Fly Ash: More Questions than Answers from EPA

Bill Walsh | May 19, 2010

On May 4, 2010, the US Environmental Protection Agency released a long-awaited proposal that addresses “coal combustion residuals,” known as CCRs, which include fly ash that is frequently used as recycled content in building materials. The EPA proposal aggressively promotes this use of fly ash as a “beneficial use.”

To drastically simplify the applicable sections of that 560-page document, the EPA proposes to classify fly ash and other CCRs as “special wastes,” rather than hazardous wastes. This designation would still require a fairly strict level of waste management of the ash due to its toxic nature. However, there would be no regulation of the use of fly ash in products. When those products reach the end of their useful life, they could be disposed of as solid waste or construction waste in unlined landfills.

Fly ash and other CCRs, such as flue gas desulfurization residuals used in wallboard, contain toxic materials such as mercury, cadmium and arsenic. The proposed rule restates the agency’s 2000 determination[1] that the use of CCRs in building products does not present significant risks to human health or the environment even though “EPA did not conduct specific risk assessments for the beneficial use of these materials....”[2] My colleagues in the Pharos Project have identified two sources of EPA data generated after 2000 that document significant levels of mercury associated with the use of CCRs in wallboard.[3] Precaution dictates investigation and analysis of these findings and their implications for factory and construction workers, building occupants and even long-term market confidence.

While the EPA asserts “there is wide acceptance of the use of CCRs in encapsulated uses, such as wallboard, concrete, and bricks because the CCRs are bound into products,” we are not aware of independent studies that specifically address the questions that many green building professionals are asking about the various pathways of potential toxic migration, such as:

Volatilization of compounds or dust from exposed walls during use

Release as dust during maintenance, renovation and installation (dust from drilling into the wall)

Release as dust during demolition and/or deconstruction or recycling of aggregate at end-of-life

Certainly the agency’s own history teaches that “widespread acceptance” of chemicals in building products is no guarantee that toxic chemicals remain bound as predicted. In 1982, the agency exempted arsenic-treated wood from hazardous waste disposal regulations that would typically have applied to the chemicals in the product. By the mid-90’s, arsenic leaching from arsenic-treated wood in unlined landfills was threatening Florida’s aquifers. It turns out that the arsenic was not as well bound to the chromium and wood as originally presumed.

EPA also discusses repeatedly its commitment to avoid “stigmatizing” CCRs as a consequence of this rulemaking. But it is not the rulemaking that casts a shadow over fly ash. It is the presence of toxic heavy metals in the material and the absence of reassuring data that give green building professionals pause before leading the charge to swaddle our homes, schools, offices and hospitals in carpets, walls, floors, and ceiling tiles laced with post-industrial mercury, cadmium and arsenic waste. If ever there was a case for applying the precautionary principle, this is it.

If fly ash can be safely used in all sorts of products under foreseeable conditions – manufacture, installation, renovation, end-of-life recycling and disposal – it offers legitimate environmental benefits.[4] These benefits, however, may be coming at too serious a cost and the EPA does not appear to have the data to know. The generation of massive quantities of toxic-laden dust at the end-of-life in demolition and regrind of concrete for reuse is a particularly serious and unexplored pathway of exposure.

In the absence of information, and the post-2000 mercury data we have discovered to date, HBN cannot agree with EPA that “the most appropriate approach toward beneficial use is to leave the May 2000 Regulatory Determination [of no proven risk] in place, as the Agency, other federal agencies, academia, and society more broadly investigate these critical questions and clarify the appropriate beneficial use of these materials.”[5] Before the industry expands its investment in these products, and before the green building movement embraces them, more complete testing and analysis must be done of the potential for release of the toxic components during foreseeable use, including disruptive activities such as cement sanding, grinding and demolition.

The building industry’s historical experience with asbestos, and recent experience with Chinese wallboard, illustrate why these “critical questions” are best answered before, not after, we integrate these materials into virtually every aspect of our lives. Having finally outgrown the stigma of energy-efficient but “sick” buildings, the green building movement can ill afford to be the guinea pig in such a far-reaching experiment.



[2] See, p.131.

[3] These cases involved flue gas desulfurization (FGD) residuals, not fly ash. This information is important however, both because the proposed rule leaves FGC residuals unregulated in products, and FGD residuals are used in a manner similar to fly ash.

[4] These include: avoiding difficult, expensive industrial waste handling operations that pose their own risks to human health and the environment; substantial reductions in energy use and green house gas from the production of Portland Cement; and reduced impacts from the mining and processing of raw materials.

[5] See, p. 133.