Comparative short-term inhalation toxicity of ethylene glycol monomethyl ether and propylene glycol monomethyl ether in rats and mice

Abstract

Male and female Fischer 344 rats and B6C3F1 mice were exposed to 0, 100, 300, or 1000 ppm ethylene glycol monomethyl ether (EGME) or to 0, 300, 1000, or 3000 ppm propylene glycol monomethyl ether (PGME) 6 hr/day for a total of 9 days during an 11-day interval. Although structurally similar, the biological activities of the two materials were dramatically different. The high concentration of EGME (1000 ppm) had pronounced adverse effects on body weight gain, peripheral blood counts, bone marrow, testes, and lymphoid tissues. Similar but less pronounced changes also occurred in some animals in the 300 ppm EGME group. Exposure to 3000 ppm PGME resulted in increased liver weights in male rats as well as central nervous system depression and decreases in specific gravity of urine of both male and female rats. However, there were no gross or histopathologic changes in either rats or mice which could be attributed to exposure to PGME. Hence the treatment-related changes which occurred in rats and mice exposed to PGME vapors, even at the highest concentration (3000 ppm), would constitute, at most, a minimal effect. Although PGME and EGME have comparable vapor pressures, the potential hazard of exposure to PGME vapors appears to be distinctly less than to EGME vapors.