Simplot Soilbuilders Sunnyside

The Simplot Soilbuilders Sunnyside site is a 2.7-acre business lot at 300 South 1st Street in Sunnyside. Most of the lot is gravel with a modular office, a warehouse, and a maintenance shop on the lot.

The site has been a farm-supply yard since the early-to-mid 1960s. Workers stored, mixed, and sold fertilizer, pesticides, herbicides, and soil amendments here. Spray tanks were rinsed outside on the gravel in the northeast corner until the 1990s. Some of those chemicals soaked into the ground. The original warehouse, office. fertilizer tank area came down in 2011, replaced with a new office and a sealed concrete catch-basin. In 2012, polluted soil from the old rinse area was dug out and hauled to a permitted landfill.

Investigations from 2009 through 2023 mapped two source areas. The first is north-northwest of the warehouse, where petroleum likely leaked from an old above-ground tank. No buried tank was found. The second is the former equipment-rinse area in the northeast corner.

Most pollution is in the top 15 feet of soil and the shallow aquifer below. Contaminants include nitrates, select volatile organic compounds, heavy metals, herbicides, and petroleum-related contaminants.  No impact on the public water supply has been found in testing so far.

In late 2018, Ecology named J.R. Simplot Company a Potentially Liable Person (PLP), the legal term for people and companies who are responsible for the cleanup of the property. Ecology and Simplot signed an Agreed Order in 2019, a legal contract under Washington's cleanup law, the Model Toxics Control Act. (MTCA). Under it, Simplot agreed to investigate the pollution and prepare a cleanup plan. By 2023, the site studies were complete. A draft cleanup plan (dCAP) was submitted in 2024.  After the public has an opportunity to comment on the dCAP, actions will be taken to complete site cleanup.