Lead arsenate, a pesticide that was used regularly in orchards until the 1940s, has contributed to lead and arsenic contamination in large swaths (over 100,000 acres) of Central and Eastern Washington. Some former orchards have been converted to new uses, including residential neighborhoods, schools, and parks. To address exposure concerns and facilitate cleanup, the Department of Ecology (Ecology) has proposed a model remedy under the Model Toxics Control Act. The agency is requesting comments on the proposed remedy until June 7, 2021.

Ecology’s proposed model remedy is intended to be scalable – suitable for larger areas as well as small projects where soil is disturbed, such as during landscaping and home construction. Ecology also assumes that the remedy will address organic pesticides, such as DDT, that may be associated with historical agricultural practices as well. The remedy would include several options – excavation and removal, mixing contaminated soil with clean fill, capping in place, and consolidating the contaminated material and then capping it. For the capping-based remedies, institutional controls, such as an environmental covenant, would have to be maintained. The proposed remedy lists factors that affect which options would be appropriate. 

Ecology has identified likely impacted areas in its “Dirt Alert Map.” Ecology is requiring that properties within these areas be sampled when their use changes. If contamination is discovered, it must be reported to Ecology within 90 days. Parties that own contaminated parcels may be liable for cleaning them up. 

Model remedies are intended to expedite site cleanups and regulatory closures. They avoid the need to develop site-specific remedies and, when used, feasibility studies are not required. Ecology may also waive fees when reviewing requests for No Further Action determinations.  However, model remedies only apply when sites meet specific criteria – some initial site characterization is necessary to determine site eligibility. Parties also must decide whether to perform the cleanup independently or as part of Ecology’s Voluntary Cleanup Program. A model remedy could help to achieve site closure during the initial investigation phase before the site is placed on Ecology’s Confirmed and Suspected Contaminated Sites List.  

Along with the proposed model remedy, Ecology has also released several publications to highlight and educate the public on related issues, including the health effects of exposures, worker safety issues, sampling requirements, real estate transactions, and development projects.