Hazardous Organic NESHAP - Frequent Questions
This page contains answers to frequently asked questions about 40 CFR part 63, Subparts F, G, H, I - National Emission Standards for Hazardous Air Pollutants for the Synthetic Organic Chemical Manufacturing Industry, also known as the Hazardous Organic NESHAP (HON). The final rule was published in the Federal Register on May 16, 2024, and became effective July 15, 2024.
- What demonstrates sufficient treatment and control for removing EtO from wastewater under 40 CFR 63.104(k), such that the treated water can then be used in heat exchange systems?
- Can a facility request a compliance extension for the fenceline monitoring provisions of 40 CFR 63.184?
- How has the EPA generally interpreted 40 CFR 63.6(i)(4)(i)(A) and the phrase “necessary for the installation of controls” as it applies to extension requests for the HON?
- Did EPA intend to limit the real-time monitoring technologies for root cause investigation to the examples listed in 40 CFR 63.184(e)(1)(ii)(B)?
The EPA promulgated the requirements at 40 CFR 63.104(k) in part to limit air emissions of ethylene oxide (EtO) from heat exchange systems, as injecting or disposing of water that contains EtO through a heat exchange system could cause air emissions of EtO from a source. Once the owner or operator has properly treated EtO-laden water such that no detectable levels of EtO remain, the EPA considers the water to no longer contain “any amount of EtO.” Additionally, the EPA considers any water that “has been in contact with any process stream containing EtO” and then subjected to treatment and control of EtO to non-detect levels to be free of EtO, and thus outside the scope of the prohibition at 40 CFR 63.104(k) and available for use in a heat exchange system. This is consistent with the longstanding requirements of the HON at 40 CFR 63.138(a) that state that “Once a Group 1 wastewater stream or residual removed from a Group 1 wastewater stream has been treated in accordance with this subpart, it is no longer subject to the requirements of this subpart.”
Yes. Because the EPA promulgated fenceline monitoring provisions under Clean Air Act section 112(d), the Act allows facilities to request an extension for compliance with those provisions from the Administrator (or a State with an approved title V permit program) up to one additional year “if such additional period is necessary for the installation of controls.” See Clean Air Act section 112(i)(3)(B). The General Provisions at 40 CFR 63.6(i) provide information about such extensions. Since granted extensions are incorporated into title V permits per 40 CFR 63.6(i)(4)(i)(A), the EPA encourages facilities requesting such extensions to work with their state permitting authority.
The EPA generally interprets this regulatory provision broadly to allow an extension where an owner or operator needs additional time to make modifications necessary to comply with emission standards. The Agency considers “installation of controls” to include the installation of any equipment needed to comply with the HON, such as adding or modifying emission control equipment and/or equipment necessary to comply with the monitoring, recordkeeping, and reporting requirements of the HON.
No, the techniques identified at 40 CFR 63.184(e)(1)(ii)(B) are a non-exhaustive list of examples. The EPA recognizes that other advanced technologies could provide appropriate real-time monitoring sufficient to determine the root cause of the exceedance and satisfy the requirement in 40 CFR 63.184(e)(1)(ii)(B). When selecting a real-time monitoring system(s), sources should ensure that such system(s), at a minimum, can detect the HAP(s) of concern with sufficient limits of detection to identify the root cause of an exceedance and that the system(s) has adequate coverage within the facility to identify potential HAP emission sources.