Portland Gas Manufacturing Site Cleanup

What’s Happening?

Starting in July 2020, NW Natural began work to clean up contaminated sediment at the former Portland Gas Manufacturing site along the Willamette River in downtown Portland. This work addressed historical contamination resulting from gas manufacturing operations along the west bank of the river from the mid-1800s to early 1900s.

Cleanup activities included removal of some contaminated sediment, capping with clean sand and gravel, and enhanced natural recovery. Activated carbon was added to a portion of the cap to increase effectiveness. Work was completed using barges and small boats in an area between the Steel and Burnside Bridges, offshore of Tom McCall Waterfront Park

Project Status: Completed October 2020

As of October 2020, the cleanup team has completed this work according to the approved cleanup plan. In total, they removed over 7,000 tons of contaminated sediment and debris. NW Natural is in the process of finalizing its construction completion report, which will provide a record to DEQ of all the work that was completed. Afterwards, NW Natural will continue to monitor the river bottom long-term to confirm the effectiveness of the cleanup work and natural recovery process.

This project was successful not only because its completion marks the cleanup of the last large legacy contamination site in the downtown reach of the Willamette River, but because of the lessons learned that will inform future cleanup projects. A few of those lessons include:

  • New technology for cleanup and long-term monitoring: DEQ approved the use of two technologies not previously used in cleanup projects in Oregon: a moon pool and sampling ports. The moon pool barge has silt curtains that surrounded the area being dredged to prevent the release of contaminants to the river during work. This innovative approach’s effectiveness was confirmed by ongoing turbidity and chemical monitoring during the excavation, and the fact that work did not exceed water quality limits at any time throughout construction. Sampling ports that look like manholes were placed in the cap on the riverbed. These ports have sampling equipment inside them that will be used for long-term monitoring of the cap.
  • You never know what you’ll find: During excavation, the cleanup team found hundreds of World War II-era munitions, including live high-explosive incendiary and anti-aircraft shells. The exact origin of these munitions is unknown, but this kind of finding is not unusual for a river that used to support military operations. Upon discovery, work immediately ceased so the team could establish a plan to proceed safely. DEQ and NW Natural collaborated with the National Guard and a consulting firm that specializes in munitions disposal. At no time was there a risk to public safety.
  • Communicating and collaborating is key: Despite the additional challenges of working amidst the COVID-19 pandemic and an unprecedented summer wildfire season, this project was completed on time, within the in-water work window and safely, with no health and safety incidents. This was the result of excellent communication and cooperation among multiple resource agencies, including DEQ, DSL, ODFW and the City of Portland, and NW Natural.
  • Getting the message out: DEQ and NW Natural worked to ensure that the community was well informed of this project. In addition to this webpage, that included dropping off flyers to local apartment complexes and businesses and reaching out to tribes, community groups, and other federal, state, and local agency partners. Local media also helped in telling this story, and the links to that work are provided on the right side of this page. We hope this information was useful and welcome any feedback (please send that to Lauren Wirtis, DEQ public affairs specialist, at wirtis.lauren@deq.state.or.us).


DEQ Project Managers:
Sarah Greenfield
(503) 229-5245  |  greenfield.sarah@deq.state.or.us

Media: Lauren Wirtis
(503) 229-6488  |  wirtis.lauren@deq.state.or.us

Useful Resources

In The News

Frequently Asked Questions

What is this project and why is this cleanup project important?

This is the last large legacy contamination site in the downtown reach of the Willamette River. The cleanup effort will remove areas of contamination in the river sediments adjacent to the Portland seawall. It is important that these contaminants be removed from the river to ensure long-term protection of human health and the environment. To learn more about the Downtown Reach, see the factsheet about cleanup in this area.

Is this cleanup related to the Portland Harbor Superfund Site?

No. This site is upriver of the Portland Harbor Superfund Site and is not a part of that cleanup effort. Project represents the last significant cleanup of legacy contamination in the downtown reach of the river.

How can I get more information?

This project website contains the most recent information and additional resources are listed at the top of the page on the righthand side. Additionally, you can contact project managers at DEQ or NW Natural below:

  • DEQ: Sarah Greenfield | (503) 229-5245 | greenfield.sarah@deq.state.or.us
  • NW Natural: Dave Santen | (503) 610-7505 | Dave.Santen@nwnatural.com

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