It is important to re-calculate your Potential to Emit (PTE) each time you make a change in your operational inputs, especially when it comes to coatings, which are often updated. Coatings are typically associated with PM, VOC and Hazardous Air Pollutant (HAP) emissions. When you first applied for your facility’s permit, you calculated PTE by using the worst case scenario raw coating for each pollutant. Any time you add or switch coatings, it is imperative to evaluate how this may affect PTE and how that fits into your current permit structure. It is possible that the new coating you added has a greater PTE for VOC, PM and/or HAPs.
It is possible that a new coating could move your facility into major threshold status for HAPs or cause a permit transition without a proper permitting strategy. The problem here, for HAPs, stems from EPA’s “Once in Always in Rule”, which states that the moment a facility is subject to major source status they must always comply with major source requirements (i.e NESHAPs).
For example, let’s say in 2005 your facility permitted the coating machines in operation with the worst case coating used at that time. In 2012 a new coating was found to be preferred by your customers, so you made the switch without looking at how that coating affects PTE. If, during the 2005 permitting process your Total HAP PTE was 20 TPY and Single HAP PTE was 8 TPY, your facility was considered an area source for HAPs. Let’s say the new coating increased the facility’s PTE to 32 TPY for Total HAPs and 12 TPY for Single HAPs, both beyond major source status thresholds.
The moment the switch to the new coating was made, without appropriate permitting to limit HAPs and permit the facility as a synthetic minor source, the facility would be classified as a major source. Not only would your facility now need to comply with NESHAPs moving forward, but IDEM would likely issue a Notice of Violation for non-compliance. It could also result in the need to implement control devices such as a thermal oxidizer to comply with Best Available Control Technology (BACT) rules. All of which are time consuming and capital intensive.
Understandably, that aforementioned scenario is to the extreme, but never the less a possibility and all the reason to evaluate your processes against the permit to make sure they align.