Monitoring cleanup of former toxic dump

Forty-three years ago, the City of Shelton was ordered to develop a plan to clean up its toxic former C Street dump.

That plan was finally executed last year at the 17-acre landfill west of downtown Shelton and U.S. Highway 101 and north of Miles Sand and Gravel. Now the city is dealing with the post cleanup and monitoring.

At its Aug. 6 regular meeting, the Shelton City Council gave preliminary approval to adding $147,219 to its contract with Aspect Consulting and extending the monitoring contract through 2029. The monitoring and reporting are required as part of the state Agreed Order. The council can make the move official with a vote at its meeting at 6 p.m. Aug. 20 at the Shelton Civic Center.

"We're finally getting this thing all wrapped up," said Shelton Mayor Eric Onisko.

"It was a legacy landfill that was never closed properly, so we've had to go back and make that right," said City Manager Mark Ziegler. He added, "Hopefully, the results are what Ecology is seeking, we can put this to bed in the next few years."

The city report states "additional environmental and geotechnical services were found to be needed during construction due to the unrealized extent of the landfill waste." In May 2023, the City Council voted to increase Aspect Consulting's contract by $121,564.

Ziegler said hundreds of thousands of tons of soil were removed from the site. Some of it was 40 feet deep, he said.

Last year, the city paid almost

$2.6 million to the contractor on the cleanup, Brumfield Construction.

Private owners mined the site for sand and gravel before the city bought the land in 1928 to use as a municipal landfill.

The former Rayonier pulp mill and research laboratory dumped byproducts and demolition debris at the landfill. The city dumped sludge from its wastewater treatment sites. Between 1976 and 1981, wastewater treatment sludge containing ash from Simpson Lumber Co.'s Shelton mill was dumped at the site.

When the Shelton Hardware Store burned to the ground, all the fixtures, chemicals and pesticides were trucked to the site and dumped. Trash was burned in the open air and in an incinerator.

In a December 1981 letter to the mayor and city commissioners, then-Mason County Health Officer John Butler said the city had been observed dumping sludge from its treatment plant at the C Street dump, despite the fact that it was not a permitted solid-waste disposal site. The city was depositing about 120,000 gallons of sludge per month, creating a 4-foot-deep pond accessible to people and animals, the letter stated.

In the letter, the county ordered the city to stop disposing the sludge at the site and to establish a schedule "for submitting a plan and timetable for the Health Department for fencing or otherwise limiting access to the sludge already deposited at the Old City Dump."

In 1986, an inspector from the state Department of Ecology noted that the City of Shelton had not yet closed the landfill and cited evidence of newly dumped sludge and household waste. Citing that report, Mason County instructed the city to close the dump in compliance with state laws and monitor the groundwater. The state Department of Ecology also ordered the city to close the landfill under the State Model Toxics Control Act.

In January 2015, the department named the city the potentially liable party responsible for cleaning up the site. In October of that year, the then-Shelton City Commission gave preliminary approval to a plan to identify toxins and begin a cleanup strategy at the landfill. The commission passed an Agreed Order with DOE that made the city responsible for completing a technical memorandum identifying "chemicals of concern" and screening levels at the site; developing a remedial investigation plan; conducting a feasibility study; and defining the cleanup action plan.

In 2016, the city entered into an Agreed Order with Ecology to perform a remedial investigation and feasibility study and to submit a draft cleanup action plan for the site. The remedial investigation field work was conducted from 2017 to 2020, and the final plan submitted to Ecology in 2021. The cleanup construction was performed between January and June last year.

A 2-foot layer of native sand and gravel was placed on top of the landfill waste. A 6-inch layer of vegetative topsoil was placed on top of that. The surface of the land was hydroseeded. Finally, a 6-foot-tall chain-link fence was installed around the perimeter of the soil cap.