(A) The chemical structures of the compounds tested in this study: 2,2’-methyliminodiethanol (MDEA), diethanolamine (DEA), tetrachloroethylene (PCE), and 2,6-di-tert-butyl-p-cresol (BHT). (B) Description of the sources, routes, and limits of exposure for MDEA, DEA, PCE, and BHT. Exposure limits are determined as the 8-hr permissible exposure limit with time-weighted average.