“…Although benzene has not been identified as the metabolite of phenylhydrazine (Mclsaac et al, 1958) or its derivatives (Colvin, 1969;Juchau and Horita, 1972), Lawrason et al (1949) observed symptoms typical of benzene poisoning from treatment of swine with phenylhydrazine. Beaven and White (1954) identified benzene as the end product of phenylhydrazine or acetylphenylhydrazine incubation with oxyhemoglobin.…”