Revisiting Air Licensing Thresholds

You’re walking on air. Your licenses are in order, the license conditions are being met and you are using Sentry EHS for automatic notification as to when to start applying for license renewals.  When it comes to complying with your facility’s environmental licenses, things couldn’t look better, until, you ask yourself, “Do I have sufficient documentation that demonstrates I am below licensing thresholds for other compliance areas?” 

Even if requirements did not previously apply, it’s worth revisiting them to save you significant frustration and sleepless nights. This especially applies to air licensing. 

It is one thing to compare your normal emissions to the minor source air licensing thresholds and to make a determination as to whether your facility requires a license or not. It is another thing to determine your facility’s potential-to-emit (PTE) emissions to ensure you are not exceeding a major source air licensing threshold.  Although it seems reasonable to accept the notion that if you are below the minor source licensing thresholds then you should be below the major source licensing thresholds as well. 

Unfortunately, this is not always the case, as demonstrated within the last couple of years when inspectors from Environmental Protection Agency (EPA) Region 1 visited several boatyards and marinas in Maine. This can happen to businesses besides boatyards and marinas, such as manufacturers, auto body shops and others. In Maine, the minor source air licensing thresholds are based on normal air emissions.  One needs to determine emissions from fuel burning equipment (boilers, generators, fire pumps, etc.) and operations (coating, plating, abrasive blasting, etc.) without consideration of air pollution control equipment during a normal business day.

One of the boatyards inspected by the EPA did not have the necessary documentation that demonstrated that the facility’s normal air emissions were below the minor source air licensing threshold.

Major source air licensing thresholds are based on emissions that are assumed to have the greatest potential to be emitted (i.e., PTE).  PTE is defined (40 CFR 52.21(b)(4) as,  “Potential to emit means the maximum capacity of a stationary source to emit a pollutant under its physical and operational design .  Any physical or operational limitation on the capacity of the source to emit a pollutant, including air pollution control equipment and restrictions on hours of operation or on the type of amount of material combusted, stored, or processed shall be treated as part of its design if the limitation or the effect it would have on emissions is federally enforceable.”

Therefore, PTE can be broken down into two components: 1) limitations on the emission unit or process, and 2) enforceable restrictions on the facility’s ability to emit.  These limits could include limiting operating hours, material use and emission rates. For example limiting the operation of a spray booth to only one shift. Without that limitation, PTE would be calculated based on the assumption that the spray booth could operate (or have the potential to operate) during all three shifts and possibly in multiple buildings. 

The second component, federally enforceable, isn’t as easy. Federally enforceable has been interpreted by EPA and the courts to mean either federally enforceable or legally or practically enforceable.  In order for a limitation on an emission unit or process to be enforceable, it would have to be listed on the facility’s air emission license.  This is typically done on a synthetic minor air emission license.  The purpose of the synthetic minor license is to limit a facility’s emissions in order to avoid having the potential to be a major source requiring a major source air license.  Once these limitations are on a license they become federally enforceable.

The boatyard inspected by the EPA also did not have the documentation that demonstrated the facility’s PTE emissions were below the major source air licensing thresholds.  Once this was determined, the EPA inspector began to build their case that this boatyard was a major source and required a major source air license. Sometimes EPA inspectors have been known to:

  1. 1. Use the design capacity of the facility’s septic system as a basis for calculating the potential of having the maximum number of employees on site.  The maximum number of employees can then be used to calculate PTE emissions;
  1. 2. Use the number of buildings on site as a basis for determining the potential maximum number of spray painting operations (and fuel burning equipment to supply heat to these buildings) occurring on site, even though spray painting operations were only taking place in one building and there were no (undocumented) plans for increasing painting operations to the other buildings; and
  1. 3. Use the unused land area on site as a basis for determining the potential maximum number of spray painting or abrasive blasting operations the facility could have taking place on site even though the facility did not have any plans for doing so.

As a way to try and prevent this situation from occurring with companies in Maine—especially smaller companies—the Maine Department of Environmental Protection (MEDEP) provides a template (Self-Assessment Compliance Guide) that can be used to determine and document if a company’s PTE emissions are below the major source air licensing thresholds.  Follow this link to view their webpage.  In addition to boatyards and marinas, this template can be used for other businesses as well.

This type of documentation will help demonstrate that a company’s emissions are below the minor source and major source air licensing thresholds, however, it is not bullet-proof. This documentation, no matter how thorough it appears to be, is still not federally enforceable and therefore could be ignored by regulatory inspectors.  Much more assurance is provided when a company elects to obtain a synthetic minor source air license which provides federally enforceable limitations on the facility’s capacity to emit pollutants.

In summary, if your company does not have an air emission license, make sure it doesn’t require one by doing the necessary calculations and documentation that demonstrates its normal air emissions are below the minor source air licensing thresholds and its PTE emissions are below the major source air licensing thresholds.  If neither of the two licensing thresholds are exceeded, consider obtaining a synthetic minor air license to have federally enforceable limitations on your company’s capacity to emit pollutants.

If you have questions or require more information, please call Mike Rioux, CHMM at 207-591-7000 or email us.