Soot Happened: After an Estimated 90,000 Premature Deaths, EPA’s New Standard Finally Gets the Science Right

Got Science? | February 2013

A tragic disregard for scientific evidence was finally remedied on January 15,2013 when the Environmental Protection Agency (EPA) published a long-awaited revision of its air pollution standard for fine particulate matter—more commonly known as soot—reducing the annual allowable average amount of soot in the air from 15 to 12 micrograms per cubic meter.

It may sound like an arcane, bureaucratic change, but the implications for public health are enormous. Sadly, though, the latest development came only after a long and sorry history that serves as an object lesson about the huge consequences that can arise when politics is allowed to trump science.

Here’s what happened: the trouble arose in 2006, during the George W. Bush administration, when then-EPA Administrator Steven Johnson overruled both his staff scientists and his expert scientific advisory committee to prevent the tightening of the soot standard. At the time, EPA was conducting a review of its soot standards as mandated by the Clean Air Act. The Act requires EPA to review its standard every five years, basing its review on the best available science regarding the protection of human health. While the Act permits other factors, such as monetary costs, to be considered when the standards are implemented, it specifies that the determination of the standards themselves must be based on an analysis of the scientific data alone.

Good Policies Need Solid Science

Reviewing the data in 2006, EPA staff scientists had recommended a maximum standard for soot between 11 and 13 micrograms per cubic meter to protect public health. The agency’s Clean Air Science Advisory Committee (CASAC) concurred, noting that the existing 15 microgram standard (initially set in 1997) was not sufficiently protective of public health according to the latest scientific research.

In making their determination, EPA and CASAC scientists reviewed some 2,000 studies linking soot exposure to health problems. Soot is made up of tiny particles—a fraction of the width of a human hair—emitted by sources such as coal-fired power plants, woodstoves, and diesel exhaust. The small size of these soot particles makes them especially pernicious for human health because they penetrate deep into the lungs and are linked to a wide range of serious health effects including premature death, heart attacks and strokes as well as acute bronchitis and asthma.

In September 2006, however, EPA Administrator Steven Johnson opted to ignore his staff scientists and his expert scientific advisory committee, issuing a ruling that failed to tighten the soot standard as advised. It was the first time an EPA administrator had disregarded CASAC’s scientific advice on an air standard in the committee’s nearly 30-year history. And, given the unequivocal language of the Clean Air Act, even the legality of Johnson’s ruling was an open question.

To justify his decision to ignore the committee’s recommendations, Johnson cited “disagreement” within CASAC. But, in fact, the call for stronger standards was nearly unanimous. Rogene Henderson, a respected, and now-emeritus, biochemist at the Lovelace Respiratory Research Institute in Albuquerque, New Mexico chaired CASAC during this period and remembers the incident well. As she explains, “There was nothing unclear in our recommendations. We provided the EPA administrator a consensus opinion about the standard for fine particulate.”

After Johnson overruled CASAC’s advice, Dr. Henderson voiced her strong objection in a letter signed by all standing CASAC members, explaining that leaving the average annual limit at 15 micrograms would have a significant, negative effect on public health. Such a standard, Henderson and her colleagues wrote, simply did “not provide an ‘adequate margin of safety … requisite to protect the public health’ (as required by the Clean Air Act).”

The letter also noted that CASAC’s recommendations “were consistent with the mainstream scientific advice that EPA received from virtually every major medical association and public health organization that provided their input to the Agency,” including the American Medical Association, the American Lung Association, the American Heart Association, the American Cancer Society, and a host of others.

Restoring a Science-Based Standard

After a several-year court battle, the U.S. Court of Appeals for the D.C. Circuit held, in February, 2009, that Johnson had violated the Clean Air Act by failing to provide adequate reasoning for his rejection of CASAC’s science-based recommendations on soot. Later that year, EPA Administrator Lisa Jackson—Johnson’s successor in the first term of the Obama administration—overturned a related Bush-era directive, reaffirming the role of EPA staff scientists and CASAC advisors in developing science-based air quality standards. As she noted at the time, the changes she was authorizing would help improve the scientific basis for EPA standards. As Jackson explained: “It’s essential that the best science and the greatest transparency inform air quality standards that prevent illness and save lives.”

Finally, this year—some six years after Johnson’s ruling—EPA has authorized air quality standards on soot that are once again based on a solid scientific footing.  As Dr. Henderson commented: “I’m glad to see the EPA has made this change and that CASAC’s former consensus recommendation has been heeded. As a scientist, I believe strongly in using science to inform policy.”

EPA’s new standards do represent a welcome development. But the six-year delay in promulgating them also offers a sobering lesson about what’s at stake. A 2011 report estimated that EPA’s failure to tighten the soot standard was costing some 15,000 premature American deaths annually. That means that EPA’s failure to base their standard on the best available science in this case resulted in some 90,000 premature deaths during this period—more than even the 58,000 total U.S. military casualties during the entire Vietnam War. Add to that an estimated four million or more cases of aggravated asthma and other respiratory illnesses during this period and the deadly importance of basing policies on solid science becomes clearer than ever.

As Henderson puts it, “If there’s a lesson in this case, it’s that the science should be respected. As I said in 2006, if you’re not going to base your standard on the science, you better have a darn good reason.”