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NWCAA alleges multiple failures by Shell Puget Sound Refinery in February 2015 chemical release

Apr. 12, 2016

Shell Puget Sound Refinery allegedly took shortcuts in shutting down and decontaminating its east flare system, leading to the release of chemicals on Feb. 20, 2015, that affected hundreds of people.

“This incident sickened many people in the community, and people felt unsafe in their homes and at work,” said Mark Asmundson, Executive Director of the Northwest Clean Air Agency.

After a yearlong investigation, the Northwest Clean Air Agency is alleging Shell failed to follow shutdown and decontamination procedures while cleaning the refinery’s east flare system.

Simplified picture of Shell Puget Sound Refinery east flare system

Click to enlarge image.


Shell’s actions led to a surge of wet, chemical-laden gases moving through the flare line and extinguishing the flare flame, allowing the release of unburned chemicals to the atmosphere. The purpose of the flare flame is to combust chemicals into less odorous and toxic forms. As a condition of its permit, Shell is required to maintain the flame if chemicals might be vented to the flare.

The chemicals released included hydrogen sulfide, dimethyl sulfide, mercaptans and benzene.

“These chemicals wouldn’t have been released if the flame was burning and able to do its intended job,” Asmundson said.

Light winds from the north carried the released chemicals south from the refinery through the Swinomish Reservation and La Conner. Hundreds of people reported symptoms, including irritation of eyes, throat and lungs, headaches, nausea, fatigue and loss of appetite. Sensitive people and people with compromised respiratory systems would have experienced the strongest symptoms.

Map of generally affected area

The Feb. 20, 2015, chemical release from Shell Puget Sound Refinery affected hundreds of people on the Swinomish Reservation and in La Conner.


The Northwest Clean Air Agency received 67 complaints, mostly from individuals on the Swinomish Reservation and in La Conner. The Swinomish Tribe reported 176 written accounts of more than 550 affected people who live and work on the Swinomish Reservation. The Swinomish Tribe said 12 people sought medical treatment and five reported going to an emergency room or hospital.

“Our inspector confirmed the extent and severity of this incident in the field,” Asmundson said.

Based on the numerous complaints received by the Northwest Clean Air Agency and its inspector’s investigation during the incident, the notice of violation also alleges that the release negatively affected community members’ health, safety and welfare and interfered with their normal ability to use and enjoy their homes and properties.

The Northwest Clean Air Agency mailed a notice of violation to the Shell refinery April 8, 2016. Shell has 30 days to respond to the Northwest Clean Air Agency allegations before the agency can begin to consider what the penalty will be.


More information

Shell Puget Sound Refinery air operating permit


NWCAA Contacts:

Mark Asmundson, Executive Director, 360-428-1617

Mark Buford, Deputy Director, 360-428-1617

Katie Skipper, Communications Program Manager, desk 360-428-1617 ext. 235, cell 360-724-8766, [email protected]


The Northwest Clean Air Agency is responsible for enforcing federal, state and local air quality regulations in Island, Skagit, and Whatcom counties. In addition to permitting and regulating industrial sources of air pollution, the agency provides services and information related to asbestos, indoor air quality, outdoor burning, woodstoves and fireplaces. More information about the agency is available at