Major Oil Cleanup at Dunsmuir Railyard, Restores Sacramento River Shoreline

Over a century of contamination addressed through multi-agency cleanup effort in Northern California

An image of a railroad at night — *Image via Kaique Rocha from Pexels*

The U.S. Environmental Protection Agency (EPA) has announced the completion of a significant environmental cleanup at the Dunsmuir Railyard in northern California, where an estimated 75,000 gallons of oil and 100,000 tons of contaminated soil were removed from a site that has been leaching oil into the Sacramento River for more than a century.

The EPA also confirmed the restoration of 1,400 feet of impacted riverbank, significantly improving the environmental health of the Upper Sacramento River and surrounding ecosystems. This work caps years of investigation and remediation and marks a major milestone in efforts to address legacy pollution from the railyard, which is owned and operated by the Union Pacific Railroad Company.

The Dunsmuir Railyard has been in operation since the early 1900s, during which time it served as a key refueling point for steam locomotives. As a result, oil tanks and fueling equipment left behind a trail of contamination in the soil and groundwater beneath the site.

In 2019, the California Department of Fish and Wildlife (CDFW) contacted the EPA after oil was observed seeping into the Upper Sacramento River. The discovery prompted a federal response, with the EPA conducting investigative work that revealed that oil had likely been leaking into the river for more than 100 years.

In 2021, the EPA formally partnered with the CDFW, the Central Valley Water Quality Control Board, and Union Pacific to develop and execute a plan to stop the contamination at its source. The cleanup involved excavating and removing oil-contaminated soil, installing a barrier fill to prevent further seepage, and replacing sections of an aging retaining wall along the riverbank.

Clean fill material was brought in to rebuild the affected area, and habitat restoration was integrated into the project to support local wildlife. The restored shoreline not only improves water quality but also expands the river’s capacity and enhances its ecological value.

“The completion of this cleanup means that the Dunsmuir community and wildlife will enjoy cleaner land and water than they have in a century,” said Mike Montgomery, EPA’s Pacific Southwest Superfund and Emergency Management Director.

The project team noted that the success of the cleanup was made possible through close coordination among federal, state, and private sector partners.

Although the oil removal and shoreline restoration are complete, oversight at the site is not finished. The Central Valley Water Board will continue regulating the railyard to address remaining contamination in soil and groundwater in areas not covered by the EPA's response.

The North Dunsmuir Railyard remains an active Union Pacific facility and continues to be monitored under a Cleanup and Abatement Order issued by the California Environmental Protection Agency. Prior to the EPA-led cleanup, oil and oily water had been observed surfacing through the retaining wall and entering the Sacramento River, posing risks to water quality and aquatic life.

The Upper Sacramento River is a valued natural resource in Northern California, supporting recreation, wildlife, and drinking water supplies. The EPA’s efforts to remove long-standing pollutants have significantly improved conditions along a stretch of river that had suffered from industrial contamination for generations.

Environmental groups and local residents have long called for action at the site. While there is still work to be done to manage subsurface contamination, the completion of the EPA's major cleanup effort represents a turning point in the long history of pollution at the Dunsmuir Railyard.

The EPA says it will continue supporting state partners and monitoring the site to ensure long-term environmental protections are maintained.