Kent Wetland Waste Oil Spill

(Information on this site is considered to be accurate at the time of posting, but is subject to change as new information becomes available.)

Responders found thick heavy oil in a marshy forest just off a street end on S. 216th St. The material appeared to be waste oil, and may have been present at least a week or possibly more. The spill appears to cover about an acre and a half of wetland, and is estimated at 250 to 300 gallons.

Summary information

Date of incident:  December 27, 2015

Kent, King County, WA

Type of incident: Approximately 250 gallons or more of lube oil
Cause of incident: Under investigation
Responsible party: Under investigation

Status updates

January 11, 2016

Cleanup materials left in place on December 31 remained free of newly picked-up oil for a week. They were removed on January 8, concluding the field response.

Analysis of the oil, oily water and oily plant debris removed during the wetland cleanup showed that the effort resulted in the removal of approximately 181 gallons of oil.

The estimated cleanup cost for contractor staff time and materials is $45,000.

December 31, 2015

Ecology's environmental contractor completed three-and-a-half days of cleanup this afternoon. Workers set out oil spill cleanup pads and materials as the response shifted from active removal of oil and oiled vegetation to natural recovery. Further active cleanup could cause long-term damage to the wetland.

Crews have removed their equipment and solid and liquid waste containers that had been staged on site for the project.

Over the holiday weekend and coming weeks, Ecology will make periodic visits to monitor the recovery process. Also the contractor will make regular checks of the cleanup materials, and tend to their replacement as needed.

The estimated tab to clean up the lube oil spill now stands at $35,500 for field operations. Other costs, such as disposal of oiled solid waste and recovered oil and oily water, remain to be calculated.

December 30, 2015

Oil type identified:
Ecology’s Manchester Environmental Laboratory has identified a sample of the oil found in a Kent wetland as lube oil with a trace of diesel. Ecology continues to investigate the cause of and party responsible for the release of oil onto private property off S. 216th St.

Responders captured three live oiled frogs, cleaned them and released them to a clean portion of the wetland. No other oiled wildlife has been observed.

Cleanup activities today:
A contractor crew continued the removal of oiled vegetation and continued to operate skimming and suction equipment. The solid waste now fills almost two 20 cubic yard trash containers. Workers have collected 500 gallons of oily water and 125 gallons of oil extracted by a skimmer.

An updated cost estimate was not available for today.

The cleanup team will continue working until dark. Overnight, containment boom and oil cleanup materials will be left in place.

Transition to monitoring:
Tomorrow, contractor crews will conclude skimming and oiled vegetation removal. Oil cleanup pads and containment boom will be set in place. Further active cleanup could cause long-term damage to the wetland environment. Crews will check and replace pads as needed, and Ecology will monitor the natural recovery process in the affected area. This phase may last a number of weeks.

December 29, 2015

Environmental crews began at first light this morning on a second day of cleaning up oil discovered over the weekend in a wooded wetland in Kent.

A dog walker first noticed the spill Sunday, December 27, in the late afternoon shortly after sunset and reported it to 911. The Kent Fire Department responded and notified the Department of Ecology.

Responders found thick heavy oil in a marshy forest just off a street end on S. 216th St. The material appeared to be waste oil, and may have been present at least a week or possibly more. The oil was “weathered,” showing age signs such as grayish color and a low odor level.

The spill appears to cover about an acre and a half of wetland. That, plus the thickness of the oil, up to two inches in places, enabled Ecology to roughly estimate the spill at 250 to 300 gallons.

Cleanup started at dawn
With no responsible party identified, Ecology tapped into a state oil spill contingency fund to hire National Response Corporation to conduct cleanup work under Ecology’s direction. Crews began at first light Monday.

Workers operated small skimmers and suction pumps, deployed oil cleanup pads and removed oiled vegetation. The first day’s work yielded 500 gallons of oily water, 45 gallons of oil from the skimmer and 45 trash bags of soiled material.

Wetlands need special care
A wetland oil spill requires special techniques and much patience. Too aggressive a cleanup can cause more damage than benefit. In addition to skimming and pumping the surface, crews remove as much oiled material as possible that otherwise would continue to release oil. Workers are picking up leaves, twigs and branches, and they are trimming vegetation less than four inches in diameter.

The wetland plants will be able to re-grow, but some residual oil will remain. This normally dissipates as the oil degrades through a natural process. The oil and debris removed in the cleanup gives this process an important boost.

Responders have observed no birds in the area, and there are no reports of oiled wildlife. We would expect that small life forms, such as insects, other invertebrates and amphibians, would be affected by this oil.

The spill is on property owned by an adjoining business. The 24-acre wetland is “isolated,” which means its water does not exit by a surface stream. Instead the wetland’s water level rises and falls with the water table, and water flows out as groundwater.

Next steps
Ecology has sent a sample of the oil to its environmental laboratory. In a few days, responders will receive an analysis of the specific type of oil involved. An investigation to identify the cause and responsible party continues.

The cleanup will require at least another day. After no more active cleanup is possible, Ecology will monitor the wetland as the residual oil continues to weather and dissipate. By the time wildlife becomes more active in the spring, the affected area should present a much reduced environmental risk as vegetation sprouts and regrows.

A crew of nine continued cleanup of the oil spill in a Kent forested wetland today, and will continue until after dark this evening. The same number of workers will resume the effort at tomorrow morning’s first light.

Overnight, the site will be covered with oil spill cleanup materials, and a crew member will tend a small skimming device.

Workers are removing oiled vegetation, leaves and branches. The accumulation so far is 20 cubic yards, a volume equivalent to more than 4,000 gallons. Pumps and skimmers have recovered about 500 gallons of oil/water mixture.

Ecology has tapped into a state oil spill fund to enable the cleanup to proceed. The cost estimate for two days of contractor work is $20,800. At least one more day of cleanup is needed.


Media contact

Larry Altose, Media contact,, 425-649-7009