ABSTRACT Source oil characterization and its subsequent identification and quantification in different receiving environments are integral components of a natural resource damage assessment (NRDA) following a spill. When the M/V New Carissa broke up on the Oregon coast in February 1999, it released an estimated 70,000 gallons of two bunker fuels and two diesel fuels. Numerous oil, water, sediment, and tissue samples were subsequently analyzed for the standard suite of aliphatic and polynuclear aromatic hydrocarbon (PAH) fractions, as well as steranes and triterpanes to use in chemical fingerprinting in support of the NRDA process. The fingerprinting task was uniquely complex with this spill because of the four major source oils of highly disparate compositions and additional compositional changes occurring as a result of partial in situ burning and release of residual fuels onboard the vessel during the response effort. Also unique to NRDA process was the segregated sampling of dissolved-phase and dispersed-oil droplet fractions from the water column, information that proved invaluable in the fingerprinting process. To assist with the complex data analysis in identifying New Carissa oil in environmental samples, a combination of multivariate principal-component analyses and hierarchical agglomerative-cluster analyses, conventional double-ratio analyses of selected PAH, and custom computer displays to allow comparison of multiple graphs on a single page was developed. Results show two different mechanisms of hydrocarbon uptake into affected organisms: direct uptake of dissolved-phase PAH from the water column into crab tissues, and accumulation of aliphatic and aromatic constituents from dispersed oil droplets and oiled suspended particulate material (SPM) by filter-feeding organisms. From the combined statistical and fingerprinting process, it was possible to differentiate New Carissa oil from background combustion-derived (and sediment-associated) PAH in selected clam and oyster tissue samples from inside Coos Bay. Also documented was interstitial water contamination of otherwise clean and unoiled sandy beach substrates by offshore dissolved-phase PAH, and the accumulation of hydrocarbons from the surface microlayer by diatoms.