The history of OSHA's asbestos rule makings and some distinctive approaches that they introduced for regulating occupational exposure to toxic substances.

The Occupational Safety and Health Administration (OSHA) has regulated occupational exposure to asbestos since 1971. Since issuing its first asbestos standard, OSHA has modified it several times in response to new information about the health risk of exposure and concern expressed by workers and public health groups. As each modification has reduced worker exposure and disease risk, each also has introduced new concepts including emphasis on ancillary provisions in standards regulating occupational exposure to toxic substances to enhance worker health; medical removal protection; two attempts at emergency temporary standards; use of historical and objective exposure data to assess worker exposure; the need to eliminate significant risk of disease posed by asbestos; and the presumption of hazard in absence of exposure information. These and other advances have affected all subsequent OSHA standards aimed at reducing occupational exposure to toxic substances.

Follow-up of biologic monitoring results in cadmium workers removed from exposure.

Biological monitoring and exposure monitoring data for employees at a nickel-cadmium battery production facility were made available to OSHA for review. Sixteen employees were medically removed from occupational exposures to cadmium due to elevated levels of biological parameters (CdB, Cdu, B2U). While the biological monitoring parameters for most workers significantly declined during the 18 months of medical removal, the biological parameters for only one employee's values returned to the normal range. Only one worker had frank renal dysfunction, based on beta-2-microglobulin levels at the time of removal; this dysfunction remained throughout the 17 months of observation after medical removal. Significant policy implications of medical removal protection beyond the current 18-month period provided by the cadmium standards exist and require physician discretion. Mitigating issues which may make it ethically appropriate to return an employee to work despite elevated biologic monitoring parameters are also discussed.

Biological monitoring results for cadmium exposed workers.

As part of a settlement agreement with the Occupational Safety and Health Administration (OSHA) involving exposure to cadmium (Cd), a battery production facility provided medical surveillance data to OSHA for review. Measurements of cadmium in blood, cadmium in urine, and beta 2-microglobulin in urine were obtained for more than 100 workers over an 18-month period. Some airborne Cd exposure data were also made available. Two subpopulations of this cohort were of primary interest in evaluating compliance with the medical surveillance provisions of the Cadmium Standard. These were a group of 16 workers medically removed from cadmium exposure due to elevations in some biological parameter, and a group of platemakers. Platemaking had presented a particularly high exposure opportunity and had recently undergone engineering interventions to minimize exposure. The effect on three biological monitoring parameters of medical removal protection in the first group and engineering controls in platemakers is reported. Results reveal that both medical removal from cadmium exposures and exposure abatement through the use of engineering and work practice controls generally result in declines in biological monitoring parameters of exposed workers. Implications for the success of interventions are discussed.

OSHA's approach to risk assessment for setting a revised occupational exposure standard for 1,3-butadiene.

In its 1980 benzene decision [Industrial Union Department, ALF-CIO v. American Petroleum Institute, 448 U.S. 607 (1980)], the Supreme Court ruled that "before he can promulgate any permanent health or safety standard, the Secretary [of Labor] is required to make a threshold finding that a place of employment is unsafe--in the sense that significant risks are present and can be lessened by a change in practices" (448 U.S. at 642). The Occupational Safety and Health Administration (OSHA) has interpreted this to mean that whenever possible, it must quantify the risk associated with occupational exposure to a toxic substance at the current permissible exposure limit (PEL). If OSHA determines that there is significant risk to workers' health at its current standard, then it must quantify the risk associated with a variety of alternative standards to determine at what level, if any, occupational exposure to a substance no longer poses a significant risk. For rulemaking on occupational exposure to 1,3-butadiene, there are two studies that are suitable for quantitative risk assessment. One is a mouse inhalation bioassay conducted by the National Toxicology Program (NTP), and the other is a rat inhalation bioassay conducted by Hazelton Laboratories Europe. Of the four risk assessments that have been submitted to OSHA, all four have used the mouse and/or rat data with a variety of models to quantify the risk associated with occupational exposure to 1,3-butadiene. In addition, OSHA has performed its own risk assessment using the female mouse and female rat data and the one-hit and multistage models.(ABSTRACT TRUNCATED AT 250 WORDS)