Health advocates fear that a massive federal review of the risks posed by soot and other air pollution could be undermined by a new Environmental Protection Agency policy that would block the use of non-public scientific data, such as health studies that promised patients confidentiality.

In an exclusive interview he gave to the conservative Daily Caller website this week, EPA Administrator Scott Pruitt announced his new policy and said some studies would be ruled out because the researchers have not made the raw data public.

That change would eliminate the use of some of the main studies supporting regulations for particulate pollution, granting a boon to the fossil fuel industry and its allies, who have sought such a change for more than 20 years. It also could rule out use of science that draws on confidential business information or intellectual property that the agency is legally prohibited from disclosing.

Under the Clean Air Act, limits on particulate matter and other main forms of pollution must be set low enough to protect the public's health and updated periodically to reflect the best available science. For decades, this has meant relying on well-established population and disease surveys aggregating data on large but anonymous populations.

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Pruitt is seeking to end this practice. "We need to make sure their data and methodology are published as part of the record," Pruitt said. "Otherwise, it's not transparent. It's not objectively measured, and that's important."

Environmental and health advocates say Pruitt's so-called "secret science" argument is a red herring. The studies that have long been used have stood up to peer review, and researchers typically can gain access to data in redacted form or by agreeing to maintain its confidentiality.

The real aim, advocates for public health say, is to narrow the scope of science used in regulation.

Pruitt's policy mirrors legislation sponsored by Rep. Lamar Smith (R-Texas), chairman of the House Science Committee, that has been passed by the House of Representatives three times but has never been taken up by the Senate.

Health Studies Show Links to Lung Damage, Premature Death

The science controversy sprung from large, long-term studies by both Harvard University and the American Cancer Society in the early 1990s showing that inhaling fine particulate matter, like that spewed into the air from the burning of oil and coal, causes premature death from lung cancer and cardiopulmonary disease.

Those findings underpinned the first U.S. air quality standards on extremely fine particulate matter in 1997—one of the most significant pollution rules of that decade—as well as the cost-benefit analyses of many of the most significant air pollution regulations that followed, including the Clean Power Plan.

But researchers had obtained personal health information from tens of thousands of participants on the promise of confidentiality. This privacy measure, common in health studies, was branded as "secret science" by foes of regulation. In 1997, hearings were held on Capitol Hill, and protesters hired by a group called Citizens for a Sound Economy, which was founded by the petrochemical magnate Koch brothers and which also received funding from the Exxon Foundation that year, stood outside with signs that said, "Harvard, release the data!"

The studies were revalidated and have stood the test of time. They have been cited nearly 8,000 times in other peer-reviewed publications, and the body of work is among the most important science in the field.

Now that the EPA is producing a new assessment of health risks of particulate matter, advocates of more stringent protections are concerned that Pruitt has found a way to jettison it.

Policy Shift Coincides with Health Risk Review

The policy change comes just as the EPA is working on its first draft of a particulate matter science review—due last fall but not expected to be completed until late this year.

"The goal is to reduce the number of studies that can be included, or to imply that they are not as valid or as respectable in terms of their evidence," said Janice Nolen, assistant vice president for national policy at the American Lung Association. She said that many studies have been published that corroborate the findings of the Harvard and ACS studies, including ones that use publicly available data, like that from Medicaid records. But the Harvard and ACS studies have become a target, Nolen argued, because they were "transformative."

"That is the power of these studies—they have caused us to change the way we thought about this air pollutant," she said.

EPA is required under the Clean Air Act to do periodic reviews of the science underpinning its health standards; its last look at particulate matter was published in 2009. The review included 300 new epidemiological studies, and ultimately led to the Obama administration tightening its standard for particulate matter of 2.5 microns or less, known as PM2.5, in 2012. That standard, an annual mean of 12 micrograms per cubic meter, is not as stringent as the World Health Organization guideline of 10 micrograms per cubic meter.

The Trump administration indicated its view on the importance of PM2.5 science recently in a draft report by the Office of Management and Budget, required by Congress, on the economic justification for regulations over the past 10 years. OMB tallied up the benefits of air pollution rules as outstripping the costs by a factor of at least 4-to-1, but said that the benefits are "mostly attributable to the reduction in public exposure to fine particulate matter." The Clean Power Plan is an example—a co-benefit of reducing coal-burning that causes carbon dioxide is that it reduces particulate matter, too, which is added into the justification of the rule.

Steve Milloy, a senior fellow at the fossil fuel industry-funded Energy and Environment Legal Institute and publisher of Junkscience.com, who has been agitating against the PM2.5 studies for years, hailed Pruitt's new policy at his website with the headline, "WINNING!" Milloy said he hopes Pruitt's new policy will keep research like the Harvard and ACS studies out of EPA's health assessment of particulate matter and will allow more consideration of reports that found no associated health risk. That new health risk assessment, in turn, will be the basis for new air regulations—or, in the case of Pruitt's agenda, the legal justification for deregulation and the repeal of rules like the Clean Power Plan.

"I can't think of anything more urgent," Milloy said. "The most devastating rules of the Obama administration—mercury and air toxics, the Clean Power Plan, even [ozone], they all depend on PM2.5 junk science," he said. "Those are the biggest, most expensive and highest profile rules the EPA has ever issued. ... They are the heart and soul of the 'War on Coal'."

Pruitt's Science Advisory Board Changes Matter

Pruitt's edict comes at the same time he is reconstituting the EPA's science advisory boards to include more industry-sponsored scientists and to eliminate scientists who receive federal funding. Under the ethics rules that he has put into place, it is considered a conflict of interest for a science advisory committee to receive EPA funding, but not a problem for a committee member to receive industry funding.

The newly installed chairman of the Clean Air Science Advisory Committee, which will have a key role in reviewing EPA's particulate matter science assessment, is Louis Anthony (Tony) Cox Jr., a Denver-based consultant. Cox published a study funded by the American Petroleum Institute last May that concludes socioeconomic factors are to blame for asthma—not air pollution like particulate matter.

Nolen, of the Lung Association, said that "in a normal world" the advisory committee could be counted on to make sure that the EPA was relying on well-corroborated science, and not outlier findings, in its health assessment. But she is not sure that will be the case under the advisory committees as remade by Pruitt.

"When you're trying to stack the deck as to who does the review, and which research you review, you are really trying to shape the outcome of their review, and that is a great concern," she said.