This criteria document reviews available information about the adverse health effects associated with occupational exposure to metalworking fluids (MWFs) and MWF aerosols. Substantial evidence indicates that workers currently exposed to MWF aerosols have an increased risk of nonmalignant respiratory disease and skin diseases. To prevent or greatly reduce the risk of adverse health effects in exposed workers, NIOSH recommends that exposures to MWF aerosols be limited to 0.4 mg/m3 of air for thoracic particulate mass (or 0.5 mg/m3 for total particulate mass) as a time-weighted average (TWA) concentration for up to 10 hr/day during a 40-hr workweek. Total particulate mass is an acceptable substitute for thoracic particulate mass until thoracic samplers are widely available. This recommended exposure limit (REL) is based on evaluation of health effects data, sampling and analytical feasibility, and technological feasibility. The NIOSH recommendation for reducing MWF aerosol exposures is supported by substantial evidence associating some MWFs used before the mid-1970s with cancer at several organ sites, and by the potential for current MWFs to pose a similar carcinogenic hazard. However, the primary basis of the NIOSH recommendation is the risk that MWFs pose for nonmalignant respiratory disease. In addition to the REL, NIOSH recommends that a comprehensive safety and health program be developed and implemented as part of the employer's management system. This program should include safety and health training, worksite analysis, hazard prevention and control, and medical monitoring of exposed workers.
NIOSH-Criteria-Document; Metalworking-industry; Cutting-oils; Biological-effects; Exposure-limits; Aerosols; Pulmonary-system-disorders; Respiratory-system-disorders; Respiratory-protective-equipment; Personal-protective-equipment; Ventilation; Dermatitis; Skin-irritants; Skin-diseases; Skin-disorders; Cancer