Data are presented to support a modified ASTM sampling and analytical method—D 7049-04—for metal working fluids (MWFs). The modified method replaces ASTM method PS42-97, a gravimetric procedure that employs a ternary blend of methanol, dichloromethane, and toluene to separate the MWF from cosampled particulate. The revised method is also a gravimetric procedure that employs the ternary blend as well as a binary blend of methanol and water to remove MWF from insoluble particulate collected on polytetrafluoroethylene (PTFE) filters. The method has been evaluated at the National Institute for Occupational Safety and Health (NIOSH) by spiking known aliquots of five MWFs—one straight, one soluble, one semisynthetic, and two synthetic—onto PTFE filters, and extracting them after 24 h of storage with the ternary and binary blends. Samples were spiked at the following levels: straight: 230–940 μg; soluble: 260–1130 μg; semisynthetic: 64–260 μg; synthetic I: 110–480 μg; and synthetic II: 90–372 μg. Limits of quantitation, computed from blanks carried through the analysis, were determined to be 73 μg and 80 μg, respectively, for the total-weight and extracted-weight procedures. On average, fractions extracted (weight recovered/weight spiked) for all fluids for all levels tested exceeded 0.94. Pooled estimates of the coefficients of variation of analysis over all samples tested were 0.043 for the total weight samples and 0.046 for the extracted weights. The extraction efficiencies for all five fluids were also tested by analysis of the binary blend extracts for characteristic marker elements in each fluid. Only for the lone ternary blend insoluble fluid were definitive marker element results obtained, with between 60 % (potassium) and 100 % (phosphorus) of two marker elements extracted. The extractability of tobacco smoke particulate and polycyclic aromatic hydrocarbons (PAHs) from the PTFE filters is also addressed.