Portland Gas Manufacturing Site Cleanup

Contaminated sediment being dredged from the river. The orange fabric marks the moon pool where sediment curtains drop down to the river bottom to prevent contamination from going outside the removal area.

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 is addressing historical contamination resulting from gas manufacturing operations along the west bank of the river from the mid-1800s to early 1900s.

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

Project Status

Last updated: July 24, 2020

  • July 6-10: A portion of the Portland seawall walkway was fenced off for safety, and the in-water work area established. Buoys and orange boom are present within the river to identify the work area.
  • July 13-23: Dredging of contaminated sediment is in progress, and the area of tar-like material offshore of the seawall has been removed. Along with the tar and contaminated sediment, a large volume of debris has been removed from the river bottom including concrete, steel, brick and a large anchor.
  • October 12-16: Portland seawall walkway closed for removal of equipment and fencing


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

Dan Hafley
(503) 229-5417 

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.

Why are there restrictions to the walkway and the river area?

In order for staff to safely conduct and monitor the work along the Portland seawall, river navigational restrictions and walkway restrictions are necessary. There will be signs at either end of the project area along the walkway to ensure that people know how to move around the site. The project team has been coordinating with local, state and federal agencies and groups to communicate these closures with all impacted parties.

How are you making sure workers remain protected from COVID-19?

DEQ, NW Natural and contractors hired to assist with the cleanup have all established health and safety plans that include protocols for minimizing person-to-person exposure, which can lead to the spread of COVID-19.

I see an oily sheen on the water, has there been a spill?

You may see an oily sheen on the water surface within the work area during the removal of contaminated sediment, as old petroleum material is being dredged that could create a sheen. Dredging will be completed within an enclosure, called a moon pool, to prevent the release of contaminants to the river. Water quality will be monitored throughout both dredging and placement of clean fill. DEQ will be on-site regularly to oversee the work being done. If you do have any concerns, please contact DEQ Project Manager, Dan Hafley, at (503) 229-5417 or hafley.dan@deq.state.or.us.

I can smell the chemicals being dug up, is that something dangerous?

The smell, something like mothballs or driveway sealer, is coming from the waste products from the contamination being removed from the river, including naphthalene and benzene. Naphthalene is especially noticeable; it has the distinct odor of mothballs and can be smelled at very low concentrations.

You can smell naphthalene and benzene at concentrations much lower than DEQ levels of concern. The health-risk level of naphthalene is approximately 10 to 50 times higher than the level at which most people can smell it. For this project, the concentration of naphthalene is not expected to reach unhealthy levels. Benzene will also be at levels that are significantly lower than the levels considered to be unhealthy.
NW Natural will provide multiple layers of air monitoring for naphthalene and benzene – including handheld and static monitors in the project area – to help ensure the safety of residents, workers and visitors in the area, as well as on-site project crews.

Although it’s not unsafe at low levels, the odor of some materials being removed is unpleasant. NW Natural has developed a vapor management approach that strives to limit these unpleasant odors.

How long will this cleanup work take?

The cleanup work is currently scheduled to begin in early July 2020 and will continue through the in-water work window that closes at the end of October. This includes removing the contaminated sediment and placing clean soil on top of it.

Once cleanup work is completed, long-term monitoring will occur to confirm the integrity of the sediment cap and natural recovery of the cleanup area.

What kind of traffic impacts will there be during construction?

Traffic impacts should be minimal since the removal work will be completed using barges and small boats. Navigational restrictions on the river may have a small impact depending on the level of boat traffic.

Will this make it unsafe to swim or boat in the river?

This cleanup will not affect recreational safety on 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: Dan Hafley | (503) 229-5417 | hafley.dan@deq.state.or.us
  • NW Natural: Dave Santen | (503) 610-7505 | Dave.Santen@nwnatural.com

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