The mutagenic potential of ethylene-glycol-monobutyl-ether (111762) (EGBE) was examined in the Ames test to investigate the reported unique responsiveness of Salmonella-typhimurium strain TA-97a to this compound. The EGBE sample used was found to be 99.04% by weight pure, and contained 23 parts per million peroxides. EGBE was added to TA-97a, TA-100 or WP2uvrA at 0, 500, 1,000, 2,500, 5,000, 8,500, or 10,000 micrograms per plate without metabolic activation or with metabolic activation by 2.5% or 10% S9, prepared from livers of male Sprague-Dawley rats. The number of revertants observed on the test material plates were similar to control plates and clearly indicated a lack of mutagenicity for EGBE with either TA-97a or the other tester strains under any activation conditions. The authors conclude that the results obtained using a well characterized test material and a standardized experimental protocol do not confirm the unique sensitivity of TA-97a in detecting mutagenicity with EGBE, adding additional support to the general lack of genotoxic potential for this material.