Exposure to Asbestos from Asbestos Gaskets

Abstract

For more than 50 years, asbestos gaskets have been used in piping, valves, pumps, and other equipment to prevent leakage of fluids between solid surfaces. Although exposure data are available for workers in the gasket manufacturing industry, there are no published reports on asbestos exposures for gasket users. This article presents data on asbestos exposures during use and handling of asbestos gaskets in the oil and chemical industries. Users' time-weighted average exposures to asbestos during replacement of after-service gaskets, on-site fabrication (cutting) of sheet gaskets, and handling of new and after-service gaskets inside Gasket Trailers were all within the Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit. The practice of dry removal of after-service sheet gaskets, followed by dry polishing of the seating surfaces with a power sander, could create a short-term asbestos exposure level in excess of the OSHA Excursion Limit. This type of potential, short-term, high exposure, however, can be eliminated simply by wetting the gaskets and seating surfaces prior to gasket replacement.

In July 1989, the U.S. Environmental Protection Agency (EPA) prohibited the manufacture, importation, processing, and distribution in commerce of most asbestos gaskets by 1994. EPA's decision to ban asbestos gaskets was based solely on exposure data obtained from the gasket manufacturers. However, asbestos gaskets will continue to be used for many years in the workplace as in-service gaskets are removed and existing supplies are installed. Data from this investigation suggest that asbestos gaskets can be safely handled if proper procedures are followed.