# Evaluating Worker Risks to TCE

The Status of TCE Occupational Exposure Limits 

## The Importance of Informed Substitution 

# EPA TCE Workshop July 29, 2014 

## Julia Quint, PhD 

## CA Dept. of Public Health (Retired)

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# Presentation 

# Overview ► Evaluating Worker TCE Health Hazards / Risks Basis of TCE Occupational Exposure Limits ► Protecting CA Workers from Chemical Hazards 

## “Early Warnings” and Risk- Based PELs ► Challenges in Evaluating Worker TCE Health Risks ► 

## Identifying Safer Substitutes for TCE ► Case Studies of Regrettable TCE Substitutes n - Hexane and 1 - Bromopropane34 

# Why QRA is Used to Develop PELs  Benzene Court Decision (1980)  OSHA responsible for demonstrating significance of risk when developing PELs  Significant cancer risk is between 1/billion and 1/1000 (Judge) 4Selected OSHA Cancer Risk Estimates (Excess Cancers per 1,000 Workers) Federal Register V. 71, No. 39, 2006 Standard Risk at Prior

PEL Risk at New PEL Date Ethylene oxide 63 - 109 1.2 -2.3 1984 Asbestos 64 6.7 1986 Benzene 95 10 1987 Formaldehyde 0.43 - 18.9* 0.0056 -2.64* 1987 Methylenediani line 6 - 30** 0.8 1992 Cadmium 58- 157 3 - 15 1992 1,3 - Butadiene 11.2 - 59.4 1.3 -8.1 1996 Methylene Cl 126 3.6 1997 Chromium VI 101 - 351 10-45 2006

5 * Range is based on maximum likelihood estimate (0.43, 0.0056) and upper 95% confidence limit (18.9, 2.64). ** Estimated exposure, no prior standard .6 

## 1997 Cal OSHA Airborne Contaminants Advisory Committee ― PEL Recommendations

• Acetaldehyde

• Carbon tetrachloride • Cobalt, elemental and inorganic compounds, as Co • Cr VI compounds • p - Dichlorobenzene • 1,1 –Dimethylhydrazine • Glass, fibrous • Heptachlor • Hexachlorobenzene • Hydrazine • Perchloroethylene 

### • Phenyl glycidyl ether • Trichloroethylene • Vinyl acetate • 4-Vinyl cyclohexene • Vinyl cyclohexene dioxide7



## The Cal OSHA Airborne Contaminants

Advisory Committee Carcinogen Position Statement (1997)  These s ubstances have been identified by IARC as a carcinogen (Group 2B or higher).  The recommended exposure limits are based on other types of toxic results, damage or interference with organ systems, irritation, respiratory problems, etc.  Quantitative risk assessments can be used to estimate risks of cancer at various exposure levels in order to set a PEL.  No such risk assessments have been conducted by this committee.  N either Cal OSHA nor the Occupational Safety and Health Standards Board have standard methods for performing these assessments or a useful criterion against which limits might be set.  Cal OSHA should reconsider the proposed PELs if a carcinogen guideline policy is adopted & appropriate resources allocated.8 

# Identifying Chemical Hazards and Evaluating Risks to CA Workers Hazard Evaluation System & Information Service (HESIS), Occupational Health Branch, CDPH
 Established by CA Legislature in 1979

 Identify and evaluate workplace chemical h azards
 Translate “toxicology” into practical language


###  Issue “early warnings” on new/unrecognized hazards
 Recommend protective standards to Cal/OSHA9 9 

# Cal/EPA’s Office of Environmental Health Hazard Assessment (OEHHA) Mission Protect & enhance public health & the environment by scientific evaluation of risks posed by hazardous substances 

### Vision To be California’s leading scientific organization for evaluating risks to human & ecological health 

### Relevant Functions  Develop and recommend to the Air Resources Board health protective exposure levels for toxic air contaminants  List chemicals known to the state to cause cancer or reproductive harm to implement Proposition 65 

### Staff Resources (2005)  64 PhDs  7 Physicians  21 Masters in public health science10



# Occupational Health Hazard Risk Assessment Project for California HESIS’ project concept and contract with OEHHA:  C onduct a systematic analysis of whether existing QRA data could be used to develop protective PELs  Screen Proposition 65 List for workplace chemicals of concern ( unregulated or under - regulated chemicals)  Describe and apply methods for calculating health 

### protective air concentrations  Discuss scientific issues related to dose - response assessment for the occupational setting

# CA Occupational Health Hazard Risk Assessment Project – Some Key Findings  44 workplace chemicals listed as “known to cause cancer”* did not have PELs 

##  5 chemicals listed as “known to cause reproductive/developmental toxicity”* did not have PELs  62 Prop 65 - listed carcinogens had PELs that were 

## not based on cancer (no QRAs conducted)  14 Prop 65 - listed reproductive/developmental toxicants had PELs that were not explicitly based on this endpoint, or the PEL bases were unclear * Prop 65 List=12/2006. Final Project Report=12/2007
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# CA Occupational Health Hazard Risk Assessment Project –Findings/Conclusions  Adjusted OEHHA & EPA QRAs can be applied 

## to the workplace, which leverages resources  Using existing QRAs to develop OELs requires appropriate expertise 

##  Lifetime cancer risks at existing PELs are high for many workplace chemicals  Science - based OELs can be developed using a 

## transparent & risk- based approach  Risk managers can still take technical & economic feasibility into account to set limits

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# CA Occupational Health Hazard Risk Assessment Project – High Cancer Risks Chemical PEL Basis Cal/OSHA Risk at PEL* OSHA

Risk at PEL* Acetaldehyde Irritation 24 210 Naphthalene Irritation; blood

effects 310 310 Perchloroethylene CNS impairment 200 744 Trichloroethylene CNS impairment;

renal toxicity 53 196 Ethylbenzene Irritation; CNS

impairment 210 210 1,4- Dioxane Liver damage 135 558 p - Dichlorobenzene Kidney damage 129 959

13 *Cancer risks/1000 workers calculated using OEHHA unit risk values adjusted for occupational exposure [10 m 3/20 m 3 x 250 days/365 days x 40 years/70 years]

# Cal/OSHA QRA- Based PELs − Examples

Chemical Prior PEL QRA- Based PEL Cancer Risk/Health Endpoint 1,4- Dioxane 25 ppm 0.28 ppm 1.4/1000 Cyclonite (RDX) 0.5 mg/m 3 0.075 mg/m 3 Liver damage 1 - Bromopropane None 5 ppm Reproductive & Developmental N Methylpyrrolidone None 1 ppm Developmental Toluene 50 ppm 10 ppm Developmental Ethylbenzene 100 ppm 5 ppm 10/1000 Methyl - n - butyl ketone 5 ppm 1 ppm Peripheral Neuropathy Sulfuric acid 1 mg/ m 3 0.1 mg/ m 3 Carcinogen Designation Pulmonary function 14

# Evaluating Worker Chemical Risks
— Some of the Challenges  Large # of chemicals / limited toxicity & QRA data  Limited toxicology resources in OSHA and other occupational health agencies/programs 

##  Exposure and use information lacking—chemical prioritization is difficult  Numerous, c ompeting worker protection obligations 

## (infectious disease, heat, ergonomics, safety, etc.)  Limited participation of key stakeholders (small employer and worker representatives

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# Informed Substitution of TCE and Other Toxic Chemicals— Some General Guidelines  Safer chemical substitution—old concept, but 

## often not specific regarding recommendations  Effective substitutes must address functional uses 

##  Evaluating health and environmental hazards of substitutes prevents transfer of risks (use lists, searches, etc.). Avoid “no data” substitutes  Identify substitutes with demonstrated efficacy  Anticipate and address (if possible) other known toxic chemicals that may be used as substitutes

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# Regrettable TCE Substitute − n - Hexane  TCE, methylene c hloride, and perchloroethylene in vehicle repair cleaners were banned by CA Air Resources Board(CARB) 

#  n - Hexane put in auto cleaners as a substitute solvent 

#  Workers developed peripheral neuropathy  Condition d iagnosed by an occupational medicine physician18 

# HESIS Response to n - Hexane Illnesses19 

# Safer Auto Repair Aerosol Cleaners

Two-year EPA Pollution Prevention Grant Collaboration with the Institute for Research & Technical Assistance (IRTA) IRTA developed & demonstrated the effectiveness of safer aerosol automotive cleaners Promoted use of safer aerosol cleaners Promoted use of integrated illness, injury & P2 strategies in the industry

# Regrettable TCE Substitute − 1 - Bromopropane (Background)

20 HESIS Hazard Alert (2003 ) DBCP structural analog Replaced ozone - depleting solvents NTP CERHR Report Male, female reproductive toxicant & developmental toxicant (animals) Nerve damage (workers) Cancer (animal bioassay in progress in 2003, later positive)

# 1 - Bromopropane Use in Vapor Degreasing−

Case Report of Peripheral Neuropathy (2009)

 Machinist at microwave equipment firm worked daily with Lenium ES (80 - 90% 1 - bromopropane)
 B ilateral heel pain for 4 months
 I nitially diagnosed with plantar fasciitis
 Neurologist later diagnosed peripheral neuropathy
 Worker found the HESIS 1 - BP Alert on internet and recognized product
 Medical Examiner concluded more probable than not caused by 1 - BP
 HESIS reported case to NIOSH 21

## Some Ways to Prevent Adverse Effects on

Workers’ Health From Regrettable Substitutions  Require toxicity testing before marketing new chemicals 

### and implement restrictions, as needed, to help ensure their safe use  Support/ensure the development of safer alternatives for specific uses of toxic chemicals that are demonstrated to 

### be efficacious and cost- effective before restricting chemical use  Identify and specify chemicals that cannot be used as substitutes for restricted toxic chemicals  Integrate and coordinate strategies to protect health and the environment from toxic chemicals

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