The background and current status of the Environmental Lead Proficiency Analytical Testing (ELPAT) program were discussed. ELPAT was a cooperative program of the American Industrial Hygiene Association (AIHA), Centers for Disease Control, NIOSH, and the Office of Pollution Prevention and Toxics of the Environmental Protection Agency directed at evaluating and improving the performance of laboratories conducting analyses associated with lead (7439921) abatement. The test samples were prepared using real world matrices such as paint chips, dusts, and soils. The samples were sent to participating laboratories each calendar quarter (round). After the laboratories submitted their results, their performance was evaluated by NIOSH with sufficient time for feedback before the next round. The ELPAT program was open to all interested laboratories, including laboratories outside the United States. The performance of the participating laboratories was evaluated for each sample by comparing its reported results against an acceptable performance range, which was based on consensus values derived from analytical results obtained by reference laboratories. Specifically, the acceptable performance range was the mean plus or minus three standard deviations of the reference laboratory data. A total of 217 laboratories participated in the most recent round, in August 1993. They used primarily flame atomic absorption spectrometry and inductively coupled plasma/atomic emission (ICP/AE) spectrometry as the analytical procedures. The number of laboratories judged to be acceptable for each sample varied from 149 to 193. The highest level of acceptability was attained when analyzing paint chip samples and the lowest when analyzing dust wipe samples. A reanalysis of the round 3 data found that atomic absorption spectrometry typically produced higher values than ICPAE spectrometry. The round 5 samples were sent out in November 1993.