Fly Ash Looms as the "New Asbestos"

(Engineering News Record 4-7-2010) Concrete groups are on tenterhooks, waiting for the U.S. Environmental Protection Agency to publish a proposed rule that aims to designate fly ash and other coal-combustion by-products as hazardous waste. The concrete sector is concerned even about the ramifications of a “hybrid” rule that would allow beneficial uses of CCBs to continue.Major among these beneficial uses is fly ash in concrete. The ingredient, a partial replacement for portland cement, is known to increase concrete’s constructibility, durability and sustainability.
Concrete stakeholders say a hazardous-waste designation for fly ash would make it the “new asbestos” or “new lead paint,” dragging concrete into the fray. Questions would arise over the handling practices of both materials during production and casting as well as during the demolition and disposal of concrete structures.
A hazardous-wast e designation for fly ash would “stigmatize its use as an ingredient in concrete, even if EPA were to focus a designation only on fly ash that is disposed rather than beneficially reused,” says Andrew T. O’Hare, vice president of regulatory affairs in Portland Cement Association’s Washington, D.C., office. EPA’s possible action has pitted environmentalists against industry groups and threatened future building plans, including a $50-million fly-ash recycling facility.
The issue has raised many questions. Is it dangerous if someone drills a hole in concrete with sequestered fly ash? Should workers wear respirators? Are existing structures that contain sequestered fly ash a health hazard if they are demolished? Would contractors have to follow containment practices as they do for lead paint and asbestos? Would the material have to go to hazardous-waste landfills?
“It’s very complicated,” says Scot Horst, senior vice president in charge of the green-building rating system Leadership in Energy and Environmental Design (LEED), published by the U.S. Green Building Council, Washington, D.C. “If fly ash is a hazardous waste and it becomes part of a concrete wall, is the wall a hazardous material?”
Legal issues would also come into play. “In these risk-averse times, many end users of fly ash,” including concrete producers and construction companies, “would be discouraged by counsel to use fly ash, noting that it is not absolutely necessary,” says Thomas Adams, executive director of the American Coal Ash Association, Aurora, Colo.
In discussions, structural engineers, consultants, concrete producers, contractors and owners have indicated they would reject use of fly ash in concrete if there were potential exposure to creative tort activity, says Adams. “Attorneys have demonstrated that litigation can be initiated even without demonstrated damage,” he adds. Contractors also are concerned about the impact of an EPA ruling on insurance. It’s likely that fly ash would not be covered in new policies, says Adams.
EPA is considering reclassifying fly ash as a hazardous waste under Subtitle C of the Resource Conservation and Recovery Act. The action is a response to the Dec. 22, 2008, collapse of an earthen retaining wall of a containment structure at the Tennessee Valley Authority’s Kingston, Tenn., coal plant. The failure sent 5.4 million cu yd of toxic sludge, containing fly ash and water, flowing over 300 acres. The spill is considered the worst breech of its kind in the U.S.
Cement and concrete groups are calling for measures to ensure proper CCB containment, not overreaction. “The pill was obviously an environmental catastrophe, but it appears some officials are casting too wide a net to address this incident,” says Claude Goguen, director of technical services at the National Precast Concrete Association, Carmel, Ind. 
In 1993 and 2000, EPA determined CCBs did not warrant management as hazardous waste. Last October, EPA delivered its proposed rule to the Office of Management and Budget for interagency review and comment. The proposal is still in the hands of OMB, with no indication of when its review will be completed. EPA said in a statement, “This rule continues to be under review, and we expect to issue a proposed rule in the near future.”
The nonprofit American Concrete Institute (ACI), which publishes technical standards, has concerns about EPA’s proposed rule. Of some 400 standards and technical documents, 106 would have to be revisited were fly ash ruled to be a hazardous waste. These standards include ACI 232, which outlines the use and application of fly ash, and ACI 318, the model concrete code.
“Even if it is a hybrid ruling, we would need to evaluate the impact on applications and our documents,” says Florian Barth, ACI’s 2009-10 president and a consultant based in Los Gatos, Calif. Document review could take several years, he says, because ACI relies on its member volunteers to develop its standards.
In 2008 in the U.S., 136 million tons of CCBs were produced, according to a survey by the American Coal Ash Association (ACAA). Almost 16 million tons were used in cement and concrete production. Another 8.5 million tons went into the production of wallboard products. The use of fly ash instead of portland cement, which is an energy-intensive product, avoided 12 million tons of carbon dioxide emissions, says ACAA.
In the U.S., fly ash use in concrete ramped up beginning in the 1980s. Since 2000, the recycling rate for CCBs has increased to 44% from 30%, says ACAA. During that time, more than 1.1 billion tons of CCBs were produced, with 430 million tons recycled. In the U.S., CCBs are the second-largest waste stream after municipal solid waste, says ACAA.
Use of fly ash in concrete is considered environmentally responsible because it reduces cement content, 25% to 15%. That, in turn, reduces the carbon dioxide generated in cement production. In 2007, there was a 15-million-ton reduction of CO2 production, says ACI.
Fly ash makes concrete less permeable, which reduces infiltration of water and aggressive chemicals. The material resists unwanted alkali-aggregate and sulfate reactions, says ACI. It also increases concrete’s compressive strength, improves the workability of fresh concrete and reduces heat of hydration in mass concrete.
Fly ash is recognized by the LEED rating system as a postindustrial recycled material. “We respect EPA’s ability and role as a regulator … and are quite sure there is alignment around the beneficial use of fly ash,” says Horst. However, “if EPA designates fly ash as a hazardous waste, LEED committees will take a look at the rating system.”
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