Leak Detection and Repair (LDAR) programs are typically discussed in the context of a regulatory trigger: a facility crosses a major source threshold, is performing a construction or modification, a permit condition requires monitoring, or a state, local, or National Emission Standards for Hazardous Air Pollutants (NESHAP) requirement brings equipment leaks into scope. But a growing number of facilities are implementing LDAR programs with no rule requiring them to do so at all. For these sites, LDAR isn’t a compliance obligation, rather, it is viewed as a strategic tool for managing potential to emit (PTE), preserving room to grow, and in some cases avoiding a permitting pathway altogether.
When implementing a voluntary LDAR program, a facility chooses to monitor equipment for fugitive leaks even though no federal, state, or permit-specific rule obligates it. The LDAR program can be conducted using a number of methodologies: such as auditory, visual, or olfactory (AVO) inspections, Method 21, optical gas imaging (OGI), or some combination of the three.
The PTE Problem That Drives the Decision
Facilities without an LDAR program must estimate potential-to-emit (PTE) emissions from fugitive components using EPA’s default emission factors. These factors were developed decades ago from a limited set of facilities and are deliberately conservative, since they have to account for a wide range of operating conditions and leak frequencies without any actual field data to narrow the estimate. The result is that unmonitored fugitive emissions are often calculated well above what a facility may actually be emitting.
For a facility sitting close to a prevention of significant deterioration (PSD) major source threshold, an area source cap, or a state-specific emissions limit, that gap between uncontrolled and controlled potential emissions can be the difference between staying under a threshold and triggering a much more burdensome permitting process. A voluntary LDAR program reduces the conservative default factors with control efficiencies, which in most cases brings the calculated PTE down substantially. Facilities that adopt an LDAR program before they need it are often doing so to buy themselves emissions headroom for a future expansion, a debottlenecking project, or additional equipment down the line, without having to revisit their permitting classification when that project comes along. Additionally, monitoring data pays off in annual emissions inventories and toxic release inventory (TRI) reporting. Using actual, monitored emissions instead of conservative default factors can reduce the cost of preparing these inventories and produces a more accurate public-facing emissions picture, so the public isn’t left with a skewed perception based on overstated default numbers.
Not Just Federal HAPs and VOCs
One trend worth noting is that voluntary LDAR programs are not limited to the pollutants traditionally associated with equipment leak monitoring. Facilities are increasingly extending voluntary monitoring to state-regulated air toxics that fall outside federal volatile organic compounds (VOC) and hazardous air pollutants (HAP) definitions but still carry emissions limits or reporting thresholds under state air toxics programs. A facility that has already built the infrastructure, procedures, and trained personnel for an LDAR program can often extend that same monitoring scope to state-listed compounds at a relatively low incremental cost, while gaining the same PTE benefit at the state permitting level that federal LDAR provides at the federal level.
This flexibility extends to how the program itself is scoped. A facility does not need to monitor every piece of equipment at the same frequency or with the same method to see a meaningful reduction in calculated PTE. Facilities can tailor a program around a specific emissions target, focusing monitoring on the components and streams that contribute most heavily to the pollutants of concern, and calibrating monitoring frequency and method to the level of control needed to hit that number. A facility targeting a modest PTE reduction to stay under a state minor source threshold does not need the same program design as a facility trying to avoid PSD applicability for VOCs across an entire process unit.
PSD Avoidance in Practice
That last scenario is not hypothetical. Trinity has assisted facility across the country that have used exactly this approach: implementing voluntary VOC controls, including LDAR-style leak monitoring, specifically to keep calculated VOC emissions below PSD major source thresholds. Rather than accept PSD applicability and the associated Best Available Control Technology (BACT) review, air quality modeling, and public comment process that comes with it, these facilities added control measures and monitoring commitments voluntarily, effectively creating a synthetic minor source limit for VOCs. The permitting timeline, engineering cost, and operational flexibility gained by staying under PSD applicability can far outweigh the cost of the voluntary controls themselves.
This is the calculation every facility considering voluntary LDAR should be running: what does PSD review, major source NESHAP applicability, or a state minor source exceedance actually cost in permitting time, capital for control technology, and ongoing compliance obligations, compared to the cost of a monitoring program designed to keep emissions below those thresholds in the first place? For many facilities, especially those anticipating growth, the math favors getting ahead of the threshold rather than permitting around it later.
The Takeaway
Voluntary LDAR is best understood as a form of proactive emissions management rather than a compliance checkbox. Facilities that adopt it before a rule requires it are typically doing so to correct an overly conservative emissions picture, protect headroom for future projects, or avoid a permitting pathway that would otherwise be triggered by default emission factors rather than actual facility performance. As more state air toxics programs and PSD-adjacent thresholds come into play, voluntary LDAR is likely to become a more common part of the permitting strategy conversation, not just the compliance conversation.
If your facility is approaching a PTE threshold, planning a future expansion, or looking for ways to bring emissions estimates closer to actual performance, a voluntary LDAR program may be worth evaluating well before it becomes a requirement. Trinity Consultants’ LDAR team has extensive experience designing programs scoped to a facility’s specific emissions targets, including state air toxics and PSD avoidance strategies. For more information, contact Eric Reidy, Manager of LDAR Services, at 334.531.3658.
