Large quantities of snow have damaged oil storage tanks at the Valdez Marine Terminal in Alaska, US, owned by Alyeska Pipeline Service, taking them out of service.

Alyeska spokesperson Michelle Egan told local newspaper Anchorage Daily News that the snow has sheared off valves along the upper edges of the tank roofs, venting petroleum vapours to the atmosphere. Moses Coss, an official with the Alaska Department of Environmental Conservation, told the paper that at least seven tanks were venting vapours, in violation of the state’s Clean Air Act.

Alyeska has equipped ‘dozens’ of respirator-equipped contractors, who are roped to the top of the tanks and cut off blocks of snow with saws by hand, which are then pushed over the edge. The vapours mean that power tools cannot be used. Egan said that it will take a crew of 10 people around two weeks to clear all the snow off a tank.

It is not clear exactly how many of the site’s 14 tanks, which each hold 500,000 bbl of oil, have been affected, but at present, tanker loading has not been disrupted. Valdez has reported the highest levels of snowfall in ten years, and Alyeska is blaming huge snowfall for the incident. However, Egan told Anchorage Daily News that the company is carrying out an investigation and will review its response to the incident.

(Source: Tank Storage Magazine)