view of the facility

Chemical Waste Management of the Northwest, also known as a CWM, is Oregon's only hazardous waste landfill. It is located near Arlington, in Gilliam County. ​The hazardous waste landfill is operated by Waste Management, which also operates the adjacent Columbia Ridge solid waste landfill.

DEQ regulates the treatment, storage and disposal of hazardous waste at the landfill using the following programs:



DEQ anticipates receiving hazardous waste permit modification application

Chemical Waste Management, known as CWM, has notified DEQ it’s seeking to modify its Arlington landfill permit to add a new disposal unit that would expand its capacity to properly dispose of hazardous waste and chemicals of emerging concern. The facility has an existing landfill unit that accepts this kind of waste and anticipates needing additional capacity. 

Much of the waste would arrive in the form of contaminated soil from large-scale cleanup operations occurring at former industrial sites including Superfund sites, firefighting training centers and military sites. Contaminants would include PFAS, a component of some firefighting foams and many consumer goods.

The facility would build the landfill unit to the same hazardous waste specifications as its existing units, including a triple-lined system that protects against groundwater contamination.

When DEQ receives the permit modification application, DEQ will analyze the application to ensure it meets DEQ and EPA hazardous waste requirements and Oregon environmental laws and regulations.

As part of this process, DEQ will work with CWM to hold a public information meeting (date TBD) and request comments on the permit application. DEQ will review the comments and draft the permit modification. Once the permit modification is drafted, DEQ will hold a public hearing and request comments on the draft permit modification.

Frequently asked questions

​CWM opened in 1976 to provide hazardous waste treatment, storage and disposal. EPA and DEQ jointly issued the site’s first hazardous waste permit in 1988.

​CWM is located in a very isolated, dry part of the state. The dry climate and low annual rainfall prevent potential pollutants from reaching waterways or groundwater, which is hundreds of feet underground. The facility is near a major interstate and railroad, making transportation to and from the site relatively easy.

​The hazardous waste landfill receives a wide range of both hazardous and non-hazardous waste, including solids and liquids, industrial waste and asbestos. Hazardous waste must be treated to meet land disposal requirements prior to disposal in the triple lined landfill or evaporation ponds. The evaporation ponds do not discharge off site.

​As of spring 2021, CWM receives on average approximately 15,000 tons of hazardous waste per month.

The landfill has the area and capacity to remain open for at least another several decades.

State and federal law require CWM to maintain financial assurance to properly care for the facility. This process ensures there is a source of revenue to properly close, manage and monitor the facility for many years in the future. The current requirements are for a post-closure monitoring period of 30 years.

​Leachate is collected and treated at the site, and a network of groundwater monitoring wells would detect any potential releases from the site. The distance to the river, combined with the depth to groundwater, the direction of local groundwater flow, low precipitation and triple-lined landfill design reduce the risk of potential impacts to surface water, including the Columbia River.

​Depending upon the type of transportation, the U.S. Department of Transportation’s Pipeline and Hazardous Materials Safety Administration (PHMSA), Oregon Department of Transportation (ODOT), and other public safety transportation authorities primarily regulate road transport. The Surface Transportation Board and the Federal Railroad Administration as part of the U.S. Department of Transportation have oversight of rail transport. ODOT also has some oversight of railroad safety and at-grade crossings.

The spill would be managed and cleaned up similar to any type of emergency spill. Oregon's emergency response system involves capable responders and resources from local, state and federal agencies, including Oregon DEQ, Health Authority, State Fire Marshal, U.S. Environmental Protection Agency, U.S. Coast Guard, and more. These agencies work with local communities to respond to the threat and ensure the safety of people and the environment.

Additionally, CWM's hazardous waste permit includes provisions that require CWM to retain a spill contractor to respond to and clean up any spills at the site or during transportation.



Additional information

Find additional information and records for Chemical Waste Management on DEQ's Environmental Cleanup Site Information Database: ECSI Site ID 6321.


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