Recycled fly ash: is it hazardous to our health?

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Can using recycled fly ash as a substitute for Portland cement in concrete actually be hazardous to our health? Since toxic materials, such as mercury, are frequently found in fly ash that possibility exists.

To meet the growing service demands of the Puget Sound region over several decades, King County, Washington, is building one of the most sustainable wastewater treatment systems in the country. One of its sustainable building features is the use of coal fly ash in concrete as a cement substitute.

The Environmental Protection Agency has been aggressively promoting fly ash and other waste products from coal-burning power plants. (download a copy of the EPA’s publication, Using Recycled Industrial Material in Buildings) The agency’s regulations have been challenged by Public Employees for Environmental Responsibility (PEER) for lacking “demonstrated scientific support for the safety or quantifiable benefits of using cola combustion wastes in building and consumer products.” Both the Green Guide for Health Care and the draft LEED for Health Care set strict limits on mercury levels in fly ash in all applications. Even when those applications offset greenhouse gases the limits stay in effect.

Early studies of fly ash did not detect mercury leaching from concrete products made with it. The EPA says that when mercury is used in a product, most releases occur during manufacturing or disposal. In December 2009, New York state revoked a 20-year-old “beneficial use” designation for fly ash at a cement kiln due to elevated mercury levels in nearby soil and wildlife.

A report released in August 2010 by the Environmental Integrity Project, Earthjustice and the Sierra Club documented 31 coal ash dump sites in 14 states. The report showed that at every one of the coal ash dump sites equipped with a groundwater monitoring well, concentrations of heavy metals such as arsenic or lead exceed federal health-based standards for drinking water.

According to Bill Walsh, Executive Director of the Healthy Building Network, “Before taking a neurotoxic waste material such as mercury out of a successful pollution control program and redistributing it into our homes, schools and job sites, we should take reasonable precautions. Among these would be fairly simple tests to ensure that mercury and other heavy metals do not escape during manufacturing, construction, recycling or disposal of products made from coal combustion wastes; regulations limiting the range of toxic materials in the material, and transparent monitoring and disclosure of those contents.”

“In its proposed rule, EPA emphasizes repeatedly that it does not wish to “stigmatize” fly ash by designating it as a hazardous waste. The greater concern is this: that by following the lead of the coal industry rather than taking the time to do due diligence, EPA – and the coal ash reuse industry – are leaving the green building industry vulnerable to the stigma of potentially widespread heavy metal contamination in recycled products.”

Posted by on Monday, October 25th, 2010. Filed under Technology. You can follow any responses to this entry through the RSS 2.0. Both comments and pings are currently closed.

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