The Kansas Department of Health and Environment rejected the proposal by two power companies to build a pair of 700-megawatt coal-powered plants in the town of Holcomb, saying that the greenhouse gas emissions would threaten public health and the environment.

The decision marks a victory for environmental groups that are fighting proposals for new coal-fired plants around the country. It may be the first of a series of similar state actions inspired by a Supreme Court decision in April that asserted that greenhouse gases such as carbon dioxide should be considered pollutants under the Clean Air Act.

In the past, air permits, which are required before construction of combustion facilities, have been denied over emissions such as sulfur dioxide, nitrogen oxides and mercury, but this is the first to be rejected on the basis of CO2. Bob Eye, a former state legislator, said of yesterday's decision: "Is it without precedent? Yes, as far as I know, in this state or any other." But he argued that "CO2 . . . is a pollutant, not just because the Sierra Club says it, but because the Supreme Court said it."

Gov. Kathleen Sebelius, is head of the Democratic Governors Association. Like many governors, Sebelius has been promoting the expanded use of renewable energy, especially wind. In her state of the state address this year, she said: "The question of where we get our energy is . . . no longer just an economic issue, nor solely an issue of national security. Quite simply, we have a moral obligation to be good stewards of this state."

Together the plants would have produced 11 million tons of carbon dioxide annually, nearly as much as a group of eight Northeastern states hope to save by 2020 through a mandatory cap-and-trade program they plan to impose. The attorneys general from those states had written a letter opposing the permit.

Steve Miller, the spokesman for one of the companies, SunFlower Electric Power, took offense at Sebelius' moral stewardship remark, saying "That implies that we're not moral stewards of the land, which we don't appreciate one bit," he said. But SunFlower and the other company, Tri-State, which gets two-thirds of its power from coal, will simply have to do better to compete in today's renewable market and political climate.

In order to sell power across state lines as Tri-State intended, they must meet a renewable portfolio standard adopted recently by Colorado. And while they supported the measure, which requires utilities to use renewable energy sources to meet 10 percent of their sales, the company currently uses less than 1 percent renewable resources.

With environmental standards being incorporated into law, and viable renewable energy alternatives on the market, the salad days for cheap polluters may be finally coming to an end.