The findings of the Proficiency Analytical Testing (PAT) Program as of May 30, 1997 were presented. The PAT Program tested the proficiency of enrolled laboratories in analyzing samples containing metals, silica (68855549), asbestos (1332214) fibers, and organic solvents. In April of 1997, a total of 1,154 laboratories submitted results on Round 129 of the PAT Program. The contaminants analyzed in this round included cadmium (7440439), lead (7439921), zinc (7440666), silica, chrysotile (12001295) fibers, 1,2-dichloroethane (107062), tetrachloroethylene (127184), and trichloroethylene (79016). Combining the results of Rounds 126 through 129, 90% of the labs were rated proficient for organic solvents, 94% of the labs were rated proficient for metals, 95.4% of the labs were rated proficient for asbestos/fibers, and 98.7% of the labs were rated proficient for silica. For the PAT Passive Monitor Practice Round 128 of January, 1997, sample kits containing benzene (71432), toluene (108883), and o-xylene (95476) were sent to 173 participating laboratories. The passive monitors used included 142 3M monitors, 19 SKC monitors, and 12 Assay Technology monitors. In all, 960 results were submitted, of which 76 were analytical errors, 22 calculation errors, and 27 a combination of the two. The performance limit for this practice round was +/-18% of the reference value. If at least 75% of the analyses reported by a laboratory were acceptable according to this performance limit, the laboratory was rated proficient. Of the 149 laboratories submitting results in Practice Round 128, 121 were rated proficient. In conclusion, the authors indicate that the results of the PAT Program Round 130 will soon be available. This is the first official round to include passive monitors.