United States EPA Document# 740-R1-4003 Environmental Protection Agency August 2014

Office of Chemical Safety and Pollution Prevention

TSCA Work Plan Chemical Risk Assessment

Methylene Chloride: Paint Stripping Use

CASRN: 75-09-2

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August 2014

TABLE OF CONTENTS LIST OF TABLES .............................................................................................................................................................. 6

LIST OF FIGURES............................................................................................................................................................10

AUTHORS/CONTRIBUTORS/ACKNOWLEDGEMENTS/REVIEWERS .................................................................................12

GLOSSARY OF TERMS AND ABBREVIATIONS .................................................................................................................14

EXECUTIVE SUMMARY ..................................................................................................................................................19

1 BACKGROUND AND SCOPE ..................................................................................................................................27

1.1 INTRODUCTION........................................................................................................................................27 1.2 BACKGROUND..........................................................................................................................................28

1.2.1 Rationale for Selecting DCM for Risk Assessment ....................................................................................28 1.2.2 Overview of DCM Uses and Production Volume ......................................................................................28 1.2.3 Overview of !ssessments of DCMs Human Health Hazards ...................................................................28 1.2.4 Overview EP!s Regulatory History of DCM .............................................................................................29

1.3 SCOPE OF THE ASSESSMENT.....................................................................................................................30 1.3.1 Selection of DCM Uses..............................................................................................................................30 1.3.2 Selection of Exposure Pathway ................................................................................................................30 1.3.3 Identification of Human Populations Exposed During the Use of DCM-Based Paint Strippers ................30 1.3.4 Why Environmental Risks Were Not Evaluated For DCM-Based Paint Strippers .....................................32

2 SOURCES AND FATE.............................................................................................................................................33

2.1 PHYSICAL AND CHEMICAL PROPERTIES....................................................................................................33 2.2 DCM PRODUCTION AND USES..................................................................................................................34

2.2.1 Market Trends and Uses ..........................................................................................................................34 2.2.1.1 Consumer Uses.......................................................................................................................................................... 37 2.2.1.2 Paint Stripping Applications ...................................................................................................................................... 38

2.3 SUMMARY OF ENVIRONMENTAL FATE ....................................................................................................38

3 HUMAN HEALTH RISK ASSESSMENT ....................................................................................................................39

3.1 OCCUPATIONAL EXPOSURE ASSESSMENT FOR THE USE OF DCM IN PAINT STRIPPING............................39 3.1.1 Approach and Methodology for Estimating Occupational Exposures......................................................39

3.1.1.1 Identification of Relevant Industries ......................................................................................................................... 39 3.1.1.2 Estimation of Potential Workplace Exposures for Paint Stripping Facilities.............................................................. 40 3.1.1.3 Summary of Occupational DCM Exposure Estimates ................................................................................................ 46 3.1.1.4 Worker Exposure Limits for DCM.............................................................................................................................. 49

3.2 CONSUMER EXPOSURE ASSESSMENT FOR THE USE OF DCM IN PAINT STRIPPING ..................................50 3.2.1 Approach and Methodology for Estimating Consumer Exposures...........................................................50 3.2.2 Overview of the MCCEM ..........................................................................................................................50 3.2.3 MCCEM Input Parameters and Assumptions ...........................................................................................52

3.2.3.1 Estimation of Emission Profiles for Paint Removers/Strippers .................................................................................. 52 3.2.3.2 Method of Application .............................................................................................................................................. 53 3.2.3.3 Amount Applied to the Surface (Product Mass)........................................................................................................ 53 3.2.3.4 Stripping Sequence ................................................................................................................................................... 54 3.2.3.5 Amount of Chemical Released .................................................................................................................................. 55 3.2.3.6 Airflow Rates and Volumes ....................................................................................................................................... 55 3.2.3.7 Locations of Exposed Individuals............................................................................................................................... 56

3.2.4 MCCEM Modeling Scenarios ....................................................................................................................56 3.2.4.1 Sensitivity Analysis .................................................................................................................................................... 57 3.2.4.2 Exposure Scenarios for the DCM Inhalation Exposure Assessment .......................................................................... 60

3.2.5 Consumer Model Results..........................................................................................................................65 3.3 HAZARD/DOSE-RESPONSE ASSESSMENT .................................................................................................67

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3.3.1 Approach and Methodology ....................................................................................................................67 3.3.1.1 Selection of Peer-Reviewed Hazard/Dose-Response Assessments as the Source Documents for the DCM TSCA

Assessment ............................................................................................................................................................... 67 3.3.1.2 Chronic Hazard and Dose-Response Assessment: EPA IRIS Toxicological Review of Methylene Chloride................ 68

3.3.1.2.1 Carcinogenic Effects Following Chronic Exposure to DCM................................................................................ 68 3.3.1.2.2 Non-Cancer Effects Following Chronic Exposure to DCM ................................................................................. 69

3.3.1.3 Acute Hazard and Dose-Response Assessment......................................................................................................... 72 3.3.1.3.1 SMACs ............................................................................................................................................................... 73 3.3.1.3.2 Californias !cute REL ....................................................................................................................................... 74 3.3.1.3.3 AEGLs ................................................................................................................................................................ 75

3.3.2 Human Health Hazard Summary .............................................................................................................78 3.3.2.1 Absorption, Distribution, Metabolism and Excretion................................................................................................ 78 3.3.2.2 Human and Animal Toxicity Following Acute Exposure to DCM ............................................................................... 79 3.3.2.3 Human and Animal Toxicity Following Repeated Exposures to DCM........................................................................ 80

3.3.2.3.1 Non-Cancer Effects ........................................................................................................................................... 80 3.3.2.3.2 Carcinogenic Effects.........