the IIOAC model to estimate daily average and annual average formaldehyde concentrations
in ambient air at three pre-defined di stances from a releasing facility (100, 100 to 1,000, and 1,000
meters; 0.05 to 0.5 miles). All results from the IIOAC modeling for both TRI and NEI release datasets
Page 61 of 191
-------
by industry sector are provided in the Ambient Air Exposure Assessment Results and Risk Calcs
Supplement A (U.S. EPA. 2024a).
These results include daily estimated concentrations from all reported releases of formaldehyde from
industrial processes attributed to TSCA COUs and combustion. The estimated annual average
concentration results are also included, but separation between TSCA COUs and combustion is not
included because there were no unexpectedly high modeled concentrations outside of the general range
of ambient monitoring data as described in the Ambient Air Exposure Assessment for Formaldehyde
(U.S. EPA. 2024a). The IIOAC modeling results were used in this risk assessment to characterize
exposures, derive risk estimates, and characterize risks for people living near releasing facilities.
2.4.2.1.1 Estimated Daily Average Formaldehyde Concentrations
EPA uses the modeled concentration results from the following conservative exposure scenario to assess
daily average exposures and associated risk estimates in this risk assessment. The basis for selecting this
scenario is described in the Ambient Air Exposure Assessment for Formaldehyde (U.S. EPA. 2024a).
Release scenario: Maximum release reported by industry to either TRI or NEI for each industry sector.
Modeled concentration: High-end (95th percentile) modeled air concentrations at the 100-meter finite
distance from the release point.
Operating scenario: 365 days per year, 7 days per week, 24 hours per day.
Daily average exposure concentrations attributed to TSCA COUs ranged from 0.0004 to 66.2 |ig/m3 and
are presented in Figure 2-9. The two highest concentrations in Figure 2-9 are from the Wood Product
Manufacturing and Paper Manufacturing industry sectors and are cross-walked to nine different TSCA
COUs. These results are carried through to the derivation of risk estimates, risk characterization, and can
inform regulatory decision-making for TSCA COUs.
When interpreting the results presented in Figure 2-9, there are several instances where the same
concentration is identified for multiple TSCA COUs. This occurs because modeling was done across an
entire industry sector, as described in Section 2.1.1. of the Ambient Air Exposure Assessment for
Formaldehyde (U.S. EPA. 2024a). and several industry sectors cross-walk to multiple TSCA COUs as
described in the Environmental Release Assessment for Formaldehyde (U.S. EPA. 2024g). This pattern
will carry through the derivation of risk estimates and the risk characterization.
Page 62 of 191
-------
Processing-Reactant-lntermediate -
Processing-Incorporation into an Article-Adhesives and Sealant Chemicals -
Commercial Use-Chemical substances in automotive and fuel products-Automotive care products: Lubricants and greases: Fuels and related products -
Recycling -
Processing-Reactant-Bleaching Agent -
Processing-Reactant-Adhesives and Sealant Chemicals-
Processing-Incorporation into a formulation, mixture, or reaction product-Intermediate -
Processing-Reactant-Processing aids, specific to petroleum production
Processing-Incorporation into a formulation, mixture, or reaction product-
Processing-Incorporation Into Article-Finishing Agents -
Processing-Incorporation into a formulation, mixture, or reaction product-Bleaching Agents
Commercial Use-Chemical substances in furnishing treatment/care products-Floor coverings
Processing-Incorporation into a formulation, mixture, or reaction product-Agricultural chemicals (Nonpesticidal)-
Domestlc Manufacturing -
Industrial Use-Non-incorporative activities-used in: construction
Industrial Use-Chemical substances in industrial products-Paints and coatings: adhesives and sealants: lubricants-
Industrial Use-Non-incorporative activities-Oxidizing/reducing agent: processing aids, not otherwise listed (e.g.. electroless copper plating)-
Processing-Incorporation into an Article-Paint additives and coating additives
Processing-Incorporation into a formulation, mixture, or reaction product-Surface Active Agents
Processing-Incorporation into a formulation, mixture, or reaction product-Paint additives and coating additives not described by other categories-
Processing-Incorporation into a formulation, mixture, or reaction product-Solvents (which become part of a product formulation or mixture) -
Processing-Incorporation into a formulation, mixture, or reaction product-Ion exchange agents
Processing-Incorporation into a formulation, mixture, or reaction product-Plating agents and surface treating agents
Processing-Incorporation into a formulation, mixture, or reaction product-Other: Laboratory Chemicals-
Processing-lncorporation into a formulation, mixture, or reaction product-Processing aids, specific to petroleum production-
Processing-Incorporation into a formulation, mixture, or reaction product-Solid separation agents
Disposal
Processing-Reactant-Agricultural Chemicals
Commercial Use-Chemical substances in agriculture use products-lawn and garden products
Commercial Use-Chemical substances in metal products-Construction and building materials covering large surface areas, including metal articles
Commercial Use-Chemical substances in furnishing treatment/care products-Construction and building materials covering large surface areas
Commercial Use-Chemical substances in construction, paint, electrical, and metal products-Adhesives and Sealants: Paint and coatings
Processing-Incorporation into a formulation, mixture, or reaction product-Lubricant and lubricant additive
Processing-Incorporation into a formulation, mixture, or reaction product-Adhesive and Sealant Chemicals
Commercial Use-Chemical substances in electrical products-Electrical and electronic products
Commercial Use-Chemical substances in packaging, paper, plastic, hobby products-Ink, toner, and colorant products: Photographic supplies
Processing-Incorporation into Article-Additive
Commercial Use-Chemical substances in packaging, paper, plastic, hobby products-Paper products: Plastic and rubber products: Toys, playground, and sporting equipment
Commercial Use-Chemical substances in packaging, paper, plastic, hobby products-Arts, crafts, and hobby materials
20 40
Concentration (pg/m3)
60
Figure 2-9. Daily Average Exposure Concentrations by TSCA COU using IIOAC non-site specific analysis.
Page 63 of 191
-------
Formaldehyde daily average exposure concentrations linked to combustion ranged from 2 to 662 |ig/m3
based on the maximum release reported to TRI or NEI. The highest modeled exposure concentrations
from either TRI or NEI are presented in Table 2-6.
The first three columns in Table 2-6 include information on the industry sector, site reporting the
fugitive and stack releases, and the major process unit source(s) from which those releases came. The
release dataset column notes the source of the reported data, either TRI or NEI. The fugitive and stack
columns provide the industry reported source apportioned release values which were used as direct
inputs to the IIOAC model. The total exposure concentration column presents the sum of the exposure
results modeled for fugitive and stack releases modeled at 100 meters from a releasing facility.
As previously described in the Ambient Air Exposure Assessment for Formaldehyde (U.S. EPA. 2024a)
and shown in Table 2-6, all the maximum releases within each of the top five industry sectors
attributable to combustion are from combustion sources like airplanes, on-site vehicles, process heaters,
turbines, and reciprocating internal combustion engines (RICE). With the exception of the "utilities"
industry sector these concentrations attributable to combustion range from 169 to 662 |ig/m3 and are a
magnitude greater than the highest monitored concentration obtained from the AMTIC archive.
Similarly, these concentrations are much higher than modeled concentrations found with HEM and the
2019 AirToxScreen results. Additional land use analysis revealed these highest releases were from
facilities with no homes within 1,000 meters of the release points. Finally, when these handful of
combustion sources are excluded from the release dataset, the revised range of modeled daily average
concentrations was 0.0004 to 66.2 |ig/m3. This range of concentrations is within the same order of
magnitude as the AMTIC archive dataset and other modeled data.
EPA further considers the representativeness of these maximum releases for these five industry sectors
attributable to combustion by comparing the reported maximum release to the calculated 95th percentile
release within the same industry sectors. EPA's findings from this deeper dive found the highest 95th
percentile releases were at least 1 to 2 orders of magnitude lower than the maximum releases within the
same industry sector. This can be seen in the TRI/NEI comparison sections of this assessment in the
Ambient Air Exposure Assessment for Formaldehyde (U.S. EPA. 2024a). Based on the additional
investigation/deeper dive into the highest maximum reported releases, EPA concludes these combustion
releases are likely outliers within their respective industry sectors and not representative of national level
releases within the respective industry sectors. While EPA carries these releases attributable to
combustion separately through the risk estimates, and risk characterization, caution is required when
considering use of these highest release values in a national level assessment to inform regulatory
decision-making.
Page 64 of 191
-------
Table 2-6. Five Highest Exposure Concentrations Attributable to Combustion Based on IIP AC Modeling of Maximum Release Value
Industry Sector
Facility
(County, State)
Major Process
Unit Source(s)
Maximum Release Value (kg/year)
Total
Exposure
Concentration
(lug/m3)
Release
Dataset
Fugitive
Stack
Wholesale and Retail Trade
Columbus AF Base
(Lowndes, MS)
Aircrafts
NEI
138,205
662
Transcontinental Gas
Pipeline Company, LLC
(Henry, GA)
RICE,
Turbines
95,159
Oil and Gas Drilling,
Extraction, and Support
Activities
Chevron USA Inc.
(Kern, CA)
Process
heaters, RICE,
Turbines
NEI
22,742
334
Frenchie Draw Central
Compressor Station
(Fremont, WY)
RICE
1,412,023
Non-Metallic Mineral
Product Manufacturing
Cemex Black Mountain
Quarry Plant
(San Bernardino, CA)
On-Site
Vehicles
NEI
41,190
198
Thermafiber Inc
(Wabash, IN)
Not reported
36,492
Services
Pope Airforce Base
(Cumberland, NC)
Aircrafts
NEI
34,155
169
Seneca Energy LFGTE
Facility
(Seneca, NY)
RICE
63,483
Page 65 of 191
-------
Industry Sector
Facility
(County, State)
Major Process
Unit Source(s)
Maximum Release Value (kg/year)
Total
Exposure
Concentration
(lug/m3)
Release
Dataset
Fugitive
Stack
Utilities
Lorain County LFG
Power Station
(0247100968)
(Lorain, OH)
RICE
NEI
10,108
61
Basin Creek Power
Services
(Silver Bow, MT)
RICE
101,968
Page 66 of 191
-------
2.4.2.1.2 Estimated Annual Average Formaldehyde Concentrations
EPA uses the modeled concentration results from the following exposure scenario to assess annual
average exposures and associated risk estimates in this risk assessment for both chronic non-cancer and
cancer. The basis for selecting this scenario is described in the Ambient Air Exposure Assessment for
Formaldehyde (U.S. EPA. 2024a).
Release scenario: 95th percentile release calculated for either TRI or NEI datasets for each industry
sector.
Modeled concentration: High-end (95th percentile) modeled air concentrations at the 100 to 1,000
meters area distance from the release point.
Operating scenario: 365 days per year, 7 days per week, 24 hours per day.
Results for annual average exposure concentrations attributable to TSCA COUs range from 0.0001 to
5.7 |ig/m3 and are presented in Figure 2-10. The two highest concentrations in Figure 2-10 are from the
Nonmetallic Mineral Product Manufacturing and Textiles, Apparel, and Leather Manufacturing industry
sectors and are cross-walked to six different TSCA COUs. These results are carried through to the
derivation of risk estimates, risk characterization, and can inform regulatory decision-making for TSCA
COUs. As described in Section 2.4.2.1.2, instances where the same concentration is identified for
multiple COUs occurs because several industry sectors cross-walk to multiple COUs.
Page 67 of 191
-------
Commercial Use-Chemical substances m automotive and fuel prod
Procss
Commercial Use-Cherrecai substances in fum
industrial Use-Chemical subst;
Processing-Incorporation into a formuh
~
tndi
"O
c
o
O
Processing-Incorporation Into a forr
F'ocessing-lnccrDoraticn into s formuiatic
Process
fv
Processing-Reactant-Processinq aids, specific tc
Comme
Co
Commercial Use-Chemical
Commercial Use-Chemical substances in packaging paper, plastic, hobby products-Paper products. Plastic and rubber predt
Commercial Use-Chemical substances m packaging, paper, plastic, he
Figure 2-10. Annual-Average Exposure Concentrations by TSCA COU
2 4
Concentration (pg/nf)
Page 68 of 191
-------
2.4.2.2 AirToxScreen
EPA used 2019 AirToxScreen to understand the relative contributions of various sources of
formaldehyde to total concentrations in the ambient air. AirToxScreen is an EPA screening tool used to
evaluate air toxics from all known sources across the United States and estimates air concentrations at
the census tract scale using a combination of models and data sources (Scheffe et al.. 2016). Census
tracts are a statistical subdivision of counties that are usually between 1,200 and 8,000 people. They can
be a small as a few city blocks or as large as several square miles. The 2019 AirToxScreen data for
biogenic sources, secondary sources, point sources, and total sources are shown in Figure 2-10. Figure
2-11 does not include AirToxScreen results for on-road sources, near-road sources, off-road sources,
wildfire sources, etc.
Secondary production of formaldehyde was the largest contributor of formaldehyde to ambient air with
modeled concentrations ranging from 0.085 to 1.8 |ig/m3 according to the AirToxScreen results.
Secondary production is the atmospheric formation of formaldehyde from natural and manmade
compounds. This can include the degradation of isoprene (a compound naturally produced by animals
and plants) to formaldehyde and other complex air chemistries. AirToxScreen is not able to apportion
the relative contributions from different secondary sources (source apportion).
Biogenic sources also have a significant contribution to total concentration with a range of 0.0014 to
0.67 |ig/m3. Biogenic sources include those emissions from trees, plants, and soil microbes. For this
assessment, the 95th percentile of biogenic sources (0.28 |ig/m3) was estimated.
Point source contributions to total formaldehyde concentrations range from 0.0 to 0.88 |ig/m3. However,
as described above, the AirToxScreen data are averaged across census tracts, which can result in a
considerable underestimation of exposures relative to a source-specific contribution to which
populations living nearby releasing facilities are exposed. Additionally, while the AirToxScreen data
provides estimates for point sources and may include TSC A sources, the results cannot be apportioned
to represent TSCA COUs vs. other sources. Therefore, these results are not directly comparable to the
modeled concentrations from IIOAC.
Page 69 of 191
-------
Total
Secondary Production
0)
o
s—
o
CO
Point Source -
Biogenic Production
...i ...'....i
...i ...'....i ...'....i ...'....I ...'....i ...'....i
...i ...'....i
10
-12
-4
10 10
Concentration (|jg/m3)
10L
Figure 2-11. 2019 AirToxScreen Modeled Data for All Sources, Secondary Production Sources,
Point Sources, and Biogenic Sources for the Contiguous United States
After the Draft Risk Evaluation for Formaldehyde was released, results from the 2020 AirToxScreen
assessment were released by the Office of Air and Radiation (https://www.epa.gov/AirToxScreen/2020-
airtoxscreen-assessment-results). Total formaldehyde concentrations range from 0 to 17.2 ng/m3, which
has a higher maximum compared to the 2019 results. This difference may be attributed to the scale of
the model. As mentioned, the 2019 results are at the census tract scale. The 2020 results are modeled at
the census block scale, which is much smaller and provides less area for estimating ambient air
concentrations. Several hot spots with elevated concentrations of formaldehyde were present in Oregon
(max 17.2 |ag/m3), Puerto Rico (max 9.7 |ag/m3), Texas (max 9.6 |ag/m3), and Colorado (max 9.1 ng/m3).
While some general conclusions may be attempted when comparing 2019 to 2020 AirToxScreen data,
the results are not directly comparable between 2019 and 2020. Nonetheless, both results show that
secondary formation, biogenic production, and point sources are the largest contributors to total ambient
air concentrations of formaldehyde (Figure 2-12).
Page 70 of 191
-------
Total
Secondary Production
Q
0
1
=3
o
C/)
Point Source
Biogenic Production
10~12 10~9 10~6 10~3 10°
Concentration (|jg/m3)
Figure 2-12. 2020 AirToxScreen Modeled Data for All Sources, Secondary Production Sources,
Point Sources, and Biogenic Sources for the Contiguous United States
2.4.2.3 Human Exposure Model (HEM)
EPA used the Human Exposure Model (HEM 4.2) to estimate formaldehyde concentrations on a site-
specific basis at multiple distances from releasing facilities. These estimates are based on the highest
reported release for each site reporting releases to TRI across the six years of TRI data as described in
more detail in the Ambient Air Exposure Assessment for Formaldehyde (U.S. EPA. 2024a). HEM 4.2
has two components: (1) an atmospheric dispersion model, AERMOD, with included regional
meteorological data; and (2) U.S. Census Bureau population data at the Census block level. The current
HEM version utilizes 2020 Census data—including all 50 states, the District of Columbia, Puerto Rico,
and the U.S. Virgin Islands. AERMOD estimates the magnitude and distribution of chemicals
concentrations in ambient air in the vicinity of each releasing facility within user-defined radial
distances out to 50 km (about 30 miles). HEM also provides chemical concentrations in ambient air at
the centroid of over 8 million census blocks across the United States. This higher tier model was
selected to expand on the IIOAC results by providing more granularity in modeling individual facilities
and more discrete distances, geospatial data associated with modeling results for mapping and further
analysis, and population data associated with modeled results.
Ambient air concentrations at the census block level were modeled by HEM and are shown in Figure
2-13. These aggregated concentrations are the summed stack and fugitive modeled concentrations,
which can include the summation of multiple adjacent facilities, at specific locations. The site-specific
concentration results represent the expected annual average ambient air concentration attributable from
all modeled TRI releases of TSCA COUs, in some census blocks accounting for concentrations from
multiple releasing facilities. Concentrations within those census blocks ranged from 0 to 8.9 ug/in3.
Census blocks with modeled total concentrations below the 95th percentile biogenic formaldehyde
threshold of 0.28 |ig/m3 are presented in grey. Turquoise dots show census blocks with concentrations
ranging from 1 to 5 times the 95th percentile biogenic concentration, purple dots show concentrations
Page 71 of 191
-------
from 5 to 10 times the 95th percentile biogenic concentration, and pink dots show values greater than 10
times the 95th percentile biogenic concentration. In total, the HEM population analysis shows 105,463
people (based on 2020 Census data) across the country live within census blocks where the HEM
modeled ambient air concentrations exceed the 95th percentile biogenic concentration..
Elevated ambient air concentrations of formaldehyde from industrial releases appear most densely
concentrated in the southeastern United States. Census blocks with elevated concentrations are found
throughout the country, with some regions showing fewer overall TRI facilities, and fewer releases
resulting in elevated air concentrations.
Patterns in the relative contribution of stack and fugitive releases, and the distribution of results at
varying radial distances from the releasing facility were examined (Figure 2-14). Each vertical bar and
median line indicate the shape of the distribution of concentrations by release type for individual
facilities. These results indicate that concentrations resulting from fugitive emissions are greater than
those from stack emissions closer to the releasing facility, but concentrations from stack emissions tend
to become greater at further distances. As many facilities report only a single release type (either
fugitive or stack), the total concentration distributions represent a greater number of facilities than the
corresponding fugitive and stack distributions and tend to fall somewhere between the fugitive and stack
values. Total modeled concentrations tend to reach their maximum within 1,000 m of a facility. Values
represented in this analysis are directly modeled at the 16 radial points around each distance ring, rather
than census block centroids, and can therefore be located much closer to the releasing facility and
represent much higher concentrations. These points are not associated with population estimates, and in
some cases the modeled distances may still be within a facility property boundary.
Page 72 of 191
-------
iZ,/^ Tribal Lands
I I States
Modeled Formaldehyde
Concentration from TRI Releases by
Census Block (|jg/m3)
0 • 0.28
• 0.28 - 1.4
• 1.4 - 2.8
• 2.8 - 8.9
1,600
3 Kilometers
Figure 2-13. Map of Contiguous United States with HEM Model Results for TRI Releases Aggregated and Summarized by Census
Block
Census blocks with modeled total concentrations below the 95th percentile biogenic concentration of 0.28 jig/m3 are presented in grey.
Turquoise dots show census blocks with concentrations ranging from 1 to 5 times the biogenic threshold, purple dots show concentrations
from 5 to 10 times the biogenic threshold, and pink dots show values greater than 10 times the biogenic threshold.
Page 73 of 191
-------
£ 101
O)
•2 10u
2
c
0
g 10 1
O
o
-in_2-s—
< 10 -p
O 10" :
Release Type and Metric
| Fugitive Median
Fugitive Max
| Stack Median
Stack Max
| Total Median
Total Max
2,500
Distance (m)
15,000
Figure 2-14. Median and Maximum Concentrations (Fugitive, Stack, and Total Emissions) across
the 11 Discrete Distance Rings Modeled in HEM
2^4.3 Integrating Various Sources of Formaldehyde Data
Monitoring data from AMTIC, modeled exposures calculated from IIOAC, and modeled data from
AirToxScreen were compiled to understand how exposures from TSCA COUs fit into the broader
context of available information on formaldehyde. Figure 2-15 shows the distributions of data from
these datasets. As shown these distributions overlap. At the national scale, populations are exposed to
many different sources of formaldehyde (COUs, secondary, biogenic, etcj. Modeled exposure estimates
downwind from TSCA COU releases are variable across COUs and locations. In some locations the
concentrations from TSCA COUs dominate total concentrations of formaldehyde in ambient air. In most
of the country however, ambient air concentrations are dominated by other sources (secondary, biogenic,
etc.) according to AirToxScreen.
Page 74 of 191
-------
AMTIC (Monitoring)
(N= 199.466)
IIOAC (Modeled)
(N=35)
AirTox Total Sources (Modeled)
(N=76.726)
ro AirTox Point Sources (Modeled)
O (N=76,364)
AirTox Biogenic Sources (Modeled)
(N=76.726)
AirTox SecondarySources (Modeled)
(N=76.726)
Legend
25* Percentile 75* Percentile
Median 1.5*IQR
IQR
+
%
¦O,
Concentration (pg/m3)
'o
%
'Co
Data Source
• AMTIC (Monitoring) • AirTox (Modeled) • IIOAC (Modeled)
Figure 2-15. Distributions of AMTIC Monitoring Data, IIOAC Modeled Data, and AirToxScreen
Modeled Data
EPA recognizes that the different model estimates are not directly comparable. For example, the IIOAC
results represent a 95th percentile annual average concentration between 100 to 1,000 m from the release
point. In contrast, AirToxScreen concentrations represent annual average concentrations at the census
tract scale. Given the spatial scale difference it is expected that AirToxScreen results could considerably
underestimate concentrations on a smaller scale {i.e., near facilities) or have lower concentration
estimates than IIOAC and this difference can be seen in Figure 2-15. Additionally, only point source
data within AirToxScreen may represent a broader set of formaldehyde releases that include releases
associated with TSCA COUs.
Furthermore, the AMTIC data represent a range of samples collected at various locations (independent
of TSCA releases of formaldehyde) and collection durations are much shorter than a year (5 minutes to
24 hours). Despite these uncertainties, these data suggest that formaldehyde concentrations from TSCA
sources are higher than formaldehyde concentrations that are expected to occur due to natural formation.
These higher concentrations will be driven by the location of release. These COUs are listed in Section
2.4.2.1 and this conclusion is further supported by the HEM analysis.
2.5 Weight of Scientific Evidence and Overall Confidence in Exposure
Assessment
As described in the 2021 Draft Systematic Review Protocol (U.S. EPA. 2021c). the weight of scientific
evidence supporting exposure assessments is evaluated based on the availability and strength of
exposure scenarios and exposure factors, measured and monitored data, estimation methodology and
model input data, and, if appropriate, comparisons of estimated and measured exposures. The strength of
Page 75 of 191
-------
each of these evidence streams can be ranked as either robust, moderate, slight, or indeterminate. For
each component of this exposure assessment, EPA evaluated the weight of scientific evidence for
individual evidence streams and then used that information to evaluate the overall weight of evidence
supporting each set of exposure estimates. General considerations for evaluating the strength of evidence
for each evidence stream are summarized in Table 7-6 of the Draft Systematic Review Protocol
Supporting TSCA Risk Evaluations for Chemical Substances (U.S. EPA. 2021c). Specific examples of
how these considerations can be applied to overall weight of scientific evidence conclusions are
provided in Table 7-7 of the Draft Systematic Review Protocol (U.S. EPA 2021c). The weight of
scientific evidence supporting each element of the human health exposure assessment are discussed in
the occupational exposure assessment (U.S. EPA 20241) consumer exposure assessment (U.S. EPA
2024d), indoor air assessment (U.S. EPA 2024i) and ambient air assessment (U.S. EPA 2024a)
modules.
Overall confidence descriptions of high, medium, or low are assigned to the exposure assessment based
on the strength of the underlying scientific evidence. When the assessment is supported by robust
evidence, overall confidence in the exposure assessment is high; when supported by moderate evidence,
overall confidence is medium; when supported by slight evidence, overall confidence is low.
2,5.1 Overall Confidence in Occupational Exposure Assessment
The confidence in the occupational exposure assessment varies from low to high, the confidence is
based on the strengths, limitations, and uncertainties associated with the exposure estimates for each
individual occupational exposure scenario. Most COUs have medium confidence based on moderate to
robust and moderate weight of scientific evidence conclusions. The primary strength of most of the
inhalation assessments is that it uses monitoring data that is chemical-specific and is directly applicable
to the exposure scenario. The use of applicable monitoring data is preferable to other assessment
approaches such as modeling or the use of occupational exposure limits. The principal limitation of the
monitoring data is the uncertainty in the representativeness of the data due to some scenarios having
limited exposure monitoring data in the literature or the available monitoring data lacking additional
contextual information. For many of the COUs, the EPA received aggregated data from industry;
therefore, EPA was unable to distinguish each site's contribution to the exposure estimates. EPA also
assumed 250 exposure days per year based on continuous formaldehyde exposure for each working day
for a typical worker schedule. It is uncertain whether this captures actual worker schedules and
exposures.
Some of the COUs lacked monitoring data; therefore, EPA used models to estimate inhalation
exposures. 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
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 General Scenario (GS) and Emission Scenario Document (ESDs).
However, there is uncertainty as to the representativeness of the parameter distributions with respect to
the modeled scenario because the data are often not specific to sites that use formaldehyde. 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.
As described in the Occupational Exposure Assessment for Formaldehyde (U.S. EPA. 20241). EPA has
low confidence in the inhalation estimates for the three COUs below based on a slight weight of
scientific evidence:
Page 76 of 191
-------
• Commercial use - chemical substances in treatment/care products - laundry products and
dishwashing products
• Commercial use - chemical substances in outdoor use products - explosives materials
• Commercial use- chemical substances in packaging, paper, plastic, hobby products - paper
products; plastic and rubber products; toys, playground, and sporting equipment
This was mainly due to the low number of monitoring samples available, lack of information specific to
formaldehyde usage for the given COUS and uncertainties with the representativeness of the monitoring
data. However, EPA concluded that the underlying data still provides a plausible estimate of exposures
for these OESs.
EPA had moderate weight of scientific evidence conclusions for all dermal scenarios assessed. The
primary strength of the dermal assessment is that most of the data that EPA used to inform the modeling
parameter distributions have overall data quality determinations of either high or medium from EPA's
systematic review process, such as the 2020 CDR (U.S. EPA 2020b). A limitation of the assessment is
that some COUs lacked formaldehyde weight concentration data.
2,5.2 Overall Confidence in the Consumer Exposure Assessment
EPA has medium confidence in the exposure assessment for consumers. As detailed in Section 3.2 of the
Consumer Exposure Assessment for Formaldehyde (U.S. EPA. 2024d). some key strengths of the
assessment are listed below.
• Consumer inhalation exposure assessment supported by 41 high-quality air monitoring studies
associated with uses of TSCA COUs and other sources, allowing EPA to identify inhalation as a
key driver of exposure for consumers.
• SACC peer reviewed inhalation and dermal modeling approaches which have been used in
previous and ongoing chemical risk evaluations.
• Inhalation and dermal modeling of products and articles on the consumer market at the time of
this risk evaluation.
• CEM modeling parameterized with weight fractions acquired from product and article-specific
safety data sheets, 2020 CDR (U.S. EPA 2020bI activity, and product use pattern data from the
EPA's Iixposure Factors Handbook (U.S. EPA. 2011) and 1987 Westat Survey (Westat. 1987).
• Thin Film Model used for dermal exposure estimates is derived from CEM and was
parameterized using product and article-specific safety data sheets, 2020 CDR (U.S. EPA.
2020b). and the associated dermal loading constant (On) was obtained from a robust dermal
loading study published by OPPT (U.S. EPA. 1992) and has been extensively been applied in
previous and current dermal exposure assessments by OPPT and OPP including OPP's
formaldehyde dermal exposure assessment from pesticides.
On the other hand, there are some uncertainties and limitations of the consumer exposure assessment.
These are listed below.
• For CEM inhalation exposure modeling, there is some uncertainty around the applicability of the
1987 Westat Survey (Westat. 1987) data for modern product and article use patterns. While the
survey is the best available source of information, the survey may not represent current use
patterns.
• For Thin Film dermal exposure modeling, EPA assumed the consumers' hand(s), finger(s) or
other skin layer may be covered with a viscous layer of the liquid product during use and may
linger until washed away.
Page 77 of 191
-------
EPA had slight confidence in, and as a result did not assess, any consumer exposures to potential
exposures to water treatment, laundry and dish washing, and lawn and garden products, as EPA did not
identify relevant products currently on the market. EPA also had slight confidence in, and as a result did
not assess, any oral exposures to consumers as there were no evidence of reasonably foreseen uses of
consumer products now or in the future which could lead to consumer oral exposures as products are
used. Lastly, EPA had a slight confidence in its assessment of dermal formaldehyde exposures from
clothing to skin due to a lack of information of on the diffusion of formaldehyde from clothing and
whether a vapor-to-skin assumption if appropriate to formaldehyde due to its high volatility.
2.5.3 Overall Confidence in the Indoor Air Exposure Assessment
EPA has high confidence in the overall findings for the indoor air exposure assessment. As detailed in
Section 4 of the Indoor Air Exposure Assessment for Formaldehyde (U.S. EPA. 2024i). the exposure
assessment is supported by a robust monitoring dataset and robust modeling approaches. EPA has
medium confidence that the exposure scenarios evaluated in this assessment are reasonable and
representative of people who spend most time indoors. The indoor air exposure scenario assumes
continuous exposure to indoor air over a lifetime.
Strengths of the indoor air assessment:
• Formaldehyde has a robust nationally representative monitoring dataset representing multiple
home types and home characteristics;
• Monitoring data from outside the home are also integrated to characterize the spectrum of
formaldehyde concentrations in the indoor environment;
• Emissions data from real products which were used to parametrize modeled concentrations of
formaldehyde;
• Two models were used to characterize expected concentrations in the indoor environment; and.
• CEM may be more conservative at estimating long term exposures.
EPA has high confidence in the quality and representativeness of indoor air monitoring data. The set of
20 studies used as an indication of indoor air concentrations and as a basis for comparison to modeled
concentrations were rated high quality. This dataset includes the American Healthy Homes Survey II, a
quality nationally representative formaldehyde residential indoor air monitoring study administered by
EPA and the U.S. Department of Housing and Urban Development (HUD). Though, indoor air
monitoring data, even if recent, may not represent future potential exposures in homes. This may be an
artifact of how monitoring data cannot fully reflect how and when formaldehyde-emitting materials
(including imported articles from places with varying wood standards) are installed. Similarly,
monitoring data cannot explain how frequently these materials are replaced. Lastly, the monitoring data
may not reflect changes in energy efficiency home improvements that reduce ventilation (e.g., leaks).
Therefore, modeled concentrations are reasonable and representative of concentrations to which
individuals are exposed and can be relied upon for purposes of deriving risk estimates and informing
regulatory decisions under TSCA.
EPA has a medium confidence in its CEM screening exposure assessment which were generally
received from the SACC. However, since CEM was not used to estimate peak exposures for the draft
evaluation and due to uncertainties with CEM's potential overestimation of long-term exposure along
with an inability to consider first-order exponential decay for articles in the long-term, based on the E5
emission condition, this EPA also utilized IECCU as a higher tier modeling tool to characterize 15-
minute peak, 3-month average and 1-year average formaldehyde residential indoor air concentrations.
EPA had a high confidence in the higher-tier indoor air modeling approaches using IECCU which
depended on article and formaldehyde specific input data. Though, the one-year results for IECCU were
Page 78 of 191
-------
significantly lower than CEM and are likely an underestimate of indoor air exposures. Available data
suggest a biphasic emission profile (rapid emission of formaldehyde when the product is new followed
by a much slower emission of formaldehyde) for laminated wood products that is not captured in the
modeling results. This biphasic emission profile may also occur for other urea-formaldehyde based
products; however, data are not available to confirm this. As such, CEM was presented in conjunction
with IECCU to characterize 1-year average indoor air concentrations and provide an upper bound on
longer-term formaldehyde exposures.
Since the highest emissions of formaldehyde are expected from composite wood articles that are newly
manufactured and introduced into the home or other indoor air environment, and because such newly
manufactured composite wood products would be subject to the TSCA Title VI emission standards set
forth at 40 CFR part 770, EPA's IECCU modeling uses emission factors that incorporate the Title VI
emission standards. EPA expects estimated formaldehyde concentrations from wood articles made of
composite wood materials to be lower after full implementation of the Formaldehyde Standards for
Composite Wood Products regulations (40 CFR part 770) enacted under TSCA Title VI, but EPA does
not know whether full implementation will lower them beneath hazard benchmarks.
EPA's confidence in the monitoring and modeled indoor air exposure assessments reflects a
consideration of the associated strengths and weaknesses of available indoor air exposure lines of
evidence described in more detail in the weight of scientific evidence discussion in Section 4 of the
Indoor Air Exposure Assessment for Formaldehyde (U.S. EPA. 2024i).
EPA considered concordance between monitored and modeled concentrations. Monitored concentrations
are expected to reflect aggregate concentrations resulting from multiple sources of formaldehyde and are
therefore not directly comparable to modeled concentrations estimated for specific sources. While
IECCU incorporates formaldehyde's exponential decay from finished articles, according to the
literature, it does not incorporate indoor sinks that may capture and re-emit formaldehyde, various forms
of barriers (e.g., lamination, coatings, article thickness, etc.) that may delay and/or prolong
formaldehyde emissions over time, temperature and humidity fluctuations which may differ across
housing units, seasons, and regions. However, given CEM and IECCU modeled concentrations are
within the same order of magnitude as monitoring concentrations, EPA has increased confidence in the
models' combined ability to predict real world exposures to formaldehyde in American residential
indoor air from TSCA COUs. The availability of both modeled concentrations and monitoring data
provides information about both the aggregate exposures from all sources contributing to indoor air
concentrations as well as information about the relative contributions of individual TSCA COUs.
Based on consideration of the weight of scientific evidence, EPA has high confidence in the overall
findings for the indoor air exposure assessment (U.S. EPA 2024i) due to a high confidence in the
monitoring data, medium confidence in the CEM modeling, high confidence in the IECCU modeling.
2.5.4 Overall Confidence in the Ambient Air Exposure Assessment
There are many sources of formaldehyde which contribute to exposures to the general population.
The ambient air exposure assessment for formaldehyde also considers multiple lines of evidence
including measured (monitored) and modeled formaldehyde concentrations to characterize exposures.
Overall, the ambient air exposure assessment finds that the general population living near industrial
facilities releasing formaldehyde to the ambient air experience both short-term and long-term inhalation
exposure to formaldehyde attributable to TSCA COUs. While individual lines of evidence may not be
directly comparable, taken together the data and results support EPA's use of IIOAC daily and annual
average modeled concentrations to characterize exposures.
Page 79 of 191
-------
EPA has medium confidence in the IIOAC modeled results used to characterize exposures in this
ambient air exposure assessment. Several inputs used for the IIOAC model are generally conservative,
including the maximum and 95th percentile releases modeled and relied upon for the exposure
concentrations, stack parameters representing a low, slow moving, non-buoyant plume, and the
meteorological station within IIOAC used for the ambient air exposure assessment representing a high-
end station which leads to higher overall estimated concentrations. However, there are uncertainties in
model outputs due to assumptions made when choosing input parameters, including the use of annual
average releases to calculate daily releases and the use default parameters used within IIOAC. There is
additional uncertainty because IIOAC does not consider the location of residential areas relative to
industrial facilities associated with TSCA COUs. Similarly, the assessment was conducted independent
of the size of the facility footprint, the precise location of the release, and the relative location of
residences. Furthermore, ambient air modeling for formaldehyde does not account atmospheric
degradation (i.e. photolysis) and how local weather patterns may affect the presence of formaldehyde
over time. Furthermore, the assumption that individuals reside in the same location for the duration of
their life (i.e. 78 years) is conservative.
Additional lines of evidence provide context for the use of IIOAC modelling results. Monitoring data
from AMTIC represent the aggregate concentration of formaldehyde in the ambient air from all sources,
while IIOAC modeled concentrations represent local exposures attributable to TSCA COUs at select
distances near a releasing facility. AirToxScreen data provide further context for contributions from
multiple sources including biogenic, secondary, TSCA COUs and other sources. HEM results provide
additional context on the spatial variability of formaldehyde concentrations across the U.S. While the
individual lines of evidence provide context, the individual datasets are not directly comparable to each
other, due to spatial and temporal differences. Further, formaldehyde concentrations are highly variable
based on geographic location (e.g., HEM results show elevated concentrations in the Southeastern
United States), nearby releases, and contributions from other sources of formaldehyde. Taken together,
the totality of integrated data can and do allow for a characterization of general population exposures but
has some uncertainty.
Strengths and limitations of the ambient air exposure assessment which inform the medium confidence
are discussed in detail in the Ambient Air Exposure Assessment for Formaldehyde (U.S. EPA. 2024a)
but summarized here for reference. Overall, the approaches and methodologies presented in this ambient
air exposure assessment utilize previously peer reviewed approaches and methods. These approaches
and methodologies incorporate several additional components recommended by peer reviewers during
earlier peer reviews of other ambient air exposure assessments as well as peer review of the Draft
Ambient Air Exposure Assessment for Formaldehyde.
IIOAC Modeling: A strength of the IIOAC modelling includes use of environmental release data from
multiple databases across multiple years (including data which are required by law to be reported by
industry). These databases undergo repeatable quality assurance and quality control reviews (U.S. EPA
2024g). These release data are used as direct inputs to EPA's peer reviewed IIOAC model to estimate
concentrations at several distances from releasing facilities. However, the use of annual release data to
estimate daily average concentrations introduces uncertainty in modelling outputs estimated. Since both
TRI and NEI report a single annual release value (for stack and fugitive emissions) from each release
point, EPA assumes operations are continuous and releases are the same every day of operation in order
to calculate daily average concentrations. These assumptions may result in modeled concentrations
missing true peak releases (and associated exposures) and therefore may underestimate peak exposures.
Page 80 of 191
-------
Assumptions made when choosing input parameters for IIOAC modelling introduce uncertainty in
model estimates, likely resulting in an overestimation of exposure. For example, the maximum stack and
fugitive releases for each industry sector were used as input values for IIOAC modelling. However, the
maximum stack and fugitive releases within an industry sector are not necessarily associated with the
same facility, and it is unknown how likely it is for the maximum stack and fugitive releases to be
occuring at a single facility. There is additional conservatism built into the IIOAC modeling inputs
including using the maximum and 95th percentile releases modeled and relied upon for the exposure
concentrations, stack parameters representing a low, slow moving, non-buoyant plume, and the
meteorological station within IIOAC used for the ambient air exposure assessment representing a high-
end station which leads to higher overall estimated concentrations.
Limitations of the IIOAC modelling approaches and methods used include the fact that IIOAC modeling
is based on pre-run scenarios within AERMOD. As such, default input parameters for IIOAC are
confined to those input parameters utilized for those pre-run AERMOD scenarios and cannot be
changed. Default input parameters include stack parameters, 2011 to 2015 meteorological data, and the
lack of site-specific information like building dimensions, stack heights, elevation, and land use.
Ambient air modeling for formaldehyde does not account atmospheric degradation (i.e. photolysis) and
how local weather patterns may affect the presence of formaldehyde over time. Furthermore, the
assumption that individuals reside in the same location for the duration of their life (i.e. 78 years) is
conservative.
AirToxScreen: AirToxScreen has been previously reviewed by EPA's Science Advisory Board (SAB).
As, such EPA has confidence in the modeled data. Similarly, these data are based on the NEI, which has
been rated as a high-quality data source according to the Draft Systematic Review Protocol Supporting
TSCA Risk Evaluations for Chemical Substances (U.S. EPA. 2021c). However, note that the NEI point
source emissions are largely dependent on state-reported emissions inventories to which HAP emission
data are voluntarily reported. Furthermore, biogenic emissions are modeled estimates and are likely less
certain than point source emission estimates.
The strengths of the AirToxScreen data included in this exposure assessment are that they show the
contributions of formaldehyde to the ambient air from all sources of formaldehyde in the contiguous
United States. However, the use of AirToxScreen is limited due to the inability to isolate contributions
from TSCA COUs. EPA's use of these results provides strength to this assessment because the
AirToxScreen data are used to contextualize IIOAC modeled annual average concentrations of
formaldehyde relative to other large contributing sources to the ambient air.
HEM Modeling: The base dispersion model run by HEM 4.2 is EPA's AERMOD. AERMOD is EPA's
regulatory model which has been peer reviewed as part of the regulatory model process described in
"Appendix W" to 40 CFR Part 51. As such, EPA has high confidence in the modeling methods based on
HEM's reliance on EPA's regulatory model. However, there may be uncertainty in census population
data used as input to HEM for specific locations and populations. A limitation of the HEM model is the
exclusion of consideration of photodegradation processes within the AERMOD sub-routines, which may
be relevant to modeling ambient air concentrations of formaldehyde since it is known to undergo
photolysis within 4 hours in sunlight.
AMTIC Archive Monitoring Data: EPA has high confidence in the AMTIC archive data set (U.S.
EPA. 2022a). The AMTIC archive dataset received a high-quality rating from EPA's systematic review
process. (U.S. EPA. 2021b). Additionally, the AMTIC archive dataset undergoes review and verification
Page 81 of 191
-------
by AMTICs Ambient Air Monitoring Group. This review and verification process includes multiple
quality assurance steps to ensure data quality and certification in accordance with 40 CFR 58.15. There
is also added value from the AMTIC archive monitoring data set because they are real measured data
which reflect concentrations to which the general population would be exposed to in the time and space
the sample was taken.
The primary limitations of the AMTIC are that it represents a diverse collection of sampling durations
(none of which are annual averages) that are not directly comparable to either IIOAC or AirToxScreen
results. Additionally, because monitored data represents a total aggregate concentration from all sources
of formaldehyde contributing to ambient air concentrations, the AMTIC data cannot be associated with
TSCA COUs for purposes of characterizing exposures from TSCA COUs. Additional limitations of the
AMTIC data include the wide variety of monitoring locations represented, which may include sites both
near-to and far-from facility release points associated with TSCA COUs.
Other factors: For industrial TSCA COUs, EPA has a moderate to robust weight of scientific evidence
as the databases have high data quality scores and are supported by numerous data points. A primary
strength of TRI and NEI data is that these programs compile the best reasonably available release data
for large facilities. Limitations are that these programs may not cover some sites that emit formaldehyde
as both programs have conditions that must be met prior to being required to report releases. For
formaldehyde, the potential contribution of combustion sources is an uncertainty and use of the full
facility data complicate singular TSCA COU estimates, such that emissions at one site may include
multiple sources under multiple COUs that include combustion sources and non-combustion sources.
In general, for commercial COUs, EPA has a moderate weight of scientific evidence since the generic
scenarios on which release estimates are based have a medium to high data quality rating. EPA relied
upon professional judgement in mapping TRI and NEI industrial sectors to commercial COUs. There is
some uncertainty that a commercial TSCA COU may occur across several industrial sectors beyond the
industrial sector used for analysis. In addition, some industrial sectors cover both industrial and
commercial operations, so they may overestimate air releases occurring in a commercial setting. Four
commercial COUs either lacked sufficient data or were supported by a slight weight of evidence:
• Commercial use - chemical substances in treatment/care products - laundry and dishwashing
products;
• Commercial use - chemical substances in treatment products - water treatment products;
• Commercial use - chemical substances in outdoor use products - explosive materials; and
• Commercial use - chemical substances in products not described by other codes - other:
laboratory chemicals.
EPA used HEM to estimate the number of exposed population to modeled concentrations in ambient air
to further inform exposures and associated risks. EPA's confidence in these exposed population
estimates is medium as they are expected to be an underestimate since EPA limited these analyses to the
810 TRI facilities directly reporting with Form R. That TRI dataset is a subset of the approximately
49,000 distinct facilities with estimated emissions in NEI and therefore a smaller dataset on which
exposed population estimates rely upon. Additionally, the exposed population estimates from HEM are
derived by averaging the modeled annual concentration at the proximate census block centroids across
the census block, using site-specific meteorological conditions. Since EPA did not make facility-specific
adjustments to modeling receptor files based on land use analysis to capture the highest proximate
populations in this analysis, the population estimates are biased against capturing the populations of the
most highly exposed residents within rural (and therefore larger) census blocks.
Page 82 of 191
-------
3 HUMAN HEALTH HAZARD SUMMARY
EPA's OPP and OPPT collaborated to develop a joint hazard assessment for formaldehyde (U.S. EPA.
20240. This joint assessment evaluated available human health hazard and dose-response information
for formaldehyde and identified hazard values to support risk assessments in both offices. This hazard
assessment also reflects coordination with EPA's Office of Research and Development (ORD) and other
EPA offices, including Office of Air and Radiation (OAR), to the extent appropriate. As a result of this
collaboration across programs, multiple federal advisory committees—including the National
Academies of Sciences, Engineering, and Medicine (NASEM), TSCA Science Advisory Committee on
Chemicals (SACC), and the Human Studies Review Board (HSRB)—have provided review of various
aspects of this hazard characterization.
For cancer and non-cancer hazards associated with chronic inhalation exposures, OPP and OPPT are
using the analysis presented in the IRIS assessment on formaldehyde inhalation (U.S. EPA 2024k) and
peer reviewed by the National Academies of Sciences, Engineering, and Medicine (NASEM) (NASEM.
2023). The systematic review literature searches, data quality review, evidence integration, dose-
response analyses, and peer review performed in support of the IRIS assessment reflect the best
available science on formaldehyde hazards from chronic inhalation exposures and are consistent with
the needs of both OPP and OPPT. The IRIS assessment derived a chronic reference concentration (RfC)
for non-cancer risks and an inhalation unit risk (IUR) for cancer risks from inhalation of formaldehyde.
To identify additional available hazard and dose-response information for acute inhalation, dermal, and
oral formaldehyde exposures, EPA used a fit-for-purpose systematic review protocol, integrating the
needs and approaches of both OPP and OPPT. Details of the fit-for-purpose systematic review protocol
used in OPPT's work on this assessment are described in the Systematic Review Protocol for the Risk
Evaluation for Formaldehyde (U.S. EPA. 2024m). This approach is based in part on the OPPT
systematic review approach described in the Draft Systematic Review Protocol Supporting TSCA Risk
Evaluations for Chemical Substances (U.S. EPA. 2021c).
EPA identified a range of factors that may increase susceptibility to formaldehyde and considered
susceptibility throughout the hazard assessment. Descriptions of how EPA incorporated PESS due to
greater biological susceptibility into the risk evaluation are provided in Appendix C. Factors that may
increase susceptibility to formaldehyde exposures include chronic respiratory disease, lifestage, sex, and
co-exposure to chemical and non-chemical stressors that influence the same health outcomes.
3.1 Summary of Hazard Values
The non-cancer and cancer hazard values identified for inhalation, dermal, and oral exposures to
formaldehyde in the joint hazard assessment (U.S. EPA. 2024i) are summarized in Table 3-1.
Consistent with the recommendations of the Human Studies Review Board, OPPT solicited input on its
hazard assessment, particularly with regards to the PODs and uncertainty/extrapolation factors for acute
and chronic non-cancer assessment and the extent to which the hazard assessment for formaldehyde
appropriately considered recommendations from other federal advisory committees (e.g., NASEM,
HSRB, SACC).
Page 83 of 191
-------
Table 3-1. Hazard Values Identified for Formaldehyde
Exposure
Scenario
Hazard Value
Uncertainty
Factors
Total
Uncertainty
Factor
Study and Toxicological Effects
Inhalation
Acute
NOAEC and BMCL =
0.5 ppm
(0.62 mg/m3)
BMCL = 0.5 ppm
UFh = 3
Total UF = 3
Kulle et al, (1987)
LOAEC = 1 ppm (mg/m3) based on eye irritation in adult volunteers
Mueller et al. (2013)
LOAEC = 0.3 ppm over 4 hours, with 15-minute peaks of 0.6 ppm, based on eye
irritation in hypersensitive adult volunteers
Lane et al. (2008)
LOAEC= 0.5 ppm over 4 hours, with peaks of 1 ppm (0.62/1.23 mg/m3), based
on eye irritation in adult volunteers
Inhalation
Chronic non-
cancer3
(Long-term, >6
months)
BMCLio = 0.017 ppm
(0.021 mg/m3)
UFh = 3
Total UF = 3
POD is derived from the IRIS RfC (U.S. EPA. 2024k). The specific BMCLio
value used here is based on reduced pulmonary function in children in
Krzvzanowski et al. (1990). but is consistent with the RfC. derived based on
multiple studies of respiratory effects.
Inhalation
Chronic
Cancer
IUR (ADAF-adjusted)
0.013 ppm"1
(1.1 x 10~5 (ng/m3)"1)
Adult-based unit risk:
0.0079 ppm"1
(6.4 x 10"6 (ng/m3)"1)
N/A
N/A
IUR established bv IRIS (U.S. EPA. 2024k) based on data on nasopharyngeal
cancer in people reported in Beane-Freeman et al. (2013).
Dermal
Elicitation:
BMDLi,,= 10.5
Hg/cm2 (0.035%)
UFh = 10
Total UF= 10
Flwhohn et al.. (1997)
based on threshold for elicitation of dermal sensitization in people
Oral
Short-Term/
subchronic
(1-30 days),
HED= 6 mg/kg-day
UFa = 3
UFh = 10
Total UF = 30
Til (1988)
NOAEL= 25 mg/g-day; LOAEL =135 mg/kg-day based on gastrointestinal
histopathology in rats
Page 84 of 191
-------
Exposure
Scenario
Hazard Value
Uncertainty
Factors
Total
Uncertainty
Factor
Study and Toxicological Effects
Oral
Chronic
HED = 3.6 mg/kg-day
UFA = 3
UFH= 10
Total UF = 30
Civo Inst.(1987); Til (1989)
NOAEL= 15 mg/g-day; LOAEL = 82 mg/kg-day based on gastrointestinal
histopathology in rats
" This value is used to estimate risks from both sub-chronic and chronic occupational exposures.
Point of departure (POD) = A data point or an estimated point that is derived from observed dose-response data and used to mark the beginning of extrapolation to
determine risk associated with lower environmentally relevant human exposures; NOAEL = no-observed adverse-effect level; LOAEL = lowest-observed adverse-
effect level; UF = uncertainty factor; UFA = extrapolation from animal to human (interspecies); UFH = potential variation in sensitivity among members of the
human population (intraspecies). UFL = use of a LOAEL to extrapolate a NOAEL. UFS = use of a short-term study for long-term risk assessment. UFDb = to account
for the absence of key data (i.e., lack of a critical study). IUR= inhalation unit risk; IUR= inhalation unit risk (includes ADAF adjustment) for calculating cancer
risks associated with a full lifetime of exposure, including early life exposure; Adult-based unit risk = unit risk for calculating chronic cancer risks associated with
adult exposures not expected to include early life.
Page 85 of 191
-------
3.2 Weight of Scientific Evidence and Overall Confidence in Hazard
Assessment
As described in the Draft Systematic Review Protocol Supporting TSCA Risk Evaluations for Chemical
Substances (U.S. EPA. 2021c). the weight of scientific evidence supporting hazard assessment and dose
response is evaluated based on the quality of the key studies, consistency of effects across studies, the
relevance of effects for human health, confidence in the dose-response models, and the coherence and
biological plausibility of the effects observed. The weight of evidence and overall confidence in chronic
inhalation hazard values derived by IRIS are described in the IRIS assessment (U.S. EPA 2024k). The
weight of evidence and sources of confidence and uncertainty in dermal, oral, and acute inhalation
hazard values derived by OCSPP are described in the hazard assessment (U.S. EPA 20240. This section
summarizes overall confidence and sources of uncertainty in the hazard values used to develop risk
estimates in this risk characterization.
3.2.1 Overall Confidence in the Acute Inhalation POD
Overall confidence in the acute inhalation POD is high. As described in the joint hazard assessment
(U.S. EPA. 20240. the acute POD is based on a robust dataset of evidence for sensory irritation in
humans, including several high-quality controlled exposure studies with relevance for acute exposure
scenarios. Concordance of reported sensory irritation effects and the effect levels reported across acute
exposure studies increases confidence in the final POD. Variability across individuals' response
contributes to uncertainty around effect levels that are protective across the population. An uncertainty
factor of 3 is applied to account for uncertainty related to intraindividual variability.
There is some uncertainty around the degree to which duration influences effect levels because there are
no studies available that provide direct evidence that effect levels following 8- or 24-hour exposures are
the same as effects following 2 to 5 hours of exposure. Therefore, based on the best available
information, the acute POD focuses on defining exposure concentrations relevant to any acute exposure
duration rather than adjusting specific PODs for defined 8- or 24-hour exposure durations, as
recommended by the HSRB and supported by the SACC.
Other endpoints may also have relevance for acute hazard, but available studies do not provide sufficient
information to characterize hazard or quantify dose-response relationships for acute inhalation
exposures. This assessment assumes that sensory irritation is protective of those other endpoints.
Although this may be a potential source of uncertainty for the acute POD, available data suggest that
sensory irritation is the most sensitive endpoint resulting from acute exposures and is consistent with
several other international regulatory bodies.
3.2.2 Overall Confidence in the Chronic, Non-cancer Inhalation POD
Overall confidence described in the IRIS assessment (U.S. EPA. 2024k) for the chronic non-cancer
inhalation POD is high. The chronic POD derived by IRIS is supported by a robust database of evidence
for a range of endpoints in humans and animals. The overall POD is informed by dose-response
information in humans across multiple respiratory endpoints and reflects concordance in effect levels
identified across those endpoints. EPA also considered dose-response information for reproductive and
developmental effects in selection of the overall POD. While there is more uncertainty around the PODs
derived for these endpoints, the overall POD is expected to be protective of these reproductive and
developmental effects in humans. Many of the observational epidemiology studies providing the
quantitative basis for the chronic POD reflect relevant human exposure scenarios in homes and schools.
In addition, several of the studies include children with asthma or other sensitive groups.
Page 86 of 191
-------
EPA acknowledges that some SACC members raised concerns with the chronic RfC and recommended
an alternate approach using sensory irritation as the most sensitive endpoint. For non-cancer chronic
effects, SACC members raised concerns about the quality of the epidemiology studies used to derive the
chronic RfC and the WOE for a causal link between formaldehyde exposure and outcomes other than
sensory irritation. Many SACC members expressed reservations and difficulty with reviewing the values
due to the draft status of the IRIS assessment at the time of their review. For example, SACC stated
"Many members expressed reservations about the specifics surrounding the value of using the unedited
2022 Draft IRIS document since it is not final and the comments from NASEM review have not yet
been incorporated" (p. 32). Further the SACC noted that "One needs to access the IRIS document to
understand the basis of the 0.007 mg/m3 RfC. Since the IRIS document has not yet been finalized, it is
difficult to understand the review and selection process" (p. 59).
EPA has since finalized the IRIS assessment for formaldehyde. Discussion regarding study selection is
provided in Section 5.1.1 of the IRIS assessment. Discussion regarding the weight of evidence for
noncancer respiratory effects is provided sections 3.2, 4.2 and 5.1.5 of the IRIS assessment. Comments
on study selection, weight of evidence for noncancer effects, and sensory irritation are addressed in
Sections F.l and F.3 in Appendix F of the IRIS assessment supplemental materials.
In addition, some SACC members SACC also commented on the relevance of the chronic inhalation
POD for adult populations, stating that "The POD is based on pulmonary function response in children.
The POD representing this PESS will be protective of adults and workers. However, several Committee
members hold the view that applying the POD (based on responses in children) to adult workers is not
appropriate" (U.S. EPA 2024w).
Since the release of the draft risk evaluation reviewed by peer reviewers and public commenters, EPA
has finalized the IRIS assessment (U.S. EPA 2024k) for formaldehyde. Discussion regarding study
selection is provided in Section 2.1.1 of the IRIS assessment. Discussion regarding the weight of
evidence for noncancer respiratory effects is provided in sections 3.2, 4.2, and 5.1.5 the IRIS
assessment. Comments on study selection, weight of evidence for noncancer effects, and sensory
irritation are addressed in Sections F.l and F.3 in Appendix F of the IRIS assessment supplemental
materials.
3.2.3 Overall Confidence in the Chronic IUR
Overall confidence described in the IRIS assessment (U.S. EPA 2024k) for the preferred unit risk
estimate is medium. The IUR derived for nasopharyngeal cancer is informed by a robust dataset of both
human and animal data. The availability of human data eliminates the need to extrapolate from animal
studies, increasing the confidence in the IUR. In addition, the IUR derived from animal data is similar to
the IUR derived from human evidence, further increasing confidence in the IUR. Sources of uncertainty
in the IUR include reliance on extrapolation from high doses that occur in occupational settings to lower
doses that may occur in the general population, reliance on data from a single high quality occupational
cohort study that may not capture the sensitivity of susceptible populations or lifestages, and reliance on
mortality data as a surrogate for cancer incidence.
EPA recognizes that the SACC report (U.S. EPA 2024w) states that "The majority of the information
presented in session did not favor a IUR approach, and rather supported a threshold approach."
However, the SACC report also states that "Several Committee members disagreed with this approach
and supported the IUR approach as the most appropriate." Overall, "The Committee recommended that
the EPA consider the best available science to determine if a threshold or non-threshold approach is best
for evaluating cancer, and if needed revise the Draft Human Health Hazard Assessment." Many of the
Page 87 of 191
-------
scientific issues raised by SACC members and some public commenters on the draft TSCA risk
evaluation regarding the approach taken in the draft IRIS formaldehyde assessment were considered
during the IRIS process and are addressed in the final IRIS assessment. Further discussion on how IRIS
derived the cancer IUR is provided in Section 5.2 of the IRIS assessment. Comments suggesting a
threshold approach for cancer are addressed in Section F.4 in Appendix F of the IRIS Supplemental
Information document (U.S. EPA. 2024k).
EPA was not able to derive IURs for all tumor sites associated with formaldehyde exposure. This is a
source of uncertainty and may lead to an underestimate of risk. Although EPA was able to derive a unite
risk estimate for myeloid leukemia, the lack of confidence in the dose-response data and IUR for
myeloid leukemia is a source of uncertainty. The cancer risk estimates presented in this risk
characterization do not include risks for myeloid leukemia and other tumor sites. Based on the IUR
estimated for myeloid leukemia in the IRIS document, IRIS estimated that consideration of myeloid
leukemia may increase the age-dependent adjustment factor (ADAF)-adjusted IUR by as much as four-
fold.
EPA acknowledges that some members of the SACC (U.S. EPA 2024w) questioned the association
between formaldehyde exposure and myeloid leukemia, noting that "there is no biologically plausible
mode of action whereby formaldehyde can arrive at the bone marrow to result in direct toxicity" (p. 88
of the SACC Report). Other SACC reviewers agreed that there is "evidence that formaldehyde can cause
acute and chronic myelogenous leukemia" (p. 103 of the SACC Report). EPA is not quantifying the risk
to myeloid leukemia. Discussion of the available evidence for myeloid leukemia can be found in Section
3.3.3 of the IRIS assessment (U.S. EPA 2024k). The IRIS conclusions for cancer hazard are
summarized in Section 4.3. Comments on the IRIS hazard conclusion regarding formaldehyde and
myeloid leukemia are addressed in Section F.4.1 in Appendix F of the IRIS assessment supplemental
materials (U.S. EPA 2024k). Ultimately, EPA only included quantitative cancer risk for the
nasopharyngeal cancer outcome as part of the final IUR.
3.2.4 Overall Confidence in the Dermal POD
Overall confidence in the dermal POD is high. As described in the OCSPP joint hazard assessment (U.S.
EPA. 2024i). the dermal POD is derived from an extensive dataset on dermal sensitization in human,
animal, and in vitro studies. Multiple streams of evidence from studies evaluating elicitation thresholds
in sensitive people and induction thresholds in animal and in in vitro assays arrive at similar effect
levels. While there are some uncertainties associated with the human studies related to lack of clarity in
methods and data reporting, concordance in effect levels across multiple streams of evidence increases
confidence in the POD. The potential impact of methanol present in available dermal formaldehyde
studies is a source of uncertainty in the POD. While there is substantial variation in sensitization
responses across individuals, application of an uncertainty factor of 10 is used to account for uncertainty
related to intraindividual variability.
3.2.5 Overall Confidence in the Subchronic and Chronic Oral PODs
Overall confidence in the subchronic and chronic oral PODs is medium. As described in the OSCPP
joint hazard assessment (U.S. EPA. 2024i). the subchronic and chronic oral PODs rely on a limited
database of animal studies but are supported by three studies that report consistent patterns of
gastrointestinal damage at similar dose levels. The chronic oral POD is consistent with the oral POD
identified by IRIS as the basis for the 1990 RfD (U.S. EPA. 1990). though it has been modified to reflect
more recent guidance on dosimetric adjustments.
Page 88 of 191
-------
Due to technical challenges around generating pure and stable formaldehyde treatments for oral
exposure, most of the available animal studies have major limitations and uncertainties. Among the
available studies that are not confounded by the presence of methanol, gastrointestinal effects are the
most sensitive endpoint evaluated. Reduced drinking water intake in the high dose groups reduced
confidence in each of the chronic studies when considered in isolation. However, when considered in
conjunction with the results of the 28-day study that included water-restricted controls, EPA has
confidence that the reported effects are attributable to formaldehyde exposure.
There is very limited information on reproductive, developmental, and immune endpoints following oral
exposure to formaldehyde. While there are some studies that suggest effect levels for these endpoints
may be more sensitive than those used as the basis for the POD, the only studies that evaluate immune,
reproductive, or developmental endpoints are confounded by the presence of methanol. Evidence of
reproductive and developmental effects reported in humans and animals following inhalation exposure
to formaldehyde indicates that such effects are possible following formaldehyde exposure. Similarly, the
available data do not evaluate factors that may increase susceptibility to oral formaldehyde exposure in
sensitive groups or lifestages. The lack of data on these endpoints and sensitive groups and lifestages
following oral exposure could be perceived as uncertainty; however, the likelihood of a lower POD
being identified based on these outcomes is low given the effect used as the basis of the current PODs
(gastrointestinal effects) are close to the portal of entry, first pass metabolism via the oral route, and the
reactivity of formaldehyde.
Page 89 of 191
-------
4 HUMAN HEALTH RISK CHARACTERIZATION
4.1 Risk Characterization Approach
The exposure scenarios, populations of interest, and toxicological endpoints used for evaluating risks
from acute and chronic exposures are summarized below in Table 4-1. EPA estimated cancer and non-
cancer risks from occupational, consumer, and general population exposures as described below.
While EPA will consider the standard risk benchmarks shown in Table 4-1 associated with interpreting
margins of exposure and cancer risks, EPA cannot solely rely on those risk values. Risk estimates
include inherent uncertainties and the overall confidence in specific risk estimates varies. The analysis
provides support for the Agency to make a determination about whether formaldehyde poses an
unreasonable risk to human health and to identify drivers of unreasonable risk among exposures for
people (1) with occupational exposure to formaldehyde, (2) with consumer exposure to formaldehyde,
(3) with exposure to formaldehyde in indoor air, and (4) who live or work in proximity to locations
where formaldehyde is released to air.
Table 4-1. Use Scenarios, Populations of Interest, and Toxicological Endpoints Used for Acute and
Chronic Exposures
Populations
of Interest
and
Exposure
Scenarios
Workers 11
Acute - Adolescent (>16 vears old) and adult workers exposed to formaldehyde in a single
workday for 15 min or longer
Chronic - Adolescent (>16 vears old) and adult workers exposed to formaldehyde over a full-shift
workday for 250 days per year for 40 working years
Consumers and Bystanders
Acute - Consumers across all aae aroups (depending on the product or article) exposed to
formaldehyde result from product or article use. Exposures are estimated to be 15-minute peak
concentrations. It should be noted that the 15-minute peak concentration for a given TSCA COU
and exposure scenario may occur several hours after product use.
General Population Indoor Air Exposure b
Acute - People across all aae aroups exposed to formaldehyde throuah indoor air over short
periods. Exposures are estimated to be 15-minute peak concentrations.
Chronic - People across all aae aroups exposed to formaldehyde throuah indoor air continuously
up to 78 years.
General Population Outdoor Ambient Air Exposure b
Acute - People across all aae aroups exposed to formaldehyde throuah ambient air over short-
term. Risk estimates are based on daily average modeled concentrations.
Chronic - People across all aae aroups exposed to formaldehyde throuah ambient air near
industrial release site continuously up to 78 years. Risk estimates are based on annual average
modeled concentrations
Health
Effects,
Hazard
Values and
Benchmarks
Non-cancer Acute Hazard Values
Acute inhalation health effect: sensory irritation
• Acute inhalation POD (15-minute duration) = 0.5 ppm (0.62 ma/m3)
• Uncertainty Factors (Benchmark MOE) = 3 (UFa = 1; UFh = 3; UFl = 1; UFs=l; UFd=1)
Acute dermal health effect: sensitization (elicitation)
• Acute POD = 10.5 [ia/cm2
• Uncertainty factors (Benchmark MOE) = 10 (UFa = 1; UFh = 10; UFl = 1; UFs=l;
UFd=1)
Acute oral health effect: no acute oral PODs identified
Non-cancer Subchronic Hazard Values
Subchronic oral health effects: Gastrointestinal effects
Page 90 of 191
-------
• Oral HED = 6 mg/kg-day
• Uncertainty Factors (Benchmark MOE) = 30 (UFa = 3; UFh = 10; UFl = 1; UFs=l;
UFd=1)
Non-cancer Chronic Hazard Values
Chronic inhalation health effects: Respiratory effects, including reduced pulmonary function,
allergy-related conditions, and asthma (prevalence and degree of asthma control).
• Inhalation HEC = 0.017 ppm (0.021 mg/m3)
• Uncertainty Factors (Benchmark MOE) = 3 (UFa = 1; UFh = 3; UFl = 1; UFs = 1; UFd =
1)
Chronic oral health effects: Gastrointestinal effects
• Oral HED = 3.6 mg/kg-day
• Uncertainty Factors (Benchmark MOE) = 30 (UFa = 3; UFh = 10; UFl = 1; UFs = 1; UFd
= D
Cancer Hazard Values
Inhalation cancer hazard for formaldehyde is based on nasopharyngeal cancers
• IURC = 0.013 ppnT^l.l x 10~5 (ng/m3)-1)
• Adult-based unit risk1' = 0.0079 ppm 1 (6.4/10"6 ((.ig/nr1) ')
Oral and dermal cancer hazards are not quantified because there is insufficient data to support
derivation of cancer slope factors for these routes of exposure.
" Adult workers (>16 years old) include both female and male workers.
b Inhalation exposures are described in terms of air concentrations and do not include lifestage-specific adjustments; risk
estimates based on air concentrations are intended to address risks to all lifestages.
c Age-dependent adjustment factors applied for early life exposures
''Unadjusted IUR applied for exposure scenarios where early life exposure is not anticipated
MOE = margin of exposure; UFA = Interspecies uncertainty factor for animal-to-human extrapolation; UFH = Intraspecies
uncertainty factor for human variability; UFL = LOAEC-to-NOAEC uncertainty factor for reliance on a LOAEC as the POD
4.1.1 Estimation of Non-cancer Risks
EPA used a margin of exposure (MOE) approach to identify potential non-cancer risks. The MOE is the
ratio of the non-cancer POD divided by a human exposure dose. Acute and chronic MOEs for non-
cancer inhalation and dermal risks were calculated using Equation 4-1:
Equation 4-1.
MOEacute or chronic ~
Non — cancer Hazard value (POD)
Human Exposure
Where:
MOE = Margin of exposure (unitless)
Hazard value (POD) = HEC (ppm) or HED (mg/kg-d)
Raman Exposure = Exposure estimate (in ppm or mg/kg-d)
MOE risk estimates may be interpreted in relation to benchmark MOEs. Benchmark MOEs are typically
the total UF for each non-cancer POD. If the numerical value of the MOE is less than the benchmark
MOE, this relationship is a starting point to determine if there are unreasonable non-cancer risks. On the
other hand, if the MOE estimate is equal to or exceeds the benchmark MOE, risk is not indicated.
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 discretion to consider other risk-related factors apart from risks identified in risk
characterization.
Page 91 of 191
-------
4.1.2 Estimation of Cancer Risks
Extra cancer risks for repeated inhalations exposures to formaldehyde were estimated using Equation
4-2:
Equation 4-2.
Inhalation Cancer Risk = Human Exposure x IUR
Where:
Risk = Extra cancer risk (unitless)
Raman exposure = Exposure estimate (LADC in ppm)
IUR = Inhalation unit risk
The IRIS assessment (U.S. EPA. 2024k) includes the age-dependent adjustment factor (ADAF) as part
of cancer risk assessment, consistent with the approach described in EPA's Supplemental Guidance for
Assessing Susceptibility from Early-Life Exposure to Carcinogens (U.S. EPA. 2005b). To be consistent
with ORD, OPP and OPPT have applied the ADAF to chronic exposure scenarios which include
children. For lifetime exposures, the overall impact of applying the ADAF approach is less than a 2-fold
change in cancer risk.
EPA recognizes that some members of the SACC raised scientific questions about the conclusions
related to formaldehyde exhibiting a mutagenic mode of action (U.S. EPA. 2024w). EPA IRIS's mode
of action analysis is provided within Section 3.2.5 of the final IRIS assessment and responses to
comments on mode of action analysis and consideration of comments suggesting a threshold approach
for cancer are addressed in Section F.4 in Appendix F of the IRIS Supplemental Information document
(U.S. EPA).
Estimates of extra cancer risks are interpreted as the incremental probability of an individual developing
cancer over a lifetime following exposure (i.e., incremental, or extra individual lifetime cancer risk).
4.2 Risk Estimates
4.2.1 Risk Estimates for Workers
EPA estimated cancer and non-cancer risks for workers exposed to formaldehyde based on the hazard
values determined in Section 3.1 and occupational exposure estimates that were described in Section
2.1. For many TSCA COUs, EPA did not identify inhalation exposure data for ONUs, and therefore
evaluated chronic risks using the central tendency estimates for workers. EPA did not identify
information for short-term exposures by ONUs and therefore did not quantify acute inhalation risks for
ONUs. Acute risks to ONUs are assumed to be equal to or less than risks to workers who handle
materials containing formaldehyde as part of their job.
These risk estimates are based on exposures to workers in the absence of PPE such as gloves or
respirators. Section 2.5.1 contains an overall discussion on strengths, limitations, assumptions, and key
sources of uncertainty for the occupational exposure assessment. Additionally, the Occupational
Exposure Assessment for Formaldehyde (U.S. EPA. 20241) contains comprehensive weight of scientific
evidence summaries, which presents an OES-by-OES discussion of the key factors that contributed to
each weight of scientific evidence conclusion. Overall confidence in risk estimates for workers via
inhalation exposure varies per COU, depending on the confidence in the hazard and the exposure
assessment for each OES.
Page 92 of 191
-------
4.2.1.1 Risk Estimates for Inhalation Exposures
This section describes the acute non-cancer and chronic cancer risks to workers and ONUs via the
inhalation route. In Appendix H, EPA discusses chronic non-cancer risks.
Workers are a population that experience greater exposure to formaldehyde. For each COU, EPA
provides a high-end and a central tendency risk estimate. For acute effects, the use of the high-end risk
estimate is justified as the hazard effect can occur after experiencing the exposure once, therefore no
assumptions on frequency are needed. EPA has incorporated both routine and non-routine exposure data
for these estimates. For long-term risks, risk characterization is also based on the high-end risk
assessment unless otherwise noted. This is because EPA is generally using monitoring data (i.e.,
workplace measured concentrations) that may include a range of worker activities and sites, which in
most cases could not be further characterize to a specific worker exposure groups. For example, a
worker unloading or loading product at the same site may experiences routine exposures that are closer
to the high-end estimate, while an operator's routine exposure may fall within the range of the central
tendency estimate.
High-end risk estimates are based on the 95th percentile of the exposure data and the central tendency
risk estimates are based on the 50th percentile of the exposure data. For cancer risk, EPA assumes that
those exposure levels are experienced for 31 years for central tendency and 40 years for high-end
estimates. The distributions may show large variability for given exposure scenarios due to variations in
work tasks, different processes and engineering controls across the different sites represented in the data.
Providing the central tendency (50th percentile) in addition to the high-end (95th percentile) of the
dataset shows a more complete picture of magnitude of the workers exposures within the exposure
scenario that may result in risk within U.S. workplaces.
EPA's occupational exposure assessment is supported by a large body of workplace monitoring data
specific to the exposure scenarios being assessed. EPA received monitoring data from industry sources,
identified data from peer-reviewed journal articles as well as governmental sources. Some of the
monitoring data identified (e.g., OSHA CEHD) were limited in contextual information such as worker
activities and process conditions, such that EPA used the North American Industrial Classification
System (NAICS) codes to assign data to the respective exposure scenario. For example, sites in the
commercial printing and publishing industry were used to characterize risk for Commercial Use -
Chemical substances in packaging, paper, plastic, hobby products- Ink, toner, and colorant products;
Photographic supplies.
4.2.1.1.1 Acute Inhalation Risks
As shown in Figure 4-1 and Figure 4-2, acute non-cancer risk estimates for worker exposure to
formaldehyde in air range from 0.003 to 291 based on sensory irritation effects. Sensory irritation,
irritation of eyes and upper airways, is commonly used as a parameter for setting occupational exposure
limits. Protection from sensory irritation also protects from other health effects or workplace events that
could reduce job performance or lead to undesirable outcomes such as falling or reduced visibility. For
COUs with multiple OESs or estimation approaches, the estimate with the highest high-end value was
illustrated.
For acute risks, EPA calculates risk across different distributions of the monitored datasets. First, EPA
calculated the 50th and 95th percentiles of the exposure data measured for a 15-minute period. A 15-
minute sampling period is the recommended sampling duration for short-term exposure limit (STEL)
compliance checks. The current OSHA STEL is 2 ppm, therefore these measurements taken for 15-
minutes can be assumed to occur during times of high formaldehyde exposure potential. The selection of
Page 93 of 191
-------
when and which tasks to monitor for STEL compliance are usually determined by an industrial hygiene
professional who has knowledge of the process and sources of formaldehyde. In cases of enforcement
actions, the professionals may have less knowledge on the day-to-day process.
As recommended in public and peer review feedback, EPA also considered estimates based on other
ranges of sampling durations. For example, although 15-minute sampling duration is recommended, an
industrial hygiene professional may still measure longer durations for the purposes of STEL compliance.
EPA added estimates based on samples that were measured for 15 minutes and up to 60 minutes. In
addition, EPA considered samples that fell between 15 minutes and 330 minutes, the cut-off EPA used
for full-shift estimates. EPA used the highest central tendency and high-end estimates between these
distributions to inform acute risks.
EPA has high confidence in the acute inhalation POD. It is based on evidence in healthy adults in
controlled exposures. Generally, EPA has medium confidence in the exposure estimates for short-term
exposures, but it varies from low to high across the scenarios assessed. EPA considers both the
confidence in the hazard value and the exposure estimate in determining the confidence in the risk
estimates.
Processing-Recycling -
Statistical Descriptor
O Central Tendency Processing-Formulations -
O High-End
Processing-Article-Transportation -
Processing-Article-Textiles -
Processing-Article-Rubber Product-
r)
O
o
Processing-Article-Adhesive and sealant chemicals -
Processing- Reactant-
Manufacturing -
Import/Processing-Repackaging -
Distribution in Commerce -
Figure 4-1. Acute, Non-cancer Occupational Inhalation Risk by TSCA Manufacturing/Processing
COUs
Acute non-cancer MOE risk estimates with lower MOE values indicating greater risks. For COUs with multiple OESs or estimation
approaches, the estimate with the highest high-end value was illustrated.
|Increasing Risk| ^ O ®j
O •
^ : o
o : o
<$> : o
o »
O mP
O
® o |
¦C
o
c
S
O m
® ; o
1 r 1 1 1—
10'* 10"' 10° 101
Acute MOE
Page 94 of 191
-------
For Manufacturing/Processing TSCA COUs, all of these COUs indicate high-end acute risks with MOEs
below the benchmark MOE of 3 as illustrated in Figure 4-1. For these COUs, the confidence in the risk
estimates range from medium to medium-to-high confidence. For the Manufacturing/Processing COUs,
the underlying exposure estimates come from real-world concentrations of formaldehyde measured in
U.S. workplaces. All of these estimates used personal sampling measurements, which are taken near the
breathing zone of the worker. With the use of this kind of occupational monitoring data, the risk
estimates inherently account for the variability in workplace practices and the engineering controls used
across U.S. sites. EPA integrated data from industry stakeholders, peer-reviewed literature, and
governmental sources to estimate these risks.
The risk estimate at the central tendency are slightly above the benchmark MOE of 3 for all COUs with
the exception of Manufacturing. Acute inhalation risk estimates for Manufacturing were derived using
16 personal breathing zone sample data collected at two U.S. formaldehyde manufacturing facilities in
1992, one U.S. manufacturing facility in 2016 and one U.S. formaldehyde manufacturing facility in
2020. Due to a limited amount of recent monitoring data, there is some uncertainty in the
representativeness of the estimates at current manufacturing facilities. The acute risks also incorporate a
non-routine accidental measurement, which EPA considers for acute risk. Without consideration of this
non-routine event, Manufacturing significantly decreases but still indicates risks below the MOE of 3 for
both the central tendency and high-end estimates. EPA has medium confidence in the risk estimates for
this COU.
Water Treatment Products
Used in Construction
Process Aid in Oil and gas drilling...
Paper products...*
Paints, Coatings, Adhesives(IU/CU)...
Oxidizing/reducing agent...
Machinery, mechanical...
Lawn and garden products
Laundry and dishwashing products*
Laboratory Chemicals
Ink, toner, and colorant...
Floor coverings, Foam...
Explosive materials*
Disposal
Construction and building[wood and other articles]...
Construction and building[metal]...
Automotive care product...
Arts, crafts, and hobby materials
~ •
I Increasing Risk | ~
~
«•
~ •
~
~ o
<
o
•
~ o
~ •
~
~
~
0 o
0
~ o ' ~
o
Benchmark MOE
*
Statistical Descriptor
O Central Tendency
0 High-End
10
Acute MOE
Figure 4-2. Acute, Non-cancer Occupational Inhalation Risk by TSCA Industrial/Commercial Use
COUs
Acute non-cancer MOE risk estimates with lower MOE values indicating greater risks. For COUs with multiple OESs or estimation
approaches, the estimate with the highest high-end value was illustrated. Indicates that the exposure scenario for the given COU has a
slight weight of scientific evidence. For Process Aid in Oil and gas drilling, the central tendency is 291 which is not shown on the graph.
For industrial/commercial TSCA COUs, 11 COUs have central tendency risk estimates above the
benchmark MOE of 3, indicating no acute risks at the central tendency. However, only two COUs have
Page 95 of 191
-------
high-end risk estimates above the benchmark of 3, indicating no acute risks based on high-end estimates
via the inhalation route:
• Commercial Use- Chemical substances in treatment/care products-laundry and dishwashing
products
• Disposal
Therefore, 48 out of the 50 TSCA COUs have risks below the benchmark MOE of 3.
The confidence in risk for Commercial Use- Chemical substances in treatment/care products-laundry
and dishwashing products is low based on a slight weight of scientific evidence conclusion for the
exposure estimate. EPA identified exposure data from a dry-cleaning shop which used a solvent
containing formaldehyde. All of the measurements were either below the detection limit or the
quantification limit of monitoring method. Although, formaldehyde was noted to be included in laundry
detergents, EPA did not identify data at industrial or institutional laundries nor identify a concentration
of formaldehyde in laundry detergent. Therefore, EPA has low confidence in the risk estimates for this
COU. The confidence in the disposal risk estimates is medium. EPA relies on exposure data from the 4
sites in the waste treatment industry.
Acute risks for industrial or commercial uses are greatest for Commercial use - chemical substances in
automotive and fuel products - automotive care products; lubricants and greases; fuels and related
products. EPA has medium confidence in the risk estimates for this COU based on a high confidence in
the acute POD and medium confidence in the exposure estimate. Three occupational exposure scenarios
are estimated for this COU, the exposure scenario with the highest central tendency exposure estimate
was selected for risk characterization of this condition of use. The automotive care products OES was
modeled for the worker activity of applying a detailing product containing formaldehyde. The scenario
was modeled using two approaches: an approach that model complete evaporation of the expected
formaldehyde contained in the detailing product during application, and an approach using measured
VOC data. To account for variability, EPA performed 100,000 Monte Carlo iterations where parameters
were varied based on industry defaults such as number of cars detailed per site, amount of product used,
and concentration of formaldehyde in the product. EPA calculated vapor generation using the chemical
properties of formalin as well as reported VOC emissions in the automotive detailing industry. Some of
the limitations of this modeled estimate is that it does not account for if any engineering controls are
used during application, and the model use a wide range of concentrations of formaldehyde in the
product based on the only available source, 2020 CDR.
Although the commercial Use- chemical substances in packaging, paper, plastic, hobby products- paper
products; plastic and rubber products; toys, playground, and sporting equipment, and the commercial
Use- chemical substances in outdoor use products- explosive materials have risk estimates that indicate
acute risks, EPA has a low confidence in these COUs based on the limitations and uncertainties in the
exposure estimates. For commercial Use- chemical substances in packaging, paper, plastic, hobby
products- paper products; plastic and rubber products; toys, playground, and sporting equipment, EPA
highest estimates were from two 15-minute samples taken at a parcel delivery company. Due to the low
number of data points, the highest value of the range was used as a substitute for the 95th percentile of
the actual distribution, and the midpoint as the 50th percentile. However, these substitutes are uncertain.
The effects of these uncertainties on the occupational exposure assessment are unknown, as the
uncertainties may result in either overestimation or underestimation of exposures depending on the
actual distribution of formaldehyde air concentrations and the variability of work practices among
different sites. For commercial use- chemical substances in outdoor use products- explosive materials,
the primary limitation of this data was the high uncertainty that the measurements were associated with
exposure from explosives as workers can be assumed to be far away during the use of explosives and
Page 96 of 191
-------
therefore uncertainty that the formaldehyde measured at the military sites were from this source of
formaldehyde.
4.2.1.1.2 Cancer Inhalation Risks
For chronic risks, EPA uses full-shift exposure estimates. Full-shift estimates are typically 8-hour or 12-
hour time weighted averages of the formaldehyde air concentrations. These estimates are inclusive of
tasks where a worker may be directly exposed to formaldehyde and tasks that may have little to no
formaldehyde exposure during the worker's shift. These air concentrations along with the exposure
frequency (i.e., days exposed within a year) as well as worker tenure (i.e., years exposed), are used to
calculate the lifetime average daily concentration (LADC) used for the chronic cancer risk assessment.
To estimate cancer risks for workers with chronic inhalation exposure to formaldehyde, EPA used an
adult-based unit risk without ADAF adjustment.
For cancer inhalation risks, EPA has medium confidence in the cancer inhalation unit risk. Generally,
EPA has medium confidence in the exposure estimates but confidence for individual scenarios varies
from low to high across the scenarios assessed. For most exposure scenarios, EPA estimated full-shift
exposures by integrating discrete data identified from peer-reviewed literature and other sources. EPA
establish a cut-off total sampling duration of 5.5 hours to reduce uncertainties by using data most
expected to represent full-shift exposures. EPA then calculated an 8-hour TWA assuming that
unsampled time was zero. This approach may lead to underestimation of risks if workers were still
exposed to formaldehyde for the unsampled time. A sensitivity analysis on these assumptions were
included in the Occupational Exposure Assessment for Formaldehyde (U.S. EPA. 20241).
EPA expects most manufacturers to operate year-round given the high production volume of
formaldehyde and its use as a commodity chemical. EPA does not expect that a worker is exposed year-
round (i.e., 365 days/year), EPA generally assumes that workers are exposed for 250 days per year.
For commercial uses, the work frequency is likely to vary as workers in retail and commercial
businesses may work part-time or for shorter work shifts and weekly schedules (e.g., retail stores).
Commercial businesses may also have employees who work longer than 8 hour-shifts and 250 days per
year based on the nature of the business. In the absence of chemical-specific data, EPA assumes that
commercial workers used the commercial product containing formaldehyde every day; however, it is
possible that it is only used for specific or non-routine applications. In the absence of scenario-specific
data on the frequency of the chemical exposed, EPA assumes that the worker is exposed for 250 days (8
hrs/day, 5 days per week for 50 weeks) unless additional information suggest otherwise. For
Commercial Use - Lawn and garden products, EPA varied the worker frequency based on the type of
application (e.g., agricultural vs. landscaping) because the use of fertilizer is a seasonal activity, with
most use occurring during a specified time during the growing season for the specific region.
The second parameter in the LADC calculations is the time that the worker may retain a specific
job/exposure scenario (i.e., worker tenure). This may vary by individual workers. Data on worker tenure
at a formaldehyde manufacturing facility or industrial or commercial site using formaldehyde is not
reasonably available. EPA assumes 31 years for central tendency and 40 years for high-end estimates.
This is based on survey data from the U.S. census and the U.S. Bureau of labor on the number of years
people stayed with their current employer and the number of years worked across all employers,
respectively.
Worker cancer risk estimates across all TSCA COUs for inhalation exposure range from 6.7x 10~9 to
1.3xl0~2 for both high-end and central tendency exposures, as shown in Figure 4-3 and Figure 4-4. For
COUs with multiple OESs or estimation approaches, the scenario with the highest central tendency
Page 97 of 191
-------
value was illustrated. Of the 50 TSCA COUs evaluated, 43 TSCA COUs have cancer risk estimates
greater than 1 in 10,000. All risk estimates including for all exposure scenarios evaluated are provided in
the Supplemental file: Occupational Risk Calculator.
3
O
o
cn
c
(ft
M
0)
o
O
O)
c
o
£
13
£Z
CO
Processing-Recycling
Processing-Formulations -
Processing-Article-Transportation -
Processing-Article-Textiles
Processing-Article-Rubber Product -
Processing-Article-Adhesive and sealant chemicals
Processing- Reactant
Manufacturing
Import/Processing-Repackaging -
Distribution in Commerce -
10"
o O
o O
O
O
o O
• 0 | Increasing Risk |—~
10"
10"
Cancer Risk
Statistical Descriptor
o Central Tendency
O High-End
10"
Figure 4-3. Chronic Cancer Occupational Inhalation Risk by TSCA Manufacturing/Processing
COUs
As shown in Figure 4-3, the COUs under the manufacturing or processing lifecycle indicate increased
cancer risk above the 50th percentile of exposure data. The central tendency risk estimates are generally
between 1 in 100,000 and 1 in 10,000 increased cancer risks. The high-end risk estimates are generally
between 1 in 10,000 and 1,000 increased cancer risks. For Processing- Incorporation into an Article-
Additive in Rubber Product Manufacturing, the current available information indicates that most
workers fall below l.OxlO-4 cancer risks but some individuals will be exposed to levels that indicate
cancer risks at 1.28x 10~4. Based on the underlying monitoring data, workers whose job duties included
calendaring, extruding, and weighing of the resins and other raw materials contributed to the high-end
risk estimates.
For the COU with the highest high-end estimates, EPA has medium to high confidence in the risk
estimates for Processing as a Reactant. The underlying occupational exposure scenario covers, in
general, processes that use formaldehyde as a reactant for a variety of downstream products. This
scenario integrates data from a variety of sources (e.g., industry submissions, OSHA CEHD data) for a
total of 202 8-hr TWA samples. Limitations within the monitoring data is a lack of additional details on
Page 98 of 191
-------
worker activities for the individual samples. There is some uncertainty on the representativeness of the
50th and 95th percentiles towards the true distribution for the exposed population for this scenario.
Two COUs, Manufacturing-Import and Processing- Repackaging, are based on one exposure scenario of
sites expected to be repackaging formalin or some other formaldehyde containing product. These
generally include chemical wholesalers who sell a variety of chemicals in different container sizes for
downstream users. EPA initially estimated the cancer risks using full-shift exposure data that were
measured on workers for a majority of their day (>330 minutes). As shown in Figure 4-4, the cancer
risks are estimated to be close to the 1 in 10,000 using this initial estimate based on the 7 full-shift
estimates identified. However, this scenario had short-term exposure data that indicated higher 8-hour
time weighted average if considered. EPA calculated an 8-hour time weighted average based on all of
the relevant monitoring data for the scenario as EPA expects that industrial hygienists may not have
measured full days if the worker rotated to repackaging other chemicals during their day. By adjusting
these values to assume all unsampled time is zero, this calculates minimum 8-hr TWA from these
workers. Figure 4-4 shows the cancer risk estimate considering the full set of data for repackaging
adjusted to an 8-hour time weighted average where the unsampled time was set to 0.
in
=>
O
O
<1)
£
£
o
O
cn
~o
Processing- Repackaging [All]
Processing- Repackaging [>330 min]
Statistical Descriptor
o Central Tendency
O High-End
10-5 1CT4 10~3 10"2
Cancer Risk
Figure 4-4. Cancer Risk for Manufacturing- Import and Processing - Repackaging
Figure 4-5 illustrates the cancer risks for COUs under the industrial or commercial use lifecycle stage.
EPA identified 6 COUs where cancer risks at the high-end are below l.Ox 10~4 :
• Industrial Use- Non-incorporative activities- Process aid in: Oil and gas drilling, extraction, and
support activities; process aid specific to petroleum production, hydraulic fracturing;
• Industrial Use- Non-incorporative activities- Oxidizing/reducing agent; processing aids, not
otherwise listed;
Page 99 of 191
-------
• Commercial Use - Chemical substances in packaging, paper, plastic, hobby products- Paper
products; Plastic and rubber products; Toys, playground, and sporting equipment;
• Commercial Use- Chemical substances in agriculture use products- Lawn and garden products;
• Commercial Use - Chemical substances in treatment/care products- Laundry and dishwashing
products;
• Commercial Use- Chemical substances in outdoor use products- Explosives materials; and
• Disposal
For the Commercial Use - Water Treatment Products, the calculated cancer risk for high-end estimates
is slightly above the 1 in 10,000 benchmark. EPA modeled using the Tank Truck and Railcar Loading
and Unloading Release and Inhalation Exposure Model. For this condition of use, EPA concluded the
weight of scientific evidence is slight to moderate and, given that the model assumes use of vapor
balance system and does not cover other activities that could occur which may underestimate exposures.
In addition, EPA found limited use information for TSCA regulated activities of formaldehyde used for
water treatment (i.e., non-biocidal uses).
O
o
a>
Z)
To
o
1—
E
E
o
O
To
* ¦
oO
o ~
O o
o O
oO
o O
o ~
o O
o
O o
Statistical Descriptor
O Central Tendency
O High-End
10"'
10 10
Cancer Risk
10"
Figure 4-5. Chronic Cancer Occupational Inhalation Risk by TSCA Industrial/Commercial COUs
Note: Commercial Use- Chemical substances in treatment/care products-Laundry and dishwashing products. Commercial
Use- Chemical substances in packaging, paper, plastic, hobby products- Paper products; Plastic and rubber products; Toys,
playground, and sporting equipment, and Commercial Use- Chemical substances in outdoor use products- Explosive
materials all have a slight weight of scientific evidence. For Process Aid in Oil and gas drilling, the central tendency is
6.7 x 10 6 which is not shown on the graph.
Four COUs were based on limited monitoring data:
Page 100 of 191
-------
• Commercial Use - Chemical substances in treatment/care products- Laundry and dishwashing
products;
• Commercial Use - Chemical substances in packaging, paper, plastic, hobby products- Paper
products; Plastic and rubber products; Toys, playground, and sporting equipment;
• Commercial Use- Chemical substances in outdoor use products- Explosives materials; and
• Disposal
For these COUs, the assessed exposure levels are less likely to be representative of worker exposure
across the entire job category or industry. Ideally, EPA will present 50th and 95th percentiles for each
exposed population. For COUs with less than 6 data points identified, EPA used the mean or midpoint
of the range to serve as a substitute for the 50th percentile of the actual distributions. Similarly, the
highest value of a range may serve as a substitute for the 95th percentile of the actual distribution.
However, these substitutes are uncertain. The effects of these uncertainties on the occupational exposure
assessment are unknown, as the uncertainties may result in either overestimation or underestimation of
exposures depending on the actual distribution of formaldehyde air concentrations and the variability of
work practices among different sites. Although the weight of scientific evidence is low, EPA has
concluded that the underlying data still provide plausible estimates of exposures for all COUs.
EPA has slight confidence for three of these COUs based on a slight weight of scientific evidence. For
the laundry and dishwashing products, EPA identified 12 data points at one dry cleaner where
formaldehyde was indicated to be present in a solvent. EPA did not identify exposure data at industrial
or institutional laundries, which is a major limitation in the exposure estimate. For the Commercial Use
- Chemical substances in packaging, paper, plastic, hobby products- Paper products; Plastic and rubber
products; Toys, playground, and sporting equipment, EPA received two monitoring data points from a
retail store that EPA assumes may sell paper and other hobby products. In addition to the low number of
data points, the potential of overlap with other sources of formaldehyde at such a site was considered.
Lastly for explosive materials, EPA did identify sufficient monitoring data from ammunitions centers
and military bases, although there is uncertainty that the sampled formaldehyde may have come from
other sources. These uncertainties may result in either overestimation or underestimation of exposures
depending on the actual distribution of formaldehyde air concentrations for the specific COU.
4.2.1.2 Risk Estimates for Dermal Exposures
Acute non-cancer risk estimates for dermal exposure range from 3.40x10 3 to 19 (benchmark MOE of
10) for central tendency exposures and high-end exposures (see Figure 4-6). Risk estimates are greatest
for TSCA COUs: Commercial use - chemical substances in automotive and fuel products - automotive
care products; lubricants and greases; fuels and related products; and TSCA COUs: Processing -
incorporation into an article - paint additives and coating additives not described by other categories in
transportation equipment manufacturing (including aerospace); Industrial use - paints and coatings;
adhesives and sealants; lubricants; commercial use - chemical substances in construction, paint,
electrical, and metal products - adhesives and sealants; paint and coatings. Both OESs assumed an
immersive dermal loading on the skin during the exposure scenario.
Page 101 of 191
-------
WaterTreatment Products -
Used in Construction -
Processing-Recycling -
Processing-Reactant -
Processing-Formulations -
Processing-Article-Textiles -
Processing-Article-Rubber Product-
Processing-Article-Adhesive and sealant chemicals -
Process Aid in Oil and gas drilling... -
Paints, Coatings, Adhesives [IU/CU] -
Oxidizjng/reducing agent... -
Manufacturing -
Machinery, mechanical... -
Lawn and garden products -
Laundry and Dishwashing Products -
Laboratory Chemicals-
Ink, toner, and colorant,... -
Import/Processing-Repackaging -
Floor coverings, Foam... -
Explosive Materials -
Disposal -
Construction and building[wood and other articles] -
Construction and building[metal]... -
Construction and building[metal] -
Automotive Car Products -
Arts, crafts, and hobby materials -
[ Increasing Risk|
~ *
~ •
~ *
~ •
~ •
10'
10 10
Acute MOE
^. 111
~ • O
03
E
_£Z
O
£=
-------
4.2.2 Risk Estimates for Consumers
EPA estimated short-term risks for exposure to formaldehyde resulting from exposure to formaldehyde
in consumer products. For this analysis, EPA relied on the consumer exposure estimates modeled in the
Consumer Exposure Assessment for Formaldehyde (U.S. EPA. 2024d) and summarized in Section 2.2.
4.2.2.1 Risk Estimates for Inhalation Exposure to Formaldehyde in Consumer
Products
Acute inhalation risk estimates range from 4,Ox 10 2 to 8.9xl0+2 across all exposure scenarios. See
Figure 4-7 for a summary of the estimated risks associated with the TSCA COU representative
scenarios. These acute risk estimates are calculated using high-end air concentrations modeled for a 15-
minute period based a set of high-end model input assumptions and TSCA COU-specific assumptions
about exposure frequency and duration. Acute non-cancer risk estimates are based on high-end
consumer and bystander exposure estimates and the acute POD for sensory irritation reported in
controlled human exposure studies in healthy adult volunteers. Acute risk estimates below 3 indicate
that exposure is greater than the level of exposure associated with benchmark MOE. Lower MOE values
indicate greater risks. All risk estimates including for all exposure scenarios evaluated are provided in
the Supplemental file: Consumer - Indoor Air Acute and Chronic Inhalation Risk Calculator.
Page 103 of 191
-------
Adhesives and Sealants; Paint and coatings
Paper products; Plastic and rubber products; Toys,,
playground, and sporting equipment
Floor coverings; Foam seating and bedding
products; Cleaning and furniture care products;
Furniture & furnishings including stone, plaster,
cement, glass and ceramic articles; metal
articles; or rubber articles
3
O
O
Ink, toner, and colorant products; Photographic
supplies
Construction and building materials covering
large surface areas, including wood articles;
Construction and building materials covering
large surface areas, including paper articles;
metal articles; stone, plaster, cement, glass and
ceramic articles
Automotive care products; Lubricants and greases;
Fuels and related products
Fabric, textile, and leather products not covered
elsewhere (clothing)
+•
+
+
Zone
• Far Field
A Near Field
¦ Zone 1
+ Zone 2
1CT1
10"
Peak 15-min Inhalation MOE
Figure 4-7. Peak 15-Minute Inhalation Risk by COUs in Consumer Products
Results are presented according to COUs.
Page 104 of 191
-------
For some products, air concentrations were modeled for near-field and far-field (generally describing
differences in exposure within the same room) while for other products concentrations were modeled for
zones 1 and 2 (generally describing different rooms). Risks from near-field and zone 1 exposures
generally represent risks from direct exposures to consumer users while far-field and zone 2 tend to
represent risks to consumer bystanders. For instance, an individual applying floor coverings: Varnishes
and floor finishes in a living room can be described as a consumer of that product in zone 1 or near-field
of the application area. On the other hand, while the product is being applied there may be someone else
either also in the room of use and assumed to be away from the immediate application area (or in the far-
field), or in a completely different room from where the product is being applied (also known as zone 2).
The x-axis presents the 15-minute peak inhalation non-cancer concentration, and the y-axis presents the
modeled TSCA COUs.
EPA has medium confidence in the consumer inhalation risk estimates based on SACC peer-reviewed
modeling and input data, including TSCA COU-specific product weight fractions identified from SDS
of consumer products currently on the market, the quality and applicability of the CEM for the
assessment of realistic consumer exposure scenarios that are representative of COUs, common consumer
use patterns (e.g., TSCA COU-specific amount used, duration and frequency of use (U.S. EPA 2019))
according to the EPA Exposure Factors Handbook (U.S. EPA. 2011) and the 1987 Westat survey
(Westat 1987) and applicable to most population groups. Though the 1987 Westat survey (Westat.
1987) is the best available source of consumer user patterns, its reported use patterns may have changed
for some products and articles over time and may not be representative of today's consumer use
patterns. EPA also has medium confidence in the quality and representativeness of air monitoring data
regarding consumer exposures. As described in Section 3.2, EPA has high confidence in the acute
inhalation POD based on evidence in healthy adult volunteers in controlled exposure conditions.
Page 105 of 191
-------
4.2.2.2 Risk Estimates for Dermal Exposure to Formaldehyde in Consumer Products
EPA estimated non-cancer risks for acute dermal exposure to formaldehyde in consumer products.
Dermal risk estimates were calculated for low, central tendency and high-end exposure estimates using
the POD based on skin sensitization responses observed in adults. The estimated dermal risks based on
high-end exposures range from 3.24/10 3 to 1.08xl0+1 and are presented in Figure 4-8. Acute risk
estimates below 10 indicate that exposure is greater than the level of exposure associated with
benchmark MOE. All risk estimates including for all exposure scenarios evaluated are provided in the
Supplemental file: Consumer - Indoor Air Acute and Chronic Inhalation Risk Calculator.
Polish and wax - (Exterior Car Wax and
Polish)
Photographic Supplies - (Liquid photographic
processing solutions)
03
c
CD
O
CO
"O
CD
TD
O
Adhesives and Sealants - (Glues and
Adhesives, small or large scale)
Cleaning and Furnishing Care Products -
(Textile & Leather Finishing (stain remover,
waterproofing, tanning))
Building / Construction Materials -
(Liquid-based concrete, cement, plaster
(prior to hardening))
Arts, Crafts, and Hobby Materials - (Crafting
Paint (direct and incidental contact))
Modeled
Exposure Level
¦ High
_J I I
icr io_l
Acute Dermal MOE
10
Figure 4-8. Acute Dermal Loading Risk by High-End Exposure Scenarios in Consumer Products
The y-axis presents the modeled scenarios written as TSCA COU followed by relevant exposure scenario.
EPA has medium confidence in the dermal risk assessment for consumers. As detailed in Section 3.2.1
of the Consumer Exposure Assessment for Formaldehyde (U.S. EPA. 2024d). EPA has medium
Page 106 of 191
-------
confidence in the Thin Film Model, which EPA used to estimate dermal loading from spray and liquid
consumer products, and in default model input values used in the dermal exposure assessment of
realistic consumer exposure scenarios, which are representative of COUs, common consumer use
patterns, and applicable to most population groups. EPA has high confidence in the TSCA COU-specific
product weight fractions identified from SDSs of consumer products currently on the market and
medium confidence in the applied quantity remaining on skin Ou constant. Although a Ql± of 10,3
mg/cm2 (most protective value for consumers using oil-based products (U.S. EPA 1992)) is assumed to
be realistic and protective of most liquid product consumer dermal exposures to formaldehyde, it is
conceivable that a lower Ou may be applicable for some consumer exposure scenarios (e.g., consumer
uses liquid product with PPE that prevents development of thin film of formaldehyde on the skin). This
information in addition to the dermal loading identified in the literature (U.S. EPA 1992) were used to
parameterize the Thin Film model which has been peer reviewed by the SACC and used in previous
OPPT existing chemical risk evaluations based on TSCA uses and OPP's formaldehyde risk evaluation
based on pesticidal uses. No monitoring data are available on dermal exposures for consumers. As
described in Section 3.2, overall confidence in the dermal hazard value is medium.
4.2.3 Risk Estimates for Indoor Air
EPA considered, residential and nonresidential monitoring data for its evaluation of formaldehyde
indoor air concentrations since it allows the agency to characterize realistic ongoing formaldehyde
indoor air exposures among Americans. However, these monitoring data do not differentiate between
TSCA and other sources of formaldehyde, which means that EPA was unable to perform any exposure
source attribution, including determining what portion of the reported indoor air concentrations are from
TSCA COUs versus other sources.
Monitoring data are also not expected to represent peak exposures since the air monitoring reported,
often occurs some period long after articles have been installed in a home. Instead, EPA expects the
indoor air monitoring data to be more representative of long-term exposures to formaldehyde. Therefore,
the Agency used a combination of monitoring and modeling data to best characterize formaldehyde
indoor air exposures while considering the relative contributions of TSCA COUs to the indoor air
environment. EPA evaluated its findings for exposures resulting from the use of consumer articles
containing formaldehyde, under TSCA, and assessed indoor air exposures for four COUs expected to be
significant sources of formaldehyde in indoor air.
EPA used CEM as a tier 1 modeling tool to estimate 1-year average formaldehyde residential indoor air
exposures, and refined its formaldehyde indoor air exposure modeling results using IECCU, a tier 2
modeling tool, to estimate 15-minute peak, 3-month average and 1-year average formaldehyde
residential indoor air concentrations from specific consumer article categories by incorporating relevant
low-, median-, and high-end emission factors and surface areas of articles expected in a room of use,
according to the literature.
The following subsections provide a summary of potential acute, chronic non-cancer, and cancer risks
according to the indoor air exposure monitoring data and relevant modeling of significant TSCA COU
contributors to indoor air exposures.
4.2.3.1 Risk Estimates Based on Indoor Air Monitoring Data
Monitoring data provide information about actual concentrations of total formaldehyde in indoor air, but
the data reflect aggregate concentrations from all TSCA and other sources present. Monitoring data are
therefore a good indication of aggregate formaldehyde exposures and risks in a range of indoor
environments, but do not provide information about the relative contributions of each source.
Page 107 of 191
-------
EPA estimated chronic risks based on levels of formaldehyde detected in indoor air in monitoring
studies representing a range of indoor air environments. The American Healthy Home Survey II is a
survey published in 2021 that is representative of residential indoor air conditions across a wide range of
American households. It is the most current nationally representative survey of formaldehyde in indoor
air in American homes and is likely the best representation of the current range of aggregate exposures
and risks from all sources of formaldehyde in indoor air. Other monitoring datasets considered in this
analysis generally target indoor environments that typically have higher formaldehyde concentrations,
such as trailers and mobile homes. Available indoor air monitoring datasets, for some indoor air
environments, may not represent current conditions in indoor air following Title VI regulation of wood
products. Figure 4-9 summarizes chronic non-cancer risk estimates, while Figure 4-10 summarizes
chronic cancer risk estimates based on indoor air monitoring data, relying on the assumption that these
monitored concentrations could represent average exposures in indoor air and that exposure to these
concentrations may be experienced continuously over time. This may be a snapshot of risks as indoor air
concentrations may change over time, and people typically live in multiple homes over the course of
their lives and may add new articles in the home at varying frequencies.
Page 108 of 191
-------
-------
CD
O
3
o
CO
CD
¦4—*
ro
Q
O)
£Z
96 unoccupied FEMA trailers
4 FEMA camper trailers
Travel trailers (360)
All structures (519)
Mobile homes (69)
Park models (90)
Inner-city homes
108 new SF homes in CA
Various
96 homes in Quebec City, Canada
Canada
7 new site-built homes
U.S. government offices (A)
4 new manufactured homes
U.S. government offices (B)
Los Angeles (41) - Winter
NY City (46) - Summer
New homes in eastern/SE U.S.
59 homes in Prince Edward Island
Elizabeth, NJ; and Houston, TX
Portable Classroom
Los Angeles (41) - Fall
100 randomly selected U.S. commercial buildings
Traditional Classroom
Office space in commercial building
NY City (46)-Winter
234 homes in Los Angeles County, CA
Classrooms in U.S. school buildings
4 new relocatable classrooms
Increasing Risk
Metric
Range
Reported
o Central
Tendency
. .
. . . 1 . .
10"
10 * 10 J 10 z
ADAF-Adjusted Cancer Risk
Figure 4-10. Cancer Inhalation Risk by Indoor Air Monitoring Data Source
Air monitoring data sources listed on the y-axis are described in more detail in the Indoor Air Assessment for Formaldehyde.
Cancer risk estimates presented in Figure 4-10 range from 2.74xl0"6 to 4.60xlCT2 These ranges of risk
estimates correspond to measured minimum concentrations of 3.7x 10° ppm from a study of 96
unoccupied FEMA trailers (ATSDR. 2007). and a measured maximum concentration of 2.2x 10~4 ppm
from the American Healthy Home Survey II (OuanTech. 2021). All calculated monitoring indoor air
cancer risks were greater than 1 in 1,000,000. All risk estimates including for all exposure scenarios
evaluated are provided in the Supplemental file: Consumer - Indoor Air Acute and Chronic Inhalation
Risk Calculator.
Page 110 of 191
-------
4.2.3.1.1 Monitoring Information in Consideration of Aggregate Risk
Given the ubiquity of formaldehyde in indoor environments, risks from individual sources rarely occur
in isolation. EPA has therefore also considered monitoring data as an indication of aggregate exposure
and risks from all sources contributing to formaldehyde in indoor air.
As previously noted, the AHHS II is the most current nationally representative survey of formaldehyde
in indoor air in American homes. Therefore, among all monitoring sources, it is likely the most
appropriate source for the estimation of aggregate risks in American residential indoor air across all
households, including old and new homes. Using the maximum estimated monitoring indoor air estimate
for formaldehyde in AHHS II (including contributions from both TSCA and other sources), it may be
assumed that indoor air aggregate chronic non-cancer risks are as low as 1.68xl0_1. Chronic non-cancer
risk estimates below 3 indicate that exposure is greater than the benchmark MOE identified for
exposures based on sensory irritation reported in controlled human exposure studies in healthy adult
volunteers. Lower MOE values indicate greater risks. Based on AHHS II monitoring data, Aggregate
cancer risks are as high as 1.27xl0"3 in typical U.S homes. All calculated AHHS II monitoring indoor air
cancer risks were greater than 1 in 1,000,000. All risk estimates including for all exposure scenarios
evaluated are provided in the Supplemental file: Consumer - Indoor Air Acute and Chronic Inhalation
Risk Calculator. The same can be inferred from mobile home, classroom, and other monitoring indoor
air risk estimates.
In general, EPA has high confidence in the estimation of chronic non-cancer and cancer risk estimates
based on the indoor air monitoring data as it relies on actual formaldehyde concentrations from various
American indoor air settings. As discussed in Section 2.3.1, such data are expected to be representative
of long-term aggregate exposures and are expected to include TSCA and other sources. As described in
Section 3.2, EPA has high confidence in the chronic POD based on respiratory effects and medium
confidence in the cancer IUR.
4.2.3.2 CEM Indoor Air Modeling Risk Estimates
Indoor air concentrations modeled for specific COUs provide an indication of the contributions of
individual COUs to formaldehyde exposure and risk. EPA estimated chronic non-cancer risks based on
formaldehyde concentrations modeled based on long-term emissions associated with specific COUs, as
described in 2.3.1. The modeled air concentrations used as the basis for chronic risk estimates for indoor
air were designed to estimate concentrations at the central tendency. As described in the Indoor Air
Exposure Assessment for Formaldehyde (U.S. EPA. 2024i). there is substantial uncertainty related to the
degree of dissipation of formaldehyde over time and how exposures from specific products change over
the course several years. For this reason, EPA has low confidence in exposure estimates modeled over
longer than a year for specific TSCA COUs contributing to formaldehyde in indoor air. EPA therefore
did not calculate cancer risk based on chronic indoor air exposures resulting from specific TSCA COUs.
Figure 4-11 summarizes chronic non-cancer risk estimates and Figure 4-12 summarizes cancer risk
estimates based on modeled average indoor air concentrations estimated to result from specific TSCA
COUs over the course of the first year of product use.
Page 111 of 191
-------
Building I Construction Materials - Wood Articles:
Hardwood Floors (residential)
o
co Furniture & Furnishings -Wood Articles: Furniture
^ (residential)
o
W
Fabrics: Clothing (residential)
Paper-Based Wallpaper
Figure 4-11. Chronic Non-cancer Inhalation Risk Based on CEM-Modeled Air Concentrations for
Specific TSCA COUs
Increasing Risk
<
''''
10
Chronic MOE
Chronic non-cancer risk estimates for TSCA COU representative scenarios presented in Figure 4-11 are
calculated using exposures estimates based on CEM modeling and the chronic POD based on respiratory
effects. Based on indoor air concentrations modeled for specific COUs, non-cancer risk estimates range
from 5,92/ 10 to 1.39x10+1 across all scenarios. Hardwood floors and wood furniture estimated chronic
non-cancer risk risks were below 3 which indicate that exposure is greater than the level of exposure
associated with the benchmark MOE. Lower MOE values indicate greater risks.
Page 112 of 191
-------
Building / Construction Materials - Wood Articles:
Hardwood Floors (residential)
o
co Furniture & Furnishings -Wood Articles: Furniture
(residential)
o
CD
Fabrics: Clothing (residential) -
Paper-Based Wallpaper -
Figure 4-12. Cancer Inhalation Risk Based on CEM-Modeled Air Concentrations for Specific
TSCA COUs
Increasing Risk
' j I ' ' i i i i i j i i i i i i i i j
itr5 104 itr3
ADAF-Adiusted Cancer Risk
Cancer risk estimates are presented in Figure 4-12 for representative scenarios. Cancer risk estimates
range from 1.54xl05 to 3.61xl04 across all scenarios. All modeled TSCA COUs', including wood
articles, furniture covers and paper-based wallpaper, indoor air cancer risks were greater than 1 in
1,000,000 across all exposure scenarios. All risk estimates including for all exposure scenarios evaluated
are provided in the Supplemental file: Consumer - Indoor Air Acute and Chronic Inhalation Risk
Calculator. These risk estimates account for dissipation that occurs over time due to the depletion of
formaldehyde from the article and air exchange but do not account for the half-life of formaldehyde.
In general, EPA has medium confidence in IECCU's ability to assess formaldehyde chronic non-cancer
and cancer risks in indoor air. Medium quality studies were used to incorporate TSCA COU-specific
emission rates in IECCU. EPA used high quality CEM modeling data inputs to generate TSCA COU-
specific indoor air concentrations, and comparability between modeled outputs and residential indoor air
monitoring data. The inability to account for a first-order decay decreased confidence in overall
inhalation risk estimates for indoor air. For this reason, risk estimates using CEM may be conservative
relative to IECCU. Therefore, it is unclear whether the modeling results are reflective of most indoor air
home environments in American residences. As described in Section 3.2, EPA has high confidence in
the chronic POD based on respiratory effects and medium confidence in the cancer IUR.
Page 113 of 191
-------
4.2.3.3 IECCU Indoor Air Risk Estimates
EPA used IECCU to estimate acute (15-minute peak), intermediate (3-month average), chronic non-
cancer (1-year average), and cancer (lifetime) risks for exposure to formaldehyde in indoor air
associated with specific TSCA COUs, as described in 2.3.1. Through IECCU modeling, EPA considered
decay rate of formaldehyde and the estimated concentrations are within the same order of magnitude as
the AHHS II monitoring data. Below are the IECCU indoor air modeling risk estimates for acute
(Section 4.2.3.4), intermediate (Section 4.2.3.5), chronic non-cancer and cancer (Section 4.2.3.6).
4.2.3.4 IECCU Indoor Air Acute Risk Estimates
EPA estimated acute (15-minute peak), risks for exposure to formaldehyde in indoor air. For this
analysis, indoor air concentrations modeled for specific COUs provide an indication of the contributions
of individual COUs to formaldehyde exposure and risk within 15 minutes of installing an article into the
home. Figure 4-13 summarizes acute indoor air risk estimates for formaldehyde according to TSCA
COUs.
New Construction Aggregate -
Laminate Flooring -
c Living Room Decor Change Aggregate
CD
O
C/D
Pressed Wood Furniture-
Textile Furniture Covers -
Wallpaper-
Increasing Risk
Metric
Range
v Low
~ Medium
a High
_l I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I
10'
1CT
10°
Acute MOE
1(T
10°
Figure 4-13. Acute Inhalation Risk Based on IECCU Modeled Air Concentrations for Specific
TSCA COUs
Acute non-cancer risk estimates for TSCA COU representative exposure scenarios, presented in Figure
4-13, are based on air concentrations modeled in IECCU and the acute POD for sensory irritation
reported in controlled human exposure studies in healthy adult volunteers. Acute risk estimates based on
indoor air concentrations of all modeled individual scenarios range from 4.3 to 87,730 and from 3.8 to
Page 114 of 191
-------
204.7 for aggregate scenarios (as described in Table 2-5 of the Indoor Air Exposure Assessment for
Formaldehyde (U.S. EPA. 2024iV). Acute risk estimates below 3 indicate that exposure is greater than
the level of exposure associated with benchmark MOE. Lower MOE values indicate greater risks.
In general, EPA has high confidence in IECCU's ability to assess formaldehyde acute risks in indoor air.
Medium quality studies were used to incorporate TSCA COU-specific emission rates in IECCU. EPA
used high quality IECCU modeling data inputs (i.e., article-specific emission rates and building
environmental inputs including building volumes, ventilation rates, and interzonal air flows from CEM
for improved comparability with CEM results) to generate TSCA COU-specific indoor air
concentrations, and comparability between modeled outputs and residential indoor air monitoring data.
As described in Section 3.2, EPA has high confidence in the acute inhalation POD based on evidence in
healthy adult volunteers in controlled exposure conditions.
4.2.3.5 IECCU Indoor Air Intermediate Risk Estimates
EPA estimated intermediate (3-month average) risks for exposure to formaldehyde in indoor air. For this
analysis, indoor air concentrations modeled for specific COUs provide an indication of the contributions
of individual COUs to formaldehyde exposure and risk within 3-months of installing an article into the
home. Figure 4-14 summarizes intermediate indoor air risk estimates for formaldehyde according to
TSCA COUs.
New Construction Aggregate -
Laminate Flooring -
c Living Room Decor Change Aggregate
CD
O
C/D
Pressed Wood Furniture-
Textile Furniture Covers -
Wallpaper-
A ~
Increasing Risk
_i i i I I I 111
10"
10' 1(f 10°
Intermediate MOE
1(T
Page 115 of 191
-------
Figure 4-14. Intermediate Non-cancer Inhalation Risk Based on IECCU-Modeled Air
Concentrations for Specific TSCA COUs
Intermediate non-cancer risk estimates for all representative exposure scenarios, presented in Figure
4-14, are calculated using exposures estimates based on IECCU modeling and the chronic non-cancer
POD based on respiratory effects. Intermediate non-cancer risk estimates range from 6,7/10 to
2.1xl0+4 across all individual scenarios, and from 0.7 to 41.8 for aggregate scenarios. Intermediate risk
estimates below 3 indicate that exposure is greater than the level of exposure associated with the
benchmark MOE . Lower MOE values indicate greater risks. These risk estimates account for
dissipation that occurs over time due to the depletion of formaldehyde from the article and air exchange
and account for the exponential decay of formaldehyde.
In general, EPA has high confidence in IECCU's ability to assess formaldehyde intermediate non-cancer
risks in indoor air. Medium quality studies were used to incorporate TSCA COU-specific emission rates
in IECCU. EPA used high quality IECCU modeling data inputs (i.e., article-specific emission rates and
building environmental inputs including building volumes, ventilation rates, and interzonal air flows
from CEM for improved comparability with CEM results) to generate TSCA COU-specific indoor air
concentrations, and comparability between modeled outputs and residential indoor air monitoring data.
As described in Section 3.2, EPA has high confidence in the chronic POD based on respiratory effects.
4.2.3.6 IECCU Indoor Air Chronic Risk Estimates
EPA estimated chronic non-cancer (1-year average), and cancer (lifetime) risks for exposure to
formaldehyde in indoor air. For this analysis, indoor air concentrations modeled for specific COUs
provide an indication of the contributions of individual COUs to formaldehyde indoor air exposure and
risks over one year or lifetime. Figure 4-15 summarizes chronic non-cancer indoor air risk estimates,
while Figure 4-16 summarizes cancer indoor air risk estimates for formaldehyde according to TSCA
COUs.
Page 116 of 191
-------
New Construction Aggregate -
Laminate Flooring -
o
c Living Room Decor Change Aggregate -
-------
New Construction Aggregate -
Increasing Risk
Laminate Flooring -
c Living Room Decor Change Aggregate -
CD
O
C/D
Pressed Wood Furniture-
Textile Furniture Covers -
Wallpaper-
~ A
Metric
Range
v Low
~ Medium
a High
J i i ¦ 111111
I I III I I I I I I I 11 I I I I I I III I I I I I I I 11 I I I I I I 111 I I I I I I I 11 I I I
1(T8 10-7 1(T6 1(T5 1(T4
ADAF-Adjusted Chronic Cancer Risk
Figure 4-16. Cancer Inhalation Risk Based on IECCU-Modeled Air Concentrations for Specific
TSCA COUs
Cancer risk estimates for representative exposure scenarios are presented in Figure 4-16. Cancer risks
range from 3.07xl09 to 6.24xl05across all individual scenarios, and 1.02x10"° to 7.02xl0"5 for
aggregate scenarios. All medium and high-end modeled individual TSCA COUs', including wood
articles, furniture covers and wallpaper, indoor air cancer risks were greater than 1 in 1,000,000. The
indoor air cancer risks for both modeled aggregate scenarios, based on TSCA COUs, were greater than 1
in 1,000,000. All risk estimates including for all exposure scenarios evaluated are provided in the
Supplemental file: Consumer - Indoor Air Acute and Chronic Inhalation Risk Calculator. These risk
estimates account for dissipation that occurs over time due to the depletion of formaldehyde from the
article and air exchange and account for the exponential decay of formaldehyde.
In general, EPA has medium confidence in IECCU's ability to assess formaldehyde chronic non-cancer
and cancer risks in indoor air. Medium quality studies were used to incorporate TSCA COU-specific
emission rates in IECCU. EPA used high quality IECCU modeling data inputs (i.e., article-specific
emission rates and building environmental inputs including building volumes, ventilation rates, and
interzonal air flows from CEM for improved comparability with CEM results) to generate TSCA COU-
specific indoor air concentrations, and comparability between modeled outputs and residential indoor air
monitoring data. The ability to account for a first-order decay, as noted in the literature (Jung and
Mahmoud. 2022). increased confidence in overall inhalation risk estimates for indoor air. However,
EPA has medium confidence in the applicability of the modeling results used to assess long-term indoor
air risks to formaldehyde because, similar to the CEM modeling, it is unclear whether the modeling
Page 118 of 191
-------
results are reflective of most indoor air home environments in American residences. Chamber study data
submitted from industry showed a biphasic emission profile (rapid emission of formaldehyde when the
product is new followed by a much slower emission of formaldehyde) for laminated wood products that
is not captured in the modeling results. This biphasic emission profile may also occur for other urea-
formaldehyde based products; however, data are not available to confirm this. For this reason, it is
possible that IECCU modeled estimates underestimated actual chronic risks in indoor air. As described
in Section 3.2, EPA has high confidence in the chronic POD based on respiratory effects and medium
confidence in the cancer IUR.
4.2.4 Risk Estimates for Ambient Air
EPA evaluated short-term (acute) and long-term (chronic non-cancer and cancer) risks resulting from
human exposure to formaldehyde via the ambient air pathway, inhalation route using previously peer-
reviewed methodologies and considering multiple lines of evidence. These methodologies and lines of
evidence include evaluating releases from two separate databases (TRI and NEI) using several peer-
reviewed models (IIOAC, HEM, AirToxScreen), and consideration of ambient monitoring data from
EPA's AMTIC archive. Figure 4-17 summarizes the risk estimates based on all the results identified by
EPA for several of these lines of evidence. A description of each line of evidence and the associated risk
estimates included in Figure 4-17 is provided below.
EPA recognizes that the risk estimates from the various lines of evidence presented in Figure 4-17 are
not directly comparable due to spatial and temporal differences, as described in Section 2.4.3 and the
Ambient Air Exposure Assessment for Formaldehyde (U.S. EPA. 2024a). These risk estimates are
conservative and have some uncertainties at the local scale as previously described. In summary,
ambient air modeling for formaldehyde does not account atmospheric degradation (i.e. photolysis) and
how local weather patterns may affect the presence of formaldehyde over time. Furthermore, the
assumption that individuals reside in the same location for the duration of their life (i.e. 78 years) is
conservative.
4.2.4.1 Risk Estimates Based on Ambient Air Monitoring
There is abundant monitoring data on formaldehyde in ambient air. As described in Section 2.4.1,
monitoring data from EPA's AMTIC archive (U.S. EPA 2022a) include a range of air monitoring data
collected across the country under a variety of experimental designs and across heterogenous
environments.
Considering the ubiquity of formaldehyde in the ambient air and the diversity of sources contributing to
the monitored concentration at each monitoring site, EPA considers the AMTIC dataset reflective of the
range of total aggregate formaldehyde concentrations in a variety of outdoor environments attributable
to TSCA COUs and all other sources of formaldehyde (including biogenic sources and secondary
formation). As such, the risk estimates based on the AMTIC data provide an indication of the total
aggregate risk from all sources contributing to ambient air concentrations of formaldehyde which may
be present in the real world. Additionally, EPA expects the monitoring data would be inclusive of all
independent sources contributing to formaldehyde in the ambient air (i.e., show the additive nature of
each independent contributor to the total aggregate concentration of formaldehyde and associated risks).
EPA calculated chronic cancer risks based on air concentrations reported in AMTIC across 6 years and
summarizes this data at the top of Figure 4-17. These risk estimates rely on the assumption that
monitored concentrations represent a chronic exposure to a single individual over a lifetime. Since this
monitoring data captures a snapshot of air concentrations at a single timepoint, there is uncertainty
Page 119 of 191
-------
around the extent to which the available monitoring data are accurate representations of long-term
chronic exposures. Furthermore, this data set is not reflective of national emission standards recently
enacted under the Clean Air Act for industrial manufacturing facilities (i.e. Hazardous Organic National
Emission Standards for Hazardous Air Pollutants) or the updated multi-pollutant emission standards for
light-duty and medium-duty vehicles.
The overall AMTIC dataset had risk estimates ranging from 0 to 6.11 x 10"4 with a median of
1.63xl0"5 and a mean risk estimate of 2.1><10"5 [± 2.2 [j,g/m3].
Page 120 of 191
-------
ro
,o
OT
If)
o
ADAF-Adjusted Risk
Data Source
AMTIC (Monitoring) • AirTox (Modeled) • IIOAC (Modeled)
Figure 4-17. ADAF-Adjusted Cancer Risk for Monitoring and Modeling Ambient Air Data
Page 121 of 191
-------
4.2.4.2 Risk Estimates Based on Modeled Concentrations near Releasing Facilities
EPA estimated risks associated with short-term (acute non-cancer) and long-term (chronic non-cancer
and cancer) exposure to formaldehyde in the ambient air. All results by industry sector for all three
health endpoints and all scenarios evaluated are included in the Ambient Air Exposure Assessment
Results and Risk Coles Supplement A (U.S. EPA. 2024a). EPA consolidates all results and risk estimates
by industry sector and distance and cross-walks those results to TSCA COUs in the Ambient Air
Exposure Assessment Results and Risk Coles Supplement B (U.S. EPA. 2024a). Finally, EPA pulls out
the results from the specific scenarios relied upon in this human health risk assessment for deriving
short-term and long-term risk estimates in the Ambient Air Exposure Assessment Results and Risk Coles
Supplement C (U.S. EPA. 2024a).
EPA presents and summarizes the short-term (acute) risk estimates to be protective of sensitization
effects. EPA also presents and summarizes long-term (chronic) risk estimates to be reasonably
protective of both chronic non-cancer and cancer effects in this human health risk assessment. The
exposure scenarios relied upon for deriving risk estimates for these endpoints are described in Section
2.4.2.1 of this human health risk assessment as well as Sections 2.1.1.2.1 and 2.1.1.2.2 of the Ambient
Air Exposure Assessment for Formaldehyde (U.S. EPA. 2024a).
As described in Section 4.1.1, non-cancer risk estimates further below the respective non-cancer
benchmark MOE indicate higher risks. The relative non-cancer benchmark MOE for both acute and
chronic non-cancer for formaldehyde is 3.
As described in Section 4.1.2, cancer risk estimates further above the respective cancer benchmark
indicate higher risks. The relative cancer benchmarks considered in this human health risk assessment
for ambient air are 1 x 10"6, 1 x 10"5, and 1 x 10"4.
4.2.4.3 Short-Term Risk Estimates for Ambient Air
Short-term risk estimates for ambient air in this assessment are based on the maximum release scenario
and the 95th percentile modeled daily average exposure concentrations at 100 meters from a releasing
facility as described in Section 2.4.2.1.1 and the Ambient Air Exposure Assessment for Formaldehyde
(U.S. EPA. 2024a). EPA separately presents short-term risk estimates for exposures primarily
attributable to the COUs and combustion in this assessment.
Short-term risk estimates based on IIOAC modeled results attributable to the COUs range from 9 to
3,732 and are presented in Figure 4-18. These values represent the highest risk estimates across all
industry sectors cross-walked to the same COU. EPA found zero acute non-cancer risk estimates below
the acute benchmark MOE of 3 for exposures primarily attributable to the COUs. The top five acute
non-cancer risk estimates representing the highest risks which are linked to the COUs are provided in
Table 4-2.
The first two columns in Table 4-2 include information on the industry sector and the industry sector
crosswalk to TSCA COUs. The release dataset column notes the source of the reported data, either TRI
or NEI. The fugitive and stack columns provide the industry reported source apportioned release values
which were used as direct inputs to the IIOAC model. The acute risk estimate column presents the risk
estimates derived from the sum of the modeled exposure results for fugitive and stack releases at 100
meters from a releasing facility.
Page 122 of 191
-------
Commercial Use-Chemical substances in packaging, paper, plastic, nobby products-Paper products; Plastic and rubber products: Toys, playground, and sporting equipment
Commercial Use-Chemical substances in packaging, paper, plastic, hobby products-Arts, crafts, and hobby materials
Processing-Incorporation Into Article-Additive
Commercial Use-Chemical substances in packaging, paper, plastic, hobby products-Ink, toner, and colorant products; Photographic supplies
Commercial Use-Chemical substances in electrical products-Electrical and electronic products
Processing-Incorporation into a formulation, mixture, or reaction product-Lubricant and lubricant additive
Processing-Incorporation into a formulation, mixture, or reaction product-Adhesive and Sealant Chemicals
Commercial Use-Chemical substances in metal products-Construction and building materials covering large surface areas. Including metal articles
Commercial Use-Chemical substances in furnishing treatment/care products-Construction and building materials covering large surface areas
Commercial Use-Chemical substances in construction, paint, electrical, and metal products-Adhesives and Sealants: Paint and coatings
Processirig-Reactant-Agricultural Chemicals
Commercial Use-Chemical substances in agriculture use products-lawn and garden products
Disposal
Processing-Incorporation into a formulation, mixture, or reaction product-Solid separation agents
Processing-Incorporation into a formulation, mixture, or reaction product-Processing aids, specific to petroleum production
Processing-Incorporation into a formulation, mixture, or reaction product-Plating agents and surface treating agents
Processing-Incorporation Into a formulation, mixture, or reaction product-Other Laboratory Chemicals
Processing-Incorporation into a formulation, mixture, or reaction product-Solvents (which become part of a product formulation or mixture)
Processing-Incorporation into a formulation, mixture, or reaction product-Ion exchange agents
Processing-Incorporation into a formulation, mixture, or reaction product-Surface Active Agents
Processing-Incorporation into a formulation, mixture, or reaction product-Paint additives and coating additives not described by other categories
Processing-Incorporation into an Article-Paint additives and coating additives
Industrial Use-Non-incorporative activities-Oxidizing/reducing agent; processing aids, not otherwise listed (e g., electroless copper plating)
Industrial Use-Non-incorporative activities-used in: construction
Industrial Use-Chemical substances in industrial products-Paints and coatings; adhesives and sealants; lubricants
Domestic Manufacturing
Processing-Incorporation into a formulation, mixture, or reaction product-Agricultural chemicals (Nonpesticidal)
Processing-Incorporation into Article-Finishing Agents
Processing-Incorporation into a formulation, mixture, or reaction product-Bleaching Agents
Commercial Use-Chemical substances in furnishing treatment/care products-Floor coverings
Processing-Reactant-Processing aids, specific to petroleum production
Processing-Incorporation into a formulation, mixture, or reaction product
Processing-incorporation into a formulation, mixture, or reaction product-Intermediate
Recycling
Processing-Reactant-Bleaching Agent
Processing-Reactant-Adhesives and Sealant Chemicals
Processing-Reactant-lntermediate
Processing-Incorporation into an Article-Adhesives and Sealant Chemicals
Commercial Use-Chemical substances in automotive and fuel products-Automotive care products: Lubricants and greases; Fuels and related products
10
100
Acute MOE
1000
Figure 4-18. Acute Risk Estimates based on Estimated Daily Concentrations by TSCA COU for the Maximum Release Scenario and
95th Percentile Modeled Concentration at 100 m from Industrial Facilities Releasing Formaldehyde
Page 123 of 191
-------
Table 4-2. Top Five Acute Non-cancer Risk Estimates Indicating the
lighest Risks Attributable to TSCA COl
Js
Industry Sector
COUs
Maximum Release Value (kg/year)
Acute Risk
Estimate
Release
Dataset
Fugitive
Stack
Commercial Use-Chemical substances in
automotive and fuel products-Automotive care
products; Lubricants and greases; Fuels and related
products
NEI
9,774
157,547
9
Wood Product
Processing-Incorporation into an Article-Adhesives
and Sealant Chemicals
Manufacturing
Processing-Reactant-Adhesives and Sealant
Chemicals
Processing-Reactant-Bleaching Agent
Processing-Reactant-Intermediate
Recycling
Commercial Use-Chemical substances in
automotive and fuel products-Automotive care
products; Lubricants and greases; Fuels and related
products
NEI
11,585
23,929
11
Paper
Manufacturing
Processing-Incorporation into an Article-Adhesives
and Sealant Chemicals
Processing-Reactant-Intermediate
Recycling
All Other Basic
Organic
Commercial Use-Chemical substances in
automotive and fuel products-Automotive care
NEI
11,036
9,053
12
Page 124 of 191
-------
Industry Sector
COUs
Maximum Release Value (kg/year)
Acute Risk
Estimate
Release
Dataset
Fugitive
Stack
Chemical
Manufacturing
products; Lubricants and greases; Fuels and related
products
Processing-Incorporation into a formulation,
mixture, or reaction product
Processing-Incorporation into a formulation,
mixture, or reaction product-Intermediate
Processing-Reactant-Adhesives and Sealant
Chemicals
Processing-Reactant-Intermediate
Processing-Reactant-Processing aids, specific to
petroleum production
Textiles,
Apparel, and
Leather
Commercial Use-Chemical substances in
automotive and fuel products-Automotive care
products; Lubricants and greases; Fuels and related
products
TRI
9,347
18,644
14
Commercial Use-Chemical substances in furnishing
treatment/care products-Floor coverings; ...
Manufacturing
Processing-Incorporation into a formulation,
mixture, or reaction product-Bleaching Agents
Processing-Incorporation into Article-Finishing
Agents
Pesticide,
Fertilizer, and
Commercial Use-Chemical substances in
automotive and fuel products-Automotive care
TRI
8,922
15,588
14
Page 125 of 191
-------
Industry Sector
COUs
Maximum Release Value (kg/year)
Acute Risk
Estimate
Release
Dataset
Fugitive
Stack
Other
Agricultural
Chemical
Manufacturing
products; Lubricants and greases; Fuels and related
products
Processing-Incorporation into a formulation,
mixture, or reaction product-Agricultural chemicals
(Nonpesticidal)
Processing-Reactant-Intermediate
Page 126 of 191
-------
Short-term risk estimates based on IIOAC modeled results attributable to combustion range from 1 to 4
and are presented in Table 4-2. These values represent the risk estimates indicating the highest risk
within each industry sector. EPA found two of the top five acute non-cancer risk estimates below the
acute benchmark MOE of 3 for exposures primarily attributable to combustion.
The first three columns of Table 4-3 include information on the industry sector, site reporting the
fugitive and stack releases, and the major process unit source(s) from which those releases came. The
release dataset column notes the source of the reported data, either TRI or NEI. The fugitive and stack
columns provide the industry reported source apportioned release values which were used as direct
inputs to the IIOAC model. The acute risk estimate column presents the risk estimates derived from the
sum of the modeled exposure results for fugitive and stack releases at 100 meters from a releasing
facility.
As previously described in Section 2.4.2.1.1, the Ambient Air Exposure Assessment for Formaldehyde
(U.S. EPA. 2024a) and shown in Table 4-3, all the maximum releases within each of the top five
industry sectors are from combustion sources like airplanes, on-site vehicles, process heaters, turbines,
and RICE. The modeled concentrations used to derive the associated estimates are much higher than the
highest concentrations found with the AMTIC, HEM, and 2019 AirToxScreen datasets. EPA's deeper
dive into these high values showed that the highest 95th percentile releases evaluated for this assessment
were at least 1 to 2 orders of magnitude lower than the maximum releases within the same industry
sector. Based on the additional investigation/deeper dive into the highest maximum reported releases,
EPA concludes these facilities are likely outliers within their respective industry sectors and not
representative of national level releases within the respective industry sectors for TSCA purposes.
Nonetheless, the risk estimates are provided for transparency and may inform other EPA programs.
Page 127 of 191
-------
Table 4-3. Top Five Acute Non-cancer Risk Estimates Indicating the Highest Risks Attributable to Combustion
Industry Sector
Facility
(County, State)
Major Process
Unit Source(s)
Maximum Release Value (kg/year)
Acute Risk
Estimate
Release
Dataset
Fugitive
Stack
Wholesale and Retail Trade
Columbus AF Base
(Lowndes, MS)
Aircrafts
NEI
138,205
1
Transcontinental Gas
Pipeline Company, LLC
(Henry, GA)
RICE, Turbines
95,159
Oil and Gas Drilling,
Extraction, and Support
Activities
Chevron USA Inc.
(Kern, CA)
Process heaters,
RICE, Turbines
NEI
22,742
2
Frenchie Draw Central
Compressor Station
(Fremont, WY)
RICE
1,412,023
Non-Metallic Mineral Product
Manufacturing
Cemex Black Mountain
Quarry Plant
(San Bernardino, CA)
On-Site
Vehicles
NEI
41,190
3
Thermafiber Inc
(Wabash, IN)
Not reported
36,492
Services
Pope Airforce Base
(Cumberland, NC)
Aircrafts
NEI
34,155
4
Seneca Energy LFGTE
Facility
(Seneca, NY)
RICE
63,483
Utilities
Lorain County LFG
Power Station
(0247100968)
(Lorain, OH)
RICE
NEI
10,108
10
Basin Creek Power
Services
(Silver Bow, MT)
RICE
101,968
Page 128 of 191
-------
4.2.4.4 Long-Term Risk Estimates for Ambient Air
Long-term risk estimates for ambient air in this assessment are based on the 95th percentile release
scenario and the 95th percentile modeled annual average exposure concentrations within the area
distance of 100 to 1,000 meters from a releasing facility as described in Section 2.4.2.1.2 and the
Ambient Air Exposure Assessment for Formaldehyde (U.S. EPA. 2024a). Long-term risk estimates are
derived for both chronic non-cancer effects and cancer in this assessment.
Long-term risk estimates based on IIOAC modeled results for chronic non-cancer effects range from 4
to 10,180 and are presented in Figure 4-19. These values represent the highest risk estimates across all
industry sectors cross-walked to the same COU. EPA found zero chronic non-cancer risk estimates
below the chronic benchmark MOE of 3 for exposures primarily attributable to TSCA COUs. The top
five chronic non-cancer risk estimates representing the highest risks which are linked to the COUs are
provided in Table 4-4.
Page 129 of 191
-------
Commercial Use-Chemical substances in packaging, paper, plastic, hobby products-Paper products: Plastic and rubber products: Toys, playground, and sporting equipment-
Commercial Use-Chemical substances in packaging, paper, plastic, hobby products-Arts, crafts, and hobby materials-
Processing-Incorporation into Article-Additive-
Commercial Use-Chemical substances in electrical products-Electrical and electronic products-
Processing-Reactant-Agricultural Chemicals -
Commercial Use-Chemical substances in agriculture use products-lawn and garden products -
Commercial Use-Chemical substances in packaging, paper, plastic, hobby products-ink, toner, and colorant products: Photographic supplies-
Processing-Incorporation into a formulation, mixture, or reaction product-Lubricant and lubricant additive-
Processing-Incorporation into a formulation, mixture, or reaction product-Adhesive and Sealant Chemicals-
Commercial Use-Chemical substances in metal products-Construction and building materials covering large surface areas. Including metal articles-
Commercial Use-Chemical substances in furnishing treatment/care products-Construction and building materials covering large surface areas -
Commercial Use-Chemical substances in construction, paint, electrical, and metal products-Adhesives and Sealants: Paint and coatings-
Industrial Use-Non-incorporative activities-Oxidizing/reducing agent: processing aids, not otherwise listed (e g . electroless copper plating)-
Processing-lncorporation into a formulation, mixture, or reaction product-Rating agents and surface treating agents -
Processing-Incorporation into a formulation, mixture, or reaction product-Other: Laboratory Chemicals -
Disposal -
Processing-Reactant-Processing aids, specific to petroleum production-
Processing-Repackaging -
Manufacturing-Importing -
Processing-Incorporation into a formulation mixture, or reaction product-Surface Active Agents -
Processing-incorporation into a formulation mixture, or reaction product-Agricultural chemicals (Nonpesticidal)-
Processing-lncorporation into a formulation, mixture, or reaction product-Solvents (which become part of a product formulation or mixture)-
Processing-lncorporation into a formulation, mixture, or reaction product-Paint additives and coating additives not described by other categories -
Processing-Incorporation into a formulation, mixture, or reaction product-Ion exchange agents-
Processing-Incorporation into a formulation, mixture, or reaction product-Solid separation agents-
Processing-Incorporation into a formulation, mixture, or reaction product-
Domestic Manufacturing -
Industrial Use-Non-incorporative activities-used in: construction -
Recycling -
Processing-Reactant-lntermediate-
Processlng-Reactant-Bleaching Agent -
Processing-Reactant-Adhesives and Sealant Chemicals-
Processing-Reactant-Functional fluid -
Processing-Incorporation into a formulation, mixture, or reaction product-Processing aids, specific to petroleum production-
Industrial Use-Non-incorporative activities-Processing aids-
Processing-lncorporation into an Article-Paint additives and coating additives-
Industrial Use-Chemical substances in industrial products-Paints and coatings , adhesives and sealants , lubricants-
Processing-Incorporation into Article-Finishing Agents -
Processing-Incorporation into a formulation, mixture, or reaction product-Bleaching Agents -
Commercial Use-Chemical substances in furnishing treatment/care products-Floor coverings: Foam seating and bedding products-
Processing-Incorporation into an Article-Adhesives and Sealant Chemicals-
Processing-lncorporation into a formulation, mixture, or reaction product-Intermediate-
Commercial Use-Chemical substances in automotive and fuel products-Automotive care products: Lubricants and greases: Fuels and related products-
10 100 1000
Chronic Non-Cartcer MOE
Figure 4-19. Chronic Non-cancer Risk based on Modeled Annual Average Air Concentrations Attributable to TSCA COUs
Page 130 of 191
-------
Table 4-4. Top Five C
ironic Non-cancer Risk Estimates Indicating the Highest Risks Attributable to TSCA COUs
Industry Sector
COUs
Maximum Release Value
(kg/year)
Chronic Risk
Estimate
Release Dataset
Fugitive
Stack
Non-metallic Mineral
Product
Manufacturing
Commercial Use-Chemical substances in
automotive and fuel products-Automotive care
products; Lubricants and greases; Fuels and
related products
TRI
8,407
27,961
4
Processing-Incorporation into a formulation,
mixture, or reaction product-Intermediate
Processing-Incorporation into an Article-
Adhesives and Sealant Chemicals
Processing-Reactant-Intermediate
Textiles, Apparel, and
Leather
Manufacturing
Commercial Use-Chemical substances in
automotive and fuel products-Automotive care
products; Lubricants and greases; Fuels and
related products
TRI
8,042
3,315
5
Commercial Use-Chemical substances in
furnishing treatment/care products-Floor
coverings; Foam seating and bedding products;
Furniture & furnishings.
Processing-Incorporation into a formulation,
mixture, or reaction product-Bleaching Agents
Processing-Incorporation into Article-Finishing
Agents
Transportation
Equipment
Manufaturing
Commercial Use-Chemical substances in
automotive and fuel products-Automotive care
products; Lubricants and greases; Fuels and
related products
TRI
3,146
40,823
6
Industrial Use-Chemical substances in industrial
products-Paints and coatings; adhesives and
sealants; lubricants
Processing-Incorporation into an Article-Paint
additives and coating additives
Page 131 of 191
-------
Industry Sector
COUs
Maximum Release Value
(kg/year)
Chronic Risk
Estimate
Release Dataset
Fugitive
Stack
Oil and Gas Drilling,
Extraction, and
Support Activities
Commercial Use-Chemical substances in
automotive and fuel products-Automotive care
products; Lubricants and greases; Fuels and
related products
NEI
4,117
7,265
8
Industrial Use-Non-incorporative activities-
Processing aids
Processing-Incorporation into a formulation,
mixture, or reaction product-Intermediate
Processing-Incorporation into a formulation,
mixture, or reaction product-Processing aids,
specific to petroleum production
Processing-Reactant-Functional fluid
Wood Product
Manufacturing
Commercial Use-Chemical substances in
automotive and fuel products-Automotive care
products; Lubricants and greases; Fuels and
related products
NEI
3,807
7,9601
9
Processing-Incorporation into an Article-
Adhesives and Sealant Chemicals
Processing-Reactant-Adhesives and Sealant
Chemicals
Processing-Reactant-Bleaching Agent
Processing-Reactant-Intermediate
Recycling
Page 132 of 191
-------
Long-term risk estimates for cancer based on 95th percentile IIOAC modeled concentration results
range from 2.1 x 10"8 to 5.9x 10"5 and are presented in Figure 4-20. These values represent the highest risk
estimates across all industry sectors cross-walked to the same COU. When comparing the derived risk
estimates for cancer attributable to TSCA COUs to the three cancer benchmarks considered in this risk
assessment, EPA found 31 TSCA COUs have cancer risk estimates greater than the cancer benchmark
of 1 x 10"6. EPA found 23 TSCA COUs with cancer risk estimates greater than the cancer benchmark of
1 x 10"5 and zero TSCA COUs with cancer risk estimates greater than the cancer benchmark of 1 x 10"4
The top five cancer risk estimates representing the highest risks which are linked to the COUs are
provided in Table 4-5.
Risk estimates derived from the 95th percentile IIOAC modeled concentrations fall within the lower
range of the risk estimates derived from the AMTIC monitoring dataset. This is expected since the risk
estimates derived from the 95th percentile IIOAC modeled concentrations represent localized impacts of
industrial facilities associated with a TSCA COU while the risk estimates derived from the AMTIC
monitoring dataset represent a total aggregate risk from all sources of ambient formaldehyde including
TSCA COUs, secondary formation, biogenic sources, mobile sources, and other sources.
Overall, based on the results, the long-term risk estimates for cancer derived from the 95th percentile
IIOAC modeled concentrations which are attributable to TSCA COUs, are generally representative of
risks to individuals residing near industrial facilities releasing formaldehyde to the ambient air. This
conclusion is supported by the comparison to the risk estimates derived from the AMTIC dataset. These
conclusions assume individuals live within 1,000 meters of one or more industrial facilities releasing
formaldehyde to the ambient air for a full 78-year lifetime.
Page 133 of 191
-------
Processing-Incorporation into an Article-Adhesives and Sealant Chemicals
Processing-Incorporation into a formulation, mixture, or reaction product-Intermediate
Commercial Use-Chemical substances in automotive and fuel products-Automotive care products; Lubricants and greases; Fuels and related products
Processing-Incorporation into Article-Finishing Agents
Processing-Incorporation into a formulation, mixture, or reaction product-Bleaching Agents
Commercial Use-Chemical substances in furnishing treatment/care products-Floor coverings; Foam seating and bedding products; Furniture & furnishings
Processing-Incorporation into an Article-Paint additives and coating additives
Industrial Use-Chemical substances in industrial products-Paints and coatings; adhesives and sealants; lubricants
Processing-Reactant-Functional fluid
Processing-Incorporation into a formulation, mixture, or reaction product-Processing aids, specific to petroleum production -
Industrial Use-Non-incorporative activities-Processing aids-
Recycling
Processing-Reactant-lntermediate
Processing-Reactant-Bleaching Agent
Processing-Reactant-Adhesives and Sealant Chemicals
Industrial Use-Non-incorporative activities-used in: construction
Domestic Manufacturing
Processing-Incorporation into a formulation, mixture, or reaction product
Processing-Incorporation into a formulation, mixture, or reaction product-Solid separation agents
Processing-Incorporation into a formulation, mixture, or reaction product-Solvents (which become part of a product formulation or mixture)
Processing-Incorporation into a formulation, mixture, or reaction product-Paint additives and coating additives not described by other categories
Processing-Incorporation into a formulation, mixture, or reaction product-Ion exchange agents
Processing-Incorporation into a formulation, mixture, or reaction product-Agricultural chemicals (Nonpesticidal)
Processing-Incorporation into a formulation, mixture, or reaction product-Surface Active Agents
Processing-Repackaging
Manufacturing-Importing
Processing-Reactant-Processing aids, specific to petroleum production
Disposal
Processing-Incorporation into a formulation, mixture, or reaction product-Plating agents and surface treating agents
Processing-Incorporation into a formulation, mixture, or reaction product-Other; Laboratory Chemicals
Industrial Use-Non-incorporative activities-Oxidizing/reducing agent: processing aids, not otherwise listed (e.g., electroless copper plating)
Commercial Use-Chemical substances in metal products-Construction and building materials covering large surface areas, including metal articles
Commercial Use-Chemical substances in furnishing treatment/care products-Construction and building materials covering large surface areas
Commercial Use-Chemical substances in construction, paint, electrical, and metal products-Adhesives and Sealants; Paint and coatings
Processing-Incorporation into a formulation, mixture, or reaction product-Lubricant and lubricant additive
Processing-Incorporation into a formulation, mixture, or reaction product-Adhesive and Sealant Chemicals
Commercial Use-Chemical substances in packaging, paper, plastic, hobby products-Ink, toner, and colorant products; Photographic supplies
Processing-Reactant-Agricultural Chemicals
Commercial Use-Chemical substances in agriculture use products-lawn and garden products
Commercial Use-Chemical substances in electrical products-Electrical and electronic products
Processing-Incorporation into Article-Additive-
Commercial Use-Chemical substances in packaging, paper, plastic, hobby products-Paper products; Plastic and rubber products; Toys, playground, and sporting equipment
Commercial Use-Chemical substances in packaging, paper, plastic, hobby products-Arts, crafts, and hobby materials
TiTnT"
10" 10 10"
ADAF-Adjusted Cancer Risk Estimate
Figure 4-20. Lifetime Risk Estimates for Cancer based on Modeled Annual Average Air Concentrations Attributable to TSCA CO Us
Page 134 of 191
-------
Table 4-5. Top Five Cancer Risk Estimates Indicating the Highest Risks Attributable to TSCA CPUs
Industry Sector
COUs
Maximum Release Value
(kg/year)
Cancer Risk
Estimate
Release Dataset
Fugitive
Stack
Non-metallic Mineral
Product
Manufacturing
Commercial Use-Chemical substances in
automotive and fuel products-Automotive care
products; Lubricants and greases; Fuels and
related products
TRI
8,407
27,961
5.9xl0"5
Processing-Incorporation into a formulation,
mixture, or reaction product-Intermediate
Processing-Incorporation into an Article-
Adhesives and Sealant Chemicals
Processing-Reactant-Intermediate
Textiles, Apparel, and
Leather
Manufacturing
Commercial Use-Chemical substances in
automotive and fuel products-Automotive care
products; Lubricants and greases; Fuels and
related products
TRI
8,042
3,315
4.6xl0"5
Commercial Use-Chemical substances in
furnishing treatment/care products-Floor
coverings; Foam seating and bedding products;
Furniture & furnishings.
Processing-Incorporation into a formulation,
mixture, or reaction product-Bleaching Agents
Processing-Incorporation into Article-Finishing
Agents
Transportation
Equipment
Manufaturing
Commercial Use-Chemical substances in
automotive and fuel products-Automotive care
products; Lubricants and greases; Fuels and
related products
TRI
3,146
40,823
3.5xl0"5
Industrial Use-Chemical substances in industrial
products-Paints and coatings; adhesives and
sealants; lubricants
Page 135 of 191
-------
Industry Sector
COUs
Maximum Release Value
(kg/year)
Cancer Risk
Estimate
Release Dataset
Fugitive
Stack
Processing-Incorporation into an Article-Paint
additives and coating additives
Oil and Gas Drilling,
Extraction, and
Support Activities
Commercial Use-Chemical substances in
automotive and fuel products-Automotive care
products; Lubricants and greases; Fuels and
related products
NEI
4,117
7,265
2.6xl0"5
Industrial Use-Non-incorporative activities-
Processing aids
Processing-Incorporation into a formulation,
mixture, or reaction product-Intermediate
Processing-Incorporation into a formulation,
mixture, or reaction product-Processing aids,
specific to petroleum production
Processing-Reactant-Functional fluid
Wood Product
Manufacturing
Commercial Use-Chemical substances in
automotive and fuel products-Automotive care
products; Lubricants and greases; Fuels and
related products
NEI
3,807
7,9601
2.4xl0"5
Processing-Incorporation into an Article-
Adhesives and Sealant Chemicals
Processing-Reactant-Adhesives and Sealant
Chemicals
Processing-Reactant-Bleaching Agent
Processing-Reactant-Intermediate
Recycling
Page 136 of 191
-------
4.2.4.5 Population Analysis for Cancer Risks using HEM
EPA used the HEM to help understand how modeled air concentrations (and associated risks) at the
national level intersected with populated areas. The HEM is capable of estimating exposures to
populations at one or more user-defined distance(s) from releasing facilities (out to 50,000 meters
(approximately 31 miles)) and at the centroid of census blocks across the nation based on the most
recent census data integrated into the HEM. When estimating exposures (in particular at the centroid of
census blocks), the HEM results represent an aggregation of exposures from multiple nearby facilities
(e.g., facilities in proximity to others releasing formaldehyde to the ambient air).
EPA expands the population analysis to include the demographic characteristics of exposed populations
who may be experiencing an increased cancer risk from industrial facilities releasing formaldehyde to
the ambient air. This population and demographic analysis use the highest reported releases across six
years of TRI data for each industrial facility reporting releases to TRI. EPA considers the same cancer
benchmarks for this analysis as it does for the IIOAC modeling described in the previous section (see
Section 4.2.4.4).
A full summary of estimated populations by level of risk estimate with stratification by demographics is
presented in Table 4-6. For the demographic analysis, an individual is identified as one of five
racial/ethnic categories: White, African American, Native American, Other and Multiracial, or
Hispanic/Latino. To avoid double counting, the "Hispanic or Latino" category is treated as a distinct
demographic category for these analyses. While population counts are summarized at the census block
level, the demographic information is summarized by census block group, and applied to each census
block within the census block group.
EPA's population analysis using HEM estimated a total population of 1,023,773 people experience a
lifetime cancer risk of at least one in one million (lxlO"6). EPA's population analysis estimated 6,935
people were estimated to experience risk greater than 10 in 1 million (1 x 10"5), and 19 were estimated to
experience risk greater than 100 in 1 million (1 x 10"4). No population was found with estimated risks
exceeding 200 in 1 million.
Across the entire modeling domain, including census blocks within 50 km of any TRI facility reporting
formaldehyde releases, the average risk to the entire population of 232,907,302 people was estimated to
be 0.04 in 1 million. This average risk was slightly higher for the African American and Native
American demographics included in the modeling, at an estimate of 0.06 in 1 million.
Table 4-6. Population Summary for Cancer Risk Estimates Derived from HEM Modeling of TRI
Range of Lifetime
Individual Cancer
Risk
Number of People within 50 km of any Facility in Different Ranges for Lifetime
Cancer Risk
Total
Population
White
African
American
Native
American
Other and
Multiracial
Hispanic or
Latino
< 1 in 1 million
232,907,302
140,083,682
30,322,675
881,180
21,243,988
40,375,778
1 to <5 in 1 million
1,023,773
665,609
171,444
7,929
54,384
124,408
5 to <10 in 1
million
40,652
26,742
5,429
542
2,884
5,055
Page 137 of 191
-------
Range of Lifetime
Individual Cancer
Risk
Number of People within 50 km of any Facility in Different Ranges for Lifetime
Cancer Risk
Total
Population
White
African
American
Native
American
Other and
Multiracial
Hispanic or
Latino
10 to <20 in 1
million
6,935
4,430
1,057
21
246
1,181
20 to <30 in 1
million
2,692
1,901
388
8
64
331
30 to <40 in 1
million
509
359
70
4
11
65
40 to <50 in 1
million
555
379
117
0
18
41
50 to <100 in 1
million
338
202
101
0
7
27
100 to <200 in 1
million
19
10
6
0
1
2
>200 in 1 million
0
0
0
0
0
0
Total population
within model
domain
233,982,775
140,783,315
30,501,287
889,684
21,301,603
40,506,886
Average risk
(chance in 1
million)
0.04
0.04
0.06
0.06
0.03
0.03
Further breakdown of relative population demographics compared to national averages is presented in
Table 4-7. This summary of results shows that among the population with estimated cancer risk higher
than (lxlO"6), some population groups are disproportionately represented as indicated by a higher
percentage of a population group experiencing elevated risk than the overall nationwide percentage of
the population representing that group. These groups include white, African American, and Native
American demographics, as well as those with income below the poverty level and those aged over 25
years without a high school diploma.
Table 4-7. Demographic Details of Population with Estimated Cancer Risk Higher than or Equal
to 1 in 1 Million, Compared with National Proportions
Demographic
Nationwide
Population with Cancer Risk Higher than or
Equal to (lxlO 6)
Total Population
329,824,950
1,075,473
Race and ethnicity by percent
White
59.5%
65.1%
African American
12.1%
16.6%
Native American
0.6%
0.8%
Other and Multiracial
8.8%
5.4%
Hispanic or Latino
19.0%
12.2%
Income by percent
Below Poverty Level
12.8%
15.7%
Page 138 of 191
-------
Above Poverty Level
87.2%
84.3%
Below Twice Poverty
Level
30.2%
34.9%
Above Twice Poverty
Level
69.8%
65.1%
Education by percent
Over 25 and without a
High School Diploma
11.6%
12.3%
Over 25 and with a
High School Diploma
88.4%
87.7%
Linguistically isolated by percent
Linguistically Isolated
5.2%
2.2%
Overall confidence in risk estimates based on modeled air concentrations from HEM is high because, as
described in Section 2.4.2, HEM (and its underlying dispersion model AERMOD) are peer reviewed
models which use industry reported releases across multiple years of data from two databases (TRI and
NEI) as direct inputs to the HEM. Both databases have high-quality ratings under EPA's systematic
review process. Additionally, the modeling approaches and methods used for this analysis have been
peer reviewed and integrates recommendations by SACC from previous peer reviewed approaches and
methods
As described in Section 3.2, overall confidence in the acute and chronic, non-cancer hazard POD used to
derive risk estimates is high while overall confidence in the inhalation unit risk for formaldehyde used to
derive cancer risk estimates is medium.
4.2.4.6 Integration of Modeling and Monitoring Information
EPA evaluated and characterized exposures and risks to the general population from industrial releases
of formaldehyde to the ambient air using actual reported releases and peer reviewed models to estimate
exposures at select distances from releasing facilities. EPA also evaluated and characterized exposures
and risks to the general population based on ambient monitoring data obtained from AMTIC.
Modeling and monitoring results show comparable exposures and risks to the general population from
formaldehyde in the ambient air. However, direct comparisons between modeled and monitored
concentrations and associated risks should be made with caution because of spatial and temporal
differences among the various lines of evidence. Additionally, individually each line of evidence
represents different contributions to the overall exposures and associated risks used in this risk
characterization. For example, EPA's modeling represents individual exposures to formaldehyde from
industry reported releases specific to TSCA COUs at pre-defined distances from releasing facilities. The
ambient monitoring data, on the other hand, represents total ambient concentrations of formaldehyde
from all sources releasing formaldehyde to the ambient air (e.g.. biogenic sources, secondary formation,
mobile sources, etc.) and cannot be readily associated with a TSCA COU. Furthermore, monitoring data
is direct measured concentrations (rather than estimated concentrations) at many different distances and
locations which may or may not be nearby industrial facilities releasing formaldehyde to the ambient air.
While individual lines of evidence may not be directly comparable, taken together the data and results
support EPA's use of IIOAC daily and annual average modeled concentrations to derive risk estimates
and characterize risks.
Page 139 of 191
-------
4.2.4.7 Overall Confidence in Exposures, Risk Estimates, and Risk Characterizations
for Ambient Air
There are many sources of formaldehyde which contribute to exposures to the general population.
This ambient air exposure assessment for formaldehyde considers multiple lines of evidence including
measured (monitored) and modeled formaldehyde concentrations to derive risk estimates and
characterize risk. Overall, this human health risk assessment finds that the general population living near
industrial facilities releasing formaldehyde to the ambient air experience both short-term and long-term
inhalation exposure to formaldehyde attributable to TSCA COUs. While individual lines of evidence
may not be directly comparable, taken together the data and results support EPA's use of IIOAC daily
and annual average modeled concentrations to derive risk estimates and characterize risks.
EPA has medium confidence in the IIOAC modeled results used to derive risk estimates and
characterize risks. Several inputs used for the IIOAC model are generally conservative, including the
maximum and 95th percentile releases modeled and relied upon for the exposure concentrations, stack
parameters representing a low, slow moving, non-buoyant plume, and the meteorological station within
IIOAC used for this assessment representing a high-end station which leads to higher overall estimated
concentrations. However, there are uncertainties in model outputs due to assumptions made when
choosing input parameters, including the use of annual average releases to calculate daily releases and
the use default parameters used within IIOAC. There is additional uncertainty because IIOAC does not
consider the location of residential areas relative to industrial facilities associated with TSCA COUs.
Similarly, the assessment was conducted independent of the size of the facility footprint, the precise
location of the release, and the relative location of residences.
Additional lines of evidence provide context for the use of IIOAC modelling results. Monitoring data
from AMTIC represent the aggregate concentration of formaldehyde in the ambient air from all sources,
while IIOAC modeled concentrations represent local exposures attributable to TSCA COUs at select
distances near a releasing facility. AirToxScreen data provide further context for contributions from
multiple sources including biogenic, secondary, TSCA COUs and other sources. HEM results provide
additional context on the spatial variability of formaldehyde concentrations across the U.S. The
additional population and demographic analysis conducted using EPA's HEM supports the presence of
individuals within distances (centroids of census blocks) evaluated for this risk evaluation and the
increased risk estimates for cancer at those locations. While the individual lines of evidence provide
context, the individual datasets are not directly comparable to each other, due to spatial and temporal
differences. Further, formaldehyde concentrations are highly variable based on geographic location (e.g.,
HEM results show elevated concentrations in the Southeastern United States), nearby releases, and
contributions from other sources of formaldehyde. Taken together, the totality of integrated data can and
do allow for a characterization of general population risks but has some uncertainty.
For formaldehyde, the contribution of combustion activities to the high-end exposure and risk estimates
observed with the maximum release scenario is apparent and remains an uncertainty. However, as
described in the Ambient Air Exposure Assessment for Formaldehyde (U.S. EPA. 2024a) and Section
2.4.2.1, releases primarily attributable to combustion activities are limited to a handful of very high
reported releases within the NEI dataset. When modeled, these releases result in modeled concentrations
at least an order of magnitude greater than the highest monitored concentrations from the AMTIC
dataset. Additionally, when compared to the 95th percentile release values these maximum releases
appear to be outliers relative to the remaining reported releases within a given industry sector.
Use of the full facility release data (all facilities across a single industry sector) to develop the four
release statistics modeled with IIOAC complicate singular TSCA COU estimates because reported
Page 140 of 191
-------
releases at one site may include multiple sources under multiple COUs that include combustion sources
and non-combustion sources. As such, for industrial COUs, EPA has a moderate to robust weight of
scientific evidence as the databases have high data quality scores and are supported by numerous data
points. EPA has a moderate weight of scientific evidence for the commercial COUs since certain
assumptions around industrial releases getting cross-walked to commercial COUs may not be fully
representative for a commercial release value.
Overall confidence in risk estimates based on air concentrations modeled near release sites is medium
for non-cancer estimates and medium for cancer estimates based on the hazard values. As described in
Section 3.2, overall confidence in the chronic, non-cancer hazard POD is high, while overall confidence
in the inhalation unit risk for formaldehyde is medium.
4.2.5 Comparison of Non-cancer Effect Levels and Air Concentrations
Hazard and risk assessments often lack human data on the specific concentrations at which an effect
occurs in people and risk estimates often incorporate a substantial amount of uncertainty. In the case of
formaldehyde, a robust database of epidemiology studies provides information about the air
concentrations of formaldehyde that have been associated with respiratory effects in people and supports
hazard values with minimal uncertainty.
Figure 4-21 indicates that the respiratory effects of formaldehyde in people can occur within the range of
air concentrations reported in monitoring studies. This comparison suggests that chronic exposure to
some of the indoor and outdoor air concentrations captured in available monitoring data are at levels that
may be expected to result in adverse health effects based on available human evidence.
Page 141 of 191
-------
ra
a
Typical indoor air monitoring
(American Healthy Homes Survey II)
Outdoor air monitoring (AMTIC)
Peak expiratory flow rate
Krzyzanowski et al., 1990
Rhinoconjunctivitis prevalence (children)
Annesi-Maesana et al., 2012
JD
CL
o
©
D.
o
3=
LU
£•
o
2
CL
CO
(U
a:
Asthma control (children with asthma)
Venn et al., 2003
Current asthma prevalence (children)
Annesi-Maesano et al., 2012
Current asthma prevalence (children)
Krzyzanowski et al., 1990
Eye irritation symptoms (adult)
Kulleetal., 1987
Eye irritation symptoms (adult)
Andersen, 1983
o«
~ I
O ~!
~
~I
~ Air concentration range
o Air concentration median
¦LOAEL
• BMC (5-10% change)
oPOD based on BMCL
~ POD based on NOAEL
Composite Uncertainty
Factor
o
o
10
100
1000
Formaldehyde Concentration (pg/m3
Figure 4-21. Comparison of Non-cancer Health Effect Levels Reported in People and Indoor and
Outdoor Air Concentrations
Indoor air monitoring data summarized here are the American Healthy Homes Survey II data described
in Section 2.3.3 and reflect the range of typical indoor air concentrations. Outdoor air monitoring data
summarized here are the AMTIC dataset and include a diverse range of outdoor air monitoring sources.
Black shapes indicate air concentrations at which adverse health effects were reported in epidemiology
studies or controlled human exposure studies (LOAEL or BMC), grey circles and squares indicate
concentrations at which no significant health effects were reported (NOAEL or BMCL), and grey bars
indicate the total uncertainty factors identified for each study. Effect levels (LOAEL, BMC, NOAEL
and BMCL) and composite uncertainty factors for each study are presented as reported in the IRIS
assessment (U.S. EPA 2024k).
4.2.6 Potentially Exposed or Susceptible Subpopulations
EPA considered PESS throughout the exposure and hazard assessments supporting this analysis. Table
4-8 summarizes how PESS were incorporated into the risk evaluation through consideration of increased
exposures and/or increased biological susceptibility. The table also summarizes the remaining sources of
uncertainty related to consideration of PESS. Appendix C provides additional details on PESS
considerations for the formaldehyde risk evaluation.
The available data suggest that some groups or lifestages have greater exposure to formaldehyde. For
example, people exposed to formaldehyde at work, those who frequently use consumer products
containing high concentrations of formaldehyde, people living or working near facilities that emit
Page 142 of 191
-------
formaldehyde, and people living in mobile homes and other indoor environments with high
formaldehyde concentrations are expected to have greater exposures. In this assessment, EPA evaluated
risks anticipated for a range of scenarios under TSCA COUs where exposures are expected to be
greatest. In addition to high exposures associated with COUs, some people will have greater exposure to
formaldehyde through sources that are not being assessed under TSCA. For example, those living near
major roadways, people living in areas with frequent exposure to wildfire smoke, smokers, and people
exposed to second-hand smoke, are expected to have greater exposures to formaldehyde. For these
groups, higher exposures from other sources of formaldehyde may increase susceptibility to additional
exposures from TSCA sources. As described in Section 4.3, EPA assessed risks from several aggregate
exposure scenarios; however, the wide range of possible combinations of aggregate sources are expected
to be highly variable across individuals and are a remaining source of uncertainty.
Some groups or lifestages may be more susceptible to the health effects of formaldehyde exposures. For
example, children have developing respiratory systems and narrower airways that may make them more
susceptible to the respiratory effects of formaldehyde. The chronic inhalation hazard value is derived in
part based on dose-response information in children with asthma and is supported by dose-response
information on lifestage-specific reproductive and developmental effects in humans and animals. The
chronic inhalation hazard value incorporates information on several sensitive groups; therefore, EPA
used a value of 3 for the UFh to account for human variability.
Other factors that may increase susceptibility to formaldehyde include chronic disease, co-exposures,
sex, lifestyle, sociodemographic status, and genetic factors. People with chronic respiratory diseases
(e.g., asthma) may be more susceptible to the respiratory effects of formaldehyde. Co-exposure to other
chemical or non-chemical stressors that increase risk of asthma, reduced pulmonary function,
reproductive and/or developmental toxicity, nasopharyngeal cancer or myeloid leukemia, may increase
susceptibility to the effects of formaldehyde on the same health outcomes. While these factors are not
quantitatively accounted for in the hazard characterization, EPA used values of 3 or 10 for the human
variability UFh to account for increased susceptibility when quantifying risks from exposure to
formaldehyde. The Risk Assessment Forum, in A Review of the Reference Dose and Reference
Concentration Processes (U.S. EPA. 20021 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 (2002). however, did not discuss many of
the factors presented in Appendix C.
As described in Section 4.1.2 and in the IRIS assessment (U.S. EPA. 2024k). EPA applied ADAFs to
lifetime cancer risk estimates to account for increased susceptibility to nasopharyngeal cancer following
inhalation exposure during early life.
Page 143 of 191
-------
Table 4-8. Summary of PESS Considerations Incorporated throughout the Analysis and Remaining Sources of Uncertainty
PESS
Categories
Potential Exposures Identified and
Incorporated into Exposure Assessment
Potential Sources of Biological Susceptibility Identified and
Incorporated into Hazard Assessment
Lifestage
EPA considered several scenarios in which lifestage may
influence exposure. For air exposures, the impacts of
lifestage differences were not able to be adequately
quantified and so the air concentrations are used for all
lifestages. Consumer exposure scenarios include lifestage-
specific exposure factors for adults, children, and formula-
fed infants (U.S. EPA. 2024d). Based on physical chemical
properties and a lack of studies evaluating potential for
accumulation in human milk following inhalation, dermal
or oral exposures, EPA did not quantitatively evaluate the
human milk pathway. This is a remaining source of
uncertainty. In the consumer exposure assessment, EPA
also considered potential oral exposure associated with
mouthing behaviors in infants and young children (U.S.
EPA. 2024d); however. EPA did not have sufficient
information on this exposure route to quantify risks.
EPA identified potential sources of biological susceptibility to
formaldehyde due to lifestage differences and developmental toxicity
as described in the IRIS assessment (U.S. EPA. 2024k). the hazard
value for chronic inhalation was informed in part by dose-response data
on asthma in children, male reproductive toxicity, female reproductive
effects and developmental toxicity and is expected to be protective of
these endpoints. A 3x UF was applied for human variability.
For oral, dermal, and acute inhalation hazard values, EPA did not
identify quantitative information on lifestage differences in toxicity and
this is a remaining source of uncertainty. A 10* UF was applied for
human variability.
EPA has concluded that a mutagenic mode of action is operative in
formaldehyde-induced nasopharyngeal carcinogenicity. To account for
increased cancer risks from early life inhalation exposures to
formaldehyde, EPA applied an age dependent adjustment factor
(ADAF) to cancer risk estimates to account for increased susceptibility
to nasopharyngeal cancer following exposure during early life.
Pre-existing
Disease
EPA did not identify health conditions that may influence
exposure. The potential for pre-existing disease to
influence exposure (due to altered metabolism, behaviors,
or treatments related to the condition) is a source of
uncertainty.
EPA identified the potential for pre-existing health conditions, such as
asthma, allergies, nasal damage, or other respiratory conditions to
contribute to susceptibility to formaldhyde. As described in the IRIS
assessment (U.S. EPA. 2024k). EPA considered quantitative dose-
response information in children with asthma in derivation of the
chronic inhalation hazard value. A 3x UF was applied for human
variability.
For oral, dermal, and acute inhalation hazard values, the potential
influence of pre-existing diseases on susceptibility to formaldehyde
remains a source of uncertainty. A 3x or 10* UF was applied for
human variability.
Lifestyle
Activities
EPA identified smoking as an additional other source of
exposure to formaldehyde that may increase aggregate
exposure for smokers and people exposed to second-hand
EPA qualitatively described the potential for biological susceptibility
resulting from smoking, alcohol consumption and physical activity but
Page 144 of 191
-------
PESS
Categories
Potential Exposures Identified and
Incorporated into Exposure Assessment
Potential Sources of Biological Susceptibility Identified and
Incorporated into Hazard Assessment
smoke. To some degree, formaldehyde exposure from
smoking is indirectly accounted for in some indoor air
monitoring data but it is not directly quantified.
did not identify quantitative evidence of increased susceptibility to
formaldehyde. This is a remaining source of uncertainty.
Occupational
Exposures
EPA evaluated risks for a range of occupational exposure
scenarios that increase exposure to formaldehyde,
including manufacturing, processing, and use of
formulations containing formaldehyde. EPA evaluated
risks for central tendency and high-end exposure estimates
for each of these scenarios (Section 4.2.1). Firefighters are
an occupational group expected to have increased exposure
to formaldehyde associated with combustion and burning
building materials but those exposures are beyond the
scope of this assessment.
EPA did not identify occupational factors that increase biological
susceptibility to formaldehyde. This is a remaining source of
uncertainty.
Geographic
Factors
EPA evaluated risks to communities in proximity to sites
where formaldehyde is released to ambient air (Section
4.2.4). In the environmental release assessment, EPA
mapped tribal lands in relation to air, surface water and
ground water releases of formaldehyde to identify potential
for increased exposures for tribes due to geographic
proximitv (U.S. EPA. 2024a). EPA also identified living
near major roadways or in areas with frequent exposure to
wildfire smoke as potential sources of increased exposure
to formaldehyde for some populations. These other sources
of exposure are a source of uncertainty that is not directly
incorporated into risk estimates for outdoor air exposures.
EPA did not identify geographic factors that increase biological
susceptibility to formaldehyde. This is a remaining source of
uncertainty.
Socio-
demographic
Factors
EPA did not identify specific sociodemographic factors
that influence exposure to formaldehyde. Income and other
sociodemographic factors may be correlated with some of
the exposure scenarios that result in greater exposure from
both TSCA and other sources (e.g., living near industrial
release sites, or near roadways). This is a remaining source
of uncertainty.
EPA qualitatively described the potential for biological susceptibility
due to socioeconomic factors, such as race or ethnicity and sex or
gender, but did not identify quantitative evidence of increased
susceptibility to formaldehyde. This is a remaining source of
uncertainty.
Page 145 of 191
-------
PESS
Categories
Potential Exposures Identified and
Incorporated into Exposure Assessment
Potential Sources of Biological Susceptibility Identified and
Incorporated into Hazard Assessment
Nutrition
EPA did not identify nutritional factors influencing
exposure to formaldehyde. This is a remaining source of
uncertainty.
EPA did not identify nutritional factors that affect biological
susceptibility to formaldehyde.
Genetics
EPA did not identify genetic factors influencing exposure
to formaldehyde. This is a remaining source of uncertainty.
EPA qualitatively described the potential for biological susceptibility
due to genetic variants, which was accounted for applying a 10 x UF for
human variability. The specific magnitude of the impact of genetic
variants is unknown and remains a source of uncertainty.
Unique
Activities
EPA did not identify specific exposure scenarios that are
unique to tribes or other groups that expected to increase
exposure to formaldehyde. Potential sources of increased
exposure to formaldehyde due to specific tribal lifeways or
other unique activity patterns are a source of uncertainty.
EPA did not identify unique activities that influence susceptibility to
formaldehyde. This is a remaining source of uncertainty.
Aggregate
Exposures
EPA evaluated risk from multiple sources releasing to
indoor or outdoor air and aggregate exposures across
multiple exposure pathways or exposure scenarios. While
EPA assessed risks from several aggregate exposure
scenarios, the wide range of possible combinations of
aggregate sources are expected to be highly variable across
individuals and are a remaining source of uncertainty.
EPA does not identify ways that aggregate exposures would influence
susceptibility to formaldehyde. This remains a source of uncertainty.
Other
Chemical and
Non-chemical
Stressors
EPA did not identify chemical and nonchemical stressors
influencing exposure to formaldehyde. This is a remaining
source of uncertainty.
EPA qualitatively described the potential for biological susceptibility
due to chemical or nonchemical factors such as chemical co exposures
but did not identify specific quantitative evidence regarding
susceptibility to formaldhyde based on chemical and non-chemical
stressors. This remains a source of uncertainty.
Page 146 of 191
-------
4.3 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 or sentinel exposures under the COUs were considered and the basis for
their consideration.
EPA considered how aggregate exposures to formaldehyde from multiple sources, across multiple
routes, or across pathways may increase the overall risk for some people.
The relative contributions of each source of formaldehyde to overall exposure and risk varies across
individuals, locations, and scenarios. For example, in communities living near industrial facilities with
high releases, those point sources may be one of the greatest sources of exposure to formaldehyde in
outdoor air. For people living near roadways, formaldehyde emitted from vehicles as a combustion
byproduct may be a greater source of exposure. For people living in mobile homes or other indoor
environments with high formaldehyde concentrations, indoor air in their homes may be the greatest
source of exposure. Some people may be exposed to formaldehyde from multiple sources in indoor and
outdoor air and through work or use of consumer products. For example, some people living near release
sites may also be exposed at work and through high concentrations of formaldehyde in indoor air at
home. Although there are too many possible combinations of exposures to evaluate all iterations, EPA
considered a range of scenarios in which aggregate exposures within and across exposure pathways may
increase total exposure and risk.
EPA qualitatively considered aggregate exposures and risks across inhalation, oral, and/or dermal routes
of exposure. For formaldehyde, cancer risk is only quantified for inhalation exposures and therefore
cannot be quantitatively aggregated across multiple routes. Non-cancer risks for formaldehyde are
highly route-specific and each route-specific hazard value was based on effects that occur near the portal
of entry. Because the non-cancer effects are specific to the route of exposure, EPA concluded that the
non-cancer risks are not additive across routes. Similarly, because EPA determined that risks are not
additive across routes, EPA did not aggregate exposure and risk across pathways for which exposure
routes are not the same (e.g., EPA did not aggregate inhalation exposure through outdoor air with
dermal exposure associated through use of consumer products).
EPA considered the combined exposures that may result from multiple sources releasing formaldehyde
to air in a particular indoor or outdoor environment. Monitoring data for formaldehyde is the best
available indication of aggregate exposures that occur in indoor or outdoor air under a range of
conditions. As described in Section 4.2.3 and Section 4.2.4, EPA considers the range of risk estimates
based on monitoring data to provide an estimate of the range of risks from aggregate exposures in air.
However, risk estimates based on monitoring do not provide information about the relative contribution
of different sources. EPA therefore also used the HEM model to evaluate aggregate risks based on
modeled air concentrations for multiple TSCA sources releasing formaldehyde to outdoor air (Section
4.2.4.2 and the Ambient Exposure Assessment for Formaldehyde (U.S. EPA. 2024a)). As described in
Section 2.3.1, the Agency considered aggregating air concentrations estimated for plausible
combinations of TSCA COUs expected to co-occur in specific indoor air environments including "decor
change", "new build" composite indoor air exposure scenarios, and an alternative aggregate indoor air
exposure scenario whereby an individual was assumed to be exposed to the highest modeled
concentration of formaldehyde from laminate flooring simultaneously with average residential indoor air
monitoring concentrations reported from the AHHSII. However, EPA acknowledges that such aggregate
scenarios may represent conservative, though realistic, indoor air estimates according to TSCA COUs.
In Sections 4.2.3.4, 4.2.3.5, and 4.2.3.6 EPA presented acute, intermediate, chronic non-cancer and
Page 147 of 191
-------
cancer aggregate risk estimates respectively for the TSCA COU aggregate composite exposure
scenarios.
EPA qualitatively considered the aggregate exposures individuals may experience from multiple
exposure scenarios. For example, given the ubiquity of formaldehyde, individuals exposed to
formaldehyde through work or through use of consumer products are expected to also have exposure to
formaldehyde through indoor air at home. In many potential combinations of exposures scenarios, the
exposures and risks from one scenario are much greater than from the other scenarios that may be
aggregated with it (e.g., occupational risks for a particular COU may be orders of magnitude greater
than risks from formaldehyde in outdoor air). When this is the case, aggregate risk would be very similar
to risk from the scenario with the highest risk. In cases where risks from two exposure scenarios are
similar (e.g., occupational risks for some COU may be in the same range as risks from indoor air
exposures as home based on AHHS II monitoring data), aggregate risks could be as much as double the
risk from each pathway in isolation. These types of aggregate risks were not quantified for specific
combinations of scenarios. Risks for individual exposure scenarios should be interpreted with an
appreciation for potential aggregate exposures and risks.
Page 148 of 191
-------
REFERENCES
Annesi-Maesano. I; Hulin. M; Lavaud. F; Raherison. C; Kopferschmitt. C; de Blav. F; Charpin. DA;
Denis. C. (2012). Poor air quality in classrooms related to asthma and rhinitis in primary
schoolchildren of the French 6 Cities Study. Thorax 67: 682-688.
http://dx.doi.Org/10.l 136/thoraxjnl-2011-200391
Appelman. LM; Woutersen. RA; Zwart A: Falke. HE: Feron. VJ. (1988). One-year inhalation toxicity
study of formaldehyde in male rats with a damaged or undamaged nasal mucosa. J Appl Toxicol
8: 85-90. http://dx.doi.org/10.1002/iat.25500802Q4
Asian. Ft; Songur. A: Tunc. AT: Ozen. OA: Bas. O: Yagmurca. M; Turgut M; Sarsilmaz. M: Kaplan. S.
(2006). Effects of formaldehyde exposure on granule cell number and volume of dentate gyrus: a
histopathological and stereological study. Brain Res 1122: 191-200.
http://dx.doi.Org/10.1016/i.brainres.2006.09.005
ATSDR. (2007). An update and revision of ATSDR's February 2007 health consultation: Formaldehyde
sampling of FEMA temporary-housing trailers (Baton Rouge, Louisiana, September-October,
2006). Atlanta, GA: U.S. Department of Health and Human Services.
https://www.atsdr.cdc.gov/substances/formaldehyde/pdfs/revised formaldehyde report 1007.pd
f
Bateson. TF; Schwartz. J. (2008). Children's response to air pollutants [Review], J Toxicol Environ
Health A 71: 238-243. http://dx.doi.org/10.1080/152873907Q1598234
Beane Freeman. LE; Blair. A; Lubin. JH; Stewart. PA; Haves. RB; Hoover. RN; Hauptmann. M. (2013).
Mortality from solid tumors among workers in formaldehyde industries: an update of the NCI
cohort. Am J Ind Med 56: 1015-1026. http://dx.doi.org/10.1002/aiim.22214
Bover. IJ; Heldreth. B; Bergfeld. WF; Belsito. DV; Hill. RA; Klaassen. CD; Liebler. DC; Marks. JG;
Shank. RC; Slaga. TJ; Snyder. PW; Andersen. FA. (2013). Amended safety assessment of
formaldehyde and methylene glycol as used in cosmetics. Int J Toxicol 32: 5S-32S.
http://dx.doi.org/10.1177/1091581813511831
California Air Resources Board. (2004). Report to the California Legislature: Environmental health
conditions in California's portable classrooms. Sacramento, CA: CalEPA.
https://ww2.arb.ca.gov/sites/default/files/classic/research/apr/reports/13006.pdf
CDC. (2020). CDC Health Topics A-Z: Healthy food environments: Improving access to healthier food.
Available online at https://www.cdc.gov/nutrition/healthy-food-environments/improving-access-
to-healthier-food.html
CDC. (2021). CDC Health Topics A-Z: Micronutrients. Available online at
http s ://www. cdc. gov/nutriti on/mi cronutri ent-
malnutrition/index.html?CDC AA refVal=https%3A%2F%2Fwww.cdc.gov%2Fimmpact%2Fin
dex.html
CDC. (2022). CDC Health Topics A-Z: Physical activity. Available online at
http s ://www. cdc. gov/phy si cal activity/index. html
CDC. (2023a). CDC Health Topics A-Z: Cancer. Available online at https://www.cdc.gov/cancer/
CDC. (2023b). CDC Health Topics A-Z: Infertility FAQs. Available online at
https://www.cdc.gov/reproductivehealth/infertilitv/index.htm
CDC. (2023c). CDC Health Topics A-Z: Nutrition. Available online at
http s ://www. cdc. gov/nutriti on/index. html
CDC. (2023d). CDC Health Topics A-Z: Stress at work. Available online at
https://www.cdc.gov/niosh/topics/stress/
Ceballos. DM; Burr. GA. (2012). Evaluating a persistent nuisance odor in an office building. J Occup
Environ Hyg 9: D1-D6. http://dx.doi.org/10.1080/15459624.2012.635131
Civo Institute TNO. (1987). Chronic (2-year) oral toxicity and carcinogenicity study with formaldehyde
in rats, including interim kills after 12 and 18 months (final report) [TSCA Submission], In
Page 149 of 191
-------
Chronic oral toxicity and carcinogenicity study with formaldehyde in rats, pharmacokinetics and
metabolism of ingested and inhaled formaldehyde with cover letter dated 041988.
(v87.422/241112. OTS0000612-0. FYI-OTS-0588-0612. TSCATS/303710). Hoechst Celanese.
Deltour. L; Foglio. MH; Duester. G. (1999). Metabolic deficiencies in alcohol dehydrogenase Adhl,
Adh3, and Adh4 null mutant mice. Overlapping roles of Adhl and Adh4 in ethanol clearance
and metabolism of retinol to retinoic acid. J Biol Chem 274: 16796-16801.
http://dx.doi.org/10.1074/ibc.274.24.16796
Dingier. FA: Wang. M; Mu, A: Millington. CL; Oberbeck. N: Watcham. S: Pontel. LB: Kamimae-
Lanning. AN: Langevin. F; Nadler. C: Cordell. RL: Monks. PS: Yu. R: Wilson. NK: Hira. A:
Yoshida. K: Mori. M: Okamoto. Y; Okuno. Y; Muramatsu. H: Shiraishi. Y; Kobavashi. M;
Moriguchi, T; Osumi, T; Kato, M; Miyano, S; Ito, E; Kojima, S; Yabe, H; Yabe, M; Matsuo, K;
Ogawa, S; Gottgens, B; Hodskinson, MRG; Takata, M; Patel, KJ. (2020). Two aldehyde
clearance systems are essential to prevent lethal formaldehyde accumulation in mice and
humans. Mol Cell 80: 996-1012.el019. http://dx.doi.Org/10.1016/i.molcel.2020.10.012
Dodson. RE: Houseman. EA: Levy. JI; Spengler. JD: Shine. JP: Bennett. DH. (2007). Measured and
modeled personal exposures to and risks from volatile organic compounds. Environ Sci Technol
41: 8498-8505. http://dx.doi.org/10.1021/es071127s
Falk. JE: Juto. JE: Stridh. G: Bylin. G. (1994). Dose-response study of formaldehyde on nasal mucosa
swelling. A study on residents with nasal distress at home. Am J Rhinol Allergy 8: 143-146.
http://dx.doi.org/10.2500/105Q65894781874412
Fishbein. L. (1992). Exposure from occupational versus other sources [Review], Scand J Work Environ
Health 18: 5-16.
Flyvholm. MA: Hall. BM: Agner. T; Tiedemann. E; Greenhill. P; Vanderveken. W: Freeberg. FE;
Menne. T. (1997). Threshold for occluded formaldehyde patch test in formaldehyde-sensitive
patients. Relationship to repeated open application test with a product containing formaldehyde
releaser. Contact Derm 36: 26-33. http://dx.doi.org/10.1111/i. 1600-0536.1997.tb00918.x
Gilbert. NL: Gauvin. D: Guav. M; Heroux. ME: Dupuis. G: Legris. M; Chan. CC: Dietz. RN: Levesque.
B. (2006). Housing characteristics and indoor concentrations of nitrogen dioxide and
formaldehyde in Quebec City, Canada. Environ Res 102: 1-8.
http://dx.doi.Org/10.1016/i.envres.2006.02.007
Gilbert. NL: Guav. M; David Miller. J: Judek. S: Chan. CC: Dales. RE. (2005). Levels and determinants
of formaldehyde, acetaldehyde, and acrolein in residential indoor air in Prince Edward Island,
Canada. Environ Res 99: 11-17. http://dx.doi.Org/10.1016/i.envres.2004.09.009
Green. DJ: Bascom. R: Healev. EM: Hebel. JR: Sauder. LR: Kulle. TJ. (1989). Acute pulmonary
response in healthy, nonsmoking adults to inhalation of formaldehyde and carbon. J Toxicol
Environ Health 28: 261-275. http://dx.doi.org/10.1080/15287398909531347
Green. DJ: Sauder. LR: Kulle. TJ: Bascom. R. (1987). Acute response to 3.0 ppm formaldehyde in
exercising healthy nonsmokers and asthmatics. Am Rev Respir Dis 135: 1261-1266.
http://dx.doi.Org/10.l 164/arrd. 1987.135.6.1261
GWPC and IOGCC. (2022). FracFocus: Chemical disclosure registry [Database], Retrieved from
http s ://fracfocus. org/data-downl oad
Harkev. M; Hollowav. T; Kim. EJ: Baker. KR: Henderson. B. (2021). Satellite Formaldehyde to Support
Model Evaluation. J Geophys Res Atmos 126. http://dx.doi.org/10.1029/2020JDQ32881
Haves. RB: Blair. A: Stewart. PA: Herri ck. RF; Mahar. H. (1990). Mortality of U.S. embalmers and
funeral directors. Am J Ind Med 18: 641-652. http://dx.doi.org/10.1002/aiim.47001806Q3
Hedberg. JJ: Grafstrom. RC: Vondracek. M: Sarang. Z: Warngard. L; Hoog. JO. (2001). Micro-array
chip analysis of carbonyl-metabolising enzymes in normal, immortalised and malignant human
oral keratinocytes. Cell Mol Life Sci 58: 1719-1726. http://dx.doi.org/10.1007/PL0000081Q
Page 150 of 191
-------
Herrero. M; Gonzalez. N; Rovira. J; Marques. M; Domingo. JL; Nadal. M. (2022). Early-life exposure
to formaldehyde through clothing. Toxics 10. http://dx.doi.org/10.3390/toxics 10070361
Hodgson. AT; Rudd. AF; Beal. D; Chandra. S. (2000). Volatile organic compound concentrations and
emission rates in new manufactured and site-built houses. Indoor Air 10: 178-192.
http://dx.doi.Org/10.1034/i.1600-0668.2000.010003178.x
Hodgson. AT: Shendell. DG: Fisk. WJ: Apte. MG. (2004). Comparison of predicted and derived
measures of volatile organic compounds inside four new relocatable classrooms. Indoor Air 14:
135-144. http://dx.doi.org/10.1111/i. 1600-0668.2004.00315.x
Hohnloser. W: Osswald. B: Lingens. F. (1980). ENZYMOLOGICAL ASPECTS OF CAFFEINE
DEMETHYLATION AND FORMALDEHYDE OXIDATION BY PSEUDOMONAS-
PUTIDA-C1. Hoppe Seylers Z Physiol Chem 361: 1763-1766.
ICRP. (1994). Human respiratory tract model for radiological protection. Ann ICRP 24.
John. EM: Savitz. DA: Shy. CM. (1994). Spontaneous abortions among cosmetologists. Epidemiology
5: 147-155. http://dx.doi.org/10.1097/00001648-199403000-000Q4
Jung. C: Mahmoud. NSA. (2022). Extracting the critical points of formaldehyde (HCHO) emission
model in hot desert climate. Air, Soil and Water Research 15: 1-15.
http://dx.doi.org/10.1177/11786221221105082
Kerns. WD: Pavkov. KL; Donofrio. DJ; Gralla. EJ; Swenberg. JA. (1983). Carcinogenicity of
formaldehyde in rats and mice after long-term inhalation exposure. Cancer Res 43: 4382-4392.
Kriebel. D; Sama. SR; Cocanour. B. (1993). Reversible pulmonary responses to formaldehyde. A study
of clinical anatomy students. Am Rev Respir Dis 148: 1509-1515.
http://dx.doi.Org/10.1164/airccm/148.6 Pt 1.1509
Krzyzanowski. M; Ouackenboss. JJ; Lebowitz. MP. (1990). Chronic respiratory effects of indoor
formaldehyde exposure. Environ Res 52: 117-125. http://dx.doi.org/10.1016/S0Q13-
9351(05)80247-6
Kulle. TJ: Sauder. LR; Hebel. JR; Green. DJ: Chatham. MP. (1987). Formaldehyde dose-response in
healthy nonsmokers. J Air Pollut Control Assoc 37: 919-924.
http://dx.doi.org/10.1080/0894063Q.1987.10466285
Lang. I: Bruckner. T; Triebig. G. (2008). Formaldehyde and chemosensory irritation in humans: A
controlled human exposure study. Regul Toxicol Pharmacol 50: 23-36.
http://dx.doi.Org/10.1016/i.yrtph.2007.08.012
LBNL. (2008). Aldehyde and other volatile organic chemical emissions in four FEMA temporary
housing units - final report. (LBNL-254E). Berkley, CA.
https://www.cdc.gov/air/trailerstudv/pdfs/lbnl-254e.pdf
Liu. KS: Huang. FY: Havward. SB: Wesolowski. J: Sexton. K. (1991). Irritant effects of formaldehyde
exposure in mobile homes. Environ Health Perspect 94: 91-94.
http://dx.doi.org/10.2307/3431298
Liu. W; Zhang. J; Zhang. L; Turpin. BJ; Welsel. CP; Morandi. MT; Stock. TH; Colome. S; Korn. LR.
(2006). Estimating contributions of indoor and outdoor sources to indoor carbonyl concentrations
in three urban areas of the United States. Atmos Environ 40: 2202-2214.
http://dx.doi.Org/10.1016/i.atmosenv.2005.12.005
Lukcso. D; Guidotti. TL; Franklin. DE; Burt. A. (2014). Indoor Environmental and Air Quality
Characteristics, Building-Related Health Symptoms, and Worker Productivity in a Federal
Government Building Complex. Arch Environ Occup Health 71:0.
http://dx.doi.org/10.1080/19338244.2014.965246
Maddalena. R; Russell. M; Sullivan. DP; Apte. MG. (2009). Formaldehyde and other volatile organic
chemical emissions in four FEMA temporary housing units. Environ Sci Technol 43: 5626-5632.
http://dx.doi.org/10.1021/es9011178
Page 151 of 191
-------
Maronpot RR: Miller. RA; Clarke. WJ; Westerberg. RB; Decker. JR: Moss. OR. (1986). Toxicity of
formaldehyde vapor in B6C3F1 mice exposed for 13 weeks. Toxicology 41: 253-266.
http://dx.doi. org/10.1016/03 00-483X(86)90180-0
Matsunaga. I: Miyake. Y; Yoshida. T; Miyamoto. S: Ohya. Y; Sasaki. S: Tanaka. K; Oda. H; Ishiko. O;
Hirota. Y; Group. OMaCHS. (2008). Ambient formaldehyde levels and allergic disorders among
Japanese pregnant women: Baseline data from the Osaka maternal and child health study. Ann
Epidemiol 18: 78-84. http://dx.doi.Org/10.1016/i.annepidem.2007.07.095
Mueller. JU; Bruckner. T; Triebig. G. (2013). Exposure study to examine chemosensory effects of
formaldehyde on hyposensitive and hypersensitive males. Int Arch Occup Environ Health 86:
107-117. http://dx.doi.org/10.1007/s00420-012-Q745-9
Murphy. MW: Lando. JF; Kieszak. SM; Sutter. ME: Noonan. GP; Brunkard. JM; McGeehin. MA.
(2013). Formaldehyde levels in FEMA-supplied travel trailers, park models, and mobile homes
in Louisiana and Mississippi. Indoor Air 23: 134-141. http://dx.doi.Org/10.l 11 l/j.1600-
0668.2012.00800.x
Nakamura. J: Hollev. DW: Kawamoto. T; Bultman. SJ. (2020). The failure of two major formaldehyde
catabolism enzymes (ADH5 and ALDH2) leads to partial synthetic lethality in C57BL/6 mice.
Genes Environ 42: 21. http://dx.doi.org/10.1186/s41021 -020-00160-4
NASEM. (2023). Review of EPA's 2022 Draft Formaldehyde Assessment. Washington, DC.
https://nap.nationalacademies.org/catalog/27153/review-of-epas-2022-draft-formaldehyde-
assessment
ODPHP. (2023a). Healthy People 2030 - Social determinants of health literature summaries:
Neighborhood and built environment. Available online at
https://health.gov/healthvpeople/prioritv-areas/social-determinants-health/literature-
summ ari es#nei ghb orhood
ODPHP. (2023b). Healthy People 2030 - Social determinants of health literature summaries: Poverty.
Available online at https://health.gov/healthvpeople/prioritv-areas/social-determinants-
health/literature-summaries/povertv
ODPHP. (2023c). Healthy People 2030 - Social determinants of health literature summaries: Social and
community context. Available online at https://health.gov/healthypeople/prioritv-areas/social-
determinants-health/literature-summaries#social
Offermann. FJ; Robertson. J: Springer. D; Brennan. S: Woo. T. (2008). Window usage, ventilation, and
formaldehyde concentrations in new California homes: Summer field sessions. Paper presented at
ASHRAE IAQ 2007, Baltimore, MD.
Page. E; Couch. J. (2014). Evaluation of employee health concern and suspected contamination at an
office complex. (Report No. 2010-0061-3206). Washington, DC: National Institute for
Occupational Safety and Health.
OuanTech. (2021). American Healthy Homes Survey, final report: Data documentation. (AHHSII).
Washington, DC: U.S. Department of Housing and Urban Development.
https://www.hud.gov/program offices/healthy homes
Riess. U: Tegtbur. U; Fauck. C: Fuhrmann. F; Markewitz. D; Salthammer. T. (2010). Experimental
setup and analytical methods for the non-invasive determination of volatile organic compounds,
formaldehyde and NOx in exhaled human breath. Anal Chim Acta 669: 53-62.
http://dx.doi.Org/10.1016/i.aca.2010.04.049
Santiago. LY; Hann. MC: Ben-Jebria. A: Ultman. JS. (2001). Ozone absorption in the human nose
during unidirectional airflow. J Appl Physiol (1985) 91: 725-732.
http://dx.doi.Org/10.1152/iappl.2001.91.2.725
Sarsilmaz. M; Kaplan. S: Songur. A: Colakoglu. S: Asian. H; Tunc. AT: Ozen. OA: Turgut. M; Bas. O.
(2007). Effects of postnatal formaldehyde exposure on pyramidal cell number, volume of cell
Page 152 of 191
-------
layer in hippocampus and hemisphere in the rat: A stereological study. Brain Res 11: 157-167.
http://dx.doi.Org/10.1016/i.brainres.2007.01.139
Sax. SN: Bennett. DH; Chillrud. SN: Kinney. PL: Spermler. JD. (2004). Differences in source emission
rates of volatile organic compounds in inner-city residences of New York City and Los Angeles.
J Expo Anal Environ Epidemiol 14: S95-S109. http://dx.doi.org/10.1038/si.iea.7500364
Scheffe. RD; Strum. M; Phillips. SB: Thurman. J: Eyth. A: Fudge. S: Morris. M; Palma. T; Cook. R.
(2016). Hybrid Modeling Approach to Estimate Exposures of Hazardous Air Pollutants (HAPs)
for the National Air Toxics Assessment (NATA). Environ Sci Technol 50: 12356-12364.
http://dx.doi.org/10.1021/acs.est.6b04752
Singh. I: Raizada. RM; Chaturvedi. VN; Jain. SK. (1998). Nasal mucous ciliary clearance and olfaction
in atrophic rhinitis. 50: 57-59. http://dx.doi.org/10.1007/BF02996772
Summers. RM: Louie. T; Yu. C: Gakhar. L; Louie. KC: Subramanian. M. (2012). Novel, Highly
Specific N-Demethylases Enable Bacteria To Live on Caffeine and Related Purine Alkaloids. J
Bacteriol 194: 2041-2049. http://dx.doi.Org/10.l 128/JB.06637-11
Tan. T: Zhang. Y: Luo. W: Lv. J: Han. C: Hamlin. JNR; Luo. H: Li. H: Wan. Y: Yang. X: Song. W:
Tong. Z. (2018). Formaldehyde induces diabetes-associated cognitive impairments. FASEB J 32:
3669-3679. http://dx.doi.org/10.1096/fi.201701239R
Taskinen. HK; Kyyronen. P; Sallmen. M; Virtanen. SV: Liukkonen. TA; Huida. O: Lindbohm. ML:
Anttila. A. (1999). Reduced fertility among female wood workers exposed to formaldehyde. Am
J Ind Med 36: 206-212. http://dx.doi.org/10.1002/(sici) 1097-0274(199907)36: l<206::aid-
aiim29>3.0.co;2-d
Thompson. CM: Sonawane. B; Grafstrom. RC. (2009). The ontogeny, distribution, and regulation of
alcohol dehydrogenase 3: Implications for pulmonary physiology [Review], Drug Metab Dispos
37: 1565-1571. http://dx.doi.org/10.1124/dmd.109.027904
Til. HP: Woutersen. RA; Feron. VJ; Clary. JJ. (1988). Evaluation of the oral toxicity of acetaldehyde
and formaldehyde in a 4-week drinking-water study in rats. Food Chem Toxicol 26: 447-452.
http://dx.doi. org/10.1016/0278-6915(88)90056-7
Til. HP: Woutersen. RA: Feron. VJ: Hollanders. VHM; Falker. HE: Clary. JJ. (1989). Two-year
drinking-water study of formaldehyde in rats. Food Chem Toxicol 27: 77-87.
http://dx.doi. org/10.1016/0278-6915(89)90001-X
U.S. BLS. (2014). Employee Tenure News Release. Available online at
http://www.bls.gov/news.release/archives/tenure 09182014.htm
U.S. Census Bureau. (2019a). Survey of Income and Program Participation data. Available online at
https://www.census.gov/programs-survevs/sipp/data/datasets/2008-panel/wave-l.html (accessed
May 16, 2019).
U.S. Census Bureau. (2019b). Survey of Income and Program Participation: SIPP introduction and
history. Washington, DC. https://www.census.gov/programs-survevs/sipp/about/sipp-
introducti on-hi story. html
U.S. EPA. (1990). IRIS Assessment of: Formaldehyde (CASRN 50-00-0). Washington, DC: U.S.
Environmental Protection Agency, Intergrated Risk Information System.
https://cfpub.epa.gov/ncea/iris2/chemicalLanding.cfm7substance nmbr=419
U.S. EPA. (1992). A laboratory method to determine the retention of liquids on the surface of hands
[EPA Report], (EPA/747/R-92/003). Washington, DC.
U.S. EPA. (2002). A review of the reference dose and reference concentration processes [EPA Report],
(EPA630P02002F). Washington, DC. https://www.epa.gov/sites/production/files/2014-
12/documents/rfd-final.pdf
U.S. EPA. (2005a). Guidance on selecting age groups for monitoring and assessing childhood exposures
to environmental contaminant (pp. ii-36). (EPA/630/P-03/003F). Washington, DC: Risk
Page 153 of 191
-------
Assessment Forum, https://www.epa.gov/risk/guidance-selecting-age-groups-monitoring-and-
assessing-childhood-exposures-environmental
U.S. EPA. (2005b). Supplemental guidance for assessing susceptibility from early-life exposure to
carcinogens [EPA Report], (EPA/630/R-03/003F). Washington, DC: U.S. Environmental
Protection Agency, Risk Assessment Forum, https://www.epa.gov/risk/supplemental-guidance-
assessing-susceptibilitv-early-life-exposure-carcinogens
U.S. EPA. (2011). Exposure factors handbook: 2011 edition [EPA Report], (EPA/600/R-090/052F).
Washington, DC: U.S. Environmental Protection Agency, Office of Research and Development,
National Center for Environmental Assessment.
https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockev=P 100F2QS.txt
U.S. EPA. (2013). Updating CEB's method for screening-level estimates of dermal exposure. Chemical
Engineering Branch.
U.S. EPA. (2016a). Chemical data reporting: 2016 data. Washington, DC: U.S. Environmental
Protection Agency, Chemical Data Reporting. Retrieved from https://www.epa.gov/chemical-
data-reporting/access-cdr-data#2016
U.S. EPA. (2016b). Formaldehyde from composite wood products: Exposure assessment for TSCA Title
VI Final Rule. Washington, DC: Risk Assessment Division, Office of Pollution Prevention and
Toxics, Office of Chemical Safety and Pollution Prevention.
U.S. EPA. (2019). Consumer Exposure Model (CEM) 2.1 User Guide. (EPA Contract # EP-W-12-010).
Washington, DC.
U.S. EPA. (2020a). 2020 CDRData [Database], Washington, DC. Retrieved from
https://www.epa.gOv/chemical-data-reporting/access-cdr-data#2020
U.S. EPA. (2020b). 2020 CDR: Commercial and consumer use. Washington, DC.
U.S. EPA. (2020c). Final scope of the risk evaluation for formaldehyde; CASRN 50-00-0. (EPA 740-R-
20-014). Washington, DC: Office of Chemical Safety and Pollution Prevention.
https://www.epa.gov/sites/default/files/2020-09/documents/casrn 50-00-0-
formaldehyde finalscope cor.pdf
U.S. EPA. (2020d). Use Report for Formaldehyde (CASRN 50-00-0). Washington, DC: Office of
Chemical Safety and Pollution Prevention. https://www.regulations.gov/document/EPA-HQ-
QPPT-2018-043 8-0028
U.S. EPA. (2021a). About the Exposure Factors Handbook. Available online at
https://www.epa.gov/expobox/about-exposure-factors-handbook
U.S. EPA. (2021b). Best practices for review and validation of ambient air monitoring data. (EPA-
454/B-21-007).
U.S. EPA. (2021c). 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.regulations. gov/document/EPA-HQ-QPPT-2021 -0414-
0005
U.S. EPA. (2022a). Ambient Monitoring Technology Information Center (AMTIC) - Ambient
Monitoring Archive for HAPs [Database], Washington, DC. Retrieved from
https://www.epa.gov/amtic/amtic-ambient-monitoring-archive-haps
U.S. EPA. (2022b). Emission scenario document on chemicals used in hydraulic fracturing (draft). Paris,
France: Organization for Economic Co-operation and Development.
U.S. EPA. (2022c). Toxicological Review of Formaldehyde—Inhalation (Review draft). Washington,
DC: Integrated Risk Information System.
https://cfpub.epa.gov/ncea/iris drafts/recordisplav.cfm?deid=248150
Page 154 of 191
-------
U.S. EPA. (2023). Summarized data of the Building Assessment Survey and Evaluation (BASE) Study.
Available online at https://www.epa.gov/indoor-air-qualitv-iaq/summarized-data-building-
assessment-survev-and-evaluation-studv (accessed October 25, 2023).
U.S. EPA. (2024a). Ambient Air Exposure Assessment for the Formaldehyde Risk Evaluation.
Washington, DC: U.S. Environmental Protection Agency, Office of Pollution Prevention and
Toxics.
U.S. EPA. (2024b). Chemistry, Fate, and Transport Assessment for Formaldehyde. Washington, DC:
U.S. Environmental Protection Agency, Office of Pollution Prevention and Toxics.
U.S. EPA. (2024c). Conditions of Use for the Formaldehyde Risk Evaluation. Washington, DC: U.S.
Environmental Protection Agency, Office of Pollution Prevention and Toxics.
U.S. EPA. (2024d). Consumer Exposure Assessment for Formaldehyde. Washington, DC: U.S.
Environmental Protection Agency, Office of Pollution Prevention and Toxics.
U.S. EPA. (2024e). Environmental Exposure Assessment for Formaldehyde. Washington, DC: U.S.
Environmental Protection Agency, Office of Pollution Prevention and Toxics.
U.S. EPA. (2024f). Environmental Hazard Assessment of Formaldehyde. Washington, DC: U.S.
Environmental Protection Agency, Office of Pollution Prevention and Toxics.
U.S. EPA. (2024g). Environmental Release Assessment for Formaldehyde. Washington, DC: U.S.
Environmental Protection Agency, Office of Pollution Prevention and Toxics.
U.S. EPA. (2024h). Environmental Risk Assessment Characterization of Formaldehyde. Washington,
DC: U.S. Environmental Protection Agency, Office of Pollution Prevention and Toxics.
U.S. EPA. (2024i). Human Health Hazard Assessment for Formaldehyde. Washington, DC: U.S.
Environmental Protection Agency, Office of Pollution Prevention and Toxics.
U.S. EPA. (2024i). Indoor Air Exposure Assessment for Formaldehyde. Washington, DC: U.S.
Environmental Protection Agency, Office of Pollution Prevention and Toxics.
U.S. EPA. (2024k). IRIS toxicological review of formaldehyde (inhalation). (EPA/63 5/R-24/162aF).
Washington, DC: Center for Public Health and Environmental Assessment, Office of Research
and Development, https://iris.epa.gov/static/pdfs/0419tr.pdf
U.S. EPA. (20241). Occupational Exposure Assessment for Formaldehyde. Washington, DC: U.S.
Environmental Protection Agency, Office of Pollution Prevention and Toxics.
U.S. EPA. (2024m). Risk Evaluation for Formaldehyde - Systematic Review Protocol. Washington,
DC: Office of Pollution Prevention and Toxics, Office of Chemical Safety and Pollution
Prevention.
U.S. EPA. (2024n). Risk Evaluation for Formaldehyde - 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, Office of
Chemical Safety and Pollution Prevention.
U.S. EPA. (2024o). Risk Evaluation for Formaldehyde - Systematic Review Supplemental File: Data
Extraction Information for General Population, Consumer, and Environmental Exposure.
Washington, DC: Office of Pollution Prevention and Toxics, Office of Chemical Safety and
Pollution Prevention.
U.S. EPA. (2024p). Risk Evaluation for Formaldehyde - Systematic Review Supplemental File: Data
Quality Evaluation and Data Extraction Information for Environmental Fate and Transport.
Washington, DC: Office of Pollution Prevention and Toxics, Office of Chemical Safety and
Pollution Prevention.
U.S. EPA. (2024q). Risk Evaluation for Formaldehyde - 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, Office of
Chemical Safety and Pollution Prevention. https://www.regulations.gov/docket/EPA-HQ-OPPT-
2018-0438
Page 155 of 191
-------
U.S. EPA. (2024r). Risk Evaluation for Formaldehyde - Systematic Review Supplemental File: Data
Quality Evaluation and Data Extraction Information for Physical and Chemical Properties.
Washington, DC: Office of Pollution Prevention and Toxics, Office of Chemical Safety and
Pollution Prevention.
U.S. EPA. (2024s). Risk Evaluation for Formaldehyde - Systematic Review Supplemental File: Data
Quality Evaluation Information for General Population, Consumer, and Environmental
Exposure. Washington, DC: Office of Pollution Prevention and Toxics, Office of Chemical
Safety and Pollution Prevention.
U.S. EPA. (2024t). Risk Evaluation for Formaldehyde - Systematic Review Supplemental File: Data
Quality Evaluation Information for Human Health Hazard Animal Toxicology. Washington, DC:
Office of Pollution Prevention and Toxics, Office of Chemical Safety and Pollution Prevention.
U.S. EPA. (2024u). Risk Evaluation for Formaldehyde - Systematic Review Supplemental File: Data
Quality Evaluation Information for Human Health Hazard Epidemiology. Washington, DC:
Office of Pollution Prevention and Toxics, Office of Chemical Safety and Pollution Prevention.
U.S. EPA. (2024v). Risk Evaluation for Formaldehyde: Systematic review supplemental file: Data
quality evaluation information for environmental hazard. Washington, DC: Office of Pollution
Prevention and Toxics, Office of Chemical Safety and Pollution Prevention.
U.S. EPA. (2024w). Science Advisory Committee on Chemicals meeting minutes and final report No.
2024-01 (Docket ID: EPA-HQ-OPPT-2023-0613) - A set of scientific issues being considered by
the Environmental Protection Agency regarding: Peer review of the 2024 Draft Risk Evaluation
for Formaldehyde, May 20-23, 2024. (No. 2024-01). Washington, DC.
https://www.regulations.gov/document/EPA-HQ-OPPT-2023-0613-0298
Venn. AJ; Cooper. M; Antoniak. M; Laughlin. C: Britton. J; Lewis. SA. (2003). Effects of volatile
organic compounds, damp, and other environmental exposures in the home on wheezing illness
in children. Thorax 58: 955-960. http://dx.doi.Org/10.l 136/thorax.58.11.955
Wang. H; Li. H. eC: Lv. M; Zhou. D; Bai. L; Du. L; Xue. X. ia: Lin. P. u: Oiu. S. (2015). Associations
between occupation exposure to Formaldehyde and semen quality, a primary study. Sci Rep 5:
15874. http://dx.doi.org/10.1038/srepl5874
Wang. P; Hollowav. T; Bindl. M; Harkev. M; De Smedt. I. (2022). Ambient Formaldehyde over the
United States from Ground-Based (AQS) and Satellite (OMI) Observations. Remote Sensing 14:
2191. http://dx.doi.org/10.3390/rs 14092191
Westat. (1987). Household solvent products: A national usage survey [EPA Report], (EPA-OTS 560/5-
87-005). Washington, DC: Office of Toxic Substances, Office of Pesticides and Toxic
Substances. https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockev=P100754Q.txt
Woutersen. RA; Appelman. LM; Wilmer. JWG. M; Falke. HE: Feron. VJ. (1987). Subchronic (13-
week) inhalation toxicity study of formaldehyde in rats. J Appl Toxicol 7: 43-49.
http://dx.doi.org/10.1002/iat.25500701Q8
Woutersen. RA: van Garderen-Hoetmer. A: Bruiinties. JP; Zwart. A: Feron. VJ. (1989). Nasal tumours
in rats after severe injury to the nasal mucosa and prolonged exposure to 10 ppm formaldehyde. J
Appl Toxicol 9: 39-46. http://dx.doi.org/10.1002/iat.25500901Q8
Wu. H; Romieu. I: Seinra-Monge. J: del Rio-Navarro. BE: Anderson. DM: Jenchura. CA; Li. H;
Ramirez-Aguilar. M; Lara-Sanchez. I; London. SJ. (2007). Genetic variation in S-
nitrosoglutathione reductase (GSNOR) and childhood asthma. J Allergy Clin Immunol 120: 322-
328. http://dx.doi.Org/10.1016/i.iaci.2007.04.022
Zhu. L; Jacob. DJ: Keutsch. FN: Micklev. LJ; Scheffe. R; Strum. M; Gonzalez Abad. G: Chance. K;
Yang. K; Rappengltick. B; Millet. DB; Baasandori. M; Jaegle. L; Shah. V. (2017). Formaldehyde
(HCHO) as a hazardous air pollutant: Mapping surface air concentrations from satellite and
inferring cancer risks in the United States. Environ Sci Technol 51: 5650-5657.
http://dx.doi.org/10.1021/acs.est.7b01356
Page 156 of 191
-------
Zwart. A; Woutersen. RA; Wilmer. JWG. M; Spit. BJ; Feron. VJ. (1988). Cytotoxic and adaptive effects
in rat nasal epithelium after 3-day and 13-week exposure to low concentrations of formaldehyde
vapour. Toxicology 51: 87-99. http://dx.doi.org/10.1016/0300-483X(88)90083-2
Page 157 of 191
-------
APPENDICES
Appendix A ABBREVIATIONS AND ACRONYMS
ACGM
American Conference of Governmental Industrial Hygienists
ADAF
Age-dependent adjustment factor
ADC
Average daily concentrations
BMD
Benchmark dose
BMR
Benchmark response
CASRN
Chemical Abstracts Service Registry Number
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
CNS
Central nervous system
DIY
Do it yourself
DMR
Discharge Monitoring Report
EPA
Environmental Protection Agency
ESD
Emission Scenario Document
FSHA
Federal Hazardous Substance Act
GS
Generic Scenario
HAP
Hazardous Air Pollutant
HEC
Human Equivalent Concentration
HED
Human Equivalent Dose
HEM
Human Exposure Module
HERO
Health and Environmental Research Online (Database)
HUD
(U.S.) Department of Housing and Urban Development
IIOAC
Integrated Indoor-Outdoor Air Calculator (Model)
IRIS
Integrated Risk Information System
Koc
Soil organic carbon: water partitioning coefficient
Kow
Octanol: water partition coefficient
LADC
Lifetime average daily concentrations
LC50
Lethal concentration at which 50% of test organisms die
LD50
Lethal dose at which 50% of test organisms die
LOD
Limit of detection
Log Koc
Logarithmic organic carbon: water partition coefficient
Log Kow
Logarithmic octanol: water partition coefficient
MOA
Mode of action
NAICS
North American Industry Classification System
NASEM
National Academies of Sciences, Engineering, and Medicine
ND
Non-detect
NEI
National Emissions Inventory
NESHAP
National Emission Standards for Hazardous Air Pollutants
NIOSH
National Institute for Occupational Safety and Health
NPDES
National Pollutant Discharge Elimination System
OCSPP
Office of Chemical Safety and Pollution Prevention
OES
Occupational exposure scenario
ONU
Occupational non-user
Page 158 of 191
-------
OPPT
Office of Pollution Prevention and Toxics
OSHA
Occupational Safety and Health Administration
PEL
Permissible exposure limit
PESS
Potentially exposed or susceptible subpopulations
POD
Point of departure
POTW
Publicly owned treatment works
PPE
Personal protective equipment
REL
Recommended Exposure Limit
SDS
Safety data sheet
STEL
Short-Term Exposure Limit
TLV
Threshold Limit Value
TRI
Toxics Release Inventory
TSCA
Toxic Substances Control Act
TTO
Total toxic organics
TWA
Time-weighted average
U.S.
United States
WWT
Wastewater treatment
Page 159 of 191
-------
Appendix B LIST OF DOCUMENTS AND SUPPLEMENTAL FILES
List of Documents and Corresponding Supplemental Files
1. Conditions of Use for the Formaldehyde Risk Evaluation (U.S. EPA. 2024c).
2. Environmental Risk Assessment for Formaldehyde (U.S. EPA. 2024h)
3. Chemistry, Fate, and Transport Assessment for Formaldehyde (U.S. EPA. 2024b).
4. Environmental Release Assessment for Formaldehyde (U.S. EPA. 2024g).
4.1. Supplemental Air Release Summary and Statistics for NEI and TRI for Formaldehyde.xlsx
4.2. Supplemental Land Release Summary for TRI for Formaldehyde.xlsx
4.3. Supplemental Water Release Summary for DMR and TRI for Formaldehyde.xlsx
5. Environmental Exposure Assessment for Formaldehyde (U.S. EPA. 2024e)
5.1. Supplemental Water Quality Portal Results for Formaldehyde.xlsx
6. Environmental Hazard Assessment of Formaldehyde, (U.S. EPA. 2024f)
7. Occupational Exposure Assessment for Formaldehyde (U.S. EPA. 20241)
7.1. Formaldehyde Occupational Exposure Modeling Parameter Summary.xlsx
7.2. Occupational Supplemental Formaldehyde Risk Calculator.xlsx
7.3. Supplemental Occupational Monitoring Data Summary .xlsx
8. Consumer Exposure Assessment for Formaldehyde (U.S. EPA. 2024d).
8.1. Consumer Modeling, Supplemental A for Formaldehyde.xlsx
8.2. Consumer Acute Dermal Risk Calculator, Supplemental B for Formaldehyde.xlsm
8.3. Consumer - Indoor Air Acute and Chronic Inhalation Risk Calculator, Supplemental B for
Formaldehyde, xlsm
9. Indoor Air Exposure Assessment for Formaldehyde (U.S. EPA. 2024i).
9.1. Consumer Exposure Model Inputs for Formaldehyde.xlsx
9.2. Consumer Acute Dermal Risk Calculator for Formaldehyde Supplement B.xlsx
9.3. Acute and Chronic Inhalation Risk Calculator for Consumer and Indoor Air for Formaldehyde
Supplement C.xlsx
10. Ambient Air Exposure Assessment for Formaldehyde (U.S. EPA. 2024a)
10.1. IIOAC Assessment Results and Risk Calcs Supplement A for Ambient Air.xlsx
10.2. IIOAC Assessment Results and Risk Calcs for Formaldehyde Supplement B.xlsx
10.3. IIOAC Assessment Results and Risk Calcs for Formaldehyde Supplement C.xlsx
11. Human Health Hazard Assessment for Formaldehyde (U.S. EPA. 2024i).
12. Risk Evaluation for Formaldehyde - Systematic Review Protocol (U.S. EPA. 2024m)
12.1. Risk Evaluation for Formaldehyde - Systematic Review Supplemental File: Data Quality
Evaluation and Data Extraction Information for Physical and Chemical Properties (U.S. EPA.
2024r)
Page 160 of 191
-------
12.2. Risk Evaluation for Formaldehyde - Systematic Review Supplemental File: Data Quality
Evaluation and Data Extraction Information for Environmental Fate and Transport (U.S.
EPA. 2024p)
12.3. Risk Evaluation for Formaldehyde - Systematic Review Supplemental File: Data Quality
Evaluation and Data Extraction Information for Environmental Release and Occupational
Exposure (U.S. EPA. 2024q)
12.4. Risk Evaluation for Formaldehyde - Systematic Review Supplemental File: Data Quality
Evaluation Information for General Population, Consumer, and Environmental Exposure.
(U.S. EPA. 2024s)
12.5. Risk Evaluation for Formaldehyde - Systematic Review Supplemental File: Data
Extraction Information for General Population, Consumer, and Environmental Exposure (U.S.
EPA. 2024o)
12.6. Risk Evaluation for Formaldehyde - Systematic Review Supplemental File: Data Quality
Evaluation Information for Human Health Hazard Epidemiology (U.S. EPA. 2024u)
12.7. Risk Evaluation for Formaldehyde - Systematic Review Supplemental File: Data Quality
Evaluation Information for Human Health Hazard Animal Toxicology (U.S. EPA. 2024t)
12.8. Risk Evaluation for Formaldehyde - Systematic Review Supplemental File: Data Quality
Evaluation Information for Environmental Hazard (U.S. EPA. 2024v)
12.9. Risk Evaluation for Formaldehyde - Systematic Review Supplemental File: Data
Extraction Information for Environmental Hazard and Human Health Hazard Animal
Toxicology and Epidemiology (U.S. EPA. 2024n)
13. Unreasonable Risk Determination for Formaldehyde
14. Non-technical Summary for Formaldehyde
15. Response to Public and SACC Comments for Formaldehyde
Page 161 of 191
-------
Appendix C DETAILED EVALUATION OF POTENTIALLY
EXPOSED AND SUSCEPTIBLE SUBPOPULATIONS
C.l PESS Based on Greater Exposure
In this section, EPA addresses potentially exposed populations expected to have greater exposure to
formaldehyde. Table Apx C-l presents the quantitative data sources that were used in the PESS
exposure analysis for incorporating increased background and COU-specific exposures.
Page 162 of 191
-------
Table Apx (
^-1. PESS Based on Greater Exposure
Category
Subcategory
Increased Exposure from
OtherSources
Increased Exposure from TSCA COUs
Quantitative Data Sources
Lifestage
Embryo/fetus
• EPA did not identify other sources of
increased exposure anticipated for this
lifestage.
• EPA did not identify sources of increased
TSCACOU exposure anticipated for this
lifestage.
• EPA did not quantify exposures
specific to this lifestage.
Pregnant people
• EPA did not identify other sources of
increased exposure anticipated for this
lifestage.
• EPA did not identify sources of increased
TSCA COU exposure anticipated for this
lifestage.
• EPA did not quantify exposures
specific to this lifestage
Children
(infants, toddlers)
• EPA did not identify other sources of
increased exposure anticipated for this
lifestage.
• For air exposures, the impacts of lifestage
differences were not able to be adequately
quantified and so the air concentrations are
used for all lifestages.
• Consumer exposure scenarios include
lifestage-specific exposure factors for
adults, children, and infants (U.S. EPA.
2024d)
• Based on pchem properties and a lack
of studies evaluating potential for
accumulation in human milk following
inhalation, dermal or oral exposures,
EPA did not quantitatively evaluate the
human milk pathway. This is a
remaining source of uncertainty.
• In the consumer exposure assessment,
EPA also considered potential oral
exposure associated with mouthing
behaviors in infants and young children
(U.S. EPA. 2024d). however EPA did not
have sufficient information on this
exposure route to quantify risks.
• Lifestage specific consumer exposure
scenarios for infants, children, and
adults are based on information
from U.S. EPA (2005a)and U.S.
EPA (2011).
Older Adults
• EPA did not identify other sources of
increased exposure anticipated for this
lifestage.
• EPA did not identify sources of increased
COU or pathway specific exposure for
this lifestage.
• EPA did not quantify exposures
specific to this lifestage.
Sociodemo-
graphic
factors
Race/Ethnicity
• EPA did not identify specific data on
other sources of increased exposure
associated with race/ethnicity.
• EPA did not identify specific data on
increased COU or pathway specific
exposure associated with race/ethnicity.
• EPA did not quantify exposures
associated with race/ethnicity.
Page 163 of 191
-------
Category
Subcategory
Increased Exposure from
OtherSources
Increased Exposure from TSCA COUs
Quantitative Data Sources
Socioeconomic
status
• EPA did not identify specific data on
other sources of increased exposures
associated with socioeconomic status.
• EPA did not identify specific data on
increased COU or pathway specific
exposure associated with socioeconomic
status.
• EPA did not directly quantify
exposures associated with
socioeconomic status.
Unique
Activities
Subsistence Fishing
• EPA did not identify other sources of
increased exposure associated with
subsistence fishing or other exposure
scenarios unique to tribes or other groups.
• EPA did not identify sources of increased
COU or pathway specific exposure for
subsistence fishing or other exposure
pathways unique to tribes or other groups.
• EPA did not quantify exposures
associated with subsistence fishing.
Lifestyle
Smoking
• EPA identified smoking as an additional
other source of exposure to formaldehyde
that may increase aggregate exposure for
smokers and people exposed to second-
hand smoke. To some degree,
formaldehyde exposure from smoking is
indirectly accounted for in some indoor
air monitoring data described in Section
5.2.3.1, but it is not directly quantified.
• EPA did not identify sources of increased
COU or pathway specific exposure for
smoking or other lifestyle factors.
• EPA did not directly quantify
exposures associated with smoking.
Geography
Living in proximity
to sources of
formaldehyde
releases to outdoor
air
• EPA identified living near major
roadways or in areas with frequent
exposure to wildfire smoke as
potential sources of increased
exposure to formaldehyde for some
populations. To some degree, ambient
air monitoring data may indirectly
account for some of these sources but
they are not directly quantified. These
other sources of formaldehyde are a
source of uncertainty that is not
directly incorporated into risk
estimates for outdoor air exposures.
• EPA evaluated risks to communities
in proximity to sites where
formaldehyde is released to ambient
air (Section 5.2.4). In the
environmental release assessment,
EPA mapped tribal lands in relation to
air, surface water and ground water
releases of formaldehyde to identify
potential for increased exposures for
tribes due to geographic proximity
(U.S. EPA. 2024a).
• EPA quantified exposures for
communities in proximity to
release sites using air
concentrations modeled based on
releases reported to TRI, as
described in U.S. EPA (2024a)
and Section 5.2.4
• EPA did not directly quantify
exposures associated with living
near roadways or other sources of
formaldehyde in outdoor air.
Other
chemical and
non-chemical
stressors
Built Enviromnent
• EPA identified the built environment
(including building materials and
other products) as source of increased
exposure to formaldehyde associated
with other sources. Indoor air
• EPA identified the built environment
(including building materials and
other products) as a source of
increased exposure to formaldehyde
associated with COUs. Indoor air
• EPA quantified exposures
associated with specific TSCA
COUs based on 2016 and 2020
Chemical Data Reporting (U.S.
EPA. 2020a. 2016a). the
Page 164 of 191
-------
Category
Subcategory
Increased Exposure from
OtherSources
Increased Exposure from TSCA COUs
Quantitative Data Sources
concentrations assessed in Section
4.2.3 incorporate both TSCA and
other sources of formaldehyde in
indoor air.
concentrations assessed in Section
4.2.3 incorporate both TSCA and
other sources of formaldehyde in
indoor air.
Formaldehyde and
Paraformaldehyde Use Report
(U.S. EPA. 2020d) and product
weight fractions and densities
reported in chemical safety data
sheets (SDSs) identified through
product-specific internet searches;
EPA quantified exposures and
risks associated with aggregate
indoor air based on a range of
monitoring data described in the
Indoor Air Assessment (U.S.
EPA. 2024i).
• EPA did not directly quantify
indoor air exposures associated
with other sources.
Occupational
Workers and
occupational non-
users
• EPA identified firefighters as an
occupational group with increased
exposure to formaldehyde associated with
combustion containing building materials
with high concentrations to formaldehyde.
While combustion exposures are beyond
the scope of this assessment, this is a
remaining source of uncertainty in
characterizing aggregate exposures for
some groups.
• EPA identified all occupational
exposure scenarios as a potential
source of exposure to formaldehyde.
Those with higher frequency or higher
duration exposures are expected to
have the greatest exposures and risks.
EPA evaluated risks for a range of
occupational exposure scenarios that
increase exposure to formaldehyde,
including manufacturing, processing,
and use of formulations containing
formaldehyde. EPA evaluated risks
for central tendency and high-end
exposure estimates for each of these
scenarios (Section 5.2.1).
• EPA quantified occupational
exposures associated with TSCA
COUs based on a range of COU-
specific data, including
monitoring data from OSHA and
NIOSH and modeled air
concentrations. Specific data
sources are described in detail in
the Draft Occupational Exposure
Assessment (U.S. EPA. 20241).
Consumer
High frequency
consumers
• EPA identified dietary exposures through
food, food packaging, drugs, and personal
• Consumer products designed for
children (e.g., children's toys) may
• EPA quantified consumer
exposure (U.S. EPA. 2024d)
Page 165 of 191
-------
Category
Subcategory
Increased Exposure from
OtherSources
Increased Exposure from TSCA COUs
Quantitative Data Sources
High duration
consumers
care products that contain formaldehyde
as other sources that may contribute to
total formaldehyde exposure. These
exposures are beyond the scope of this
assessment and are a source of uncertainty
in characterizing aggregate exposures.
lead to elevated exposures for children
and infants.
• EPA identified all consumer exposure
scenarios involving TSCA COUs as
potential sources of exposure to
formaldehyde. Those with higher
frequency and/or higher duration
exposures are expected to have the
greatest exposures and risks.
based on the Formaldehyde and
Paraformaldehyde Use Report
(U.S. EPA. 2020d) and the
Exposure Factors Handbook (U.S.
EPA. 2011) (Ch. 17).
Page 166 of 191
-------
C.2 PESS Based on Greater Susceptibility
In this section, EPA addresses subpopulations and lifestages expected to be more susceptible to
formaldehyde exposure than others. This discussion draws heavily from the recent summary of
susceptible populations and lifestages included in the IRIS assessment (U.S. EPA. 2024k). Table Apx
C-2. presents the data sources that were used in the PESS analysis evaluating susceptible subpopulations
and identifies whether and how the subpopulation was addressed quantitatively in the risk evaluation of
formaldehyde.
Page 167 of 191
-------
Table Apx C-2. Susceptibility Category, Factors, and Evidence for PESS susceptibility
Susceptibility
Category
Specific
Factors
Direct Evidence this Factor
Modifies Susceptibility to Formaldehyde
Indirect Evidence of Potential
Impact through Target Organs or
Biological Pathways Relevant to
Formaldehyde
Incorporation of Each Factor into the
Risk Evaluation
Description of Interaction
Key Citations
Description of
Interaction
Key Citations
Embryos/
fetuses/infants
Direct quantitative human and
animal evidence for developmental
toxicity following inhalation
exposure (e.g., decreased fertility,
increased spontaneous abortions
and changes in brain structures).
Taskinen et al. (1999)
John et al. (1994)
Sarsilmaz et al. (2007)
Asian et al. (2006)
Hazard value for chronic inhalation is
supported in part by dose-response
information on female reproductive
effects and developmental toxicity and
is expected to be protective of these
endpoints
Lifestage
Infants and
Children
In some studies, children appear to
be more susceptible than adults to
respiratory effects of formaldehyde.
Early life exposures to chemicals
with a mutagenic mode of action
may increase cancer risk. EPA has
concluded that the evidence is
sufficient to conclude that a
mutagenic mode of action of
formaldehyde is operative in
formaldehyde-induced
nasopharyngeal carcinogenicity.
Bateson and Schwartz
(2008)
Venn et al. (2003)
Annesi-Maesano et al.
(2012)
Krzvzanowski et al.
(1990).
U.S. EPA (2005b)
Developing lungs
until age 6-8,
narrower airways
Different
expression of
enzymes
responsible for
metabolizing
formaldehyde
Bateson and
Schwartz
(2008)
Thompson et al.
(2009)
Hazard value for chronic inhalation is
based in part on dose-response
information on asthma
prevalence/asthma control in children.
ADAFs are applied to nasopharyngeal
cancer risk estimates to account for
increased susceptibility to cancer
following exposure during early life.
Pregnant
women
No direct evidence identified
Pregnant women
may have increased
sensitivity to the
development and
exacerbation of
atopic eczema
following exposure
to formaldehyde
Matsunaga et
al. (2008)
No direct quantitative adjustment to
hazard values or risk estimates; Use of
UFh
Males of
reproductive
age
Direct quantitative evidence in for
reduced fertility following
inhalation exposure; IRIS
assessment concludes "evidence
indicates" formaldehyde "likely
causes" male reproductive effects
based on robust evidence in animals
and slight evidence in people.
(U.S. EPA 2024k)
Possible
contributors to male
reproductive
effects/infertility
(see also factors in
other rows):
• Enlarged veins
of testes
CDC (2023b)
Hazard value for chronic inhalation is
supported in part by dose-response
information on male reproductive
toxicity and is expected to be protective
of these endpoints
Page 168 of 191
-------
Susceptibility
Category
Specific
Factors
Direct Evidence this Factor
Modifies Susceptibility to Formaldehyde
Indirect Evidence of Potential
Impact through Target Organs or
Biological Pathways Relevant to
Formaldehyde
Incorporation of Each Factor into the
Risk Evaluation
Description of Interaction
Key Citations
Description of
Interaction
Key Citations
• Trauma to
testes
• Anabolic
steroid or illicit
drug use
Cancer treatment
Older adults
No direct evidence identified
-
Older adults may
have reduced
metabolism and
higher rates of
chronic diseases
that may increase
susceptibility
-
No direct quantitative adjustment to
hazard values or risk estimates; Use of
UFh
Pre-existing
disease or
disorder
Health
outcome/
target organs
A few epidemiological studies
found that individuals with asthma
and allergies were more susceptible
to the deterioration of respiratory
function after being exposed to
formaldehyde than those without
these conditions.
Evidence from human and animal
studies indicated that individuals
with pre-existing nasal damage or a
history of respiratory issues were
more susceptible to developing
formaldehyde induced nasal cancer.
Krzvzanowski et al.
(1990)
Kriebel et al. (1993)
Woutersen et al. (1989)
Appelman et al. (1988)
Falk et al. (1994)
Individual
variations in nasal
anatomy and
soluble factors in
the upper
respiratory tract can
potentially
influence the uptake
of highly reactive
gases like
formaldehyde. This
variability could
possibly lead to
differences in the
distribution of
inhaled
formaldehyde and
susceptibility to its
health effects.
ICRP (1994)
Santiago et al.
(2001)
Singh et al.
(1998)
Acute inhalation hazard values are
based in part on dose-response
information in humans already
identified as sensitive to formaldehyde
in dermal patch test studies.
No direct quantitative adjustment to
chronic inhalation, oral or dermal
hazard values or risk estimates; Use of
UFh
Lifestyle
activities
Smoking
No direct evidence identified
Heavy smoking
may increase
susceptibility to
formaldehyde
toxicity. However,
it is unclear if this
Fishbein (1992)
CDC (2023a)
CDC (2023b)
No direct quantitative adjustment to
hazard values or risk estimates; Use of
UFh
Page 169 of 191
-------
Susceptibility
Category
Specific
Factors
Direct Evidence this Factor
Modifies Susceptibility to Formaldehyde
Indirect Evidence of Potential
Impact through Target Organs or
Biological Pathways Relevant to
Formaldehyde
Incorporation of Each Factor into the
Risk Evaluation
Description of Interaction
Key Citations
Description of
Interaction
Key Citations
increased
sensitivity is due to
additional
formaldehyde
exposure or other
chemicals in
cigarette smoke.
Alcohol
Consumption
No direct evidence identified
Chronic alcohol
consumption may
affect the
susceptibility to
reproductive and
cancer related
health outcomes.
CDC (2023a)
No direct quantitative adjustment to
hazard values or risk estimates; Use of
UFh
Physical
Activity
Studies observed that prolonged
physical activity increased an
individual's susceptibility to
formaldehyde induced respiratory
impairments. These studies
demonstrated that those who were
exposed to formaldehyde after 15
minutes of exercise experienced
more significant declines in lung
function compared to those who had
shorter exercise sessions or no
exercise at all.
Green et al. (1987)
Green et al. (1989)
Insufficient activity
may increase
susceptibility to
multiple health
outcomes
Overly strenuous
activity may also
increase
susceptibility.
CDC (2022)
No direct quantitative adjustment to
hazard values or risk estimates; Use of
UFh
Sociodemo-
graphic status
Race/ethnicity
An epidemiological study suggests
a racial difference in susceptibility
to formaldhyde toxicity, as
nonwhite individuals were found to
have higher mortality rates for
nasopharyngeal cancer and multiple
myeloma compared to their white
counterparts.
Haves et al. (1990)
No direct quantitative adjustment to
hazard values or risk estimates; Use of
UFh
Socioeconomi
c status
No direct evidence identified
Individuals with
lower
socioeconomic
status may
experience adverse
ODPHP
(2023b)
No direct quantitative adjustment to
hazard values or risk estimates; Use of
UFh
Page 170 of 191
-------
Susceptibility
Category
Specific
Factors
Direct Evidence this Factor
Modifies Susceptibility to Formaldehyde
Indirect Evidence of Potential
Impact through Target Organs or
Biological Pathways Relevant to
Formaldehyde
Incorporation of Each Factor into the
Risk Evaluation
Description of Interaction
Key Citations
Description of
Interaction
Key Citations
health outcomes
due to unmet social
needs,
environmental
factors, and limited
access to healthcare
services.
Sex/gender
A higher prevalence of burning or
tearing eyes was observed among
women compared to men,
suggesting that women may be
more sensitive to the irritant
properties of formaldehyde on the
eyes and upper respiratory tract.
Several animal studies showed that
males exhibit a higher incidence of
lesions in the upper respiratory tract
than females.
Evidence from epidemiological
studies and animal models indicates
that formaldehyde exposure can
lead to male reproductive
impairments, reduced fertility, and
increased risk of miscarriage in
women
Liu et al. (1991)
Woutersen et al. (1987)
Zwart et al. (1988)
Maronpot et al. (1986)
Kerns et al. (1983)
Taskinen et al. (1999)
John et al. (1994)
Wang et al. (2015)
Both acute and chronic inhalation
hazard values are based in part on
epidemiological studies include that
include both male and female subjects,
Nutrition
Diet
No direct evidence identified
An antioxidant
deficient diet may
exacerbate
inflammatory
responses, primarily
due to
formaldehyde's
well-known
inflammatory
properties.
CDC (2023a)
CDC (2020)
CDC (2023c)
No direct quantitative adjustment to
hazard values or risk estimates; Use of
UFh
Page 171 of 191
-------
Susceptibility
Category
Specific
Factors
Direct Evidence this Factor
Modifies Susceptibility to Formaldehyde
Indirect Evidence of Potential
Impact through Target Organs or
Biological Pathways Relevant to
Formaldehyde
Incorporation of Each Factor into the
Risk Evaluation
Description of Interaction
Key Citations
Description of
Interaction
Key Citations
Obesity can
increase
susceptibility to
cancer.
Malnutrition
No direct evidence identified
Micronutrient
malnutrition can
result in various
conditions, such as
birth defects,
maternal and infant
mortality, preterm
birth, low birth
weight, poor fetal
growth, childhood
blindness, and
undeveloped
cognitive ability.
Deficiencies in
micronutrients may
increase an
individual's
susceptibility to the
adverse health
effects of
formaldehyde,
particularly
respiratory
impairments. This
is due to the critical
role of
micronutrients in
maintaining robust
immune function,
potent antioxidant
defenses, and the
structural integrity
of the respiratory
system.
CDC (2021)
CDC (2023c)
No direct quantitative adjustment to
hazard values or risk estimates; Use of
UFh
Page 172 of 191
-------
Susceptibility
Category
Specific
Factors
Direct Evidence this Factor
Modifies Susceptibility to Formaldehyde
Indirect Evidence of Potential
Impact through Target Organs or
Biological Pathways Relevant to
Formaldehyde
Incorporation of Each Factor into the
Risk Evaluation
Description of Interaction
Key Citations
Description of
Interaction
Key Citations
Target organs
No direct evidence identified
—
Genetic disorders,
such as
Klinefelter's
syndrome, Y-
chromosome
microdeletion,
myotonic dystrophy
can affect male
reproduction/fertilit
y
CDC (2023b)
No direct quantitative adjustment to
hazard values or risk estimates; Use of
UFh
Genetics/
epigenetics
Toxicokinetics
Studies suggested that certain
genetic variants could impair the
activity of ADH and ALDH
enzyme. This potential impairment
could reduce the clearance of
formaldehyde, thereby increasing
susceptibility to adverse health
effects associated with
formaldehyde exposure.
Studies have demonstrated that
genetic variations in ADH3 and
ALDH2 genes have been associated
to higher susceptibility to asthma
and CNS toxicity, while
polymorphism in genes related to
DNA repair, such as XRCC3, have
been shown to impact susceptibility
to formaldhyde induced
genotoxicity.
Studies in experimental animals
with genetically modified ALDH2
and ALDH5 genes, responsible for
eliminating endogenous
formaldhyde, suggested that
variations in these genes could
potentially increase susceptibility to
genotoxicity.
Wu et al. (2007)
Hedberg et al. (2001)
Deltour et al. (1999)
Tan et al. (2018)
Nakamura et al. (2020)
Dingier et al. (2020)
No direct quantitative adjustment to
hazard values or risk estimates; Use of
UFh
Page 173 of 191
-------
Susceptibility
Category
Specific
Factors
Direct Evidence this Factor
Modifies Susceptibility to Formaldehyde
Indirect Evidence of Potential
Impact through Target Organs or
Biological Pathways Relevant to
Formaldehyde
Incorporation of Each Factor into the
Risk Evaluation
Description of Interaction
Key Citations
Description of
Interaction
Key Citations
Although some studies have
suggested that specific genetic
variants may influence
susceptibility to formaldehyde
toxicity, their findings have not
been conclusive.
Built
environment
No direct evidence identified
Poor quality
housing often
contains
environmental
triggers of asthma
such as pests, mold,
dust, building
materials that may
exacerbate reduced
asthma control
associated with
formaldehyde
exposure
ODPHP
(2023a)
No direct quantitative adjustment to
hazard values or risk estimates; Use of
UFh
Other
Chemical and
Nonchemical
stressors
Social
environment
No direct evidence identified
Poverty, violence,
as well as other
social factors may
make some
populations more
susceptible to the
health effects
associated with
formaldehyde
exposure.
CDC (2023d)
ODPHP
(2023c)
No direct quantitative adjustment to
hazard values or risk estimates; Use of
UFh
Chemical co-
exposures
Several studies have demonstrated
that co-exposure to formaldehyde
and other substances, including
environmental pollutants and
dietary components, could
potentially affect respiratory health,
hypersensitivity reactions, or lung
function.
Besaratinia et al. 2014
Fang et al. 2004
Gavriliu et al. 2013
No direct quantitative adjustment to
hazard values or risk estimates; Use of
UFh
Page 174 of 191
-------
Susceptibility
Category
Specific
Factors
Direct Evidence this Factor
Modifies Susceptibility to Formaldehyde
Indirect Evidence of Potential
Impact through Target Organs or
Biological Pathways Relevant to
Formaldehyde
Incorporation of Each Factor into the
Risk Evaluation
Description of Interaction
Key Citations
Description of
Interaction
Key Citations
While studies have indicated that
certain dietary components, such as
methanol and caffeine can
contribute to the endogenous
production of formaldehyde in non-
respiratory tissues, the extent to
which this influences susceptibility
to inhaled formaldehyde remains
unclear.
Environmental tobacco smoke
exposure has been associated with
an increased likelihood of
hypersensitivity responses in
individuals concurrently exposed to
formaldehyde. Studies suggest that
exposure to tobacco smoke may
potentiate the effects of
formaldehyde or even trigger such
responses at lower formaldehyde
concentrations, particularly in
children and nonsmoking adults
Hohnloser et al. (1980)
Riess et al. (2010)
Summers et al. (2012)
Krzvzanowski et al.
(1990)
Page 175 of 191
-------
Appendix D AMBIENT AIR RISK ESTIMATES - COMMERCIAL
USES
The ambient air exposure assessment for formaldehyde quantitatively evaluates exposures resulting
from industrial releases of formaldehyde to ambient air. EPA expects that releases resulting from TSCA
industrial COUs have larger point source emissions than the air emissions resulting from commercial
uses.
As discussed in the Environmental Release Assessment (U.S. EPA 2024g). where available, EPA used
TRI and NEI to inform air releases from commercial COUs. However, facilities are only required to
report to TRI if the facility has 10 or more full-time employees; is included in an applicable North
American Industry Classification System (NAICS) code; and manufactures, processes, or uses the
chemical in quantities greater than a certain threshold. Reporting to NEI depends on submissions
voluntarily provided by state, local, and tribal agencies and is supplemented by data from other EPA
programs. For NEI, the general threshold for major source is the potential to emit more than 10 tons per
year for a single Hazardous Air Pollutant (HAP), or 25 tons/year for any combination of HAPs.
Due to these limitations, commercial sites that use formaldehyde and/or formaldehyde-containing
products may not report to TRI or NEI and are therefore not included in these datasets.
EPA did not quantify releases and therefore ambient air risk estimates for the following COUs:
• Distribution in commerce
• Commercial use - chemical substances in treatment/care products - laundry and dishwashing
products
• Commercial use - chemical substances in treatment products - water treatment products
• Commercial use - chemical substances in outdoor use products - explosive materials
• Commercial use - chemical substances in products not described by other codes - other:
laboratory chemicals; and
• Commercial use - chemical substances in automotive and fuel products- automotive care
products; lubricants and greases; fuels and related products.6
EPA discusses the release potential for each COU in in the Draft Environmental Release Assessment for
Formaldehyde (U.S. EPA. 2024g) based on the available information. In general, EPA expects industrial
COUs to be the drivers of risk for ambient air from the TSCA COUs within the scope of this draft risk
evaluation.
For the following commercial COUs
• Commercial use - chemical substances in furnishing treatment/care products- floor coverings;
foam seating and bedding products; furniture and furnishings not covered elsewhere; cleaning
and furniture care products; fabric, textile, and leather products not covered elsewhere-
construction
• Commercial Use - chemical substances in construction, paint, electrical, and metal products-
adhesives and sealants; paint and coatings
6 Use of fuels may be associated with petroleum refinery and utilities, however, note formaldehyde from combustion sources
is not assessed as an independent COU subcategory in this risk evaluation
Page 176 of 191
-------
• Commercial Use - chemical substances in furnishing treatment/care products -
building/construction materials - wood and engineered wood products; building/ construction
materials not covered elsewhere
EPA expects emissions may be similar to the construction sector, which has cancer risk estimate lower
than 1 x 1CT6 based on 100 to 1,000 m from the release site for the 95th percentile annual reported release
amount.
For the following commercial COUs
• Commercial use - chemical substances in electrical products - electrical and electronic products
• Commercial use - chemical substances in metal products - metal products not covered elsewhere
EPA expects emissions may be similar to the electrical equipment, appliance, and component
manufacturing and fabricated metal product manufacturing sector, which has cancer risk estimate lower
than 1 x 10~6 based on 100 to 1,000 m from the release site for the 95th percentile annual reported release
amount.
For the following commercial COU, Commercial use - chemical substances in agriculture use products
- lawn and garden products, EPA expects emissions may be similar to the agriculture, forestry, fishing,
and hunting sector, which has risk estimate lower than 1 x 10~6 based on 100 to 1,000 m from the release
site for the 95th percentile annual reported release amount.
For the following commercial COUs
• Commercial use - chemical substances in packaging, paper, plastic, hobby products - paper
products; plastic and rubber products; toys, playground, and sporting equipment
• Commercial use - chemical substances in packaging, paper, plastic, hobby products- arts, crafts,
and hobby materials
• Commercial use - chemical substances in packaging, paper, plastic, hobby products- ink, toner,
and colorant products; photographic supplies
EPA expects emissions may be similar to the Printing and Related Support Activities & Photographic
Film Paper, Plate, and Chemical Manufacturing sector, which have risk estimates lower than 1 x 10~6
based on 100 to 1,000 m from the release site for the 95th percentile annual reported release amount.
EPA does, however, note that printing operations that use printing ink, toner, or colorant products
containing formaldehyde may occur at industrial sites such as those included in Paper Manufacturing,
which has a cancer risk estimate of 1.24xl0~5.
Page 177 of 191
-------
Appendix E OCCUPATIONAL EXPOSURE VALUE DERIVATION
EPA has calculated occupational exposure values for consideration of formaldehyde inhalation exposure
in workplace settings (see Appendix E.l). EPA calculated occupational exposure values of 0.17 ppm
(200 |ig/m3) based on the acute non-cancer hazard value for sensory irritation and 0.11 ppm (133|ig/m3)
based on the chronic cancer IUR for nasopharyngeal cancer.
TSCA requires risk evaluations to be conducted without consideration of costs and other non-risk
factors, and thus these occupational exposure values represent risk-only numbers. In risk management
rulemaking for formaldehyde following 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. In general, any existing chemical exposure limit (ECEL) used for occupational safety
risk management purposes could differ from the occupational exposure values presented in this
appendix based on additional consideration of exposures and non-risk factors consistent with TSCA
section 6(c).
The calculated values for formaldehyde are derived based on standard occupational scenario
assumptions of 8 hours/day, 5 days/week exposures for a total of 250 days exposure per year, and a 40-
year working life.
EPA expects that at the acute occupational exposure value of 0.17 ppm (200 |ig/m3), a worker or ONU
would be protected against sensory irritation effects resulting from acute occupational exposures. The
acute exposure limit is unchanged for all durations of a single exposure and also serves as the short-term
exposure limit (STEL) to protect against 15-minute exposures. EPA expects that at the cancer
occupational exposure value of 0.11 ppm (133 |ig/m3) as an 8-hr TWA, a worker or ONU would be
protected against excess risk of nasopharyngeal cancer above the 1 x 10~4 benchmark value resulting
from occupational formaldehyde exposure.
Of the identified occupational monitoring data for formaldehyde, there have been measured workplace
air concentrations below the calculated exposure values. A summary table of available monitoring
methods from the Occupational Safety and Health Administration (OSHA) and the National Institute for
Occupational Safety and Health (NIOSH) is included in Appendix E.2. The table covers validated
methods from governmental agencies and is not intended to be a comprehensive list of available air
monitoring methods for formaldehyde. The calculated exposure values are above the limit of detection
(LOD) and limit of quantification (LOQ) using at least one of the monitoring methods identified.
The Occupational Safety and Health Administration (OSHA) set a permissible exposure limit (PEL) as
an 8-hour TWA for formaldehyde of 0.75 ppm in 1992 (https://www.osha.gov/annotated-pels). with an
action level of 0.5 ppm. In addition, OSHA has set a STEL of 2 ppm. OSHA's PEL must undergo both
risk assessment and feasibility assessment analyses before selecting a level that will substantially reduce
risk under the Occupational Safety and Health Act. EPA's calculated exposure values are based on
newer information and analysis from this risk evaluation. Other international regulatory bodies such as
the European Union established a regulatory limit of 0.3 ppm (European Chemicals Agency,
http://echa.europa.eu/)7.
There are also recommended exposure limits established for formaldehyde by other governmental
agencies and independent groups. The American Conference of Governmental Industrial Hygienists
(ACGIH) set a Threshold Limit Value (TLV) at 0.1 ppm TWA and 0.3 ppm STEL in 2017. This
7 https://echa.europa.eu/substance-information/-/substanceinfo/100.000.002
Page 178 of 191
-------
chemical also has aNIOSH Recommended Exposure Limit (REL) of 0.016 ppm TWA and 15-minute
Ceiling limit of 0.1 ppm (https://www.cdc.gov/niosh/npg/).
E.l Occupational Exposure Value Calculations
This appendix presents the calculations used to estimate occupational exposure values using inputs
derived in this risk evaluation. Multiple values are presented below for hazard endpoints based on
different exposure durations. The human health hazard values used in these equations are based on the
inhalation non-cancer hazard values and the IUR summarized in Table 3-1.
Acute/Short-Term, Non-cancer Occupational Exposure Value
The acute occupational exposure value (EVaCute), equivalent to the 15-minute STEL, was calculated as
the concentration at which the acute MOE would equal the benchmark MOE for acute occupational
exposures using EquationApx E-l:
EquationApx E-l.
HECnri,rp 0.5 ppm mg
ni T UU U.LC 11 f\ '1 /" r7 f\ O u
EVacute = „ 7 , ,,nT7 = ~ = 0.167 ppm = 0.2 —
Benchmark M0Eacute 3
Lifetime Cancer Occupational Exposure Value
The EVcancer is the concentration at which the extra cancer risk is equivalent to the benchmark cancer
risk of lxl0~4:
EVr,
1X10-
Benchmark
Cancer
AT,
IUR
IR,.
input
IUR ED * EF * WY lRworkers
h 365 d
d* y * J 1.25m3//ir
* ; * ¦
7.90x10 ~3 per ppm 2h ¦¦ 250d ¦¦¦ iqv l-25m3//ir
d y 7
= 0.108 ppm = 0.133
m3
Where:
A TnECrepeat
A TnECacute
ATiur
Benchmark MOE,
¦acute
Benchmark MOE,
repeat
Benchmarkcancer
E\ acute
Averaging time for the POD/HEC used for evaluating non-cancer,
intermediate and chronic occupational risk, based on study
conditions and/or any HEC adjustments (24 hr/day for 30 days)
(see Section 4.2.2.1)
Averaging time for the POD/HEC used for evaluating non-cancer,
acute occupational risk, based on study conditions and/or any HEC
adjustments (24 hr/day) (see Section 4.2.2.1)
Averaging time for the cancer IUR, based on study conditions and
any adjustments (24 hr/day for 365 days/year) and averaged over a
lifetime (78 years) (Supplemental File: Releases and Occupational
Exposure Assessment; Appendix B).
Acute non-cancer benchmark margin of exposure, based on the
total uncertainty factor of 3 (see Table 3-7)
Short term non-cancer benchmark margin of exposure, based on
the total uncertainty factor of 100 (see Table 3-8)
Benchmark for excess lifetime cancer risk
Exposure limit based on acute effects
Page 179 of 191
-------
E\ intermediate
E\ chronic
E\ cancer
ED
EF
HECacute or repeat
IUR
IR
W Y
Existing chemical exposure limit (mg/m3), based on non-cancer
effects following repeat exposures
Existing chemical exposure limit (mg/m3), based on non-cancer
effects following repeat exposures
Exposure limit based on excess cancer risk
Exposure duration (8 hr/day) (see Table 3-8)
Exposure frequency (250 days/yr), (see Section 4.2.2.1)
Human equivalent concentration for acute or intermediate/chronic
occupational exposure scenarios, respectively (see Tables 3-7 and
3-8)
Adult-based inhalation unit risk (per ppm) (see Table 3-6)
Inhalation rate (default is 1.25 m3/hr for workers and 0.6125 m3/hr
for general population at rest)
Working years per lifetime at the 95th percentile (40 years
(Supplemental File: Releases and Occupational Exposure
Assessment; Appendix B)
Unit conversion:
1 ppm = 1.23 mg/m3 (based on molecular weight of 30.026 g/mol for formaldehyde)
E.2 Summary of Air Sampling Analytical Methods Identified
EPA conducted a search to identify relevant NIOSH and OSHA analytical methods used to monitor for
the presence of formaldehyde in air (see TableApx E-l). This table covers validated methods from
governmental agencies and is not intended to be a comprehensive list of available air monitoring
methods for formaldehyde. The sources used for the search included the following:
1. NIOSH Manual of Analytical Methods (NMAM), 5th Edition;
2. NIOSH NMAM 4th Edition: and
3. OSHA Index of Sampling and Analytical Methods.
Of note, the limit of detection provided is based on the recommended volume. The specific limit of
detection may vary depending on the time sampled and flowrate used.
Table Apx E-l. Limit of Detection (LOD) and Limit of Quantification (LOQ) Summary for Air
Sampling Analytica
Methods
dentified
Air Sampling
Analytical Methods"
Year
Published
LOD6
LOQ
Notes
Source
NIOSH Method 2016
2016
0.012
ppm
N/A
Estimated LOD is 0.07
(ig/sample. The working
range is 0.012 to 2.0 ppm
for a 15-L sample.
NIOSH Manual of
Analytical Methods
(NMAM 2016)
NIOSH Method 254lc
1994
0.24 ppm
N/A
Estimated LOD is 1
(ig/sample. The working
range is 0.24 to 16 ppm
for a 10-L sample.
NIOSH Manual of
Analytical Methods,
4th Edition
(NMAM 2541)
Page 180 of 191
-------
Air Sampling
Analytical Methods"
Year
Published
LOD6
LOQ
Notes
Source
NIOSH Method 3500'#
1994
0.02 ppm
N/A
Estimated LOD is 0.5
(ig/sample. The working
range is 0.02 to 4 ppm for
an 80-L sample.
NIOSH Manual of
Analytical Methods,
4th Edition
CNMAM 3500)
NIOSH Method 5700e
1994
0.0004
mg/m3
(0.0003
ppm)
N/A
Estimated LOD is 0.08
(ig/sample. The working
range is 0.0004 to 3.8
mg/m3 for a 1,050-L
sample. Used for
determination of
formaldehyde in both
textile and wood dusts.
NIOSH Manual of
Analytical Methods,
4th Edition
CNMAM 5700)
OSHA Method 52
1989
16 ppb
16 ppb
Detection limit and
reliable quantification
limit is 482 ng per sample
(16 ppb for 24 L)
OSHA Index of
Sampling and
Analytical Methods
(OSHA 52)
OSHA Method 1007'
https://www.osha.aov
2005
0.56, 1.70, or
0.17 ppb
(Sampler -
ChemDisk-
AL, UMEx
100, DSD-
DNPH,
respectively)
1.88, 5.68, or
0.58 ppb
(Sampler -
ChemDisk-
AL, UMEx
100, DSD-
DNPH,
respectively)
Method reports
LOD/LOQ of overall
procedure as 0.56/1.88
ppb for ChemDisk-AL
samplers, 1.70/5.68 ppb
for UMEx 100 samplers,
and 0.17/0.58 for DSD-
DNPH samplers
OSHA Index of
Sampling and
Analytical Methods
(OSHA 1007)
/sites/default/files/met
hods/osha-1007 .pdf
ppm = parts per million; ppb = parts per billion; ppt = parts per trillion
11 EPA has additional air sampling methods targeted for measurement of ambient and indoor air, the methods
listed in this table are air sampling for occupational exposures.
h These sources cover a range of LOD including both below and above the preliminary occupational exposure
value.c The method is suitable for the simultaneous determinations of acrolein and formaldehyde.
''This is the most sensitive formaldehyde method in the NIOSH Manual of Analytical Methods and is able to
measure ceiling levels as low as 0.1 ppm (1 5-L sample). It is best suited for the determination of formaldehyde
in area samples.
'' Results should be considered separately from vapor-phase formaldehyde exposure; Method measures both
"released" and formaldehyde equivalents.
'Recommends use of OSHA Method 52 when monitoring exposures resulting from the use of formalin
solutions.
Page 181 of 191
-------
Appendix F ACUTE AND CHRONIC (NON-CANCER AND
CANCER) OCCUPATIONAL INHALATION
EQUATIONS
This assessment provides estimates of 15-minute peak air concentrations, short-term air concentrations,
and full-shift (8- or 12-hour) concentrations. For calculation of risk, these exposure estimates are
incorporated with additional parameter inputs, such as working years, exposure duration and frequency,
and lifetime years.
AC is used to estimate workplace inhalation exposures for acute risks (i.e., risks occurring after less than
one day of exposure), per EquationApx F-l, EquationApx F-2, and EquationApx F-3 below.
EquationApx F-l.
C x ED x BR
AC = ^
AT
ri1 acute
Where:
AC =
Acute exposure concentration
C
Contaminant concentration in air (TWA)
ED =
Exposure duration (hr/day), 0.25 hr/day
BR
Breathing rate ratio (unitless), 1
ATacute
Acute averaging time (hr), 0.25 hr
ADC and LADC are used to estimate workplace exposures for non-cancer and cancer risks, respectively.
These exposures are estimated per Equation Apx F-2, as follows:
Equation Apx F-2.
C x ED x EF XWY x BR
ADC = —
AT
day hr
ATSC = WY X 30 i-x 24 —
month day
day hr
AT = WY x 365 — x 24—
yr day
Where:
ADC =
Average daily concentration used for chronic non-cancer risk calculations
ED =
Exposure duration (hr/day)
EF
Exposure frequency (day/yr)
BR
Breathing rate ratio (unitless),
WY =
Working years per lifetime (yr)
ATsc =
Averaging time (hr) for sub-chronic, non-cancer risk
AT =
Averaging time (hr) for chronic, non-cancer risk
Page 182 of 191
-------
EquationApx F-3.
LADC =
C x ED x EF x WY x BR
ATr
day
ATC = LT X36S — x 24
yr
hr
day
Where:
LADC =
ED =
EF
WY =
ATc =
LT
Lifetime average daily concentration used for chronic cancer risk
calculations
Exposure duration (hr/day)
Exposure frequency (day/yr)
Working years per lifetime (yr),
Averaging time (hr) for cancer risk
Lifetime years (yr) for cancer risk, 78 yr
For exposure duration, frequency, and working years used in this appendix, see Table Apx F-l.
Table Apx F-l. Ap
)endix F Formulae - Symbols, Values, and Units
Symbol
Value
Unit
ED
8 or 12
hour/day
EF
250 or 167
day/year
WY(ct)
31
years
WY(HE)
40
years
AT(ct)
271,560
hours
AT(HE)
350,400
hours
ATC
683,280
hours
Worker Years
EPA has developed a triangular distribution for working years. EPA has defined the parameters of the
triangular distribution as follows:
• Minimum value: BLS CPS tenure data with current employer as a low-end estimate of the
number of lifetime working years: 10.4 years;
• Mode value: The 50th percentile tenure data with all employers from SIPP as a mode value for
the number of lifetime working years: 36 years; and
• Maximum value; The maximum average tenure data with all employers from SIPP as a high-end
estimate on the number of lifetime working years: 44 years.
This triangular distribution has a 50th percentile value of 31 years and a 95th percentile value of 40
years. EPA uses these values for central tendency and high-end ADC and LADC calculations,
respectively.
The BLS (U.S. BLS. 2014) provides information on employee tenure with current employer obtained
from the CPS, which is a monthly sample survey of about 60,000 households that provides information
on the labor force status of the civilian non-institutional population age 16 and over. CPS data are
released every 2 years. The data are available by demographics and by generic industry sectors but are
not available by NAICS codes.
Page 183 of 191
-------
The U.S. Census' (U.S. Census Bureau. 2019a) SIPP provides information on lifetime tenure with all
employers. SIPP is a household survey that collects data on income, labor force participation, social
program participation and eligibility, and general demographic characteristics through a continuous
series of national panel surveys of between 14,000 and 52,000 households (U.S. Census Bureau. 2019b).
EPA analyzed the 2008 SIPP Panel Wave 1, a panel that began in 2008 and covers the interview months
of September 2008 through December 2008 (U.S. Census Bureau. 2019a. b). For this panel, lifetime
tenure data are available by Census Industry Codes, which can be crosswalked with NAICS codes.
SIPP data include fields for the industry in which each surveyed, employed individual works
(TJBIND1), worker age (TAGE), and years of work experience with all employers over the surveyed
individual's lifetime. Census household surveys use different industry codes than the NAICS codes used
in its firm surveys, so these were converted to NAICS using a published crosswalk (Census Bureau,
2012b). EPA calculated the average tenure for the following age groups: (1) workers aged 50 and older,
(2) workers aged 60 and older, and (3) workers of all ages employed at time of survey. EPA used tenure
data for age group "50 and older" to determine the high-end lifetime working years, because the sample
size in this age group is often substantially higher than the sample size for age group "60 and older." For
some industries, the number of workers surveyed, or the sample size, was too small to provide a reliable
representation of the worker tenure in that industry. Therefore, EPA excluded data where the sample
size is less than five from our analysis.
TableApx F-2 summarizes the average tenure for workers aged 50 years and older from SIPP data.
Although the tenure may differ for any given industry sector, there is no significant variability between
the 50th and 95th percentile values of average tenure across manufacturing and non-manufacturing
sectors.
Table Apx F-2. Overview of Average Worker Tenure from U.S. Census SIPP (Age Group 50+)
Industry Sectors
Working Years
Average
50th
Percentile
95th
Percentile
Maximum
Manufacturing sectors (NAICS 31-33)
35.7
36
39
40
Non-manufacturing sectors (NAICS 42-81)
36.1
36
39
44
Source: (U.S. Census Bureau. 2019a).
Note: Industries where sample size is less than five are excluded from this analysis.
BLS CPS data provides the median years of tenure that wage and salary workers had been with their
current employer. Table Apx F-3 presents CPS data for all demographics (men and women) by age
group from 2008 to 2012. To estimate the low-end value on number of working years, EPA uses the
most recent (2014) CPS data for workers aged 55 to 64 years, which indicates a median tenure of 10.4
years with their current employer. The use of this low-end value represents a scenario where workers are
only exposed to the chemical of interest for a portion of their lifetime working years, as they may
change jobs or move from one industry to another throughout their career.
Page 184 of 191
-------
Table Apx F-3. Median Years of Tenure wit
l Current Employer by Age Group
Age
January 2008
January 2010
January 2012
January 2014
16 years and over
4.1
4.4
4.6
4.6
16 to 17 years
0.7
0.7
0.7
0.7
18 to 19 years
0.8
1.0
0.8
0.8
20 to 24 years
1.3
1.5
1.3
1.3
25 years and over
5.1
5.2
5.4
5.5
25 to 34 years
2.7
3.1
3.2
3.0
35 to 44 years
4.9
5.1
5.3
5.2
45 to 54 years
7.6
7.8
7.8
7.9
55 to 64 years
9.9
10.0
10.3
10.4
65 years and over
10.2
9.9
10.3
10.3
Page 185 of 191
-------
Appendix G DERMAL EXPOSURE APPROACH
The dermal load (On) is the quantity of chemical on the skin after the dermal contact event. This value
represents the quantity remaining after the bulk chemical formulation has fallen from the hand that
cannot be removed by wiping the skin (e.g., the film that remains on the skin). To estimate the dermal
load for formaldehyde for occupational and consumer uses, EPA used dermal loading based on A
Laboratory Method to Determine the Retention of Liquids on the Surface of the Hands (U.S. EPA. 1992)
and formaldehyde weight concentrations relevant to the occupational use or consumer product. In
addition, only acute exposures were quantitatively assessed given the identified dermal skin sensitization
POD is likely only relevant to acute exposures (U.S. EPA 2024i). The supporting study measured liquid
retention on the surface of hands based on indirect (i.e., contact with saturated object) contact and direct
(i.e., immersive) contact.
For consumer exposures, EPA assumes a pool of a liquid product was formed on the skin, or that a rag
was used that reduced the evaporation of formaldehyde during use. A Qu of 10.3 mg/cm2 was used as
the most protective value for consumers using oil-based products expected to have longer residence
times on the skin relative to water-based products, as reported in (U.S. EPA 1992). While this is the
most protective value for consumer usage of oil-based products, it may overestimate exposures in some
cases including when using water-based liquid products. Dermal exposures are only reasonably foreseen
for consumers but not bystanders.
Owing to volatility and expected use patterns, dermal loading of formaldehyde from solid products is
unlikely, except for certain textiles including clothing that are treated with formaldehyde in dyeing and
wrinkle prevention step in the textile manufacturing process (Herrero et al.. 2022). EPA could not
identify supporting evidence for dermal loading exposures from the handling or wear of fabrics. The
Agency also could not identify a diffusion coefficient of formaldehyde for clothing. Therefore, EPA had
a low level of confidence in the estimation of dermal loading from textiles including clothing. Thus, a
qualitative assessment is reported for this product type in the Draft Consumer Exposure Assessment for
Formaldehyde (U.S. EPA. 2024d).
For occupational exposures, EPA uses the guidance in Updating CEB's Methodfor Screening-Level
Assessments of Dermal Exposure (U.S. EPA. 2013) on selection of 0„ values. EPA assumes routine and
incidental contact with liquids occur for workers during routine maintenance activities, manual cleaning
of equipment, filling drums, connecting transfer lines, sampling, and bench-scale liquid transfers. For
this event, the memorandum uses values of 0.7 to 2.1 mg/cm2-event for routine liquid contact. EPA uses
the maximum value of the range from the memorandum to estimate high-end dermal loads. EPA also
included a central tendency liquid dermal loading values, EPA used the 50th percentile of the dermal
loading results from the underlying study (U.S. EPA. 1992). The 50th percentile value was 1.4 mg/cm2-
event for routine/incidental contact with liquids.
EPA assumes routine and immersive contact with liquids occur for workers during manual spray
applications or contact with very wet surfaces. For this event, the memorandum uses values of 1.3 to
10.3 mg/cm2-event for liquid contact. EPA uses the maximum value of the range from the memorandum
to estimate high-end dermal loads. EPA also included a central tendency liquid dermal loading values,
EPA used the 50th percentile of the dermal loading results from the underlying study (U.S. EPA. 1992).
The 50th percentile value was 3.8 mg/cm2-event for routine/incidental immersive contact with liquids.
The dermal exposure estimates do not consider the use of gloves or other protective equipment.
Page 186 of 191
-------
Appendix H ADDITIONAL OCCUPATIONAL RISK
CHARACTERIZATION
The following subsections provide a summary of potential chronic non-cancer risks associated with
formaldehyde based on TSCA COUs during occupational COUs.
H.l Chronic Non-cancer Risk Estimates
As shown in Figure Apx H-l, chronic non-cancer risk estimates for worker inhalation exposure range
from 2.59x 10 3 to 3.91 x 103 for both high-end and central tendency exposures. For COUs with multiple
OESs or estimation approaches, the scenario with the highest central tendency value was illustrated.
While some healthy adult workers may be less susceptible to formaldehyde at concentrations below the
benchmark MOE, Chronic non-cancer effects may be a concern for susceptible workers such as those
with chronic respiratory disease or those with co-exposures that contribute to similar respiratory effects.
Of the 50 TSCA COUs evaluated, 48 TSCA COUs have chronic risk estimates below an MOE of 3
based on their high-end and central tendency risk estimates, with 1 TSCA COUs whose chronic risk
estimates was above an MOE of 3 for their central tendency risk estimate. Sub-chronic, non-cancer risk
estimates follow a similar risk profile and are not separately illustrated, except Commercial Use- lawn
and garden products which has central tendency and high-end estimates below the MOE of 3 for sub-
chronic non-cancer risk estimates.
Page 187 of 191
-------
Processing-Article-Rubber Product -
Processing- Reactant'
Z)
o
o
Manufacturing
Processing-Articie-Textiies -
Processing-Formulations -
Import/Processing-Repackaging
Distribution in Commerce
Processing-Article-Adhesive and sealant chemicals -
Processing-Article-Transportation -
Processing-Recycling
OO
O O
O O
til
Q
m
O o
^~| Increasing Risk
10 "
10'
10
Chronic MOE
10
10
Statistical Descriptor
O Central Tendency
O High-End
FigureApx H-l. Chronic Non-Cancer Occupational Inhalation Risks for Manufacturing/
Processing COUs
Non-cancer MOE risk estimates based on occupational exposure with lower MOE values indicating greater risks.
For COUs with multiple OESs or estimation approaches, the scenario with the highest central tendency value was
illustrated.
Page 188 of 191
-------
Laundry and dishwashing products*
Lawn and garden products
Paper products...*
Construction and building[wood and other articles]...
Disposal
Explosive materials*
Oxidizing/reducing agent...
Water Treatment Products
Ink, toner, and colorant...
Construction and building[metal]...
Machinery, mechanical...
Floor coverings, Foam...
Arts, crafts, and hobby materials
Process Aid in Oil and gas drilling...
Laboratory Chemicals
Used in Construction
Paints, Coatings, Adhesives(IU/CU)...
Automotive care product...
0
Co
'-J
~
0
«
o
o
O c
r\
>
J
a
o
~
c
0
I—i
cq
1
cq
A
'¦w1
~
o
~
o
r-.
a (
ncre^sing Risk
° L
~
{J
Statistical Descriptor
O Central Tendency
O High-End
10
10 '
10" 10
Chronic MOE
10
FigureApx H-2. Chronic Non-cancer Occupational Inhalation Risks for Industrial/Commercial
Use COUs
Non-cancer MOE risk estimates based on occupational exposure with lower MOE values indicating greater risks.
For COUs with multiple OESs or estimation approaches, the scenario with the highest central tendency value was
illustrated.
For chronic inhalation risks, EPA has high confidence in the chronic, non-cancer hazard POD. The
chronic, non-cancer hazard POD is supported by a robust database of evidence in humans and animals
that demonstrates concordance in effect levels across multiple endpoints and it includes evidence in
children with asthma and other sensitive groups. Generally, EPA has medium confidence in the
exposure estimates for full-shift exposures but confidence for individual scenarios varies from low to
high across the OESs assessed. For most exposure scenarios, EPA estimated full-shift exposures by
integrating discrete data identified from peer-reviewed literature and other sources.
Page 189 of 191
-------
Appendix I ADDITIONAL CONSUMER RISK
CHARACTERIZATION
The following subsections provide a summary of potential chronic exposures and risks associated with
formaldehyde based TSCA COUs during consumer use.
1.1 Consumer Chronic Risk Estimates
EPA estimated non-cancer risks for exposure to formaldehyde resulting from exposure to formaldehyde
in consumer products. For this analysis, EPA relied on the consumer exposure estimates modeled in the
Consumer Exposure Assessment for Formaldehyde (U.S. EPA. 2024d) and summarized in Section 2.2.
EPA does not expect most consumer exposures to be chronic in nature because product use patterns
generally tend to be infrequent with relatively short durations of use. Therefore, EPA did not estimate
potential cancer risks for consumers.
1.1.1 Risk Estimates for Inhalation Exposure to Formaldehyde in Consumer Products
EPA estimated non-cancer risks to consumers and bystanders from inhalation of formaldehyde in
consumer products.
Chronic non-cancer risk estimates for consumers based on modeled chronic inhalation exposures range
from 1.02xl0+2 to 9.98xl0+6, with lower values indicating greater risks (Figure_Apx 1-1). Non-cancer
risk estimates below 1 indicate that exposure is greater than the hazard point of departure based on
respiratory effects in sensitive groups, including children. The risk estimates for chronic exposures
presented here are based on central tendency air concentrations modeled for a set of mid-range model
input assumptions and TSCA COU-specific assumptions about exposure frequency and duration. Risk
estimates presented here represent risks to consumers who frequently use products containing
formaldehyde and are based on the consumer activity and use patterns described in the Consumer
Exposure Assessment for Formaldehyde (U.S. EPA. 2024d). For example, cancer risk estimates for the
arts, crafts, and hobby material COU presented here are not representative of all arts and crafts products.
They are based on an assumption of exposure to a specific set of products that contain 0.1 percent
formaldehyde used an average of 15 minutes/day, 300 days each year, over a period of 57 years which
are standard CEM temporal inputs primarily based upon the 1987 Westat survey of consumer activities
and use patterns (U.S. EPA. 2021a. 2019; Westat. 1987).
Page 190 of 191
-------
Increasing Risk
<
Generic Scenario (Crafting Paint/inks applied to n
Skin)" u
Liquid photographic processing solutions -
O
~
to
c
d)
o
C/5
Glues and Adhesives ¦
O
Caulk (sealant)-
Lubricants non-spray ¦
O
O
_I I I I I III
_l I I I I 1111
_l I I I I III
_l I I I I 111
_l I I I I III
Modeled Person
~ Bystander
O User
10"
10"
1Cf 1(f
Chronic MOE
10°
10'
FigureApx 1-1. Chronic Non-cancer Inhalation Risks for Consumer Products by COU
Chronic risk estimates are based on consumer and bystander exposure estimates that rely on central tendency
assumptions about product use duration and frequency. Non-cancer MOEs are based on modeled air exposure
estimates and are interpreted relative to a benchmark MOE of 3. Lower MOE values indicate greater risks. The x-
axis presents risk estimates for chronic inhalation exposure estimates, and the y-axis presents the modeled TSCA
COUs.
Overall confidence in inhalation risk estimates for consumer products is medium for chronic non-cancer
risks. As described in Section 3.2.1 of the Consumer Exposure Module, the overall confidence in
monitoring data used in the indoor air assessment is high due to reliance on 41 high quality
formaldehyde air exposure studies relevant to TSCA COUs, and CEM modeling assumptions and
inputs, which have been peer reviewed and used in previous existing chemical risk evaluations. While
EPA relied on available survey data on product use patterns, there is uncertainty around the applicability
of the generic survey data for current use patterns for specific product types. For example, for some
inputs relied on the use and activity patterns reported in the Westat survey from 1987 (Westat 1987).
Although this is a robust dataset it may not be reflective of current use patterns for the specific product
types assessed. As described in Section 3.2, overall confidence in the chronic, non-cancer hazard POD is
high because it is supported by a robust database of evidence in humans and animals that demonstrates
concordance in effect levels across multiple endpoints and it includes evidence in children with asthma
and other sensitive groups.
Page 191 of 191
------- |