Six offshore oil well tests were drilled off Key West in the late 1950s and early 1960s. Two wells were drilled on coral bottom, two on carbonate sand, and two on mixed turtle grass and gorgonian/sponge hardbottom. After locating the sites with a proton magnetometer; several underwater assessment methods were used to measure the ecological impacts of drilling. Because of differing environments and bottom types, no single method was applicable at every site.