In September, the Environmental Protection Agency published a document that laid out economic and technical support for a new rule to cut pollution from engines in forklifts, electric generators, snowmobiles and all-terrain vehicles. It's turgid stuff, directed at those trained to comb the fine print for the rationales behind rulemakings.

There's nothing unusual about such an analysis; in fact, agencies are often required to figure out what the costs and benefits of a rule may be before they decide how much society is willing to pay for cleaner air or safer workplaces. Whatever figures are arrived at, there is always a high degree of uncertainty because of the difficulty quantifying how technology, human behavior and various economic models affect the bottom line.

That said, there was something different about this report. It also contained an alternative analysis, which arrived at dramatically lower numbers for the benefits of the new rule. It did so mainly by lowering the value of a human life and suggesting that long-term exposure to fine particulates in the air would not be as significant as briefer exposures to them.

When EPA did its base calculations, it concluded that by 2030 some $77 billion in benefits would come from reduced deaths and fewer cases of chronic bronchitis. The agency considered the estimate somewhat low, in fact, because it didn't take into account things you can't put a price tag on, such as how many trips to the emergency room from asthma attacks are avoided and the worth of a beautiful vista that is preserved as a result of less pollution.

The alternative estimate came up with only $8.8 billion in benefits. In its report, EPA characterized the number as a "more conservative estimate," that was arrived at by using different scientific studies that rely on short-term, rather than long-term, exposure to particulate matter and different ways of calculating the value of a life.

One big difference is that EPA used $6.1 million as the value of a life in its base calculation; the alternative figure dropped that number to $3.7 million per life, and less for people over 70 -- $2.3 million.

This result disturbed environmentalists, who fear the Bush administration will use such economic rationalizations as a way to regulate less, or less stringently. They also didn't like the idea that the Office of Management and Budget's Office of Information and Regulatory Affairs, which reviews federal rulemakings, urged EPA to include the second set of calculations

"You can change five to six assumptions and you get a radically different number," said Frank O'Donnell, executive director of the Clean Air Trust, a nonprofit environmental-watchdog organization. "It makes health and safety look less valuable."

S. William Becker, executive director of the State and Territorial Air Pollution Program Administrators, said states might have to make up the difference if the administration regulates some industries less after making subtle changes in the tools that define the benefits of a standard. "Every time the federal government takes a shortcut from meaningful and effective regulation, it falls on us and the public," he said.

John D. Graham, administrator of OIRA, defends the alternate analysis. "OMB persuaded EPA that it was more technically responsible to present both the base and alternate estimates" than just the base alone, he said. "Together, the two estimates provide an indication of the scientific uncertainty about these difficult issues. If only one of the two estimates were presented, the regulator and the public would be given a false sense of precision about the science and economics."

OIRA played a similar role in the development of the Bush administration's Clear Skies Initiative, a pollution-abatement program introduced in Congress earlier this year. In that case, EPA economists said reductions in particulate matter and ozone would result in 11,900 fewer deaths annually. The alternate prediction said it would be more like 7,200. Similarly, EPA set benefits of the legislative proposal at $96 billion by 2020; the other projection was $11 billion.

Paul R. Portney, president of Resources for the Future, an environmental think tank, said reputable scientists can come to very different conclusions in the course of a rulemaking. In this case, Portney said, the questions raised by OIRA on the EPA approach were reasonable, while the agency had expressed a legitimate point of view on some of the issues.

"Regulation has a huge scientific component," said Portney. "But like taxing and spending, it's inherently political."

OUT FOR COMMENT: The Occupational Safety and Health Administration last week named 15 individuals to serve on its National Advisory Committee on Ergonomics to offer advice to federal rulemakers on reducing ergonomic-related injuries in the workplace. The group includes academics, safety and health specialists, a nurse and a chief executive officer. Business groups viewed the board as balanced, but union leaders said it was tilted heavily toward business, which opposes any kind of rule to abate repetitive motion injuries. One member, for example, represented the U.S. Chamber of Commerce in its years-long fight to defeat an ergonomics rule. "It's a totally employer-dominated committee," said Peg Seminario, director of AFL-CIO's department of occupational safety and health. The Postal Workers and the International Union of Operating Engineers have the labor seats at the table.