Isopropanol: summary of TSCA test rule studies and relevance to hazard identification.

The toxicity of isopropanol (IPA) has been extensively studied as a result of a Test Rule under Section 4 of the Toxic Substances Control Act. In general, the data showed that IPA has a low order of acute and chronic toxicity; does not produce adverse effects on reproduction; is neither a teratogen, a selective developmental toxicant, nor a developmental neurotoxicant; and is not genotoxic or an animal carcinogen. IPA is, however, a potential hazard for transient central nervous system depression at high exposure levels. In addition, IPA produced effects to several rodent toxicity endpoints at high dose levels (i.e., motor activity, male mating index, and exacerbated renal disease) which are of unclear relevance to human health. The data generated by these studies confirmed that IPA acts as a typical short-chain alcohol in mammalian biological systems. It produces a significant narcotic effect upon exposure at high levels for extended periods of time, with no irreversible effects even after repeated exposure, which is consistent with other short-chain alcohols. The metabolism of IPA appears equivalent across species with rapid conversion to acetone and carbon dioxide. Overall, these studies demonstrate IPA exposure is a low potential hazard to human health. This information will allow for an improved assessment of the human health risks from IPA exposure.