Assessing high-priority mixtures: A review of methanol as influenced by ethanol

The intent of this research was to identify the level of risk methanol posed to a fetus during an ethanol co-exposure. This investigation was prompted by the known competitive inhibition properties of ethanol and the developmental toxicity of methanol. Integrated into this research was the practicality necessitated by regulatory processes, namely: does the risk justify the expense of additional research. To this end, the scope and nature of exposures were summarized to illustrate the ubiquity of these chemicals and the potential for dual exposure. Similarly, severity of outcome was evaluated by systematically reviewing the LOAELs, NOAELs, and statistical significance contained in methanol-induced developmental studies. Results. Blood methanol levels corresponding to developmental effects in laboratory studies were found to be substantially higher than the blood methanol levels predicted in high-risk methanol-ethanol exposure scenarios. This indicates that ethanol would not likely exacerbate methanol toxicity to the point of teratogenicity; however, it is important to note that the developmental toxicity of ethanol—an established human teratogen—was not included in the evaluation. Ethanol's contribution as a developmental toxicant rather than merely as an attenuator of methanol toxicity undermines the severity of effects possible from this chemical combination. Therefore further evaluation is needed to assess the developmental toxicities following dual exposures before rendering methanol and ethanol a high-priority mixture.^