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Platte River Power Authority's Rawhide Energy Station north of Wellington, generates electricity using coal, natural gas and solar. (Ed Kosmicki, Special to The Colorado Sun)

When Platte River Power Authority checked the groundwater near its Rawhide power plant for coal-ash contamination last year, it found some. Levels of selenium, which can cause human hair loss and deformities in fish and wildlife, were higher than deemed safe by federal groundwater protection standards.

The authority, which released the Rawhide report in January, was already working to reduce the potential for contamination at its Larimer County site. But the statistically significant increase was a surprise, said Chris Wood, Platte River’s environmental services manager.

“The short answer is Platte River Power Authority sees no immediate harm or risk to human health or the environment,” Wood said. “…We’ve monitored it in the past, and it was never an issue. It’s not a big change, but big enough change statistically that it’s pulled us into the regulatory process. The next steps are to continue to monitor and evaluate the different corrective actions.”

Since federal regulations kicked in a few years ago, coal-fired power plants are required to monitor and publicly report what happens to the residue from burning coal and determine whether chemicals are seeping from the coal-ash disposal sites into the groundwater.

But the reporting process is inconsistent between facilities and the data collected is often complicated to interpret. So a group of environmentalists culled the data from 265 coal-fired power plants or ash dumps, including seven in Colorado, and found 91 percent had unsafe levels of one or more chemicals in nearby groundwater.

Colorado coal-ash reports

“This is only the beginning of the end,” said Abel Russ, a senior attorney for The Environmental Integrity Project, which published the report as part of a collaboration between the Sierra Club, Earthjustice and other environmental organizations. “If it’s gradually leaking and if you don’t do anything about it now, future generations will have to deal with it. And it’s not any one chemical but a bunch. Most had four different chemicals (contaminating groundwater). The coal-ash rule and our report are looking at drinking water standards, but there’s the whole fish and wildlife (ecosystem) that this doesn’t address.”

Wood said Rawhide is overhauling how it collects and disposes the coal ash and hopes that the updates will show an improvement in the next round of monitoring. And while the plant is next to the Hamilton Reservoir, which attracts birds and other wildlife, its coal-ash disposal site is “zero run off,” so ash cannot flow to nearby wildlife ponds. The Hamilton Reservoir was set up as a cooling lagoon for the Rawhide plant.

Local environmental activists said they’ll be monitoring results closely at Rawhide, which is located in a remote stretch of prairie between Fort Collins and the Wyoming border.

“They’ve detected these chemicals that in some settings pose risks to people and wildlife or both,” said Matthew Gerhart, a Denver-based staff attorney for the Sierra Club Environmental Law Program. “It’s also triggered further monitoring to see what’s the scope of contamination and what they can do to clean it up and prevent further contamination. For Rawhide, it’s a big deal unless they can show that the contamination is coming from some other source, which I don’t think they will because there’s not much else around the Rawhide plant that would release the chemicals.”

Coal-fired power plants began reporting their monitoring results last year to meet the U.S. Environmental Protection Agency Coal Ash Rule, which went into effect in 2015 and took a few years to get going.

The EPA requires coal-fired power plants to monitor the disposal of byproducts from burning coal and also monitor groundwater for contaminants. But the reports aren’t easy to read, and that’s why the Environmental Integrity Project set about interpreting the results, said Russ, with the Environmental Integrity Project.

Tri-State Generation and Transmission Association’s coal-fired Nucla Station, at the west end of Montrose County, will close by the end of 2022. The massive generation cooperative also plans to retire a coal-fired electric generation unit at Craig Station by the end of 2025. (William Woody, Special to The Colorado Sun)

The project provided a guide (on page 68 of the report) to show EPA groundwater standards for the chemicals, but it’s not easy to compare with an individual power plant’s technical report. For example, if tests were done at numerous wells at the landfill and at different times of year, the numbers could be all over the place.

The project calculated an average pollution number so consumers could compare how much arsenic was found. At the Nucla Generating Station on the Western Slope, for example, arsenic came in at three times the safe level for drinking water. Russ said the project mostly relied on EPA drinking water standards as a comparison.

“We know the public can’t make use of the data in its raw form. It’s not user friendly,” Russ said.

In Colorado, the project found excess levels of some pollutant at all seven power plants that posted reports online. The Nucla Generating Station had lithium exceeding safe groundwater levels by 83 times, and the Xcel Energy Hayden Station had molybdenum at 34 times in excess of levels deemed safe.

The Clear Spring Ranch landfill, which is operated by Colorado Springs Utilities and takes coal ash from the Martin Drake plant, and Xcel’s Pawnee Station near Brush had lesser degrees of contamination, as did two other Xcel plants, Cherokee Station in Adams County and Valmont in Boulder, where coal-fired generators have been converted to natural gas.

If energy companies do find contamination, they must continue to monitor the disposal sites and determine the source of the contamination.

Xcel called protecting the environment a priority, and the company said in a statement that it is working to meet clean air and water requirements.

It shared this statement: “During groundwater testing, we detected increased levels of some trace minerals above groundwater standards. Based on these results, we have no indication that there are impacts to local drinking water or groundwater beyond plant boundaries. We plan to do additional monitoring and are committed to working with regulators to correct any issues.”

Contamination in other states showed a much worse degree of contamination. The San Miguel Power Plant in Texas had 12 pollutants above safe levels, while near the Duke Energy Allen Steam Station in North Carolina, cobalt was found to be 500 times above safe levels. The report also pointed to a loophole in the law: Monitoring is required only at active plants, not older ones where coal-ash disposal sites have been closed.

“Sooner or later, EPA and/or the states will have to reckon with the legacy of coal ash dumping. It would be far better for the environment, for public health, and for taxpayers to make a concerted effort now, before contamination gets worse and travels farther into the environment,” says the report, which pushes for regulating and monitoring inactive sites and moving old sites to higher ground and out of areas that get wet from potential flooding or rain and snow.

Coal ash had been unregulated by the EPA for years because it wasn’t seen as a hazardous byproduct of generating electricity, said Mark Hutson, a Colorado geologist and hydrologist with Geo-Hydro Inc. who has worked on projects nationwide.  

“You’ll probably be told that all these contaminants that come off coal ash, these are all naturally recurring things that come out of coal. And if it’s natural, you can just put it back in the ground, no harm, no foul,” Hutson said. “What they don’t say is all the chemicals in the coal, they’re tied up in the carbon. When you burn the coal, the residue that’s left is no longer tied up in carbon. It therefore becomes mobile and when water goes through it, it’s able to leach out and migrate along the water.”


The EPA became more serious about regulations after a dike failed in 2008 and 5.4 million cubic yards of coal-ash slurry from the Tennessee Valley Authority’s Kingston plant spilled into 300 acres of land and nearby rivers. It was a mess that killed a lot of fish and took years to clean up.

Ten years after the spill, 30 workers who helped clean up the ash had died and 250 were sick or dying, according to a report in the Knoxville News. A federal jury in November ruled in favor of workers who were sickened while cleaning up the ash without proper protection.

The push for better practices came about with the EPA regulations in 2015, which included lining landfills to keep coal-ash waste from seeping out, and keeping impoundments and landfills properly covered.

“The key to successful storage of (ash) is to keep it dry. A good storage site is above the high water table, ideally 5 or more feet above a high water event. And then it needs an impervious cap above it for long-term storage,” Hutson said.

Colorado’s Hazardous Materials and  Waste Management Division, a part of the Department of Public Health and Environment, has been monitoring coal-ash landfills for years, said Jerry Henderson, unit leader for the solid waste permitting unit. But not to the extent expected by the new EPA rules.

“In my opinion, I feel good about where Colorado is at right now,” Henderson said. “We’ve been regulating the sites over the years, and now we have a new rule that causes us to regulate additional (contaminants). I think this is more protective now than it’s ever been.”

Still, the state’s monitoring didn’t catch the excess selenium at the Rawhide plant.

The latest Rawhide report found selenium near the plant was at 0.067 milligrams per liter, or greater than the groundwater standard of 0.05. According to the EPA, potential health effects from long-term exposure of selenium could result in hair or fingernail loss, numbness in fingers or toes and circulatory problems.

For fish and wildlife, the impact of excessive selenium is much worse. In the 1980s, thousands of birds and fish in the Kesterson Reservoir in California were found to have severe deformities that were linked to selenium run-off from area farms, according to reports in the Pacific Standard.  


Selenium’s risk to fish is more about the exposure over time, said Jessica Brandt, who got her Ph.D. at Duke University, focused on the effects of coal ash on wildlife. She is now doing post-doctoral research at Colorado State University in Fort Collins.

Groundwater contamination near power plants may not impact wildlife if contamination isn’t running into surface waters like a nearby lake. But if it were, she added, “these concentrations would be worrisome.”

There are still updates and improvements to be made at Rawhide, said Woods, with the Platte River Power Authority.

The plant stopped putting ash in wet containers in October 2018, which is two years ahead of the federal mandate. It now disposes of the ash in the dry landfill on site, Wood said.

“We’re committed to removing all the waste and removing any contaminated materials around those impoundments,” Wood said. “The decommission of (wet disposal) will be completed mostly in 2019 and the upgrades to the landfill will be completed in 2020.”

Tamara Chuang writes about Colorado business and the local economy for The Colorado Sun, which she cofounded in 2018 with a mission to make sure quality local journalism is a sustainable business. Her focus on the economy during the pandemic...