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room ventilation system intake was not equipped with toxic gas Hazardous Chemicals standard (PSM) requires facilities to
alarms or an automatic shutoff, but with a manual shutoff device. perform a process hazard analysis (PHA) on processes covered
by the PSM standard. PSM is a performance-based standard
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5.3.1 GUIDANCE AND STANDARDS that includes requirements for preventing or minimizing
Standards and industry guidance for designing buildings and the consequences of catastrophic releases of toxic, reactive,
ventilation systems to protect occupants in buildings at facilities flammable, or explosive chemicals that are covered under
handling hazardous chemicals are limited. The American the standard (Section 8.1). The PSM standard applies to
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Petroleum Institute (API) develops standards for petroleum processes that involve certain chemicals at or above specified

refineries and API Recommended Practices 550, 551, and 752 threshold quantities. PSM requires employers to perform
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provide direction around positive pressure control rooms that an initial PHA on covered processes to identify, evaluate, and
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may be helpful to other industries. The Chlorine Institute (CI) also control the hazards involved in the process. Specifically, the
provides guidance on designing building and ventilation systems PHA shall address, among other things, facility siting. When
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for facilities handling sodium hypochlorite. Although MGPI is evaluating siting, facilities should consider whether toxic or
not a member of the CI (Section 7.1), Pamphlet 64 provides flammable gases from releases are able to enter control rooms.
guidance on designing ventilation systems, which can be useful

to industries and facilities that handle sodium hypochlorite. In 2008, OSHA, under the PSM standard, cited Kuehne
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Chemical, a chlor-alkali plant in South Kearney, New Jersey,
Pamphlet 64 (Section 7.1) covers emergency response plans for failing to accurately address the ingress of chlorine gas
for sodium hypochlorite and suggests that facilities consider due to a catastrophic release from chlorine lines into the
designing building and ventilation systems to minimize the control room. Chlorine is a chemical that falls under the PSM
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impact of a release on building occupants. This includes standard if held in sufficient quantities. Although chlorine
elevated air intakes, because chlorine gas is heavier than air gas in addition to other toxic compounds entered the Mod
and tends to accumulate at lower elevations. The intakes on B building on the day of the MGPI incident, the chlorine
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the first floor of the Mod B building likely allowed for greater was a byproduct of a reaction between sulfuric acid and

concentrations of chlorine in the cloud to enter the building sodium hypochlorite, neither of which is covered by PSM.
shortly after the chemical reaction began. In addition, Pamphlet
64 recommends chlorine monitors with alarms that automatically However, other processes and chemicals at Mod B are
trigger ventilation system shutdown and filtration equipment covered by the PSM standard, including two chemicals
to remove chlorine from supply air to keep building occupants stored above threshold quantities at Mod B: propylene
safe during a chlorine release. Without these controls, operators oxide (received at the unloading area) and phosphorous
must rely on respiratory protection that, in the case of MGPI, oxychloride (not received at the unloading area). Because of

was not readily accessible during the release, given that the the MGPI incident, OSHA initially issued citations to MGPI for
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cloud entered the control room without warning (Section 5.4). 12 violations. One was for not appropriately performing
a PHA that addressed the hazard of toxic and flammable
Although it does not include specific design requirements
for control rooms, the U.S. Occupational Safety and Health
88 29 C.F.R. § 1910.119(e) (2017).
Administration (OSHA) Process Safety Management of Highly 89 29 C.F.R. § 1910.119 (2017).
90 19 C.F.R. § 1910.119(a)(1) (2017).
91 29 C.F.R. § 1910.119(e)(1) (2017).
86 The Chlorine Institute. Emergency Response Plans for Chlor-Alkali, Sodium
Hypochlorite and Hydrogen Chlorite Facilities. Pamphlet 64; 7th ed.; The Chlorine 92 29 C.F.R. § 1910. 119(e)(3)(v) (2017).
Institute: Arlington, VA, November 2014. 93 Kuehne Company. http://www.kuehnecompany.com/history/ (accessed November 27,
87 The Chlorine Institute. Emergency Response Plans for Chlor-Alkali, Sodium 2017).
Hypochlorite and Hydrogen Chlorite Facilities. Pamphlet 64; 7th ed.; The Chlorine 94 OSHA and MGPI entered an Informal Settlement Agreement on May 10, 2017, which
Institute: Arlington, VA, November 2014. reduced the number of violations and penalty. See Section 8.1.
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