NSPS Subpart OOOOa and OOOOb Reporting
If your operations involve wells, compressors or storage tanks, you’re likely required to comply with NSPS Subpart OOOOa or OOOOb, EPA’s rule for controlling methane and volatile organic compound (VOC) emissions from oil and gas facilities.
These regulations set requirements for leak detection, emissions controls and reporting, impacting both existing and newly built equipment.
NSPS Subpart OOOOa applies to equipment that was built, modified or reconstructed after September 18, 2015 and on or before December 6, 2022.
NSPS Subpart OOOOb applies to newer sources that began construction, modification or reconstruction on or after December 6, 2022 and introduces stricter leak detection and repair requirements, including potential continuous monitoring technologies.
Not sure which rule applies to your facility? We help companies determine compliance requirements based on equipment age, modifications and state-specific regulations.
Who’s Affected?
Since OOOOa covers older equipment and OOOOb applies to newer equipment, let’s clarify that both standards may apply to different parts of a facility.
Subpart OOOOa and OOOOb apply to oil and gas equipment that is either existing, newly built or recently upgraded, including:
Well sites - covers emissions from pneumatic controllers, storage tanks and well completions.
Compressor stations - requires regular inspections and repairs for gas leaks from pressurized equipment like valves, seals and pipelines, where methane and VOCs can escape due to wear and tear.
Gas processing plants - requires continuous monitoring and emissions controls for VOC and methane leaks from compressors, heat exchangers and other processing equipment.
If your facility includes new or upgraded equipment, OOOOa may still apply, but newer sources must also meet OOOOb requirements, which include more frequent inspections and potentially stricter emissions reduction measures.
What Does Compliance Require?
Find and fix leaks (LDAR)
Regular inspections and repairs to prevent methane and VOC leaks from equipment like valves, seals and pipelines.
Control emissions
Limit emissions from a variety of sources, including storage vessels, pneumatic pumps, fugitive components and well completions, as examples. Several other equipment types and processes are also subject to OOOOa and OOOOb requirements, depending on your site configuration and operations.
Keep records & report
Submit annual reports to the EPA, including detailed logs of leak inspections, repairs and emissions data.
4 Common Challenges
Challenge 1: Keeping up with leak detection and repair.
Facilities must inspect for leaks every 3 to 6 months and fix any found leaks within 30 days to stay compliant.
Challenge 2: Managing storage vessels & emission controls
If storage vessels emit more than 6 tons of VOCs per year, they must use emissions controls.
Challenge 3: Tracking reports and documentation
Facilities must submit detailed leak detection data, repair logs and emissions performance reports each year.
Challenge 4: Understanding federal vs. state requirements
Some states, like Colorado, New Mexico, and Pennsylvania, have stricter methane rules than the federal standard.
How to Stay Compliant with NSPS OOOOa and OOOOb
Stay on schedule with leak detection.
Perform required audio, visual and olfactory (AVO) and Leak Detection and Repair (LDAR) inspections on time. Also, ensure leaks are repaired within the required timeframe to avoid penalties.
Use the right detection methods.
Make sure your OGI cameras and Method 21 inspections meet EPA compliance standards. We (or other third-party experts) can help verify accuracy.
Reduce emissions from process controllers.
If your site requires low emission controllers, ensure they’re installed and working properly. Assessing the best options can save costs in the long run.
Keep detailed records.
Store inspection logs, repair reports and emissions data for at least 5 years. Well organized records make audits and reporting easier.
Submit reports on time.
Make sure your annual reports are complete, accurate and filed with the EPA by the deadline. Having compliance experts review your reports can prevent costly mistakes.
NSPS OOOOa and OOOOb FAQs
If I change the number of tanks or the amount of production going to my tanks, will I be subject to the rule?
If you increase the number of storage tanks in your battery or if you increase the condensate/oil that is sent to the storage tanks, you could be subject to OOOOb based on the modification language.
When does OOOOc start?
It’s a future concern to consider, but the details aren’t finalized yet. The EPA is still working out the specifics, so there’s nothing to act on right now. We stay on top of these changes and keep our clients in the loop, so when it does roll out, they’ll know what it means for them.
Do I have to install an air system for my process controllers?
If your process controllers were installed after December 6, 2022, they are required to be a non-emitting source. This means they need to be connected to an air system, converted to electric, or use another non-emitting control method to comply.
What is required for my flare or enclosed combustion device?
It depends on the type, installation date and emissions thresholds of your system. Since regulations vary and this is a complicated question, it’s best to reach out to us or another compliance expert so can review your specific setup.
Need Help with NSPS OOOOa and OOOOb Compliance?
Keeping up with leak inspections, repairs, emissions controls and reporting deadlines can be a lot to handle, especially when the requirements keep changing.
We help oil and gas teams:
Stay on top of leak detection schedules so nothing gets missed.
Make sure equipment meets emissions rules and works like it should.
Keep records organized so reporting is easier (and less stressful).
Sort through state and federal rules so you know exactly what applies to you.
Identify which equipment and operations fall under OOOOa and OOOOb, so you know exactly what needs to be monitored and reported.