EPA Withdraws Decades-Old Clean Air Emissions Policy


The EPA says the memo aims to reduce “unnecessary regulatory burdens” that deter “innovative efforts to improve the environment.” Lane V. Erickson/Shutterstock

The US Environmental Protection Agency (EPA) announced on Thursday that it plans to reverse a decades-old policy aimed at curbing some of the largest sources of hazardous pollutants, including mercury and lead.  

The “once-in-always-in” policy classifies major sources of hazardous air pollutants under Section 112 of the Clean Air Act.


Under the current provision, major sources of hazardous air pollutants (like power plants) must meet federal emission standards. To do so, they must employ modern technology – known as maximum achievable control technology (MACT) – to reduce pollution as much as possible.

The provision requires a “major source” of hazardous air pollution to always be treated as such, regardless of whether the party responsible made changes to production processes to eliminate or reduce hazardous emissions.

The new guideline states that sources of hazardous air pollutants previously listed as “major sources” may be reclassified as “area” sources.

Critics of the memorandum say it will greatly harm public health.


“This move drastically weakens protective limits on air pollutants like arsenic, lead, mercury and other toxins that cause cancer, brain damage, infertility, developmental problems and even death,” said John Walke, clean air director at the Natural Resources Defense Council, in a statement emailed to IFLScience.

The agency, however, says the move will reduce “unnecessary regulatory burdens” that deter “innovative efforts to improve the environment.”

“It will reduce regulatory burden for industries and the states, while continuing to ensure stringent and effective controls on hazardous air pollutants,” said Bill Wehrum, assistant administrator of EPA’s Office of Air and Radiation, in a statement.

But critics say the withdrawal is a blow to environmental progress and benefits the very industries it should be regulating, like petroleum, at the expense of public health. Others say it's one step closer to "eliminating as many environmental regulations as possible."


In the statement, the EPA says the ‘once-in-always-in’ policy did not give incentive to big emitters for voluntarily finding solutions that would reduce hazardous air pollution.

A “major source” is defined under the Clean Air Act as one that emits, or has the potential to emit, 10 tons of any hazardous air pollutant a year, or 25 tons annually of any combination of hazardous air pollutants. Facilities below this threshold fall into the lesser “area sources” category.

Specifically, Thursday's memo finds that the agency did not have "statutory authority under the Clean Air Act to place a time limit" on when a facility may be determined an area source. If approved, facilities must be given the opportunity to be reclassified if their emissions fall below the levels that define major sources.

The move is part of President Donald Trump’s effort to roll back federal regulations and further his Regulatory Reform Agenda to alleviate what he considers unnecessary regulatory burdens.


The EPA says it will next publish a Federal Register notice to take public comment.


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