PASCO — Hazardous liquids are leaking and contaminating groundwater, and there is evidence that another fire may be smoldering underground in part of a landfill just east of Pasco city limits.
Plans are being made now to clean up that and other sections of the landfill.
The Washington state Department of Ecology is taking public comment on what steps should be required of the parties identified as likely responsible for the waste.
Among the biggest differences in proposals is whether some waste could be dug up and reburied in a new lined disposal cell at the landfill, or whether it must be sent off site for treatment or disposal.
A meeting is planned in Pasco Sept. 26.
The 250-acre Pasco Sanitary Landfill near the intersection of Kahlotus Road and Highway 12 is a federal Superfund site that was closed in 1993, with the most hazardous waste buried there in the 1970s.
The area of most concern now is a section of the industrial waste area where 35,000 55-gallon drums that hold solvents, paint sludges, cleaners and other hazardous waste were buried.
Since draft studies were submitted by commercial and government parties responsible for the cleanup about a year ago, the area has become more unstable, according to a fact sheet prepared by the Washington state Department of Ecology in advance of the Pasco meeting.
“Higher than normal underground temperatures have been recorded, and liquids have leaked from drums and reached groundwater,” the fact sheet said.
The higher temperatures indicate a fire may be smoldering underground. A fire in a different area of the landfill burned for two years starting in late 2013 before efforts to put it out succeeded.
The fact sheet, distributed this month, said an immediate response is needed for the drums, located in Zone A of the landfill’s industrial area, rather than waiting until a final cleanup plan is in place.
“Removing the drums and contamination at Zone A sooner, rather than later, is necessary to address the threat to human health and environment,” the fact sheet said.
However, in recent days Ecology has been in talks with some of the parties that will be responsible for the cleanup and is considering whether it might be possible to move directly to carrying out a final cleanup plan.
The state is taking comments now on proposals for final cleanup.
Under one option, the area with the drums could be excavated down to 42 feet, with the contaminated soil and waste taken to an off-site treatment and disposal facility. A soil vapor extraction system would be used to collect volatile organic compounds more than 42 feet deep and then the chemicals would be destroyed with heat.
The work is estimated to cost $128.1 million.
The other option would be to excavate drums and contaminated soil to as little as 27 feet deep.
Contaminated soil and some waste would be moved to a new lined disposal cell at the landfill. Some intact drums with sludges or soil residues could be disposed of in the cell.
Liquids in other drums would be shipped off site for treatment or disposal.
Related alternatives call for digging deeper than 27 feet and heating soil beneath the excavation to destroy some chemicals in addition to using the soil vapor extraction system.
Those related options would cost a minimum of $56 million.
The public also can comment on cleanup plans proposed for other areas of the waste.
Other industrial waste, including 5,000 drums of herbicide-manufacturing waste, have already been dug up and sent off site for incineration and disposal.
No other waste is planned to be dug up, including 11,000 tons of sludge from paper manufacturing and about 3 million gallons of bulk liquid waste ranging from wood treatment and preservative waste to paint and paint solvent waste.
Proposed plans also call for leaving in place household and commercial waste buried at the landfill from 1958 until 1993 in place. Gases from decomposing waste would continue to be collected and burned.
Plans across the landfill call for monitoring groundwater and also maintaining — and in some places improving — protective coverings to keep animals and precipitation from infiltrating areas where waste is buried.
The state has previously identified 32 businesses and government agencies that are potentially liable for cleanup of the Superfund site.
They include companies such as Du Pont, Boeing and Union Oil of California, and government entities such as the Air Force and Franklin County.
The public meeting on the proposed cleanup options will be at 6:30 p.m. Sept. 26 at Virgie Robinson Elementary School, 125 S. Wehe Ave.
Public comments may be emailed to charles.gruenenfelder@ecy.wa.gov or mailed to Charles Gruenenfelder, site manager; 4601 N. Monroe St.; Spokane, WA 99205. The deadline is Oct. 12.
