The location of stationary sources, and the location and configuration of regulated processes and equipment within a source, can significantly affect the severity of an accidental release. The location of the stationary source in relation to public and environmental receptors may exacerbate the impacts of an accidental release, such as blast overpressures or concentrations of toxic gases, or conversely, it may allow such effects to dissipate prior to reaching receptors. Siting of processes and equipment within a stationary source can impact the surrounding community not only through the proximity of the accidental release to offsite receptors adjacent to the facility boundary (e.g., people, infrastructure, environmental resources) but also by increasing the likelihood of a secondary “knock-on” release by compromising nearby processes. EPA is proposing to emphasize the requirement to consider stationary source siting in the regulatory text to ensure that the requirement’s intent is properly incorporated in siting hazard evaluations.
The lack of sufficient distance between the source boundary and neighboring residential areas was a significant factor in the severity of several chemical accidents in the United States and internationally. The following are examples that illustrate the potential of such effects:
- 1984, Bhopal, India: Union Carbide release of approximately 40 tons of methyl isocyanate into the air killed over 3,700 people. Most of the deaths and injuries occurred in a residential area near the plant.
- 1984, Juan Ixhuatepec, Mexico: Pemex liquefied petroleum gas (LPG) tank farm LPG pipeline rupture resulted in a large ground fire that spread to nearby LPG storage vessels, initiating a series of massive explosions. The cascading explosions and fires ultimately destroyed the entire facility and many nearby residences, resulting in over 500 fatalities and thousands of severe injuries.
- 1994, Port Neal, Iowa, United States: Terra Industries explosion involving ammonium nitrate (AN) killed four workers and damaged onsite ammonia tanks, creating an ammonia cloud that resulted in the evacuation of 2,500 people in nearby neighborhoods.
- 2009, Belvidere, Illinois, United States: NDK Crystal facility catastrophic rupture of a pressure vessel resulted in one public fatality and one public injury. A building fragment propelled by the force of the blast traveled nearly 650 feet and killed a member of the public at a highway rest stop parking lot. An 8,600-pound vessel fragment traveled 435 feet and impacted a neighboring business, injuring one offsite worker and causing significant property damage.72
- 2013, West, Texas, United States: West Fertilizer Company explosion involving AN damaged an apartment complex and a nursing home located approximately 450 feet and 600 feet, respectively, from the source of the explosion, resulting in 3 public fatalities (out of a total of 15 people killed in the explosion). The explosion also caused over 260 injuries, as well as damage to over 350 homes and 3 schools located near the plant.
- 2018, Superior, Wisconsin, United States: Superior Refining Company, LLC, explosion and subsequent fire in the refinery’s fluid catalytic cracking unit resulted in 36 people (workers and community members) seeking medical attention. In addition, a portion of Superior, Wisconsin, had to be evacuated.
- 2020, Visakhapatnam, Andhra Pradesh, India: LG Polymers styrene release incident produced a toxic cloud that caused at least 11 fatalities and hundreds of injuries in the nearby community.
This list of accidents provides examples of the numerous accidents with offsite consequences resulting from the close proximity of industrial facilities to public receptors, demonstrating that the selection of locations of processes and process equipment within a stationary source can impact the surrounding community. Communities are affected not only by the proximity of accidental releases to offsite receptors (e.g., people, infrastructure, environmental resources) near the facility boundary but also by the increased likelihood of subsequent releases from other nearby processes compromised by the initial release. As accidents continue to happen, EPA is proposing to emphasize the intent of the required siting evaluation to ensure the protection of human health and the environment.
The OSHA PSM standard and RMP rule both require that facility siting be addressed as one element of a PHA (29 CFR 1910.119(e)(3)(v), and 40 CFR 68.67(c)(5)). In response to comments on the proposed PSM rule, OSHA indicated that facility siting should always be considered during PHAs and therefore decided to emphasize this element by specifically listing siting evaluation in the regulatory text.76 With the adoption of PHA regulatory text, EPA also recognized the offsite benefits of siting evaluations. EPA’s approach to the siting requirement is consistent with its general approach to PSM in the 1996 RMP rule: sound, comprehensive PSM systems can protect workers, the public, and the environment.77 The Agency chose to include additional guidance in a frequently asked questions section of its website to not only indicate the Agency’s expectations but also to provide guidance on the RMP rule’s coverage of facility siting evaluation to include consideration of offsite receptors. The guidance states: “The requirement to consider stationary source siting during the process hazard analysis means that you should consider the location of the covered vessels and evaluate whether their location creates risks for offsite public or environmental receptors, as well as onsite receptors. This analysis should consider the proximity of the vessels that could lead to a release of a regulated substance. The proximity of the vessels to onsite equipment or activities nearby will have been considered for OSHA; the proximity of the vessels in relation to offsite receptors will be considered if not already considered for OSHA. The analysis may be done qualitatively. The analysis addresses whether the location of the vessels creates risks that could be reduced by changing the location or taking other actions, such as installing mitigation systems.”
As with other aspects of the RMP rule, EPA expects regulated facilities to rely on industry guidance to help adequately address stationary source siting in PHAs. The following examples of relevant industry guidance on siting considerations are available to facility owners and operators:
• American Petroleum Institute (API) Recommended Practice 752, Management of Hazards Associated with Location of Process Plant Buildings.
• API Recommended Practice 753, Management of Hazards Associated with Location of Process Plant Portable Buildings.
• CCPS Guidelines for Evaluating Process Plant Buildings for External Explosions, Fires, and Toxic Releases.
• CCPS Guidelines for Siting and Layout of Facilities.
• NFPA Separation Distances in NFPA Codes and Standards.
The CCPS “Guidelines for Siting and Layout of Facilities” addresses external factors influencing site selection and factors internal to the source that could influence site layout and equipment spacing. The most recent edition of this CCPS publication was updated to address many developments in the last decade that have improved how companies survey and select new sites, evaluate acquisitions and expand their existing facilities. The title was also updated to emphasize not only siting of buildings and unit operations within a facility but also siting of facilities within a community. The guidance addresses identifying the process hazards and risks, selecting a facility location, selecting process unit layout within a facility, selecting equipment within a process unit, and managing changes.
As an industry-specific example for siting, the Compressed Gas Association’s (CGA’s) “G-2.1—Requirements for the Storage and Handling of Anhydrous Ammonia,”85 among other things, requires facilities with anhydrous ammonia systems to apply specific location requirements for processes, such as tank loading and unloading operations, and equipment, such as ammonia storage containers, piping, and nurse wagons. It also includes specific minimum separation distances from storage containers to railroad mainlines, highways, lines of adjoining properties, and places of public assembly and residential and institutional occupancy. Asmar Institute, a well-known agricultural industry organization, developed an RMP Program 2 Hazard Review checklist as a resource for its industry to apply CGA G-2.1 and other applicable industry standards.
Despite enforcement and the consequences of catastrophic accidents, issues of siting continue to threaten process safety. For example, in 2018, EPA took enforcement action against an agricultural anhydrous ammonia sales operation in Missouri that failed to identify the hazards associated with the proximity of the facility to a home and a nearby firehouse. In 2021, EPA took an enforcement action against a chemical manufacturing facility in Maine that did not address the facility’s proximity to a nearby bay; lack of proximity to external trained emergency responders; and process layout—specifically, the proximity of shutdown valves to operations.
EPA reviewed data from OSHA PSM PHA enforcement actions. In 2018, 16 cases were filed where facility siting was cited as a serious violation90 that could cause an accident or illness that would most likely result in death or serious physical harm.91 One of those cases was also reported as an RMP accident that occurred on September 1, 2016, at the Brookshire Grocery Company’s distribution center in Tyler, Texas. A failure in the piping on the roof of the cold storage building caused an ammonia leak. The leak caused 16 injuries and resulted in the evacuation of the building, the closure of a nearby intersection, and the need for nearby residents to shelter in place. Given the potential risk demonstrated by recurring accidents, EPA seeks to ensure that emphasis is placed on the importance of all aspects of a proper facility siting evaluation.
In a 2014 RMP request for information (RFI), EPA requested comments on whether to consider stationary source location requirements for future rulemaking. EPA specifically asked whether it should amend the RMP rule to include more specific siting requirements as part of the PHA. Though EPA received comments on the issue, EPA chose not to move forward with additional action on siting in the amendment’s final rule but indicated that the Agency would consider comments for a future rulemaking.
In response to the RFI, commenters opposed adding additional provisions to address stationary source siting, citing as rationale that:
- Existing facilities have limited flexibility to alter locations onsite.
- Specifying or requiring buffer or setback zones is a complicated issue and must be looked at differently for new and existing facilities.
- EPA would be intruding on local zoning codes when establishing siting criteria.
- Existing industry guidance is sufficient.
- Requiring additional siting requirements for both new and existing facilities could result in significant cost to the regulated entity.
One opposing commenter specifically indicated that, to date, EPA has allowed for siting considerations to be included under performance-based elements of the RMP program. The commenter stated that any modification of the existing requirements would be inconsistent with a risk-based management system approach.99 Another commenter, although generally in opposition to new siting requirements, stated that for existing facilities, the owner/operator should demonstrate that other technologies, such as early detection, early communication, prevention measures, and mitigation measures, are applied to manage risk within acceptable levels. This commenter also stated that in some cases, it may be necessary to make process changes, and in unique cases where the risk cannot be abated, owners/operators should consider
relocation of part or all facility operations.
There were also commenters who argued stationary source siting should be expanded in the RMP rule. For example, one commenter stated the PHA must address co-location issues in terms of adjacent facilities and vulnerable populations and infrastructure. This commenter stated that at a minimum, facilities must address hazards to and from adjacent facilities—including impacts that a release from their facility would have on other facilities and the impact that a release from other facilities would have on their facility—and further expansion should address buffer zones for nearby residents, hospitals, and infrastructure. The commenter argued that new facilities or expansion of facilities must consider the cumulative impacts from adjacent facilities and look at the threat that a release from the new facility or expansion would pose to other facilities, infrastructure, populations, and environmental resources. Additionally, CSB encouraged EPA to incorporate more explicit requirements for identifying, evaluating, and addressing facility siting during a PHA to assess both offsite consequences and onsite receptors within that stationary source that may be impacted by chemical fire, explosion, or release.
EPA believes that many matters outlined in comments about the current stationary source siting provision are implicit and mandatory, while not explicitly addressed within the current regulatory text. Therefore, at this time, EPA is only choosing to make more explicit what is required to be addressed in a stationary source siting evaluation. Rather than propose additional requirements, EPA is expounding on the current regulatory text to ensure that siting evaluations properly account for hazards resulting from the location of processes, equipment, building, and proximate facilities, and their effects on the surrounding community. In addition to providing some detail on what is intended by the Program 3 regulatory text on stationary source siting, EPA is also proposing to revise language to Program 2 hazard evaluations to ensure that all RMP facilities with the potential to cause offsite consequences to public receptors account for these hazards. Therefore, EPA is proposing to amend regulatory text for Program 2 and Program 3 under 40 CFR 68.50(a)(6) and 68.67(c)(5), respectively, to define stationary source siting evaluation as inclusive of the placement of processes, equipment, buildings, and hazards posed by proximate facilities, and accidental release consequences posed by proximity to the public and public receptors. The proposed amendments would make more explicit the requirement that hazard evaluations for processes under both Program 2 (hazard review) and Program 3 (PHA) need to address the matters in the siting evaluation.
Because there is a breadth of guidance on siting, EPA believes there is adequate information available for facilities to comply with the proposed text. EPA expects facilities to continue to use available resources, including those previously mentioned, and any additional industry-specific guidance to properly evaluate siting hazards.