The Green Scene

Pam McCorkhill had noticed the gray dust in her neighborhood, Lake Julian Trails, since she moved there in 2006. But to the former grade-school science teacher, the sandy material was merely an annoyance that meant extra cleaning indoors and regular deck washing. “I’ve never complained about it, and [at first] I didn’t know what it came from,” she says.

Micro-balls: In late January, some Arden neighborhoods got dusted by cenospheres, tiny sandlike balls created by burning coal at the nearby Progress Energy plant. Photo courtesy Progress Energy

In late January, however, the dust was 30 to 40 times more abundant than usual, McCorkhill estimates. “You’d go out in the morning and it looked like a dusting of gray snow on your car, on the deck, on the gardens, on the driveway,” she recalls. Gritty to the touch yet slippery, she says, “It’s like walking on ball bearings.”

But McCorkhill also noticed that her eyes were getting irritated, and both she and her fiancé were coughing and feeling congested when the dust was at its worst.

The pesky particles, she eventually learned, are called “cenospheres”—tiny, hollow balls formed when molten ash solidifies around the flue gases produced from burning coal to generate electricity at the nearby Progress Energy plant.

The U.S. Environmental Protection Agency doesn’t consider cenospheres hazardous. Their main ingredients by weight are silicon and aluminum; they also contain trace amounts of potassium, iron, sulfur, calcium, manganese and other elements, according to a recent analysis performed for Progress Energy by EMSL Analytical, a private New Jersey-based lab.

The stuff is so fine and light, it floats to the surface of the Lake Julian plant’s coal-ash pond, says Jamie Stone, president of the Chattanooga-based company Sphere One. Founded by his father in 1972, the company harvests the cenospheres and sells them as a lightweight filler that’s used to produce bowling balls and cultured marble, among other things.

His crews use a boat and floating booms to corral the gray film floating on the water’s surface. After letting the water drain off, they load the stuff onto trucks and haul it to Chattanooga for processing. “It’s like wet brown sugar,” Stone says about the material at this stage. When dry, however, the cenospheres are easily blown about by the wind. That’s why his crews wear safety glasses—and why they wet the piles down as they work.

But late January posed another problem: unusually cold temperatures. The company can’t harvest when the pond is frozen, and the cenospheres built up on the surface, dried out, and were picked up by strong winds.

Lewis Campos says he and his wife first thought they were catching colds, but they later connected their symptoms to the increased dust level in their Arden neighborhood. The Campos’ home is close to Lake Julian Trails and less than a mile from the plant. Neighbors told them about the dust problem when they moved there a few years ago, says Campos, but the January event was worrisome. “These things happen, and [we’re told] they don’t have any long-term effects, but we don’t know,” he notes, asserting that Progress Energy has a responsibility to address the problem.

The company has sent in cleanup crews to vacuum up the dust and given residents car-wash vouchers, says Darren Touchell, president of the Lake Julian Trails Home Owners Association. “The cenospheres have caused us a mess to clean up, but Progress Energy vacuumed my [property], and I was very pleased with the result,” he says. The utility has also proposed planting additional trees and other vegetation to provide a better windbreak between the pond and the neighborhoods, adds Touchell, citing a letter and ongoing discussions with company spokesperson Martha Thompson.

And Stone says Sphere One will implement extra harvests to prevent the material from building up, particularly when freezing temperatures are forecast.

Meanwhile, notes Progress Energy spokesperson Scott Sutton, “A simple wash will remove the material.” Residents, he explains, should avoid sweeping or rubbing dust-covered surfaces with a dry cloth, which can break the cenospheres into smaller particles and disperse them. “If you do get it in your eyes, you should flush [them] with water for 10 to 15 minutes,” he advises, while reiterating his company’s commitment to cleanup and prevention efforts.

“They said they’d clean up, and that’s what they’re doing,” agrees Touchell.

But McCorkhill, who works with stained glass and knows the hazards presented by grinding her materials, remains unconvinced, saying, “Unless they change their practices, it will happen again. This is just a Band-Aid.”

If you have questions for Progress Energy, contact Martha Thompson (258-5019; e-mail: A meeting between company representatives and Lake Julian Trails residents has been scheduled for Saturday, March 28; check the neighborhood Web site,, which also has a link to the chemical analysis of the cenospheres.

Send your environmental news to, or leave a message at 251-1333, ext. 152.

About Margaret Williams
Editor Margaret Williams first wrote for Xpress in 1994. An Alabama native, she has lived in Western North Carolina since 1987 and completed her Masters of Liberal Arts & Sciences from UNC-Asheville in 2016. Follow me @mvwilliams

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