A toxic cloud of gas loaded with more than 700 pounds of air pollutants spewed from a stack at Shell Oil’s refinery in Anacortes in February 2015, sickening more than 500 people.

Six years later, Equilon Enterprises, doing business as Shell Oil Products US, has agreed to a legal settlement with the U.S. Environmental Protection Agency, resolving violations of the federal Clean Air Act in connection with the toxic release. Under the settlement, the company paid a penalty of $191,000 to the EPA.

Shell calculated that an error during maintenance activities caused the release of about 700 pounds of hydrogen sulfide, benzene and other pollutants from a smokestack over several hours on Feb. 20, 2015.

The release occurred during stagnant weather conditions and more than 550 people were affected, some of whom sought medical attention, according to a news release Wednesday from the EPA’s Region 10.

In addition to the EPA penalty paid by the company, Shell also paid penalties of more than $420,000 to the Northwest Clean Air Agency and the Washington Safety and Health Agency for violations related to the release, according to the EPA.

Joseph Williams, vice chairman of the Swinomish Indian Tribal Community, said in an interview he was grateful the EPA pursued the case. He was at home when the release happened and remembered shutting his family inside the house when he smelled a sickening, hydrocarbon stink in the air.


“I found out pretty soon after, there were tribal members that were having ill effects due to inhaling those chemicals,” Williams said.

“I remember being home and smelling the air outside and I advised my wife to keep the young ones in the house. We basically just stayed indoors and tried to avoid being out as much as possible.”

The Shell and Tesoro oil refineries are located on March Point, historically the north end of the Swinomish Tribe’s reservation.

Health impacts from the 2015 event were significant, according to the tribe, including dizziness, coughing, throat irritation, nausea and gagging, lung and chest pains and more. More than 100 tribal members reported severe symptoms, according to the tribe.