School navigation


NWEA Win Forces EPA to Establish Safer Arsenic Standard for Idaho Rivers

June 07, 2016

  • Salmon River in Idaho. A new court order requires EPA to set better arsenic standards for the state's waterways.

In a federal court-signed order today, the U.S. Environmental Protection Agency (EPA) agreed to retract its 2010 approval of Idaho’s water quality standard for arsenic.

The order requires EPA to repeal its previous approval by September and to establish a new arsenic standard for Idaho by mid-2019. The EPA also committed to issue Clean Water Act discharge permits using more protective levels during the interim period before the new standards are in place.  The agreement also requires EPA to increase monitoring of pollution discharges to detect arsenic. 

The problem arose in 2010 when Idaho chose to use EPA’s standard under the Safe Drinking Water Act instead of its recommendations for protective standards under the Clean Water Act, resulting in the significant difference in human health protection.  The Clean Water Act is intended to protect people from chemicals in rivers and streams whereas the Safe Drinking Water Act protects people at the tap, after drinking water has been treated. The Safe Drinking Water Act allows the EPA to consider the costs of the project, which allowed them to falsely reduce the stringency of the water quality standards. Idaho’s adoption of a water quality standard of 10 micrograms per liter (µg/l) can be compared to EPA’s 1992 national recommendations for arsenic standards of 0.14 µg/L for consumption of fish only and 0.018 µg/L for consumption of both fish and water (both at a cancer risk of one cancer per million people). 

“EPA violated the Clean Water Act when it allowed arsenic levels in Idaho waters that are up to 1,000 times greater than the agency has determined are acceptable for this toxic chemical,” said Nina Bell, Executive Director of NWEA.  “EPA placed political expediency over human health protection,” she added.

Northwest Environmental Advocates was represented by Allison LaPlante and Lia Comerford of the Earthrise Law Center at Lewis & Clark Law School. 

Share this story on


Contact Us