A $1 million cleanup plan is being proposed for a contaminated site along the Spokane River near downtown where a gas plant and a tar company once operated.


The Washington state Department of Ecology is proposing to enter into a consent decree with Avista Corp. and Burlington Northern Santa Fe Railway Co., two potentially liable parties that tentatively have agreed to pay for the environmental cleanup. The consent decree would formalize the cleanup agreement for the site, which Ecology refers to as the Hamilton Street bridge site and is on roughly 10 acres along the south bank of the Spokane River beneath that bridge, which formally is named the James E. Keefe Bridge. A public comment period on the project ends today, July 25.


Brown Building Materials, a building materials sales and salvage business here, currently operates on the site.


Teresita Bala, an Ecology environmental engineer whos overseeing the cleanup, says an engineering-design report should be completed on the project by the end of the yearpossibly soonerand work could start shortly thereafter. The report will include a time line for the cleanup project, which is expected to cost about $1 million to complete. Public comment also will be sought.


The cleanup plan is expected to involve covering contaminated areas with clean soil or gravel and stabilizing a portion of the riverbank where erosion is occurring. The site also will be subject to long-term groundwater monitoring and five-year reviews to ensure that the cleanup measures are effective.


The contamination involves heavy concentrations of organic compounds consistent with coal tarsome of which are carcinogenicin a two- to three-acre portion of the area where Spokane Gas Co. and American Tar Co. operated plants through the first half of last century. Spokane Gas operated a coal-gas plant that provided power to parts of the Spokane area. American Tar made pitch, roof paint, pole paint, and other tar products from coal tar that Spokane Gas created as a by-product.


BNSF owns the former American Tar site, and Avista owned the Spokane Gas site until selling it to Spokane River Properties Ltd. in 1978. Spokane River Properties isnt required to participate in the cleanup studies, but it is a potentially liable party, which means it might be required to pay for part of the cleanup costs.