News Flash


EPA Reverses “Once In, Always In” Policy

On January 28, 2018, the EPA issued a policy memo allowing reclassification of major Hazardous Air Pollutant (HAP) facilities as area sources under section 112 of the Clean Air Act.

Superseding the 1995 “Once In, Always In” policy, this memo allows facilities previously identified as major HAP sources required to comply with Maximum Achievable Control Technology (MACT) standards to reclassify as an area source at any time. This means that a facility with a Potential to Emit (PTE) of 10 tons per year or 25 tons of any HAP combination can now implement emission reductions or take federally enforceable permit limits to reclassify as an area source.

What this Means for Industrial Facilities

Under the previous policy, facilities subject to the MACT standard were permanently:

  • Classified as major HAP sources
  • Required to comply with the MACT standard
  • Required to have a Title V permit

Now that the previous policy has been reversed, facilities can reclassify as an area source if the facility’s PTE supports a reclassification. This could eliminate having to comply with MACT standards and maintaining a Title V operating permit. In addition, this would reduce the burden of preparing emission inventories, an annual compliance certification and a semi-annual monitoring report.

What can be done?

There are two options:

  • If your facility has reduced potential HAP emissions to less than 10 tons per year or 25 tons per year of combined HAPs, updating your emissions inventory could identify the opportunity to reclassify as an area source.
  • If your facility has actual HAP emissions less than 10 tons per year or 25 tons per year of combined HAPs, the facility can reclassify as an area source if a federally enforceable synthetic minor limit is requested through a permit modification. This will effectively cap the HAP PTE for that facility. In this option, actual emission tracking and recordkeeping would be required on a rolling 12-month total basis.


Lain Pacini
Principal Scientist
Midwest/Eastern States


Ease Your Burden and Allow Us to Assist with Your Reclassification

• Emission Inventory Updating
• Permit Modifications
    (Synthetic Minor Limit Requests)


Joe Rubino
Principal Scientist
Western States


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