The EPA’s flawed zero tolerance policy

For the last three years, the Environmental Protection Agency has justified new air quality regulations — unprecedented in stringency and cost — on the assumption that even trace levels of particulate matter can cause early death.

A recent EPA report states that by 2020, the EPA’s rules “will prevent 230,000 early deaths.” EPA Administrator Lisa Jackson has gone so far as to testify before Congress that the new regulations would provide health benefits as valuable as a cure for cancer. If true, this is compelling. Unfortunately, such rhetoric is built on implausible assumptions, biased models, statistical manipulations and two cherry-picked studies.

Unwinding this tangled web is tedious but necessary to prevent the EPA from becoming a national economic planning agency that transforms our economy and undermines our form of democratic government, in which elected representatives — not federal technocrats — have the authority to make the country’s major policy decisions.

On Wednesday, a U.S. House subcommittee will conduct a hearing to examine the real costs and benefits of the EPA’s environmental regulations, with invited testimony from one of my former colleagues at the Texas Commission on Environmental Quality.

As I noted in my latest report for the Texas Public Policy Foundation, “EPA’s Pretense of Science,” the EPA now justifies almost every major new air quality rule on the basis of models indicating implausibly exaggerated health risks from fine particulate matter, rarely considered a killer by physicians or toxicologists.

Extrapolating from assumptions, the EPA in 2009 decided that no risk is too low, improbable or uncertain that it is not worth responding to with regulation. With a straight face, the EPA’s leadership now maintains that there is no safe level of ambient fine particulate matter — however near to zero — at which risk of “early” death ceases. Statisticians call this analytic approach a “no threshold linear regression to zero.”

The Clean Air Act requires that national air quality standards be set at levels adequate to protect human health with a margin of safety and regardless of cost. That’s a very cautious rubric. But through the no-safe-threshold assumption, the current EPA goes further: to zero risk. This methodological change leads the EPA to the implausible finding that mortal risks increase to the extent that ambient levels of fine particulates exceed natural background levels of 1 microgram per cubic meter. The current federal standard is 15 micrograms per cubic meter.

Gina McCarthy, the EPA’s assistant administrator for air, defended the no-safe-threshold approach in a recent letter to Congress: “These studies have not observed a level below which premature mortality effects do not occur. … There is no threshold level of fine particle pollution below which health risk reductions are not achieved by reduced exposure.”

While the EPA’s defense begs the question, it revealingly states the obvious: The point at which risk falls to zero cannot be proven. This is certainly true when it comes to human mortality.