Preparing for HON: Lessons Learned from Recent Petrochemical Rulemaking

On April 25, 2023, the U.S. Environmental Protection Agency (U.S. EPA) proposed revisions to several National Emission Standards for Hazardous Air Pollutants (NESHAP), including 40 CFR Part 63, Subparts F, G, H, and I (referred to as the Hazardous Organic NESHAP, or HON). These revisions were a result of U.S. EPA’s required periodic technology review, a decision to conduct another risk review of the source category (due to concern over risk from emissions of ethylene oxide), and recent court decisions related to gap filling and startup, shutdown, and malfunction exemptions. Proposed revisions to the HON affect a variety of sources, including process vents, storage tanks, heat exchange systems, pressure relief devices, and flares. The proposed revisions would also add new fenceline monitoring provisions and define new standards for sources “in ethylene oxide service”. Check out this post by Chris Ward for a full summary of all the changes in the proposed HON.

The proposed changes to HON are the latest in a string of rulemakings that add more stringent requirements for sources in the petrochemical sector, starting with the refinery sector rule (RSR) in 2015. These regulations, including NESHAP affecting the ethylene production sector and the miscellaneous organic chemical manufacturing sector included similar requirements to those in the proposed HON revisions. In this article, we’ve summarized some lessons learned from helping petrochemical sector clients with these regulatory changes to ensure an easy road to compliance with the revised HON.

Lesson 1: Start Early

This may seem obvious, but it’s not too early to start evaluating how changes to HON may affect your facility. Once finalized, existing affected facilities could have as little as one year to comply with some provisions of the proposed rule while new affected facilities could have as little as 60 days to comply. Compliance dates are summarized in Table 1.

Table 1: Proposed Compliance Times for HON Provisions

Compliance with the proposed HON may require a capital project either to install a new control device to control process vents that currently vent to atmosphere or to upgrade a control device such as an existing flare to meet the increased monitoring requirements. Capital projects could require significant engineering, procurement of equipment with long lead times, construction permitting, and even a unit shutdown; therefore, these types of projects need to be planned far in advance to be considered in budgets and production schedules. Now is a great time to evaluate your affected sources to assess if any modifications are necessary to meet the proposed revisions to the HON.

Lesson 2: Consider a Pilot Study

Fenceline monitoring is a new requirement proposed to be added to the HON. While the RSR only required monitoring for benzene, HON facilities have an expanded list of chemicals that must be monitored depending on whether they are used, produced, stored, or emitted. Monitoring frequencies may also vary – for example, ethylene oxide and vinyl chloride have a 24-hour sampling period once every five days compared to other chemicals (such as benzene) which have a 14-day sampling period. Fenceline monitoring data collected by HON facilities will be reported to U.S. EPA quarterly and made available to the public.

Many HON facilities have not collected concentration data for these chemicals at their fencelines before. A pilot study is one effective tool to better understand these concentrations and benchmark performance relative to the proposed action levels. In addition, early data collection gives your facility time to implement potential corrective actions ahead of the effective date of the rule, improving compliance once the rule is in effect. Pilot studies also provide an opportunity to try siting monitors at different locations and to understand potential offsite impacts on a facility’s fenceline monitoring data. Facilities subject to the HON can submit Site Specific Monitoring Plans (SSMP) to the U.S. EPA for approval to account for these offsite impacts. ALL4’s Air Quality Modeling and Monitoring team has deployed fenceline monitoring systems and can help conduct a pilot study at your facility.

Lesson 3: Engage Stakeholders Across Your Facility

While the environmental department is typically responsible for implementing changes to comply with the revised HON, those personnel will need buy in from across the facility and the organization to be successful. For example, operations may need to make process vent determinations, process engineering may need to design a capital project, controls engineering may need to implement new flare monitoring, and procurement may need to secure new vendors such as a turnkey fenceline monitoring service or order equipment with long lead times. Engage these resources now by sharing information about the proposed rule changes so that key decision makers aren’t surprised when the HON is finalized and the clock is ticking to comply.

ALL4 has already begun assisting our clients with developing strategies on how to comply with the proposed HON while we await the final rule, which is expected in March 2024. If you’d like to talk about what you can do to get your facility ready for compliance, you can reach out to me at klingard@all4inc.com or (470) 231-3770 or contact your ALL4 project manager.