INTRODUCTION In order to assess the possible effects of petroleum on the marine environment@ analytical methodology must be available that permits the quantitative determination of petroleum components in water@ sediment@ and tissue. The methods must be capable of determining trace quantities that may be no more than an order of magnitude above background levels. This report describes the methods for determining petroleum components in marine samples that were developed by Battelle's Columbus Laboratories under contract with the American Petroleum Institute during the period March 1@ 1972@ to October 31@ 1976.* These methods have been used successfully for the characterization of numerous samples from field and laboratory studies. *Much of this work has been presented in Anal. Chem.@ 48@ 578 (1976). and Proceedings of 1975 Joint Conference on Prevention and Control of Oil Spills@ American Petroleum Institute@ PP 97-101