When Environmental Policy Leads to Occupational Disease: A Case Study in the California Vehicle Repair Industry
When Environmental Policy Leads to Occupational Disease:
A Case Study in the California Vehicle Repair Industry.
This work has been conducted under the mentorship of S. Katharine Hammond and colleagues at UC Berkeley and pertains to solvent exposures in the California vehicle repair industry. The National Institute for Occupational Safety and Health, the University of California Toxic Substances Research and Teaching Program and the Occupational Health Branch of the California Dept of Health Services (OHB) have provided funding. Dr. James Cone (OHB) and Dr. Leslie Israel of the University of California, San Francisco are collaborators.
We have found three cases of acute, debilitating occupational disease (that is more typically seen among industrial workers in developing countries) in the automotive repair industry in the middle of California's Bay Area. The disease is n-hexane-induced peripheral neuropathy, and the exposures that led to the disease (that is, the exposures to n-hexane) ultimately resulted from environmental regulations, or more specifically, from the solvent industry's chosen response to those regulations. These are the first cases of n-hexane-induced peripheral neuropathy to be reported in the vehicle repair industry. This case study is similar to those reported in S. Korea, where 2-bromopropane, a potent reproductive hazard, was introduced as a substitute for CFCs, and Belgium where HCFCs, which are highly hepatotoxic, were also introduced as substitutes for CFCs.
We have used the tools of industrial hygiene to characterize exposures to n-hexane in automotive repair work and the tools of survey research to investigate the solvent industry's response to environmental regulations over the last 10 years.
This report primarily addresses this latter work, the regulatory history work. It represents a case study in the limitations, or the hazards if you will, of our current approach to environmental policy. I think these findings force us to think about new, more public health-oriented approaches to environmental policy. Such approaches would view communities, workplaces and differing environmental media not as isolated entities but as fluid and very much interrelated aspects of a single system of social health.
Abstract
Background: Environmental regulations have brought about much-needed changes; some, however, have resulted in unintended, deleterious consequences. 2-bromopropane was recently introduced as a substitute for chlorofluorocarbons (CFCs), resulting in ovarian failure in 17 of 25 exposed women workers at a semiconductor plant in South Korea. Another CFC substitute, hydrochlorofluorocarbon (HCFCs), was linked to an epidemic of liver disease among nine exposed workers at an industrial plant in Belgium. We report that the use of hexane-based cleaning solvents in the California automotive repair industry represents another case in which unintended occupational health consequence resulted from industry's response to environmental regulations. Occupational exposure to n-hexane is associated with peripheral neuropathy, a potentially debilitating nerve disease. The California Department of Health Services recently identified three Bay Area automotive technicians with diagnoses of n-hexane-related peripheral neuropathy. These are the first cases to be reported in the automotive repair industry. Additional possible cases are under investigation.
Methods: We administered a national survey to fifty automotive solvent producers to determine when, and for what reason, hexane-based solvents were introduced into the California vehicle repair industry, and to determine what action the solvent industry is taking in response to a California-mandated phase-out of chlorinated solvents from the state's vehicle repair industry. Seventeen of the fifty manufacturers reported selling product in California; 11 (65%) of these firms have responded as of November 13, 2001. We conducted exposure monitoring for n-hexane, acetone, toluene, xylene and methyl ethyl ketone among automotive technicians and are developing a n-hexane risk assessment based on these findings.
Findings: In the early 1990s, the largest solvent producers introduced hexane-based brake-cleaning solvents into the California vehicle repair industry as an alternative to chlorinated solvents. In 1997, acetone was added to these hexane-based products to comply with a Cal/EPA-mandated 50% cap on volatile organic compounds (VOCs). In 2001, producers began substituting chlorinated automotive brake-cleaning solvents in California with both heptane and hexane-based products. The toxicology data suggest that acetone potentiates the neurotoxic effect of n-hexane. Our preliminary exposure data show that automotive technicians who use a product containing 30% hexane and 50% acetone are exposed to each of these solvents in approximately equal proportions.
Interpretation: New hazards might result in the workplace when environmental rules are developed without careful consideration of the potential occupational health consequences. When a product is banned (such as CFCs) or restricted (such as chlorinated solvents) for environmental reasons, substitute products should be regulated based on an analysis of their potential to produce harm in the workplace as well as the environment. Poorly understood substances should not be confused with non-toxic or less toxic substances. Integrating industrial hygiene into the environmental rule-making process and regulating the introduction of substitute products would better protect public health and the environment and would establish appropriate baseline standards for industry.
Author: Michael P. Wilson
Doctoral Candidate
Environmental Health Sciences
School of Public Health, University of California, Berkeley
mpwilson@uclink4.berkeley.edu
510-622-4304
This page updated Friday March 26 2004