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OSHA Hazard Communication Letters of Interpretation
Request for interpretation of Hazard Communication Standard (HCS).
- Issued
- Record type
- Interpretation
- Historical standard
- HCS 1994, pre-GHS archive
- Current standard
- HCS 2024, as amended
ILPI assessment: HazCom coverage reaffirmed; the earlier 1986 letter was directed for deletion
This letter addresses the obsolete 1994 version of the Hazard Communication Standard (HCS). Its main conclusion remains useful: extinguishers containing hazardous chemicals are not categorically exempt. OSHA expressly identifies the May 15,1993 interpretation as the correct one and directs deletion of the conflicting September 8,1986 letter from its interpretation file. We were unable to locate a copy of the deleted letter.
Under the current HCS, apply hazard classification, gas-under-pressure criteria and current label/SDS requirements. The old 40-psi compressed-gas definition is superseded. See the May 15,1993 letter and March 15,1995 labeling letter with their current-context notes. This is documented rejection of the earlier letter's guidance, not merely an inference from a missing web page.
OSHA marks its matching original corrected 12/6/2024.
Last reviewed: .
About this ILPI assessment
This comparison with current requirements is not a finding that OSHA has formally withdrawn this letter. This assessment reflects editorial judgment informed by human review and AI assistance. It is an opinion, may contain errors or omissions, and is not an official OSHA determination. For guidance on how OSHA requirements apply to your circumstances, contact your local OSHA office.
OSHA's notice about interpretation letters
The following notice is published on OSHA's interpretation pages; it is general guidance, not a letter-specific withdrawal notice.
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 https://www.osha.gov.
Source: OSHA's original letter page.
June 2, 1995
MEMORANDUM FOR: LINDA R. ANKU, REGIONAL ADMINISTRATOR
FROM: RUTH E. McCULLY, DIRECTOR, OFFICE OF HEALTH COMPLIANCE ASSISTANCE
SUBJECT: REQUEST FOR INTERPRETATION OF HAZARD COMMUNICATION STANDARD (HCS)
Thank you for you memorandum of August 23, 1994, requesting clarification of the application of the Hazard Communication Standard (HCS) to fire extinguishers. We apologize for the long delay in our response.
In your memorandum and in follow up discussions with your staff, you referenced to a September 8, 1986 letter of interpretation that indicated that fire extinguishers were not subject to the HCS and a conflicting May 15, 1993 letter of interpretation that stated that the HCS does apply to fire extinguishers. Your memorandum requested clarification concerning which letter provided the correct interpretation.
The most recent letter (May 15, 1993) provides the correct interpretation. The HCS was modified on August 24, 1987 (52 FR 31852) to expand the coverage to all industries where employees are exposed to hazardous chemicals. The rule is fully effective and has been so since January 24, 1989. The HCS defines a hazardous chemical as any chemical which is a physical hazard or a health hazard. Under the standard, a compressed gas (defined as a gas or mixture of gases having, in a container, an absolute pressure exceeding 40 psi at 70 degrees F, or a liquid having a vapor pressure exceeding 40 psi at 100 degrees F), is considered a physical hazard and is, therefore, considered a hazardous chemical. In addition, several extinguishing agents (Halon 1211 and potential substitutes such as hydrogenated chlorofluorocarbons) are also considered hazardous chemicals by nature of their associated health hazards. Consistent with the definitions in the HCS and as discussed in the May 15, 1993 letter of interpretation, any fire extinguisher containing a hazardous chemical is subject to the requirements of the standard.
[ILPI note: At issuance: HCS 1994, pre-GHS archive. OSHA identifies the May 15,1993 letter as controlling over the conflicting 1986 guidance and explicitly directs deletion below. For current classification use Appendix B.5, not the old 40-psi definition.]
Attached for your information is a March 15 letter to Mr. Craig Trafelet of the Preventive Fire & Safety Equipment, Inc., which addresses that labeling requirements for fire extinguishers. We hope this response answers your questions regarding the applicability of the HCS to fire extinguishers. In response to your correspondence, we are directing the Directorate of Technical Support to delete the September 8, 1986 letter from the OCIS Interpretation file. If you have any further questions, please call us at (202) 219-8036.
Attachment
November 4, 1994
MEMORANDUM FOR: LINDA R. ANKU, REGIONAL ADMINISTRATOR
FROM: RUTH E. McCULLY, DIRECTOR OFFICE OF HEALTH COMPLIANCE ASSISTANCE
SUBJECT: REQUEST FOR INTERPRETATION OF HAZARD COMMUNICATION STANDARD (HCS)
We have received your memorandum of August 23, regarding application of the Hazard Communication standard to fire extinguishers.
This matter requires further research. We are attempting to respond as expediently as possible, taking into consideration the need for a thorough and responsive reply.
We regret that due to increasing requests for letters of interpretation, it will take up to 90 days for us to respond to you. For an update on the status of your inquiry, please call us at (202) 219-8036.
DATE: August 23, 1994
MEMORANDUM FOR: H. BERRIEN ZETTLER, ACTING DIRECTOR, COMPLIANCE PROGRAMS
ATTENTION: RUTH McCULLY, DIRECTOR, OFFICE OF HEALTH COMPLIANCE ASSISTANCE
FROM: LINDA R. ANKU, REGIONAL ADMINISTRATOR
SUBJECT: Hazard Communication Interpretation-Fire Extinguishers
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Attached are letters of interpretation concerning application of the Hazard Communication standard (HCS) to fire extinguishers.
A letter written to the National Association of Fire Equipment Distributors on September 8, 1986 states "in general, therefore, it would appear that fire suppression equipment and chemicals are not subject to the HCS." A letter written on May 15, 1993 states that the Hazard Communication Standard [ILPI: Original HCS 1994 context · Current HCS] does apply to fire extinguishers. The two referenced letters are in conflict with each other in interpreting the standard. Concern is raised since the 1993 letter is written to an individual company (BFPE International) which states that fire extinguishers are covered by the HCS while the letter written to the National Association of Fire Equipment Distributors states that the HCS does not, in general, apply to fire suppression equipment including fire extinguishers. Individual companies frequently request guidance from their association concerning compliance with OSHA standards. To date, the national association has not been informed that the 1986 guidance has been changed, assuming the 1993 letter represents OSHA's current position. It should also be noted that both letters appear on OCIS.
Clarification is requested concerning which letter is the correct interpretation. Please contact Jim Johnston of my staff (215-596-0712) if you have any questions.
The original official public domain version of this document is available from OSHA at https://www.osha.gov/laws-regs/standardinterpretations/1995-06-02.