Several candidate oxygenates have been proposed for use with diesel fuel. This paper examines the safety and health issues associated with the use of these oxygenates. The primary fire safety hazard associated with the use of oxygenates is increased diesel fuel volatility and consequent low flash point. Peroxide formation may be a hazard for some oxygenates, but no quantitative information on the extent of the hazard was located for any of the candidate oxygenates. Little information is available on inhalation, ingestion, or skin exposure toxicity hazards. Of the candidate ethers, only pentyl ether, 2-ethoxyethyl ether (diethyl carbitol), and dibutoxymethane (butylal) do not have low flash points or significant known toxicity problems.