Fenceline Monitoring Services
Think Environmental provides a complete, turn-key fenceline monitoring program built around EPA Methods 325A and 325B. We handle program design, field deployment, sample collection, and analytical work through our NELAP-accredited lab partner. You get clean, defensible benzene data on the schedule the rule requires.
What Method 325 Requires
Method 325A governs passive tube sampler deployment at the property fenceline — placement, two-week sampling periods, and chain of custody. Method 325B governs the lab analysis for benzene, including conditioning, blanking, thermal desorption, and reporting.
For refineries subject to the Refinery Sector Rule (40 CFR Part 63 Subpart CC), the program produces a rolling annual average action level of 9 µg/m³. Exceeding it triggers root cause analysis and corrective action.
What We Do
Sampler location determination per §63.658 spacing requirements, Site-Specific Monitoring Plan (SSMP) development, near-field source identification, background station placement, and corrective action protocols.
Weatherproof shelters built of non-outgassing powder-coated aluminum, with removable tube cassettes holding four discrete tubes. Built for Gulf Coast weather, contractor traffic, and sample integrity.
We use Carbopack® X diffusive tubes — the same tubes used in EPA’s Method 325B validation. Every tube is conditioned, blanked, and shipped in benzene-background-free Pelican™ coolers with integrated seals. Field techs deploy and retrieve on the 14-day schedule the rule requires, with full chain-of-custody documentation.
NELAP-accredited SOP through our lab partner, with results delivered in the format and timeframe your quarterly reporting requires.
Rolling annual averages, quarterly reports, root cause analysis support when the action level is approached, corrective action documentation, and coordination with your LDAR, OGI, and tank programs to identify sources.
Industries We Serve
From advanced LDAR program management to high-precision OGI inspections, we provide the technical expertise and field-proven leadership required to keep your facility safe, compliant, and efficient.
Refinery
Petrochemical Plants
Natural gas processing
Upstream oil and gas
Pulp and paper
Renewable fuels
Frequently Asked Questions
Every 14 days, per Method 325A. Our field teams handle the schedule.
For Refinery Sector Rule facilities, 9 µg/m³ benzene as a rolling annual average. Exceeding it triggers root cause and corrective action requirements.
Yes. HON updates extended similar requirements to SOCMI and Polymers & Resins facilities, and many state and Consent Decree programs require fenceline monitoring. Our methodology adapts.
We partner with an NELAP-accredited lab using a Method 325B-based SOP. From your side, it’s a single contract with Think Environmental.
Partner with the Leaders in Environmental Excellence
Secure your facility’s future with a partner who prioritizes your safety and regulatory success. Whether you need expert LDAR program management or advanced OGI inspections, Think Environmental provides the trustworthy, informed guidance you need to achieve zero compliance issues. Contact us today to discuss your project and discover how our forty years of field-proven expertise can work for you.
