Why did EPA give sources the option to comply with health-based emission standards for total chlorine in lieu of technology-based standards in the October 2005 final rule?
Under authority of CAA Section 112(d) (4), we promulgated standard procedures to allow owners and operators to establish a health-based emission limit for total chlorine in lieu of compliance with the section 112(d) (2) MACT emission standard. The health-based approach is available to all hazardous waste combustors except hydrochloric acid production furnaces. Because we finalized the MACT standard for total chlorine as a surrogate to control metal HAP, we did not allow any alternative to the chlorine standard for this source category. The alternative health-based emission limit for total chlorine is based on national exposure standards established by EPA that ensure protection of public health with an ample margin of safety. The standard consists of assuring that individual source emissions will not exceed a nationally-applicable, uniformly protective national exposure standard. Each source’s standard is based on site-specific input from each source choosing to use this approach.
