An exposure facility was designed and constructed to support health effect studies of inhaled smoke obscurants generated from light lubricating oils. Concentrations are monitored using gravimetric filter sample analysis and continuous RAM-1 aerosol monitors. Chemical consistency of the test atmospheres is monitored by observing the relative stability of fractions of the oil as measured by high performance liquid chromatographic analysis of collected aerosol samples. Toxicological parameters investigated include: Clinical chemistry (i.e. bilirubin, cholinesterase, LDH, SGOT and SGPT), and hematology immunology (i.e. natural killer cell activity and lymphocyte response to mitogens); protein content of pulmonary lavage fluid; pulmonary free cells (i.e. viability, phagocytic rates, and differential counts); pathology; cardiopulmonary physiology on unanesthetized animals studying dynamic responses such as lung compliance, airway resistance, electrocardiograms and blood gases; pulmonary physiology of anesthetized rats including lung volumes, diffusion capacity of CO, and nitrogen washout.