INTRODUCTION The objective of this study was to determine the toxicity of a selected petroleum-derived hydrocarbon@ API 83-19@ when administered to rabbits over a 4-week period by dermal application. Dosing was initiated on November 19@ 1984 and was completed on December 18@ 1984. All animals were terminated by December 21@ 1984. This study was run concurrently with a companion study assessing an additional API compound. This study is reported separately as TLI project 1712(1). The companion study had its own control group and three treated groups. A pilot five-day dermal study in rabbits (Phase I) was performed In order to determine the dose levels to be used during this study (Phase II). Phase I dosing was initiated on October 29@ 1984 and was completed on November 9@ 1984. Terminal sacrifice occurred on November 9@ 1984. The report of the Phase I study is presented in Addendum I of this report.