INTRODUCTION The objective of this study was to determine the toxicity of a petroleum derived hydrocarbon@ API 81-15@ when administered to rats over a 4-week period by dermal application@ in order to set dose levels for a thirteen-week dermal toxicity study In rats. Dosing was initiated on January 30@ 1984 (Day 1 of study) In the control group and the 400@ 2000 and 4000 mg/kg dose groups. Due to toxicity observed in the 4000 and 2000 mg/kg dose groups and at the sponsor's request@ an additional group of animals was added to the study and dosed at 1000 mg/kg. The animals used for this additional group were selected from eligible extra animals which were received at the same time and housed in the same room as the animals already assigned to study. Dosing of the 1000 mg/kg dose group was initiated on February 13@ 1984.