[en] A crude oil spill occurred at an exploratory well site near Prudhoe Bay, Alaska during drilling in the winter of 1969-70. The oil infiltrated a portion of the gravel pad and flowed onto the adjacent tundra. Although some attempts were made to clean up the site at the time, a large area of contaminated gravel and tundra remained in 1990. Based on a detailed site assessment, 2.2 hectares had such high total petroleum hydrocarbon (TPH) concentrations that excavation and incineration were selected as the most appropriate remedial actions. In the remaining less-contaminated areas that were not excavated and in subsurface soil horizons, bioremediation was selected. During the winter of 1991, an estimated 19,000 m³ of soil was excavated and incinerated in a rotary kiln. During summer 1991, biodegradation of the TPH in the remaining soil was promoted by tilling, watering and draining, and fertilizing. Excavation of the heavily contaminated soil reduced mean TPH concentrations by 89% at the tundra surface. Bioremediation for 53 days reduced mean TPH concentrations by 74%. Hydrocarbon-degrading bacteria and soil and groundwater properties important to microbial growth were also monitored. Two strains of Pseudomonas species showed a good ability to degrade crude oil and probably were responsible for the large reduction in TPH concentrations observed after one summer. 5 refs., 5 figs