UPDATE July 1, 2010: The US EPA has issues a proposed rule, followed by a revised propose rule, which will regulate coal combustion products destined for landfills. The EPA states the following regarding beneficial use CCP:
"EPA is not proposing to change the May 2000 Regulatory Determination for beneficially used CCRs, which are currently exempt from the hazardous waste regulations under Section 3001(b)(3)(A) of RCRA. However, EPA is clarifying this determination and seeking comment on potential refinements for certain beneficial uses. EPA is also not proposing to address the placement of CCRs in mines, or non-minefill uses of CCRs at coal mine sites in this action."
UPDATE: On May 4, 2010, the US EPA suspended active participation in the Coal Combustion Products Partnership, and announced a Notice of Proposed Rule Making (NPRM) concerning fly ash. The proposal includes two potential methods of regulating fly ash; neither method would classify coal combustion products as hazardous waste, but they would require special handling in conformance with the Resource Conservation and Recovery Act (RCRA). The goal of regulating these materials is to improve the impoundment, storage, and handling of fly ash and related materials using federal rules. The current rules allow states to regulate these materials.
These materials are used extensively in modern concrete. Fly ash can be used to replace 20 to 90 percent of portland cement in typical concrete, and doing so imparts several useful properties to the concrete. Production of portland cement produces significant carbon dioxide as part of the chemical reaction in a cement kiln, while fly ash and slag do not require significant additional combustion or energy input. Part of improving sustainability is the increasing use of supplemental cementitious materials (SCM), of which fly ash is the primary material. Fly ash is also used to produce high performance concrete, which is one of the advances which has made concrete the best choice for rapid-cycle projects.
When mixed into concrete, fly ash is no more hazardous than the portland cement or silicious aggregates in the mixture. The hazards which are being made sensational in the media are related to the very large volumes of fly ash in power plant impoundments; the December 2009 mishap in Tennessee resulted in the release of 5.4 million cubic yards of fly ash and water from a surface impoundment (about 3,400 acre-feet, or 5 square miles 1 foot deep.)
ACI members have significant stake in the ongoing use of coal combustion products in concrete. We are encouraging members to get involved by making comments to the NPRM.
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There has been talk lately about the U. S. Environmental Protection Agency (EPA) considering reclassification of coal combustion products, like fly ash, to that of a hazardous waste. This primarily arose after a couple of high-profile events where wet ash impoundments deteriorated and failed. The EPA in currently investigating ash pond levees and surveying their owners/operators.
The EPA's commitment to reducing the placement of coal combustion products into landfills is best demonstrated by one statement from their website: "EPA strongly supports the beneficial use of CCPs in appropriate circumstances and established a goal in its Strategic Plan to achieve a recycling rate of 50 percent of all CCPs by 2011."
Below are a few links which provide more information about US EPA fly ash programs and initiatives:
US EPA Coal Combustion Products Partnership - currently suspended by US EPA
Coal Combustion Products Benefits and Risks
Turner-Fairbanks Highway Research Center Fly Ash Information