OSHA cuts butadiene permissable exposure limit to 1 ppm upon joint recommendations.

The Occupational Safety and Health Administration (OSHA) reduced the permissible exposure limit (PEL) for 1,3-butadiene (BD) from 1,000 parts per million parts of air (ppm) to I ppm. The agency claims that almost 10,000 workers will be better protected from cancer under the new standard.

About 9,700 workers at 255 facilities nationwide are potentially exposed to BD. In 1991, the U.S. produced 3.0 billion pounds of BD. About 60% is used in rubber manufacturing. In addition to presenting an increased risk of such cancers as leukemia, BD has been shown to increase risk to the reproductive system of laboratory animals. About 7,600 workers face significant exposures, averaging as high as 10 ppm. (No U.S. workers are likely to be exposed at OSHA's former PEL of 1,000 ppm.) Compliance with the BD standard is expected to cost employers about $2.9 million per year.

The final standard, which is expected to prevent at least 79 cancer deaths over a 45-year working lifetime, also includes a 15-minute short-term exposure limit (STEL) of 5 ppm and an action level of 0.5 ppm. Other provisions cover employee training, medical surveillance, record keeping, hazard communication and exposure monitoring.

A unique feature of the standard is an exposure goal program, which encourages employers to reduce exposures to below the action level.

OSHA's action follows its receipt in January 1996 of joint labor-management recommendations to reduce butadiene exposure levels. These came from the United Steelworkers of America (USW); the International Institute of Synthetic Rubber Producers (IISRP) and the Chemical Manufacturers Association (CMA) Olefins Panel.

An epidemiologic study submitted to OSHA by the synthetic rubber industry in late 1995 demonstrated an excess risk of cancer among workers exposed to 1,3-butadiene. OSHA's earlier cancer estimates, relying on mouse studies, were in line with the actual findings for workers presented by the industry. Based on the mouse studies, these lifetime risk estimates ranged from 1.3 to 8.1 cancer deaths per 1,000 workers exposed at 1 ppm BD.

The standard includes four informational appendices covering employee information and training, technical information on BD, medical screening and surveillance issues and OSHA's sampling and analytical method and a mandatory appendix on respirator fit-testing procedures.

The 23 states and two territories with their own OSHA-approved occupational safety and health plans must adopt a comparable 1,3-butadiene standard within six months. Until state standards are adopted, federal OSHA will provide interim enforcement assistance for BD.

The new 1,3-butadiene standard is expected to appear in the Federal Register shortly.

Highlights of OSHA 1,3-Butadiene Standard

* Scope and effective dates - covers all occupational exposures; mixtures with less than 0.1% butadiene are excluded. Storage, transportation, distribution or sale of BD in sealed pipelines in excluded except for labeling and emergency response requirements. Most provisions take effect in 180 days, except employers have two years to implement engineering controls and three years to establish the exposure goal program.

* Exposure limits - eight-hour time-weighted average (TWA) permissible exposure limit (PEL of 1 part BD per million parts air [ppm]); short-term exposure limit (STEL) of 5 ppm over a 15-minute period; and an action level of 0.5 ppm.

* Exposure monitoring - mandates monitoring every 12 months if samples register at or above the action level but at or below both the PEL and the STEL; every three months if above the PEL or the STEL for eight samples within a two-year period, then every six months. Initial monitoring (or similar monitoring conducted within the two years before the effective date of the monitoring requirement) must be completed within 60 days after the effective date of the standard or the introduction of BD into the workplace. If the initial monitoring is below the action level or objective data indicate exposures below the action level and at or below the STEL, no further monitoring would be necessary unless there is a change in production, control equipment, personnel or work practices that might alter exposures. Additional monitoring needed for spills, leaks, ruptures or breakdowns. Employees to have opportunity to observe exposure monitoring with employers provision of any needed protective gear. Affected workers to receive notification of monitoring results within five business days of employer receipt and notice of corrective action within 15 business days after learning that exposures exceed PEL or STEL.

* Regulated areas - calls for employer to set aside and mark areas whatever airborne exposures exceed PEL or STEL to limit access to authorized persons only. At multi-employer worksites, must notify other employers of hazard.

* Methods of compliance - requires employer to use feasible engineering and work practice controls to achieve PEL and STEL or reduce exposures as much as possible. Respirators used for supplemental protection.