Review of the mutagenicity/genotoxicity of butylated hydroxytoluene.

Butylated hydroxytoluene (BHT) is an effective, widely used, low cost antioxidant. A host of studies examining the potential of BHT to cause point mutations have been published. They include in vitro studies on various bacterial species and strains and on various types of mammalian cell lines as well as in vivo studies on Drosophila melanogaster, silk worms and also the mouse specific locus test (involving long-term exposure). Together these studies convincingly show the absence of a potential for BHT to cause point mutations. A great number of studies on many cell types and species have also been carried out to examine the potential of BHT to cause chromosome aberrations. In vitro studies have been published using plant cells and the WI-38, CHL, CHO, and V79 mammalian cell lines. In vivo studies have been carried out on somatic and/or germ cells of Drosophila melanogaster, rats and mice. Nearly all studies, especially those using validated test systems, indicate that BHT lacks clastogenic potential. In vitro studies on bacterial, yeast and various mammalian cell lines including DON, CHO, CHL cells and primary hepatocytes demonstrate the absence of interactions with or damage to DNA. Taking all the existing data into account, the weight of evidence suggests that BHT does not represent a relevant mutagenic/genotoxic risk to man.