Fugitive Fenceline Monitoring Requirements Continue to Roll Out

The U.S. Environmental Protection Agency (U.S. EPA) and State air regulatory agencies continue to utilize U.S. EPA Methods 325A (Sampler Deployment and VOC Sample Collection) and 325B (Sampler Preparation and Laboratory Analysis) as part of new and amended regulations and Clean Air Act (CAA) Information Collection Requests (ICR) in support of National Emission Standards for Hazardous Air Pollutants (NESHAP) reviews.  Method 325A and 325B were originally promulgated in 40 CFR Part 63 Appendix A in support of amendments to the Petroleum Refinery Sector NESHAP.  The primary purpose of including fenceline monitoring in air regulations is to require facilities to monitor for and reduce fugitive emissions from their processes.

U.S. EPA Method 325A describes the collection of volatile organic compounds (VOC) at or inside a facility property boundary or from fugitive area emissions sources using passive (diffusive) tube samplers.  Method 325A describes how many samples are required and where to locate the samples based on the size and shape of a facility’s property boundary.  Per Method 325A, the passive tubes are deployed for a two-week period and, depending on the size of your facility, include 12 to 35 sample locations as well as at least one duplicate site and one sample blank for quality control (QC) purposes.

U.S. EPA Method 325B describes the preparation of the sampling tubes, shipment and storage of exposed sampling tubes, and analysis of the tubes collected.  Method 325B is primarily used by the laboratories completing the analysis.  The sampling tubes are analyzed by thermal desorption coupled with gas chromatography/mass spectrometry (TD-GC/MS) which has the ability to measure a number of VOC constituents.  Method 325B also requires measurements of local meteorological data including wind speed, wind direction, temperature, and barometric pressure collected from an on-site or nearby meteorological station following U.S. EPA’s “Quality Assurance Handbook for Air Pollution Measurement Systems – Volume IV: Meteorological Measurements” requirements which is incorporated by reference at 40 CFR §63.14.

The original Petroleum Refinery Sector NESHAP only required the measurement of benzene; however, as U.S. EPA and State agencies continue to develop new fenceline monitoring requirements the list of Hazardous Air Pollutants (HAP) of concern has expanded depending on the type of sources being evaluated.  For example, the Chemical Manufacturers ICR issued earlier this year included a request for benzene and 1,3-butadiene monitoring data and the Coke Ovens ICR issued in June 2022 included a request for benzene, toluene, ethylbenzene, xylenes, and 1,3-butadiene monitoring data.  In addition, the Chemical Manufacturers ICR included a requirement to perform a Tentatively Identified Compound (TIC) analysis with the passive tubes which is a “catch-all” type of analysis.

Currently, ALL4 is also aware of a couple proposed (and soon to be proposed) rules that will include Method 325A/B fenceline monitoring requirements.  U.S. EPA is currently under a consent order to determine if revisions are necessary to the hazardous organic NESHAP (HON) and sign a proposed rule by December 16, 2022.  It is expected that proposed revisions to HON will include Method 325A/B fenceline monitoring requirements. We may also see U.S. EPA propose to include fenceline monitoring requirements as part of their review of the Organic Liquids Distribution NESHAP this fall (you may recall that they proposed to require fenceline monitoring in 2019 but did not finalize it in the 2020 revised rule).  In addition, the Maine Department of Environmental Protection (MDEP) has proposed a rulemaking that includes requirements for owners and operators of petroleum storage facilities that operate internal or external floating roof tanks to conduct ongoing fenceline monitoring in accordance with Methods 325A and 325B to monitor for benzene, ethylbenzene, toluene, and xylenes.  ALL4 expects the trend of more and more fenceline monitoring requirements to continue for the foreseeable future, especially with agencies’ focus on addressing environmental justice and desire to reduce air toxics exposures in overburdened fenceline communities.

ALL4 continues to monitor air regulatory actions for new fenceline monitoring requirements.  If you have any questions about Method 325A/B fenceline monitoring or if your facility needs to implement a Method 325A/B fenceline monitoring program, please contact Dan Dix at ddix@all4inc.com or at 610.422.1118.