The sulfur oxides are not the only problem with emissions from coal-fired power plants. The EPA lists 189 hazardous air pollutants (HAPs) in the 1990 Clean Air Act Amendments. “Of these, 15 occur in coals: antimony, arsenic, beryllium, cad­mium, chlorine, chromium, cobalt, fluorine, lead, manganese, mercury, nickel, selenium, thorium, and uranium"(3) Not all coal contains all of these, and mer­cury is the main health hazard. The form of mercury that is hazardous is called methyl mercury, which is a potent neurotoxin. The largest source of mercury is coal plants, accounting for about one-third of mercury emissions in the United States, or about 48 tons per year. Mercury is emitted as elemental mercury, which is non-hazardous. When mercury settles out of the air, it gets deposited in streams and lakes and is converted to methyl mercury. From there it is taken up by plants, algae, and small organisms. Small fish eat these, and large fish eat the smaller fish, concentrating the mercury in body tissues. Finally, humans eat the fish and get the bioaccumulated mercury. It is because of this bioaccumulation that the Inuit people (Eskimos) of Siberia and Greenland have the highest blood levels of mercury in the world (8), even though they have no power plants. The EPA issued the Clean Air Mercury Rule in 2005 that sets a cap of 38 tons of mercury in 2010 and 15 tons by 2018, which will help reduce the problem but will add large costs to coal power plants (3). On December 21, 2011, the EPA ruled that coal- and oil-fired plants must reduce their mercury emissions by 90%. About 40% are not yet in compliance, and about 1% of them are expected to shut down rather than meet the requirement (9).