The Proficiency Analytical Testing (PAT) Program is a collaborative effort of the American Industrial Hygiene Association (AIHA) and researchers at NIOSH to provide quality control reference samples to over 1500 occupational health and environmental laboratories in over 15 countries. A combination of three metals and three organic solvents are rotated for each round. Laboratories are evaluated for each analysis by comparing their reported results against an acceptable performance limit for each PAT Program sample the laboratory analyzes. The results of PAT Round 107 were reported and compared to the rounds 104 through 106. PAT Round 108 was sent out on January 2, 1992 and included the compounds 1,1,1-trichloroethane (71556), tetrachloroethylene (127184), trichloroethylene (79016), cadmium (7440439), chromium (7440473), lead (7439921) and silica (14808607).