Fenceline Monitoring for the new HON MACT with Sensible EDP & Enthalpy Analytical

April 09, 2024 —

On March 28, 2024, the US EPA signed in to law updated National Emission Standards for Hazardous Air Pollutants (NESHAP) for the Synthetic Organic Chemical Manufacturing Industry (SOCMI) and Group I & II Polymers and Resins Industry (P&R I and P&R II). The content of the rule was released to the public on April 9, 2024. This new rule introduces changes to 40 CFR 63 Subparts F, G, H, and I, impacting more than 200 U.S. facilities.

Fenceline Monitoring Requirements

As part of this rulemaking there is a significant and ongoing burden for fenceline monitoring. An affected facility is required to commence fenceline monitoring within two (2) years after the date of publication in the federal register. The exception is P&R I affected sources producing neoprene. For this source category chloroprene fenceline monitoring must begin no later than 150 days after the publication date.

For the facilities that use, produce, store, or emit any of six air toxics, ongoing fenceline monitoring will consist of collecting and analyzing samples using Method 325A/B (passive adsorbent tubes) and/or Method 327 (canisters). Method 327, a canister-based method for determining the concentration of ethylene oxide and vinyl chloride, was published along with the new rule. The table below summarizes the target compounds, alert thresholds, and test methods.

CompoundAction LevelTest Method
Ethylene Oxide0.2 ug/m3327
Chloroprene0.8 ug/m3325 A/B
Benzene9 ug/m3325 A/B
1-3 Butadiene3 ug/m3325 A/B
Ethylene dichloride4 ug/m3325 A/B
Vinyl chloride3 ug/m3327

For Method 325A/325B, passive sampling tubes are deployed for 14 days at a minimum of twelve location points along the fenceline as outlined in EPA Method 325A. For Method 327, 24-hour canister samples are collected every five (5) days at a minimum of eight (8) location points along the facility’s fenceline.

Implementation—Siting & In-field Sample Collection

Montrose Air Quality Services, the air quality monitoring division of Montrose Environmental Group (MEG), has field technicians currently servicing Method 325 fenceline monitoring programs across the United States. Montrose field technicians and project managers complete rigorous training and certification on applicable methods and regulatory requirements prior to being qualified to participate in fenceline monitoring projects. Montrose has sited field locations to meet Method 325 requirements, and developed dozens of fenceline monitoring plans with EPA approval. Montrose deploys and collects over 5,000 samples annually ensuring our clients meet their regulatory commitments. Learn more about Fenceline Monitoring.

Laboratory Analysis

Enthalpy Analytical, the laboratory division of MEG, operates a network of nine (9) environmental laboratories across the United States. Enthalpy has over 10 years’ experience with EPA Method 325B, analyzes over 50,000 samples annually, and was closely engaged with EPA on the development of Method 327. EPA Method 327, which is based on EPA Method TO-15/15A, provides a heightened expectation for field sample collection and laboratory analysis. A standard 7-day turnaround time, mobile field application for sample collection and custom electronic data deliverables makes Enthalpy the clear choice for fenceline monitoring laboratory support.

Root Cause Analysis

If there is an exceedance of an action level for any of the six air toxics a facility must begin root cause analysis within five (5) days. Root cause analysis may consist of leak inspections using Method 21 or Optical Gas Imaging (OGI), visual inspections, or operator knowledge of a process upset. If the facility cannot determine the root cause of the exceedance within 30 days, the owner or operator will be required to use real-time monitoring techniques (e.g., mobile gas chromatographs, sensors, UV-DOAS, FTIR) to determine the root cause of the exceedance. Montrose, through its Technology Evaluation Center and partners program, will select the best hardware for a specific monitoring application.

Root Cause Analysis Requirements
Initiate within 5 days of the exceedance of the action level
If the cause cannot be determined within 30 days, real-time air monitoring is required
Root cause analysis and initial corrective action required within 45 days
If longer than 45 days to implement the corrective actions – required to submit CAP no later than 60 days after root cause analysis

Montrose Environmental Group (MEG) is uniquely qualified to support industry with implementation/citing, in-field sample collection, laboratory analysis, a unified data platform and root cause investigation of exceedances. As part of this turnkey service, data will be collected, aggregated and reported allowing facility operators to pinpoint operational induced variances of the VOCs being monitored with the Sensible Environmental Data Platform (EDP), helping ensure compliance with this new rule.

  • Reporting & Real-time Monitoring

  • Fenceline monitoring reports must be submitted on a quarterly basis using the appropriate electronic report template found on EPA’s CEDRI website . Laboratory data provide by Enthalpy is automatically ingested in to the Sensible EDP platform and the CEDRI reports created for submittal to EPA. Sensible EDP, powered by Montrose Environmental, is the leading Environmental Data Platform for industries and communities who are monitoring air, water, and soil data continuously. The Sensible EDP platform collects emissions data from a variety of sensors and mechanisms in real time. When fugitive emission leaks are detected, alerts are sent via phone, email, text, or app, pinpointing the leak location, ensuring they are repaired promptly. Reporting is available to verify compliance with federal and state regulations. Emissions data across a variety of toxics is securely stored in one place, for ongoing analysis and real time monitoring, making Sensible EDP the single source of truth for all of your emissions data management needs.

  • Montrose Environmental Group provides turnkey, integrated solutions—from siting, to root cause investigations, allows facility operations to focus on safe and environmentally compliant production. The ability to aggregate data quickly and monitor trends, will help affected facilities meet new environmental monitoring requirements.
  • Key Takeaways

  • The combined Montrose, Enthalpy and Sensible teams are experienced in existing fenceline monitoring programs and are prepared to meet the enhanced requirements of facilities covered by the updated HON MACT regulations.
  • Have more questions regarding HON MACT? Download our complimentary HON MACT FAQs, or contact info@sensible-edp.com for more information.

Contact us to learn more info@sensible-edp.com or visit our website at https://sensible-edp.com/fenceline-monitoring/. Ready to see the platform? Schedule a demo with one of our experts today.