Given the improbability of three agencies of the federal government working in such coordination, the recent combination of back-to-back Supreme Court decisions in favor of clean air, tough talk by the new EPA administrator about reducing emissions and a federal study strengthening the link between airborne mercury and birth defects can hardly be the result of a concerted campaign. Instead, call it coincidental – and, despite the underlying concerns, reassuring.

The court rulings, one in late February and the other Tuesday, confirmed Congress’s ability to delegate to the Environmental Protection Agency the authority to establish Clean Air Act standards. The second case was especially important to this region – it upheld EPA rules that compel states in the Midwest and Southeast to share the burden of cleaning up the dirty air they export to the Northeast. Given that the challenge to those rules was brought by several exporting states and that the high court has a recent history of siding with states over the federal government, that logical outcome was by no means a certainty.

Also in the category of pleasant surprises is EPA Administrator Christine Todd Whitman, former New Jersey governor – her persistent advocacy for clean air has reached a point that the smokestack industry crowd is being described as alarmed. Ms. Whitman’s interest in regulating carbon dioxide emissions from power plants, her endorsement of a Clinton administration regulation that would reduce the sulfur content of diesel fuel used by large trucks and her concern about the mounting evidence of global warming are clear indications that the Bush administration has more on its mind than tax cuts.

Which is good, considering the Centers for Disease Control study released last week that found more than 10 percent of American women of child-bearing age carry levels of mercury that raise to 1-in-10 the chances of having a baby with mental or neurological problems. Previous studies projected some 60,000 affected babies each year; the new CDC study puts it at 375,000.

Two things are particularly important abut the CDC report: unlike prior mercury studies, it did not look at mercury levels in food, but at mercury levels in people; unlike prior studies, it did not focus upon fish-eating communities, but upon the wider general population. Although the recent interest in eliminating mercury thermometers and other such items is commendable, the leading source by far of environmental mercury is smokestack emissions and fish – freshwater and salt – are the canaries in the coal mine, the link in the food chain where mercury accumulates and is transferred to humans in amounts sufficient to cause harm. Given the past hysteria re-garding mercury, the fishing industry is understandably sensitive to the issue and is quick, and correct, to point out that a diet including fish – a variety of species from a variety of sources – can be not just harmless, but healthful.

Predictably, the CDC study has prompted a new round of fish-consumption alarm, but the larger point is that the population at risk for elevated mercury is not those who eat fish but those who breathe air. It turns out we are our own canaries, but thanks to the Supreme Court rulings and the strong positions of Ms. Whitman, canaries with clout.