The May 2007 amendments establish an annual facility-wide emission limit of 60,000 kilograms (kg) of methylene chloride-equivalents (MCEs) for general degreasing operations and a 100,000 kg MCE limit for military maintenance and depot facilities. The amendments also exempt facilities involved in narrow tube manufacture, aerospace manufacture & maintenance, and those operations using web cleaning machines from the facility-wide limits. (According to the promulgated standard, 60,000 kg MCEs equals 60,000 kg/yr of methylene chloride, 14,100 kg/yr of trichloroethylene, or 4,800 kg/yr or perchloroethylene.)
In response to objections raised by environmental groups and the Pennsylvania Department of Environmental Protection about the exemptions for narrow tube, aerospace, and web cleaning, EPA issued a notice in October 2008 requesting comment on the following three options for revising the regulation:
- Option 1 no change to the May 2007 amendments (i.e., the exemptions would remain in place).
- Option 2 requires narrow tube manufacturers to meet the same facility-wide limit as general degreasing operations (60,000 MCEs); aerospace and web cleaning companies would continue to be exempt.
- Option 3 requires narrow tube manufacturers to meet 60,000 MCEs, aerospace manufactures to meet 100,000 MCEs, and requires web cleaners that exceed 60,000 kg MCEs to achieve 80% overall control efficiency.
The October 2008 notice also suggests that the EPA will consider variations on Options 2 & 3. By including a control efficiency, rather than an absolute limit, Option 3 is closer to the approach HSIA had suggested to the EPA in amending the standard. The EPA appears to base much of its rationale for Options 2 & 3 on the possibility of a switch to n-propyl bromide (nPB) as a cleaning solvent in some applications. The October 2008 notice does not include a discussion of recent reports from the Centers for Disease Control and Prevention (CDC) on occupational exposure to nPB.
For more information, visit www.hsia.org
, the website for the Halogenated Solvents Industry Alliance, Inc., or you may call (703) 741-5780.