A sign outside of Lamb Weston’s Hermiston processing facility thanks the plant’s employees on July 7, 2020. The Oregon Department of Environmental Quality on Tuesday, Sept. 27, 2022, announced it fined the company $127,800 for groundwater contamination at the potato processing facility.

The Oregon Department of Environmental Quality fined the Lamb Weston potato processing facility in Hermiston $127,800 for groundwater contamination in the Lower Umatilla Basin.

DEQ announced the fine Tuesday, Sept. 27.

Lamb Weston has a DEQ water quality permit that allows it to use the nitrogen-rich wastewater from its potato processing plant and several other facilities to irrigate and fertilize nearby farms. The permit, however, limits how much nitrogen Lamb Weston can apply to each crop. While nitrogen is a beneficial plant nutrient, too much on land can contribute to nitrate contamination in groundwater.

Lamb Weston exceeded these limits on 90 occasions between 2015-21, according to the DEQ, resulting in applying approximately 446,990 pounds of excess nitrogen on crops.

DEQ also cited Lamb Weston for failing to report noncompliance with the permit within five days of the violation and for a separate spill of almost 25,000 gallons of industrial wastewater to soil.

Many sources contribute to nitrate contamination in the area, which spans northern Morrow and Umatilla counties. The primary source of contamination — about 70% — is from fertilizer on irrigated farmland, according to the Lower Umatilla Basin Groundwater Management Area Action Plan. Additional contributors are dairy and cattle farms (about 20%), food processing facilities that reuse wastewater to irrigate fields (about 5%) and residential septic systems and other sources (about 5%).

DEQ also reported it ordered Lamb Weston to develop and implement a plan to ensure compliance with the nitrogen limits in the permit and to conduct a remedial investigation of the aquifer under its land application sites.

DEQ discovered the violations while preparing a permit renewal for the facility. DEQ is also working with other industrial facilities in the area to ensure appropriate land application practices that protect the area’s groundwater.