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Methyl Ethyl Ketone removed from Hazardous Air Pollutants list
On 13 December, 2005 the Environmental Protection Agency [EPA] signed a Final Rule removing methyl ethyl ketone (MEK) from the list of hazardous air pollutants (HAPs) under section 112(b) of the Clean Air Act. The Final Rule was published into the Federal Register on 19 December.
The ruling comes in response to a petition submitted by the American Chemistry Council ChemStar Ketones Panel back in November 1996. The Ketones Panel and the solvents industry in general are all extremely pleased that the EPA has taken this action.
In its ruling, the EPA announced that it will no longer regulate MEK as a hazardous air pollutant because it has determined after nine-plus years of research and analysis that the substance "may not reasonably be anticipated to cause human health or environmental problems." Rather, facilities that use MEK will be regulated for emissions of volatile organic compounds, precursors to formation of ground-level ozone, through other Clean Air Act programs such as the national ambient air quality standards.
Removing MEK from the Clean Air Act's list of hazardous air pollutants means EPA will not be required to issue technology-based standards for controlling air emissions. Likewise, industries using MEK will not be held to any specific technology-based standard.
MEK is used as a solvent in the surface coatings industry, specifically in manufacturing vinyl lacquers and acrylics. Industries also use it for producing adhesives, magnetic tapes, printing inks, degreasing and cleaning fluids, and as a de-waxing agent for lubricating oils and as an intermediate in the production of antioxidants and perfumes.
Three compounds previously delisted
The Clean Air Act allows the EPA to consider petitions to de-list a compound from the approved list of 188 hazardous air pollutants. During the past nine years, the EPA has de-listed three toxic air pollutants - ethylene glycol mono-butyl ether in 2004, long chain glycol ethers in 2000, and caprolactam in 1996.
"Any person may petition the EPA to modify the air toxics list by adding or removing one or more substances," the agency said in a fact sheet on MEK. But petitioners have to demonstrate that there are "adequate data" to demonstrate that emissions, outdoor concentrations, bioaccumulation, or atmospheric deposition of the substance may not reasonably be anticipated to damage human health or the environment.
As it does with all other petitions to the list of air toxics, the EPA conducted a "completeness" review of ACC's petition to determine whether there is sufficient information on which to base a decision and a "technical" review to evaluate the merits of the petition.
During the technical review, the EPA considers both information contained in the petition and information received from the public to determine whether the petition satisfies the requirements of the Clean Air Act. Once that comprehensive review is complete, the EPA decides whether to propose removing the substance from the air toxics list.
In a separate ruling in July 2005, the EPA also agreed to drop those facilities that manufacture, process or use MEK from the requirement to report annual releases under the agency’s SARA Title 313 Toxic Release Inventory.