OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at http://www.osha.gov.

June 28, 2019

Mr. Anthony M. Ordile, P.E.
Principal Engineer – Level II
Hanes Fire & Risk Consulting Corporation
1 Linda Lane; Suite B
Southampton, New Jersey 08088

Dear Mr. Ordile:

Thank you for your December 7, 2018, letter to the Occupational Safety and Health Administration (OSHA). This letter constitutes OSHA’s interpretation only of the requirements referenced below and may not be applicable to any question not included in your original correspondence. Your inquiry relates to the enforcement of OSHA’s Process Safety Management (PSM) standard, 29 CFR 1910.119, to the storage of consumer aerosol containers with flammable gas propellants in distribution centers (warehouses).

Background/Scenario: Our client stores consumer aerosol products in metal cans at their distribution center/warehouse. The metal aerosol containers contain up to 33 total ounces per container of aerosol product in items such as shaving cream, hair spray, antiperspirant, and their associated flammable gas propellants.

The flammable gas propellants used in the aerosol are typically butane, isobutane, and propane.

The distribution center/warehouse is not on the premise of a retail facility, nor is it on the premise of the aerosol manufacturer. The distribution center/warehouse ships these aerosol products to retail facilities.

It can be presumed that these distribution centers/warehouses are in-compliance with building and fire code requirements, for the storage of consumer aerosol products, including NFPA 30B, Code for the Manufacture and Storage of Aerosol Products, and the International Fire Code.

Question 1 (paraphrased): As described, is the storage of consumer aerosol products in metal aerosol containers in a distribution center/warehouse required to comply with the requirements of 29 CFR 1910.119 (Process Safety Management (PSM) Standard) if the aggregate weight of flammable gas propellants in the stored aerosol containers on the premises exceeds 10,000 pounds?

Response: Yes, the process you describe is a PSM-covered process. The reasons for PSM-coverage of this process include:

  1. Flammable gas1 such as those you stated (i.e., butane, isobutane, and propane) are PSM-covered highly hazardous chemicals (HHC);
  2. The quantity of flammable gas in your client’s process is greater than the threshold quantity (TQ) of 10,000 pounds (as given in your question).2

    The definition of process3 in the PSM standard, includes any separate vessels which are located such that a HHC could be involved in a potential release are considered a single process. In your case, the aerosol containers you specified, each contain only a small quantity of HHC/flammable gas. However, when an HHC is co-located4 in one or more vessels such as cans, packages, containers, or tanks, the individual amounts of flammable gas in the co-located aerosol cans would be aggregated to determine if a TQ of HHC exists. In addition, an employer is required to determine if a release of HHC could result from an event such as a fire, explosion, or incompatible chemical reaction. For example, if a fire occurred in a distribution center/warehouse, then it is reasonable to assume flammable gas in the aerosol cans could be released. Therefore, the individual amounts of flammable gas in the co-located aerosol cans, need to be aggregated to determine if a TQ of HHC exists in the process. Note, that when determining the boundaries of the process, engineering controls such as sprinkler systems, and administrative controls are not a consideration for determining PSM coverage of the process.5,6

  3. There is a covered activity, such as storage and on-site movement (e.g., forklifts moving pallets of boxes of aerosol cans); and
  4. None of the PSM exemptions apply, including the retail facilities exemption [29 CFR 1910.119(a)(2)(i)] because you state that your client’s aerosol distribution center/warehouse is not a retail facility.7

You noted that it should be assumed this establishment is in-compliance with building and fire code requirements for the storage of consumer aerosol products, including NFPA 30B, Code for the Manufacture and Storage of Aerosol Products and the International Fire Code. Compliance with these requirements is not a determining factor when evaluating a process for PSM coverage. Rather, if the process is a PSM-covered process, these codes would be recognized and generally accepted good engineering practices (RAGAGEP) that an employer could use to comply with OSHA’s PSM RAGAGEP requirements, e.g., 29 CFR 1910.119(d)(3)(ii).8

Question 2 (paraphrased): Is our understanding correct that the contents of OSHA’s publication OSHA 3909-03 2017, Process Safety Management for Storage Facilities is a guidance document and not part of the requirements of the PSM standard, 29 CFR 1910.119?

Response: Yes, your understanding is correct. The subject document is a guidance document and not part of the PSM standard. However, the guidance document does include information on the mandatory requirements of various OSHA standards and how they apply to storage facilities.

Question 3 (paraphrased): Given that the net weight posted on the aerosol can is presumed to be the weight of the total amount of product in the can (e.g. , shaving cream, hair spray, antiperspirant, and their associated propellants), how would OSHA and employers determine the weight of the flammable gas propellants in an individual can?

Response: If OSHA were inspecting a warehouse such as your client’s establishment we would: 1) determine the weight of propellant that is filled into each of the aerosol cans by either checking the SDS of the product or we would contact the manufacturer(s) of the aerosol cans; 2) multiply the number of cans that are co-located by the weight of flammable gas per can to determine if that amount exceeds the 10,000-pound TQ. If it exceeds the TQ, a PSM-covered process exists, presuming that a release of the HHC could cause a release of the HHC from the other aerosol cans. Your client could use the same methodology to determine if they have a covered process at their facility.

Also, being a distribution/warehouse operation, your client’s inventory of flammable gas aerosol cans may fluctuate substantially, such that the quantities stored are sometimes greater than the TQ, and other times the quantities are less than the TQ. Since the employer has not instituted control measures to keep the inventory below TQ, OSHA does not consider short periods during which the process does not contain a TQ as having eliminated a PSM-covered process.9

Thank you for your interest in occupational safety and health. We hope you find this information helpful. OSHA sets requirements by statute, standards, and regulations. Our letters of interpretation do not create new or additional requirements but rather explain these requirements and how they apply to particular circumstances. This letter constitutes OSHA's interpretation of the requirements discussed. From time to time letters are affected when OSHA updates a standard, a legal decision impacts a standard, or changes in technology affect an interpretation. To assure that you are using the correct information and guidance, please consult OSHA's website at http://www.osha.gov. If you have further questions, please contact the Office of Chemical Process Safety and Enforcement Initiatives at (202) 693-2341.

Sincerely,

 

Patrick J. Kapust, Acting Director
Directorate of Enforcement Programs


1 1910.119(a)(1)(ii) [This section applies to the following:] A process which involves a Category 1 flammable gas (as defined in 1910.1200(c)) or a flammable liquid with a flashpoint below 100 °F (37.8 °C) on site in one location, in a quantity of 10,000 pounds (4535.9 kg) or more...

2 Ibid.

3 1910.119(b) - Process means any activity involving a highly hazardous chemical including any use, storage, manufacturing, handling, or the on-site movement of such chemicals, or combination of these activities. For purposes of this definition, any group of vessels which are interconnected and separate vessels which are located such that a highly hazardous chemical could be involved in a potential release shall be considered a single process [emphasis added].

4 72 FR 109, pgs. 31453-31457, Interpretation of OSHA's Standard for Process Safety Management of Highly Hazardous Chemicals (6/7/2007) - https://www.osha.gov/laws-regs/federalregister/2007-06-07

“Accordingly, OSHA modified the definition of "process" to include the concepts of "interconnection" and "co-location" with addition of the language, "any group of vessels which are interconnected or separate vessels which are located such that a highly hazardous chemical could be involved in a potential release shall be considered a single process." 29 CFR 1910.119(b). OSHA stated in the final rule that this definition, when read in conjunction with the application section, establishes the standard's intended coverage, (57 FR 6372). Therefore, a "single process" containing a TQ of an HHC includes an "interconnected" or closely co-located process”.

5 OSHA Letter of Interpretation -
PSM applicability to warehousing flammable liquids and other HHCs ... - https://www.osha.gov/laws-regs/standardinterpretations/2002-02-01, 2/01/2002

6 OSHA Letter of Interpretation -
Akzo-Nobel Chemicals - Limits of a Process - https://www.osha.gov/laws-regs/standardinterpretations/1997-02-28, 2/28/1997

7 For additional information about how OSHA enforces it retail facility exemption see the OSHA Regional Administrators Memorandum, Subject - Process Safety Management Retail Exemption Enforcement Policy, dated April 30, 2018.

8 1910.119(d)(3)(ii) - The employer shall document that equipment complies with recognized and generally accepted good engineering practices.

9 OSHA Letter of Interpretation - HHC Standard as it Applies to Threshold Quantity - https://www.osha.gov/laws-regs/standardinterpretations/1994-06-01