AS THE CRISIS at Japan’s stricken reactors wears on, it’s increasingly clear what a step away from nuclear power will mean for Europe and Asia: more coal, which means more nasty particulates, carcinogens, carbon dioxide and other dangerous effluences spewing from sooty smokestacks around the world.

As radiation levels outside the Fukushima Daiichi plant rise, so did the value of stocks of American companies that mine and export the black stuff. Business analysts expect demand for U.S. coal to jump, along with mine owners’ profits.

Forgive us if we don’t cheer as Europe, Japan and others re-embrace this fossil fuel. In a study on coal power out this month, the American Lung Association (ALA) reported that “over 386,000 tons of 84 separate hazardous air pollutants spew from over 400 plants in 46 states” in this country, causing billions in damage to public health annually. Just one of those coal-fired facilities in Wisconsin, the ALA notes, is responsible for an estimated seven premature deaths, 100 trips to the emergency room and 520 asthma attacks every year.

Fortunately, America continues to move away from coal, though slowly and despite entrenched opposition to rational energy policy in Congress. That’s because the Obama administration is using its existing authorities under the Clean Air Act to clamp down on coal.

The Environmental Protection Agency is targeting hazardous discharges such as sulfur dioxide, nitrogen oxide and mercury; separately, it is regulating carbon dioxide emissions, which coal plants produce in abundance. Last year, Credit Suisse estimated that, along with needed upgrades, the EPA’s rules on those hazardous discharges would result in 50 or more gigawatts of coal plant closures, out of an American coal-fired fleet of 340 gigawatts. If you think that sounds too disruptive, consider that plants producing 103 gigawatts of this total have no environmental controls at all, and that 58 gigawatts more are produced with no scrubbers to reduce mercury pollution — the stuff that settles in the Potomac River and taints its fish. Seventy percent of America’s coal plants are more than 30 years old, and a third were built more than 40 years ago. These inefficient, dirty dinosaurs nearing the end of their lives are the most likely to close in response to regulation. In most cases, the likely substitute is natural gas — which is cheap, domestically sourced and, though not clean, far preferable to coal in environmental impact.

Even so, Republicans — and some Democrats — in Congress are eager to kneecap EPA’s efforts. The House GOP attempted to gut clean-air rules in the seven-month continuing resolution it approved last month. In the Senate, Minority Leader Mitch McConnell (R) is set to get a vote next week on an amendment that would strip EPA of its authority to regulate greenhouse gases. Sen. Jay Rockefeller (D-W.Va.) wants to delay the already slow pace of regulation by stopping it for another two years.

Lawmakers should back off. Americans’ health will benefit, and, as the news from Japan, Europe and elsewhere shows, U.S. leadership is needed to discourage demand for dirty fuels outside the country as well as in. President Obama can provide such leadership only if the United States begins to provide a better example at home.