Analytical method research for metalworking fluids at the National Institute for Occupational Safety and Health (NIOSH)

Exposure to certain metalworking fluids (MWFs) has been related to occupational asthma, hypersensitivity pneumonitis (HP), and possibly to cancer. NIOSH recommends that exposure to MWF aerosols be limited to 0.4 mg/m 3 measured as thoracic particulate or 0.5 mg/m 3 measured as total particulate. Method 5524, a sampling and analytical method for MWF, issued by the National Institute for Occupational Safety and Health (NIOSH) to support the standard, is described. This technique separates MWF from commingled particulate by extraction with a ternary blend of methylene chloride, methanol, and toluene. Despite lowered exposure limits, occupational disease due to MWF is still observed, indicating further analyses of MWF samples may be needed to isolate causative agents. A NIOSH analytical research program for metalworking fluids which employs liquid chromatographic techniques to separate and classify major components of the MWF according to chemical class is discussed. The analysis of biocides and nitrosamines using an electrospray-mass spectrometric technique is also described. Miscellaneous other analytical issues are also addressed.