Residue of coal-burning is being examined as possible source of mercury pollution
(COEYMANS, New York) — It’s possibly the biggest environmental mystery in the Hudson Valley: Why does the smokestack at the Lafarge cement plant release more toxic mercury than any other place in the state?
A suspect getting a closer look is coal fly ash, a fine gray powder residue of distilled pollution produced by coal-fired electric power plants and used in cement-making around the nation.
If you’ve never heard of fly ash, there’s a simple yet disturbing reason: For almost 20 years, state and federal regulators have treated the substance as if it is less hazardous than household garbage.
Now, experts suggest that an unintended consequence of a clean air push through stricter mercury rules at power plants makes ash more dangerous by concentrating heavy metals such as mercury, a potent neurotoxin that causes developmental problems in children and fetuses.
Considered “recycled air pollution control residue” by the U.S. Environmental Protection Agency, fly ash becomes airborne as coal is burned and would sail out of smokestacks if not trapped by modern pollution controls.
Nearly two decades after relaxing rules on ash use by cement plants, New York officials appear poised to tighten up. Tests sparked by high mercury readings in 2003 from Lafarge’s high-temperature cement kiln on Route 9W started this summer; results are due by the end of the year.
Other states also are giving ash a closer look. Officials in Maryland and Virginia are eyeing disposal rules after groundwater was polluted by buried ash. Outside of Norfolk, Va., wells for homes around a golf course built atop some 3 million tons of ash were tainted with boron – a toxic heavy metal linked to low birth weight.
Environmentalists charge EPA resisted mercury rules on existing cement kilns so power plants keep key customers for an increasing stream of ash. Plant owners save money by shipping ash – sometimes free of charge – to cement companies that want it rather than paying to dump ash in landfills.
“The feds don’t want to step on the toes of the power industry, who are more powerful than they are,” said Jeffrey Stant, executive director of the Indiana-based Hoosier Environmental Council and a consultant with the Clean Air Task Force, a Boston nonprofit.
Ash use in cement kilns nationwide skyrocketed this decade, from about 1 million tons in 2001 to more than 4 million tons in 2006, according to industry figures.
This year, EPA acknowledged seriously underestimating mercury pollution from cement plants, projecting that kilns produce about 23,000 pounds of mercury – nearly double the 12,000-pound agency estimate issued in 2006.
“Everyone has seen the mercury going up in fly ash,” said Tom Gentile, chief of the air toxics center at the state Department of Environmental Conservation. “It is part of the technology to clean up coal. The metals are dropping out in the ash. We realize that we are concentrating these metals to a greater degree than ever before.”
EPA has noticed. A 2007 agency study found that mercury content in ash had jumped by up to 850 percent as power plants met tougher federal mercury rules.
Eight years after a federal court ordered EPA to create mercury rules for cement plants, the agency expects to issue proposals this spring, according to spokeswoman Cathy Milbourn. EPA has demanded ash mercury content tests from Lafarge and 88 other plants of the 150 nationwide.
Ash into cement
To make cement, Lafarge blends ash with water, ground limestone, bauxite and iron ore. Called slurry, the mix is heated in a kiln to nearly 2,700 to make “clinker,” which is then ground into cement.
Fly ash contains alumnina and silica, which strengthen cement, and is a much cheaper alternative to ingredients like shale or clay.
Lafarge uses between 30,000 and 60,000 tons of ash a year, according to a prepared statement from company officials. Ash comes from the Danskammer plant in Newburgh, the Mt. Tom plant in Holyoke, Mass., and the Hudson Generating Station in Jersey City, N.J.
“Lafarge relies on the expertise of the DEC and will continue to work cooperatively with them as we share information about the ongoing voluntary mercury study,” wrote John Reagan, environmental manager for the Coeymans plant.
Waste to commodity
The federal push to reclassify fly ash from waste into a reusable material started during the Reagan administration. In 1983, EPA adopted rules favoring cement made with fly ash, and in 1988 it reported that ash was not hazardous. In 1993, the agency exempted ash from hazardhous waste regulations.
Nationwide, power plants produced nearly 72 million tons of fly ash in 2006, a 50 percent increase since 1993, according to the American Coal Ash Association, an industry trade group.
In New York, a dozen power plants created about 1.4 million tons of ash between 2005 and 2007, according to DEC records. About 900,000 tons were reused in New York and other states, although it could not be determined how much went into cement.
Into the air
The mercury that’s floated out of Lafarge each year is equivalent to the state’s four largest coal-fired power plants. Between 2003 and 2006, annual emissions totalled between 380 and 400 pounds, according to EPA’s annual Toxic Release Inventory.
Ash has been used at the Coeymans plant (one of the state’s three cement plants) since at least 1991, when the plant was owned by Blue Circle Cement, according to a Times Union review of DEC records.
“We have no way of knowing how much fly ash may have been used at the plant over the years. There has been no testing of ash on an ongoing basis,” said Thomas Lynch, supervisor of the DEC’s Beneficial Use and Special Projects Section, whose office is overseeing this summer’s pollution tests at Lafarge.
Lynch also said the state, which is considering renewal of Lafarge’s air pollution permit, is preparing changes to its 1993 ash rules to require mercury testing and reporting by cement plants.
In a cement kiln, mercury and other metals in fly ash volatize at high temperatures, transforming metal into vapor that attaches to particles which rise out of the stack, said David Carpenter, director of the Institute of Health and the Environment at the University at Albany.
Mercury that falls into water converts into methyl mercury, which is consumed by aquatic life and concentrated up the food chain. Just one-70th of a teaspoon of mercury will contaminate a 25-acre lake, making the fish in it unsafe to eat, according to a 1991 study published in Science News.
Carpenter said mercury isn’t the only concern in fly ash. Modern pollution controls at power plants are also capturing more carcinogens such as chromium and arsenic, and other “nasty metals” such as thalium, which Carpenter called “terribly dangerous.”
By BRIAN NEARING, Staff writer