POCATELLO, Idaho — An Idaho fertilizer facility must undergo $150 million in upgrades under a federal legal settlement that also imposes a $1.5 million penalty on its owner, the J.R. Simplot Co.

The U.S. Environmental Protection Agency filed a complaint accusing the agribusiness company of illegally storing or disposing of hazardous wastes from the manufacture of phosphate products at the Pocatello facility.

The lawsuit also alleged that fluoride emissions from the facility’s cooling towers exceeded federal limits and that Simplot failed to warn regulators of toxic releases of hydrogen fluoride at the site.

While the company disputed the claims, it agreed to a consent decree under which it will invest in recovering and reusing phosphate from waste byproducts that would otherwise be stored in a pile known as a gypstack.

Under the deal, Simplot also agreed to shut down its cooling towers within three years and replace them with cooling ponds that will decrease fluoride emissions from the facility. Aside from paying the $1.5 million civil penalty, the company will dedicate $200,000 to mitigate habitat degradation from phosphorous in the Portneuf River.

The facility has previously agreed to remedial actions under settlements with federal and state regulators in 2002, 2008 and 2016 at the nearly 80-year-old facility, which encompasses more than 1,700 acres.

Before the gypstack was lined under a previous settlement deal, acidic wastewater leached from it and contaminated the soil and groundwater, according to the complaint. Other than some wastewater that’s applied to farmland under an Idaho permit, such discharges aren’t allowed from the facility.

The EPA entered into a similar settlement with Simplot in 2020 regarding a Wyoming phosphate fertilizer plant and has brought legal actions against 13 other phosphate facilities alleging environmental violations.

Simplot makes “no admission of law or fact” with respect to EPA’s allegations and continues to deny violating any environmental laws in court documents, but agreed to the settlement “for the purpose of avoiding litigation.”