On December 15, 1976, the tanker ARGO MERCHANT ran aground on Fishing Rip of Nantucket Shoals off the Massachusetts coast. Within one week she had broken into three parts. Chemists from the U.S. Coast Guard Research and Development Center (USCGRDC) using u.v. fluorescence spectroscopy conducted on-board hydrocarbon screening of water and sediment samples collected on three of these cruises. As in the previous cruises, USCGRDC chemists screened the sediments for their hydrocarbon content immediately after collection. These data were used to assign additional stations to provide more detail within the planned sampling grid. In addition to the analyses provided by the Coast Guard, the sediments were also analyzed at the Graduate School of Oceanography (URI) using gas chromatography. Since both groups analyzed samples from the same container, it was hoped that the two sets of data would provide an opportunity to compare, using actual field samples, two different analytical techniques for determining sediment petroleum hydrocarbon concentrations. The environmental significance of these studies has been discussed elsewhere.