MINERAL WOOL FIBER

OSHA comments from the January 19, 1989 Final Rule on Air Contaminants Project extracted from 54FR2332 et. seq. This rule was remanded by the U.S. Circuit Court of Appeals and the limits are not currently in force.

CAS: None. Chemical Formula: None

OSHA proposed a limit of 10 mg/m³ TWA for mineral wool fiber, measured as total particulate containing less than 1 percent quartz; this was the same limit recommended by the ACGIH (1986/Ex. 1-3). NIOSH recommends a 5 mg/m³ (8-hour TWA) limit, measured as total dust, as well as a 3-fiber/cc limit for fibers greater than 10 um long.

Extensive evidence was submitted to the record regarding the proposed PEL for mineral wool. Because of the conflicting nature of some of the evidence and the complexity of the issues raised, OSHA has not yet been able to reach a final conclusion. Therefore, OSHA is temporarily delaying a final decision regarding the establishment of a separate PEL for mineral wool fiber; however, OSHA will make this final decision within a reasonable period of time.