- State officials have confirmed that an underground fire which had been burning at the closed 250-acre Pasco Sanitary Landfill in Washington since 2013 is now extinguished.
- The fire covered an area of approximately 90 square feet which contained tires and municipal solid waste that had been compacted into bales.
- A draft study will be released to help guide the clean-up process. An estimated 32 businesses and government agencies, including the local county, are potentially liable.
Though the affected area was small, officials and area residents were concerned because the landfill is also a Superfund site.
An estimated 35,000 drums of solvent, paint sludge and cleaners were buried near the fire. The site also holds sludge from paper manufacturing, residues from plywood resin waste, lime sludge and bulk liquid waste.
Water couldn't be used because it could potentially leach contaminants into the soil below. Attempts to smother the fire with soil and inject liquid carbon dioxide in years past were unsuccessful. The ultimate solution was to box the fire in with 35-feet deep underground walls and mix the waste with grout. Once it cooled down, the flammable waste was then dug up, sorted and disposed of in another landfill.
Fires are one of multiple potential hazards that must be managed at landfills, whether active or not. Recent research showing a possible rise in landfill temperatures has added to potential concerns over fires and officials must continue to be vigilant on this issue.