The results of round 18 of the Environmental Lead (7439921) Proficiency Analytical Testing (ELPAT) program were presented. ELPAT was a program administered by the American Industrial Hygiene Association (AIHA) in cooperation with NIOSH and the Office of Pollution Prevention and Toxics, Environmental Protection Agency (EPA) to evaluate and improve the performance of laboratories performing analyses associated with lead abatement. The program was part of the National Lead Laboratory Accreditation Project, an EPA sponsored program for accrediting private and state laboratories. Any interested laboratory could have participated in the ELPAT program. Proficiency test samples for the participating laboratories were prepared by the Research Triangle Institute, an AIHA contractor, using paint chips, dust wipes, and soils. Four samples were sent out each calendar quarter (round). Laboratories were rated based upon their performance in the ELPAT program over the past year (four rounds) for each lead matrix: paint chips, soil, and dust wipes. A laboratory was rated proficient if all four sample results for each matrix were reported and designated acceptable for the last two consecutive rounds or at least 75% of the results reported in the last four consecutive rounds were judged acceptable. A total of 392 laboratories were enrolled for round 18, the samples for which were sent out in February 1997. A total of 369 laboratories (94%) submitted results. Flameless atomic absorption spectrometry and inductively coupled plasma atomic emission spectrometry were the major analytical methods used. Of the 359 laboratories that reported results for the paint chip samples, 96% reported results judged to be acceptable. Of the 306 laboratories that submitted results for the soil samples, 94% reported acceptable results. Of the 326 laboratories that submitted results for the dust wipes, 95% reported acceptable results.