Energy, Regulatory Developments

Updates on Petroleum Refinery NESHAP

In a final rule containing technical amendments to the EPA’s National Emission Standards for Hazardous Air Pollutants (NESHAP) for petroleum refineries, the Agency is also announcing its decisions regarding petitions for reconsideration of the NESHAP received from industry and environmental groups. For four issues for which reconsideration was requested, the EPA says it believes that no changes to the existing regulations are necessary.
Oil Refinery


In December 2015, the EPA promulgated its residual risk and technology review (RTR) for the petroleum refinery NESHAP. The RTR considered at least three existing rulemakings—the original NESHAP or Maximum Achievable Control Technology (MACT) rule for refineries published in 1995 (called MACT 1); a second MACT standard issued in 2002 (called MACT 2); and a revised MACT 1 in 2009.

The 2015 RTR was a lengthy and complex rulemaking and contained many amendments of consequence for industry. Following publication of the action, the EPA received the petitions noted above. The Agency subsequently announced which issues in the petitions it would reconsider. One of those issues related to delayed coker units (DCUs) employing a water overflow design and was addressed in a set of final amendments published in November 2018.


The current rule describes decisions on four additional issues raised in the petitions.

  • Work practice standards for pressure relief devices (PRDs). In June 2014, the EPA proposed to prohibit atmospheric releases of hazardous air pollutants (HAPs) from PRDs at refineries. Petitioners variously contended that such a prohibition did not reflect the manner in which the best-performing facilities operate, was unachievable and/or very costly, and would have negative environmental impacts due to additional flares that would need to be installed and operated in standby mode to accept the PRD releases. Commenters on the proposal suggested that the Agency instead adopt the four-part work practice standard (WPS) for PRDs used by several California air districts. These standards require actions such as recording information about each pressure release, developing measures to minimize a release to the atmosphere, and undertaking corrective action. The Agency agreed that sources complying with California’s WPS were the best-performing facilities; promulgated the four-part WPS in the December 2015 rule; and, in the current action, does not make the changes to those standards requested in the petitions.
  • WPS for emergency flaring. In the December 2015 rule, the EPA promulgated a WPS that requires refinery owners or operators to develop flare management plans to identify the flare system smokeless capacity and flare components, waste gas streams that are flared, monitoring systems and their locations, procedures that will be followed to limit discharges to the flare that cause the flare to exceed its smokeless capacity, and prevention measures implemented for PRDs that discharge to the flare header. According to some petitioners, this WPS is not sufficient to prevent HAP emissions; according to others, it is too burdensome, primarily because of recordkeeping requirements. The Agency now states that no information it has received leads it believe this WPS should be amended.
  • Assessment of risk after implementation of the PRD and emergency flaring WPSs. In its RTR, the EPA found that cancer and noncancer health risks following implementation of the WPSs were within the acceptable range. Petitioners argued that the review was deficient because it was not based on a worst-case scenario and also did not consider cancer risks for all pathways. The EPA disagreed. “As supported by the screening analysis published with the December 2015 rule, the additional risk from the PRD and emergency flaring work practice standards did not significantly alter the risk estimates in the EPA’s 2014 analysis,” responded the Agency. Hence, in the context of the WPSs, the Agency stands by its decision that the health risks posed by the sector are acceptable.
  • Alternative sampling frequency for burden reduction for fenceline monitoring. The December 2015 rule established a WPS requiring refinery owners to monitor benzene concentrations around the fenceline or perimeter of the refinery. The standard included provisions that were not proposed that would allow for reduced monitoring frequency after 2 years of continual monitoring at locations that recorded concentrations below a specified level. Some petitioners said the better-performing refineries should be subject to a less stringent WPS. Other petitioners said that with less frequent fenceline monitoring, operators would not be able to identify leaks or operating problems related to equipment that cannot practically be monitored, tested, or evaluated for compliance on a frequent basis. The EPA responded that alternative sampling frequency requirements will not alter the effectiveness of the program because the requirements do not change the facility-level procedures and frequency for calculating and reporting. Hence, no change was made to the fenceline monitoring provision.

Other Actions

The final rule contains a clarifying amendment relating to equipment leak requirements for PRDs.

In addition, the rule includes a brief discussion of amendments to the delayed coking water overflow alternative provisions contained in the December 2015 RTR rule. These amendments, which the Agency issued in November 2018, included a limited 2-year compliance extension for only those delayed coking units that use the water overflow method of cooling, provided the need to design, procure, and install a disengaging device is documented.

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