Western North Slope rig move cleanup surpasses spill estimate, monitoring continues

Months after Doyon Rig 26 toppled off a gravel road near Nuiqsut, the Western North Slope cleanup has become a test of how safely industrial rig moves are being managed on tundra that still has not fully given up the spill. Crews were still removing contaminated snow and recovering product from the site in Phase 3 of the response, while monitoring was set to continue through breakup and summer sampling.

The accident happened Jan. 23 at 4:40 p.m. about 6.5 miles northwest of Nuiqsut, when the self-propelled drilling module left the road and rolled onto the tundra. Alaska regulators said the maximum potential product on board included 8,400 gallons of diesel, 1,930 gallons of hydraulic oil and 85 gallons of ethylene glycol. Initial estimates put the release at about 4,000 gallons of diesel and 600 gallons of hydraulic oil, and eight personnel were treated on the North Slope and released with minor injuries.

By late April, responders had recovered about 5,435 gallons of spilled product, more than the 4,735-gallon estimate cited in the cleanup update. Another 41 gallons of ethylene glycol had been removed earlier from the rig’s coolant system. The higher recovery total does not necessarily mean the spill grew; it reflects the difficulty of measuring oil and water once contaminated snow and ice are flushed, vacuumed and hauled away. Crews used heated-water flush-and-recover methods to float oil to the surface, where it could be vacuumed for disposal.

The site still carried visible signs of the work. Shore-seal booms ringed part of the area, the snow fence remained in place and heavy equipment was expected to be demobilized before spring breakup makes ice-road access impossible. Unified Command said 100% of the downed rig had been recovered, removed and transported from the site by March 31, but the remaining cleanup focused on tundra impacts, remediation and monitoring. Alaska Department of Environmental Conservation said the spill area lay in critical habitat for denning and non-denning polar bears and in habitat used by caribou, Arctic fox, muskox, ptarmigan and migratory birds important to subsistence.

The incident also landed in the middle of a wider North Slope fight over oil development and winter access. ConocoPhillips said its winter exploration program would continue with substitute rig Doyon 142, and Judge Sharon Gleason later denied a request to stop that work. Sovereign Iñupiat for a Living Arctic said the collapse showed how quickly risks on the land become risks for the people, food sources and places communities depend on. With more sampling ahead and breakup closing in, the cleanup remains more than a recovery operation; it is a live measure of whether North Slope industrial work is being managed with enough care.