Piperonyl butoxide, carcinogenicity

Cocarcinogenicity may also be an expression of inhibition of a detoxication reaction, as in the case of the cocarcinogenicity of piperonyl butoxide, a P450 inhibitor, and the carcinogens, freons 112 and 113. 

Very little is known about the chronic effects of piperonyl butoxide. The US Environmental Protection Agency has categorized piperonyl butoxide as a group C carcinogen based on limited evidence of cancer in laboratory animals. 

Graham, C. (1987). 24-mouth Dietary Toxicity and Carcinogenicity Study of piperonyl butoxide in the Albino Rat. Unpublished report no. 81691) from Bin-Research Lid. Laboratory, Seneville, Quebec. Canada Undertaken for the PBO Task Force, Washington DC. USA. 

Mackawa, A., Onotlera, fl., F nnita, K., Tanigawa. H., Ogiu. T- and Hayashi. Y. (1985). Lack of evidence of carcinogenicity of technical-grade piperonyl butoxide in F334 rats selective induction of ileoeaccal niters. Food Chcm. Toxicol. 1, 675 -682. 

US National Cancer institute (1979), Bioassay of Piperonyl Butoxide for Possible Carcinogenicity. DHEW Publ. no, 79-1376. Bethesda, Maryland, USA, US Department of Health, Education and Welfare. 

A 1961 report, "Toxic and possible carcinogenic effects of 4-allyl-l,2-methylenedioxybenzene (safrole) in rats," led to further in vitro studies that culminated in a ban by the FDA (CFR 2011 Homburger et al. 1961). Safrole s potential damage of DNA has not been confirmed in humans, yet it is of such substantial consequence that public health agencies are inclined to err on the side of safety. Safrole is also used as a precursor in the synthesis of the insecticide synergist piperonyl butoxide and for the clandestine manufacture of MDMA (ecstasy) (Barceloux 2008), which raises suspicions about politicization of the regulation. 

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