Comparative Acute Toxicity of Shale and Petroleum Derived Distillates

Abstract

In anticipation of the commercialization of its shale oil retorting and upgrading process, Unocal Corp. conducted a testing program aimed at better defining potential health impacts of a shale industry. Acute toxicity studies using rats and rabbits compared the effects of naphtha, Jet-A, JP-4, diesel and “residual” distillate fractions of both petroleum derived crude oils and hydrotreated shale oil. No differences in the acute oral (> 5 g/kg LD₅₀) and dermal (> 2 g/kg LD₅₀) toxicities were noted between the shale and petroleum derived distillates and none of the samples were more than mildly irritating to the eyes. Shale and petroleum products caused similar degrees of mild to moderate skin irritation. None of the materials produced sensitization reactions. The LC₅₀ after acute inhalation exposure to Jet-A, shale naphtha, (> 5 mg/L) and JP-4 distillate fractions of petroleum and shale oils was greater than 5 mg/L. The LC₅₀ of petroleum naphtha (> 4.8 mg/L) and raw shale oil (> 3.95 mg/L) also indicated low toxicity. Results demonstrate that shale oil products are of low acute toxicity, mild to moderately irritating and similar to their petroleum counterparts. The results further demonstrate that hydrotreatment reduces the irritancy of raw shale oil.