Ethylene oxide is a carcinogenic compound which is also an ethylene metabolite. Ethylene oxide forms macromolecular adducts with proteins and nucleic acids. Targets in proteins are the amino acids cysteine, histidine and valine (if N-terminal, as in hemoglobin). The major DNA adduct is 7-(2-hydroxyethyl)-guanine. Methods for detection of this adduct include radiolabelling and GC-MS. The sensitivity of current GC/MS methods can be improved by selective enrichment of adducts from DNA samples. Studies in this direction are presently being performed.