This EPA fact sheet gives some background on the rule, stressing the anticipated reductions of mercury emissions. What the fact sheet does not mention is that, the lack of meaningful federal mercury controls notwithstanding, mercury emissions have declined since 1990. As the EPA’s Report on the Environment shows between 1990–93 and 2005, mercury emissions declined by 58 percent. Coal-burning facilities — which are covered by the new rule — represent the lion’s share of the rest.
The emission trends are positive. So, too, are trends in blood mercury levels. As the same EPA report shows blood mercury levels in women have declined, particularly among those at the 90th and 95th percentiles. From the EPA report: “during the 1999–2000 survey, 10 percent (i.e., 90th percentile value) of surveyed women age 16 to 49 had blood mercury levels of 4.9 µg/L or higher. In the 2007–2008 survey, however, the 90th percentile value had decreased to 2.7 µg/L.” That’s a significant drop for those with among the highest levels in the country.
These positive trends do not mean additional mercury controls are unnecessary, but it does put their urgency in perspective. It also suggests that the Bush Administration’s approach, which would have utilized a more flexible cap-and-trade approach instead of facility-specific limits, may have been good policy after all, even if it was horribly bad law.
via volokh.com