See the latest EHS federal and state regulatory updates due to COVID-19

Leak Detection and Repair (LDAR) involves finding facility components that are leaking and fixing them. The U.S. Environmental Protection Agency (EPA) has a long history of regulating industries (such as petroleum refining and chemical manufacturing), and more specifically, the components within those industries that have the potential to leak pollutants to the atmosphere. But over the last few years, EPA has focused its policy efforts toward regulating the upstream and midstream oil and gas industry. Of particular note are the LDAR requirements under New Source Performance Standards (NSPS) in Subparts OOOO and OOOOa, as well as the equipment leak emissions reporting requirements under EPA's Greenhouse Gas Mandatory Reporting Rule (GHG MRR) (40 CFR 98 Subpart W). In recent years, various states with high concentrations of oil and gas operations have also adopted state LDAR requirements for the industry.

Environmental staff at affected facilities are challenged to understand and comply with LDAR requirements. What needs to be monitored? How often is monitoring required and what equipment is acceptable for monitoring? How is a leak defined? When must the repair be made? All of these are valid and critical questions, and the answers can vary depending on the underlying requirement(s) of the requisite LDAR program. In addition, an operation can be subject to multiple overlapping regulations, potentially leading to another layer of complexity. Furthermore, not every source that emits pollutants qualifies as a leak, and not every leak is easy to identify. While one LDAR program might cover flanges, connectors, and valves, another program might also include pneumatic controllers or pressure relief valves. Depending on the detailed requirements of the underlying program in question, the gas emitted from those types of sources may or may not be considered a leak. Thus, a firm understanding of the detailed applicable requirements is imperative to avoid costly mistakes and to ensure a comprehensive compliance program is in place. This article discusses best practices for managing LDAR data efficiently and cost-effectively.

LDAR Best Practices

Best practices for managing LDAR data include the following:

Identify Applicable Requirements

To ensure compliance with the many and varied LDAR regulatory requirements, it is imperative to have a robust system with which to track initial production/applicability dates for each affected facility so that you can determine and document the state and/or federal LDAR regulations that apply. The applicable regulations will determine the frequency and scope of LDAR inspections, as well as the schedule for repairs and other required program elements (e.g., reporting and monitoring plan requirements). Because various state and federal LDAR requirements may have common, overlapping, or conflicting requirements, this initial step is critical to identify all applicable requirements and to inform program development and implementation strategies. One way to conduct this analysis is to prepare a matrix with side-by-side comparisons of applicable requirements. A simplified example is shown below for a wellpad in the state of Pennsylvania that is authorized under the current Exemption 38 criteria and also subject to NSPS Subpart OOOOa requirements. As illustrated by this table, it is important to understand the various requirements and how they differ between programs in order to develop an efficient LDAR program that meets all compliance obligations.

LDAR Program AreasPADEP Exemption 38NSPS Subpart OOOOaGHG Subpart W
Monitoring FrequencyAnnualSemi-AnnualMust use OOOOa survey data*
Components CoveredAll**AllExcludes thief hatches on tanks and components on small piping < 0.5” diameter
Repair Timeline15 days30 daysNo repair required
Reporting RequirementsOn-timeAnnualAnnual
Monitoring Plan RequirementsNoneWritten plan with observation paths for LDARFacility Monitoring Plan for all GHG sources

*Onshore production facilities that are not subject to NSPS OOOOa have the option of using leak survey data for Subpart W reporting. However, monitoring data must meet the specified criteria (effectively the same as NSPS OOOOa).
**Exemption 38 states “valves, flanges, connectors, storage vessels/storage tanks, and compressor seals in natural gas or hydrocarbon liquids service.” This has been interpreted to mean all components.

Plan and Schedule Inspections Efficiently

The execution of routine LDAR inspections can be time-consuming and burdensome, especially when the affected facilities are distributed across a large geographic area and/or may be on different monitoring schedules based on varying production/applicability dates. This means that the inspection due dates for such facilities may not fall on the same day (for the ones that are nearby), potentially causing multiple trips for field personnel. Economies of scale can be achieved by looking at the due dates for such facilities in the same area, geography, or route and adjusting the inspection dates to maximize efficiency without missing key regulatory deadlines. This can reduce the number of trips needed, and consequently, the man-hours required to complete inspections. In addition, component monitoring paths at each facility can be efficiently planned to optimize the time that field personnel spend at each site.

Consider the “Highest Common Denominator” Approach

Many operators approach LDAR compliance by following individual applicable regulations selectively on a site-by-site basis in an attempt to minimize costs and resources. However, the complex nuances of the various applicable regulatory programs, coupled with the sheer volume of affected facilities at most companies, can result in confusion by field personnel leading to poor data quality or gaps in required program elements. As an alternative, operators can take a more proactive “highest common denominator” approach that reduces the risk of non-compliance with multiple overlapping regulations by electing to comply with the more restrictive requirements at all facilities.

As an example, consider the reporting requirements under Subpart W of EPA's MRR for GHGs. Sites that are not subject to NSPS Subpart OOOOa LDAR, but are subject to state-required LDAR, have the option of using that LDAR data for Subpart W reporting. However, the monitoring must be done in accordance with one of the methods prescribed in Subpart W (which state-level monitoring may not meet). So for these situations, operators may need to “beef up” their LDAR program (i.e., follow OOOOa) in order to be able to use that data for Subpart W reporting. Depending on the state-specific requirements, this may or may not be a significant change. Some operators will see an advantage to using all available LDAR data, since this will likely result in lower reportable emissions. This may be an especially attractive strategy for companies that have committed to GHG or VOC emissions reductions under corporate sustainability goals or other initiatives.

Employ an EMIS to Manage Data

LDAR programs are inherently complex with many moving parts and requirements. From tracking of key applicability dates to scheduling of inspections, there are many time-sensitive, facility-specific task tracking needs. In addition, LDAR programs are especially data intensive, requiring component leak counts, operating hours, and emissions calculations to be performed. Managing this information manually becomes tedious and impractical for most operations. Environmental Management Information System (EMIS) technology solutions such as Intelex ACTS with Mobile forms allow capturing of data on mobile devices in the field along with real-time multimedia/digital image files. These tools function efficiently to ensure that required records are maintained in such a way that data can be easily translated or migrated into emissions calculation or reporting spreadsheets for various agency reports. The use of these systems can eliminate or significantly minimize the time spent manually reviewing and organizing leak data for emissions calculation, agency reporting, or internal auditing purposes.


With the many complex facets of LDAR program management, the single most important step facilities can take is careful and comprehensive planning. This is most effective when it involves a cross-functional team of environmental and safety staff, EHS data management experts, operations and maintenance personnel, and LDAR surveyors. Clear and concise communication of monitoring requirements and leak repair deadlines can help avoid deviations and potential violations and monetary penalties. For operators with multiple facilities with differing LDAR requirements, compliance strategies such as aligning all sites to the most stringent monitoring frequency and repair schedule may be desirable.  A wide array of tasks are required for comprehensive LDAR program management, including developing monitoring plans, conducting surveys, auditing compliance, performing emission calculations, and preparing reports. Selection and implementation of various software applications (or EMIS) may be a powerful tool to support compliance.

In summary:

  1. Evaluate all applicable program requirements and make company-specific strategic decisions regarding LDAR program management.
  2. While it may seem cost-effective to implement only the minimum requirements for each facility, this approach may also increase the time and compliance risk involved in managing multiple programs across the company. Communication and training of applicable requirements across the organization, along with execution of inspections and repairs, is simplified when the “highest common denominator” approach is used.
  3. EMIS solutions can be a valuable and effective compliance tool for managing the wide-array of tasks and LDAR data elements, especially for operators with many facilities and/or applicable programs.

For assistance with effective LDAR monitoring, please contact Christi Wilson at (724) 935-2611 or

For assistance with selecting and implementing a technology solution to manage LDAR data, please contact Varun Anand at (713) 552 1371 or