While it still wants to restrict exposures to straight mineral oil mist, the American Council of Governmental Industrial Hygienists has decided its proposed restriction does not apply to metalworking fluids, a significant conclusion for fluid manufacturers and users.
In a Feb. 1 letter to the Independent Lubricant Manufacturers Association, ACGIH Science Manager Ryan Peltier said, Note that the proposed TLV [threshold limit value] does not apply to mineral oils in metalworking fluids, because of the complex and highly variable composition of these fluids. Peltier added that the Alexandria, Va. based trade associations comments on the issue were considered in its decision.
ACGIH had for several years proposed limiting the threshold limit value time-weighted average for exposures to mineral oil used in metalworking fluids to 0.2 milligrams per cubic meter, a 25-time reduction from the current OSHA Permissible Exposure Limit for mineral oil. ILMA and others have argued that occupational exposure issues associated with metalworking fluids have little to do with highly refined base oils and are not addressed by a single-number exposure limit. Rather, ILMA has supported a systems approach to controlling exposures to the contaminants generated while metalworking fluids are in use.
If ACGIH had adopted the TLV, ILMA Counsel Jeffrey Leiter told Lube Report, it would have been adopted [by reference] in the OSHA Hazard Communication Standard. This would have placed unnecessary and inappropriate regulatory burdens on fluid manufacturers, he contended. Metalworking fluids are complex. A systems approach, not a single number, is the right approach to exposure control and fluid management, Leiter said.
The association considers ACGIHs shift to be a significant change in the regulatory landscape for metalworking fluids. Exposures to used fluids are associated with a range of respiratory and dermal illnesses, and ILMA, whose members manufacture 80 percent or more of the metalworking fluids sold in the United States, has actively promoted fluid management programs.