Hansville Landfill

The landfill has been closed.

An engineered landfill cap prevents rainfall from entering the landfill. This limits migration of landfill contaminants to ground water. An active landfill gas extraction and flaring system is installed within the former municipal solid waste and demolition landfill units to control methane migration and to enhance the removal of volatile organic compounds from the subsurface soil and groundwater.

Based on the surface cover and cleanup levels, it was determined that the Site was eligible for a ‘No Further Action’ determination if an environmental covenant was recorded for the property.

A Covenant was recorded with Kitsap County for the Site in August 22, 2011 that imposed the following limitations:

1. No groundwater any be taken from the property for domestic, agricultural, or industrial use except for collection of samples from monitoring wells or maintenance activities of as otherwise provided for the in the Consent Decree and Cleanup Action Plan. The Property contains three former landfill units with caps. The Owner shall not alter, modify, or remove any existing cap in a manner that may result in the release or exposure to the environment contamination or create a new exposure pathway without prior approval from Ecology.

2. Any activity on the Property that may interfere with the integrity of the Remedial Action and continued protection of human health and the environment is prohibited.

3. Any activity on the Property that may result in the release or exposure to the environment of a hazardous substance that remains on the Property as part of the Remedial Action, or create a new exposure pathway, is prohibited without prior written approval from Ecology.

4. The Owner of the Property must give thirty (30) days advanced written notice to Ecology of the Owner’s intent to convey an interest in the Property. No conveyance of title, easement, lease or other interest in the Property shall be consummated by the Owner without adequate and complete provision for continued monitoring, operation, and maintenance of the Remedial Action.

5. The Owner must restrict leases of uses and activities consistent with the Covenant and notify all lessees of the restriction on the use of the Property.

6. The owner must notify and obtain approval from Ecology prior to any use of the Property that is inconsistent with the terms of the Covenant. Ecology may approve any inconsistent use only after public notice and comment.

7. The Owner shall allow authorized representatives of Ecology the right to enter the Property at reasonable times for the purpose of evaluating the Remedial action; to take samples, to inspect remedial actions conducted at the Property, determine compliance with this Covenant, and to inspect records that are related to the remedial Action.

8. The Owner of the Property reserves the right under WAC 173-340-440 to record an instrument that provides that this Covenant shall no longer limit use of the Property or be of any further force or effect. However, such an instrument may be recorded only if Ecology, after public notice and opportunity for comment, concurs.

Institutional controls are in place, including an environmental covenant with Kitsap County for the landfill portion of the Site, and a Protection Area managed by the Port Gamble S’Klallam Tribe for the portion of the Site on tribal land.

The institutional controls appear to be effective in protecting human health and the environment from exposure to hazardous substances and protecting the integrity of the cleanup action.

No annual reports on the institutional controls from the Port Gamble S’Klallam Tribe have been provided (as agreed upon in the 2007 Settlement Agreement between the Port Gamble S’Klallam Tribe, Kitsap County, and Waste Management of Washington Inc.).

The Hansville Landfill operated as a municipal landfill serving the northern portion of Kitsap County from about 1962 until June 1989.

The landfill is divided into three separate areas: a 13-acre municipal solid waste landfill; a four-acre demolition landfill that accepted construction, demolition, and land clearing wastes; and a one-third acre septage lagoon that accepted septic tank pumping waste. The remaining landfill property consists of access roads, a soil borrow area, and wooded land.

All three landfill units are capped with a final cover system. An active landfill gas extraction system extracts methane gas generated within the municipal solid waste and demolition landfill units. The methane is burned off.

Contaminated ground water flows from the landfill on to the Port Gamble S’Klallam Reservation. The contaminant concentrations decrease due to natural decay. The rate of attenuation is being monitored. The contamination is projected to decay to below applicable standards by 2034.

Ecology recognizes the importance of protecting and managing Washington's natural and cultural resources in collaboration with Tribes.

We engage with Tribes both in formal government-to-government relationships and through broader outreach whenever cleanup activities or contamination discoveries may affect tribal interests and resources. This engagement provides opportunities for tribal input throughout the cleanup process.

Ecology also works closely with the Department of Archaeology and Historic Preservation to ensure that any ground-disturbing activities comply with state and federal historical and archaeological preservation laws.

We are committed to providing environmental justice to our most vulnerable communities. It is a priority in our efforts to restore and protect land, air, and water. 

Ground water: Arsenic, manganese, and vinyl chloride.
Surface water: Arsenic, manganese, and vinyl chloride.

The Model Toxics Control Act (MTCA)is Washington’s environmental cleanup law. It provides requirements for contaminated site cleanup and sets standards that protect human health and the environment. Ecology enacts the MTCA and oversees cleanups.

The MTCA site cleanup process is completed in steps over a variable timeline.

What's In My Neighborhood shows contamination cleanup sites in Washington state. Learn more and subscribe to other cleanup sites. Ecology encourages cleanup of these sites to protect the health of people, plants, and animals. Cleanups are projects that remove, treat, or contain potentially harmful substances. 

To report an environmental problem or concern, any time, day or night, use the online reporting form.

Counties: Island, King, Kitsap, San Juan, Skagit, Snohomish, and Whatcom
Email: nwroerts@ecy.wa.gov
Phone: 206-594-0000

We offer translation and interpretation services at no cost. To request these services or an ADA accommodation, please email nlui461@ecy.wa.gov or call 425-393-5679. For Washington Telecommunications Relay, dial 711.