Environmentalists claim a win for Charlotte’s drinking water. Here’s why.

In this 2009 photo, a cloud of steam rises from a 365-foot stack at Allen Steam Station near Belmont.
In this 2009 photo, a cloud of steam rises from a 365-foot stack at Allen Steam Station near Belmont. Charlotte Observer file photo

Duke Energy has withdrawn its request to add a chemical compound at several of its coal-fired plants that curbs air pollution but appeared to have caused a 2015 spike in contaminants in Charlotte’s drinking water.

The company “proactively addressed” bromides in the Catawba River basin two years ago, company spokeswoman Erin Culbert said Monday night, “and it does not pose a concern for drinking water quality.”

The company, she said, was “very transparent about this and even participated in a news conference with Charlotte Water at the time.”

The new step the company took recently was to notify state regulators that Duke Energy would not seek to add halides – bromides are a type of halides – in its plant permits. Plants in the immediate Charlotte area include Allen Steam Station in Gaston County and Marshall Steam Station on Lake Norman, off N.C. 150 in Catawba County just west of Mooresville.

“We’d had that step reserved as an option to help enhance air quality from our plants if needed, and we’ve been able to successfully meet air quality requirements without it,” Culbert said in an email reply to the Observer.

Earlier Monday, Catawba Riverkeeper Sam Perkins said Duke Energy made the request after the Catawba Riverkeeper Foundation, represented by the Southern Environmental Law Center and joined by Clean Air Carolina, filed a lawsuit challenging the company’s requested permit “to put more cancer-causing bromide in North Carolina’s rivers and drinking water supplies.”

Perkins called Duke’s withdrawal request “a victory in protecting drinking water from a very real problem we have experienced in recent years.”

Perkins said municipalities throughout the region have struggled with meeting federal standards for trihalomethanes in treated drinking water. “Yet Duke continued to pursue permits allowing their coal-fired power plants to discharge the bromides that caused the trihalomethanes to form at such high levels,” he said.

Elevated levels of trihalomethanes – disinfection byproducts – came close to federal and state limits but did not make the water unsafe, authorities said in 2015. THMs may cause liver, kidney or central nervous system problems and may increase cancer risks.

THM levels in drinking water began to rise in mid-2014, the Observer reported in 2015. The compounds are more likely to form as water warms.

But it was also about a year after Duke began using calcium bromide, in 2013, to wash coal at its Marshall and Allen power plants on lakes Norman and Wylie. The bromide wash reduced releases of toxic mercury into the air when coal is burned.

Bromide reacts with chlorine, which is used to disinfect drinking water, to form THMs.

Duke stopped using calcium bromide at the plants in May 2015, but the region’s drought at the time kept it from being flushed out of the lakes immediately

Duke acknowledged earlier that year that bromide releases from power plants could cause THM problems in water systems downstream.

In a $102 million settlement of federal charges over coal ash contamination, Duke agreed to set up a claims process for water utilities that felt harmed by bromide released by power plant scrubbers, which also clean air emissions.

Duke had already paid two cities that draw water downstream of its Belews Creek power plant, Eden and Madison, $2.3 million and $770,000 respectively to modify their treatment systems.

“It is incredible how extensive the impact of Duke Energy’s coal plants is on our communities and the air and water that we rely on,” June Blotnick, executive director of Clean Air Carolina, said in a joint statement with Perkins on Monday. “We cannot allow the addition of more poisonous chemicals by Duke Energy, like bromides, into the process. We all live downstream or downwind of these types of facilities, and we must be diligent in preventing any more harm to come.”

Joe Marusak: 704-358-5067, @jmarusak