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.
