Abstract
5,6-Epoxy-5,6-dihydro-7-methylbenz(a)-anthracene, a K-region epoxide of the carcinogenic hydrocarbon 7-methylbenz(a)anthracene, had only low activity as a carcinogen in the subcutaneous tissues of the rat and mouse or in the skin of the mouse under conditions which permitted the parent hydrocarbon to exhibit moderate to high carcinogenicity in these tissues. Likewise, 5,6-epoxy-5,6-dihydrobenz(a)anthracene or its 7-methyl derivative showed little or no activity as initiators of papilloma formation in mouse skin.