Bringing The World Home To You

© 2025 WUNC North Carolina Public Radio
120 Friday Center Dr
Chapel Hill, NC 27517
919.445.9150 | 800.962.9862
Play Live Radio
Next Up:
0:00
0:00
0:00 0:00
Available On Air Stations

Foul smell at Kings Mountain lithium mine raises local concerns

Albemarle started draining the Kings Mountain lithium mine last spring. Several hundred million gallons remain.
Zachary Turner
/
WFAE
Albemarle started draining the Kings Mountain lithium mine last spring. Several hundred million gallons remain.

In Cleveland County, Albemarle is draining the old Kings Mountain mine to reopen it and extract the key ingredient for many rechargeable batteries: lithium.

The company started drying out the mine last spring. The company expected some smells to come from the decomposed materials at the bottom of the lake. But in December, residents started to notice something fishy—or rather, eggy.

“Soon as you walk out the front door, it would hit you,” said Kings Mountain resident, Jason Nail.

Nail moved to the Kings Mountain area from Gaston County about two decades ago. He said the smell wafted as far as the nearby town of Grover. The smell is also intermittent — Nail said that as of Jan. 23, he hadn’t smelled the odor in a few days.

The City of Kings Mountain contacted Albemarle to confirm the presence of a potential natural gas leak on Dec. 6.

The mining company first posted about it on Facebook the following day. In a written statement provided to WFAE, Albemarle said that residents didn’t contact the company until mid-January — around the time the company released two press releases (first press release and second press release) about the smell on its website.

Nail posted several times about his conversations with state regulators in the town’s Facebook group — each post drew over 100 comments. One woman said her house smelled whenever she did the dishes or showered. Many commenters questioned the company and state regulators’ claims that the phenomenon was strictly natural.

“They’re always blaming it on lake turnover,” Nail said.  

Albemarle and state regulators attributed the smell to a natural phenomenon called turnover. It occurs when cold weather cools the surface of a body of water. The denser surface water sinks, displacing the water at the bottom of the lake.

Conversely, the water on the bottom of the lake rises to the surface, bringing a smelly hitchhiker along for the ride: hydrogen sulfide gas.

Lake turnover occurs when cold weather cools the lake's surface. The surface water sinks, switching places with the water on the lake's bottom.
Albemarle
Lake turnover occurs when cold weather cools the lake's surface. The surface water sinks, switching places with the water on the lake's bottom.

How dangerous is hydrogen sulfide?

“If it does turnover and releases a fair amount of hydrogen sulfide, then, in fact, you’re going to have that odor in that community,” said Glenn Miller, a geochemist and emeritus professor of environmental sciences at the University of Nevada, Reno.

Hydrogen sulfide, commonly known as “sewer gas” or “swamp gas,” forms as bacteria break down organic matter, like plant or animal proteins, or metal sulfides. Petroleum refineries, food processing plants and other manufacturing processes release the gas as a byproduct.

“Instead of oxygen, they breathe sulfate,” Miller said.  

This process also occurs during digestion, as bacteria in the mouth and stomach break down food. The toxic gas is both lethal in high exposure and a tool for regulating our gut health, similar to carbon monoxide, except it smells bad.

The U.S. Department of Health and Human Services compared the smell of hydrogen sulfide to “rotten eggs.” In a written statement provided by Albemarle, the company described it as a sulfurous smell akin to what you might smell in a marsh.

Hydrogen sulfide degrades quickly in the air as it oxidizes, according to Miller. Humans can smell traces of the chemical — about 0.0005 parts per million — many times less than what is dangerous. The gas may cause discomfort at concentrations under 1 ppm, but most people wouldn’t experience adverse effects under 10 ppm, depending on the length of exposure.

Albemarle’s air monitors show that hydrogen sulfide levels have not exceeded 1 ppm near the pit. It all comes down to the concentration, and because the human nose can detect very low levels of it, the smell test doesn’t necessarily mean danger. But it still stinks.

“I’ve been around marshes and the beaches my whole life, all over, and never smelt the strength of this odor anywhere,” Nail said.

What’s all the stink about?

Fortunately, the issue is seasonal, and once the mine is empty, there won’t be anything left to turn over.

“If they get rid of the water, there’s no problem,” Miller said. “There may be some sulfidic material on the bottom, but it’s going to oxidize pretty fast.” 

Kings Mountain resident Jason Nail said he also thinks the mine’s activities have exacerbated this natural phenomenon, making the smell worse.

“I know it’s because they’re pumping the mine out,” Nail said. “During this time of year — with lake turnover — the warm water generally drops to the bottom, and they’re pumping from the bottom.”

Albemarle did reposition one of the pumps deeper, but the company did so to reduce the smell. By pumping the sulfide-rich water out, the company aims to reduce the amount of gas released by turnover.

The water is pumped straight to a water treatment facility that strips sulfates from the water before it’s released into Kings Creek. To date, sulfide levels have not exceeded 0.22 parts per billion — the limit set by the company’s wastewater permit.

Republican Representative Tim Moore sent a letter to the EPA on Jan. 17, asking the federal agency to monitor hydrogen sulfide levels at the mine. Moore urged regulators to ensure the safety of residents as Albemarle reopened the mine, acknowledging the mine’s “strategic importance.”

Aside from the smell itself, Nail wanted more transparency about the air quality surrounding the pit lake.

“They put out a post saying they put more air monitoring systems in, but they won’t share the data for the last 25 days,” Nail said.  

The company installed additional air monitors around the pit following the smell’s appearance. An Albemarle spokesperson said the company is also considering taking measures to reduce wind over the lake and adding chemicals to the water to reduce the smell.

Edit on 01/28/25: Mining operations are in Cleveland County, not Gaston County.

Sign up for our weekly climate newsletter

Zachary Turner is a climate reporter and author of the WFAE Climate News newsletter. He freelanced for radio and digital print, reporting on environmental issues in North Carolina.
More Stories