PacifiCorp’s coal-fired Naughton power plant has one of the nation’s highest levels of toxic chemicals in its active coal ash dumps, according to a report published March 5 by several environmental groups.

In 2015, the Environmental Protection Agency created the Coal Ash Rule, which requires utilities to test and report the pollutants in active coal ash dumps. Coal ash is the waste produced when coal is burned for electricity.      

Utilities must report the concentrations of contaminants like radium, arsenic and lithium at their coal ash deposit sites.

Pacificorp’s Jim Bridger plant ranked third worst and the Naughton plant in Kemmerer ranked fourth worst in the report. PacifiCorp published the contamination data for its six coal ash deposit ponds at Naughton. Another Pacificorp plant south of Salt Lake City made the list of the country’s 10 worst contamination sites.

The report analyzing data required by the Coal Ash Rule is titled “Coal’s Poisonous Legacy.” It is part of the Environmental Integrity Project. Representatives from Earthjustice, the Prairie Rivers Network, the Sierra Club and Appalachian Voices also analyzed the data to produce the report.

The report states that the levels of lithium and selenium in the groundwater at Naughton near one coal ash deposit site are 100 times the standard for safe drinking water. Arsenic is present at five times the safe drinking water standard. Other contaminants present in small amounts include lead, radium and arsenic.

Ninety-one percent of the country’s coal-fired power plants have some level of unsafe contaminants in the groundwater at coal ash deposit sites, according to the monitoring reports required by the Coal Ash Rule.

The worst levels of contamination at coal ash deposit sites were found near the San Miguel Power Plant south of San Antonio, Texas. Monitoring of that plant found unsafe levels of arsenic, beryllium, boron, cadmium, cobalt, fluoride, lithiu, mercury, radium, selenium, sulfate and thallium.

The report says that drinking water wells near coal ash sites do not require testing by the EPA, so any potential contamination in actual drinking water is difficult to measure.

PacifiCorp spokesperson David Eskelsen told Wyoming Public Media that the utility was aware of the contaminants and was working diligently to become compliant with the latest EPA regulations.

“One thing I’d like to emphasize is that in these three plant locations, natural groundwater is already of very low quality,” said Eskelen. “It’s Class IV, which is a class of water that is not usable for any (uses except) some limited industrial uses.”

The Environmental Integrity Project report suggested that utilities combat potential pollution by increasing monitoring of contaminants at all coal ash deposit sites, not just active ones.

“The only way to restore groundwater quality, and to prevent risks to human health and aquatic life, is to control all sources of coal ash pollution at each site,” the report states.