The 2024 amendments to the USEPA’s Hazardous Organic NESHAP (HON Rule) revise standards under 40CFR Part 63 for facilities in the Synthetic Organic Chemical Manufacturing Industry (SOCMI) and related Polymers and Resins sectors.
These changes affect more than 600 chemical plants nationwide, including over 125 facilities required to conduct fenceline monitoring and nearly 300 with updated flare provisions.
Key requirements include:
Fenceline Monitoring – Programs for six air toxics: ethylene oxide (EtO), benzene, 1,3-butadiene, chloroprene, ethylene dichloride, and vinyl chloride.
Revised Flare Standards – New combustion and monitoring standards including compliance with MACT CC requirements for Net Heating Value (NHV), visible emissions, and updated Flare Management Plans.
Mandatory Public Reporting – Quarterly fenceline data must be submitted to EPA and made public via CEDRI one year after program start.
July 2025 Update: A presidential declaration granted two-year deferrals to 52 chemical facilities. For all other facilities, the original compliance schedule remains in effect.
Whether your site received an exemption or not, compliance requirements are imminent. Facilities that prepare now will have more flexibility to refine system design, allocate budgets, and avoid last-minute implementation hurdles.
Run Pilot Studies to Gather Baseline Data
Establishing a pre-compliance emissions baseline helps your team understand where high concentrations are most likely to occur. Pilot studies determine site-specific factors like wind direction, source proximity, and facility layout that influence the accuracy of your monitoring program.
Identify Root Causes Before Public Reporting Begins
Once compliance deadlines are reached, any exceedance of annual average action levels requires a root cause analysis with results submitted to EPA and made publicly available through CEDRI. Short-term deployments like mobile GC emission studies help identify hotspots early, allowing time to respond internally before formal reporting begins.
Assess Your Flare System and Flare Management Plan
The amendments introduce tighter combustion efficiency standards and expanded monitoring expectations. Many existing Flare Management Plans were developed before these requirements and need updating to align with current standards.
Clarify State vs Federal Requirements
Even with a federal delay, your state agency may still require emissions controls or fenceline monitoring. States like California and Colorado have their own ambient air monitoring programs that may apply.
Establish baseline emissions data and optimize monitor placement before compliance deadlines, giving you time to address issues internally.
Sub-ppb detection using open-path FTIR and UV-DOAS systems meets EPA method specifications for all six targeted HAPs.
Our Tsunami platform and customized dashboards handles real-time data collection, QA/QC, and public reporting infrastructure so you're ready when mandatory disclosure begins.
Let our experts design a pilot study that sets your compliance program on the right path.
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