WASHINGTON, DC — The US Environmental Protection Agency (EPA) has proposed rules to limit emissions of toxic chemicals from power plants at a national level for the first time, including regulations that would impose a 91 percent cut in mercury emissions from coal plants.

The rules, targeting new and existing coal and oil-fired plants, would regulate not only mercury (Hg), but also arsenic, chromium, nickel and acid gases, such as hydrogen chloride (HCl) and hydrogen fluoride. It would give facilities four years to deploy the technology required to reduce emissions.

The regulations would replace a mercury limitation clause under the 1990 amendments to the Clean Air Act with a single, national standard. Previously, the EPA had targeted high emitters in an attempt to bring their mercury levels down, but there was no level playing field for all power stations.

As part of the reforms, the EPA also proposed a change to the new source performance standards (NSPS) governing emissions of particulate matter (PM), sulphur dioxide (SO2), and nitrogen oxides (NOx).

Defending the proposals, the EPA cited evidence that municipal and medical waste incinerators, which are the two other major emitters of mercury, saw reductions in emissions of at least 96 percent between 1990 and 1996, largely because they were regulated at a federal level. However, power plants saw only a 10 percent reduction in mercury emissions during the same period.

The proposal, which should be finalized as a rule in November, would affect the 44 percent of coal plants that have not already implemented technology to limit emissions, forcing them to deploy these measures.

"Reducing toxic power plant emissions will cut fine particle pollution and prevent thousands of premature deaths and tens of thousands of heart attacks, bronchitis cases and asthma episodes," the Agency said.

The EPA has taken an increasingly hard line on power plants, having issued guidance and permitting requirements for plants in December that are designed to curb greenhouse gas emissions by requiring them to deploy the most energy-efficient technologies available when undertaking upgrade work or building new facilities.

This article originally appeared on BusinessGreen and is reprinted with permission.

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