Tesoro Refining & Marketing Company

We approved the Tesoro Marathon Anacortes refinery's dangerous waste permit modification request and finalized the corrective action permit and oily water Agreed Order. Both are effective on Nov. 1, 2021.

• Dangerous waste permit modification approval
• Final Corrective Action Permit, including Agreed Order 16299
• Fact sheet (a support document explaining our decisions, including the response to comments)
• Associated SEPA DNS
• SEPA checklist

Tesoro's Marathon refinery is located on West March Point Road in Anacortes, WA. It processes an average of 105,000 barrels of crude oil each day to make a variety of petroleum products. Learn more about current operations

Oily Water Sewer

The Oily Water Sewer (OWS) was built in the 1950s and includes underground pipes, drain bugs, manholes, hatches, and other access points. While we're not aware of any current releases from the oily water sewer, we're working on an Agreed Order that requires the refinery to investigate and clean up any soil or groundwater contamination. Contaminants of concern include metals, volatile organics, and semi-volatile organics.

Leaded Tank Farm Disposal Areas

Tank dike areas in the main tank farm were used for burying tank bottoms from leaded gasoline tanks. Contaminants of concern include:

• Benzene, toluene, ethyl benzene, and total xylenes (BTEX)
• Polycyclic aromatic hydrocarbons (PAHs)
• Dissolved arsenic
• Dissolved chromium
• Dissolved lead 

Tesoro installed five new monitoring wells in January 2014 to investigate contamination in groundwater.