In "separate but closely related" actions, EPA has proposed rules to limit mercury (and nickel) emissions from utility units and proposed an "Interstate Air Quality Rule" to address ozone and fine particulate pollution concerns in the Eastern United States. These rules were proposed simultaneously because they "dovetail well" based on the suggested "co-benefit" that SO2 and NOX controls would provide toward mercury reductions.
In a very unusual move, EPA proposed two completely
separate potential rules for reducing mercury. EPA
apparently followed this unusual approach because it
appears to have changed its original December 2000
opinion that a MACT based standard is the best way to
regulate mercury. These options are
"co-proposed" and EPA is soliciting comments on
both potential rules. Presumably, only one of these
options can and will become a final rule and will depend
upon "whether EPA takes final action to revise the
December 2000 section 112 (n) (1) (a) finding."
The first proposed option is to regulate mercury (and nickel) via Section 112 of the Clean Air Act through a MACT standard. EPA states that this approach will reduce mercury by 14 tons/yr by 2007. In contrast, the second proposed approach would reduce mercury under Section 111 of the Clean Air Act by a "standard of performance" cap and trade program. Under this option, mercury would be cut by 33 tons annually in 2010, representing a 69% reduction of current utility emissions.
The Interstate Air Quality Rule would create a budget program similar to the NOX SIP Call and require power plants and other industrial sources to make steep cuts in SO2 and NOX emissions. It would reduce emissions in two phases. By 2010, 3.7 million tons of SO2 and 1.4 million tons of NOX would be cut annually. When the rule is fully implemented in 2015, emissions would be permanently capped with annual cuts of 6.0 million tons of SO2 and 1.7 million tons of NOX, reducing SO2 by approximately 70% and NOX by about 50% from current levels.
In contrast to the proposed mercury rules, which would apply across the country, the proposed Interstate Air Quality Rule will effect only sources in the following 29 states and the District of Columbia:
Copies of the preambles to each proposed rule and both proposed mercury rule options can be found in our FTP Library. The proposals include standards for mercury CEMS and mercury reference methods that would be used to certify the performance of such devices. Comments on these proposed rules are due within 60 days after they are published in the Federal Register.
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