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 30, 1997

MEMORANDUM FOR:         CHRIS LEE, Acting Regional Administrator
                       Region IX

FROM:                   JOHN B. MILES, JR., Director
                       Directorate of Compliance Programs

SUBJECT:                Sodium Azide as Used in the Manufacturing Process of
                       Automobile Air Bags

The following is a response to a memorandum from you to Steve Witt, Director of Technical Support, dated February 10, 1997, requesting information as to how OSHA classifies Sodium Azide. Your request was forwarded to this office for reply. Please accept our apologies for the delay in our response.

Based on conversations with a member of your staff, there are two issues which need to be addressed related to your request. The first issue is whether an interpretation OSHA issued in 1980 related to the classification of assembled automobile air bag inflation modules (modules) applies to the manufacturing process of these modules. The second issue is whether the 29 CFR 1910.119 (Process Safety Management of Highly Hazardous Chemicals and Explosive and Blasting Agents [PSM]) standard applies to the module's manufacturing process. The following responses are based on: the 1980 interpretation issued by OSHA related to assembled modules (attached); conversations with a member of OSHA's Health Response Team that participated in an on-site evaluation of a module manufacturing process at a TRW facility in Mesa, Arizona, and a compliance officer from the Arizona Division of Occupational Safety and Health; and a review of process safety information related to the module manufacturing process. The two issues which were raised are addressed below:

Issue #1

Does the subject 1980 OSHA interpretation apply to the manufacturing of modules?

 

Background: On September 12, 1980, OSHA's Office of Federal Compliance and State Programs issued an interpretation to Ford Motor Company related to the application of OSHA's standard 29 CFR 1910.109 (Explosives and Blasting Agents) to assembled modules. OSHA said that since Ford had obtained an exemption from the United States Department of Transportation (DOT) to classify the assembled modules as a flammable solid instead of a Class B explosive, OSHA would accept DOT's classification of Ford's assembled modules. This was based on the OSHA standard which defines an explosive [29 CFR 1910.109(a)(3)]. OSHA provides an exemption from the 29 CFR 1910.109 requirements for explosives if DOT otherwise specifically classifies the chemical compounds, mixtures or devices. In this case, DOT did specifically classify Ford's assembled modules as flammable solids, instead of a Class B explosive. Therefore, OSHA accepted the flammable solid classification for Ford's assembled modules.

Reply #1

The subject 1980 interpretation only applies to final assembled modules which are classified by DOT as other than explosive. The subject 1980 OSHA interpretation does not apply to the manufacturing process of the modules.

Issue #2

Would the manufacturing of the modules be covered by the PSM standard?

 

Background: TRW manufactures the modules at its Mesa, Arizona facility. Additionally, many of the individual components of the modules are manufactured at the site. Several of the individual components which are manufactured for the modules are listed as Class B explosives by DOT, including but not limited to propellant grains, gas generator propellant, sodium azide based propellants and even the module assembly for the passenger air bag restraint. Manufacturing activities related to the Class B explosive components include but are not limited to weighing, mixing, blending, coating, handling, and packaging.

Reply #2

The manufacturing of explosives is covered by the PSM standard, 29 CFR 1910.119 as set forth in OSHA standard 29 CFR 1910.109(k)(2). OSHA considers the manufacturing of explosives to mean: mixing, blending, extruding, synthesizing, assembling, disassembling and other activities (such as those listed above which are specific to TRW's module manufacturing process) involved in the making of a product or device which is intended to explode or contains DOT-classified explosive materials as described above. For example, TRW manufactures Class B explosive components such as propellant grains and gas generator propellants which are components or materials used in the manufacturing process of the modules. The manufacturing process of the modules which includes the manufacturing of the individual explosive material components of the modules is covered by the PSM standard.

OSHA does not intend that the PSM standard apply to the installation of explosive devices into larger finished products or devices which are not intended to explode (See attached letter from John B. Miles, Jr. to Mr. Glynn Reentry, Aerospace Industries Association, dated December 12, 1994). Therefore, the installation of the final assembled modules into air bag restraint systems which are not intended to explode in automobiles would not be considered manufacturing of explosives and would not be covered by the PSM standard. If the final assembled modules are classified as an explosive, then the preceding activity is considered a handling activity covered by 29 CFR 1910.109.

If you have any question contact Mike Marshall at 202-219-8118 ext. 12

Attachments



September 12, 1980

Mr. Theodore C. Milch
Staff Attorney
Office of the General Counsel
Ford Motor Company
Dearborn, Michigan 48121

Dear Mr. Milch:

In a meeting held on May 2, 1980, representatives of your company met with OSHA representatives to discuss OSHA's classification of assembled auto air bag inflation modules. This letter provides the clarification that your company requested.

The subject modules contain an igniter, booster, and a pelletized mixture of sodium azide and copper oxide, iron oxide, or some other material that when set off, forms a nitrogen gas that inflates the air bag. The Department of Transportation (DOT) gave Ford exemptions for the modules from being a Class B explosive to that of a flammable solid. The Treasury Department, Bureau of Alcohol, Tobacco, and Firearms, also does not classify the modules as explosives. Section 1910.109(a)(3) defines an explosive as:

 

" . . . any chemical compound, mixture, or device, the primary or common purpose of which is to function by explosion, i.e., with substantially instantaneous release of gas and heat, unless such compound, mixture, or device is otherwise specifically classified by the U.S. Department of Transportation: see 49 CFR Chapter ..."

Since DOT has otherwise specifically classified the modules as being flammable solids and not Class B explosives, Section 1910.109 will not be applied to these exempted air bag inflation modules, provided the provisions of the DOT exemption are met.

A copy of this letter will be forwarded to all OSHA Regional Office's. If we may be of further assistance, please call or write.

Sincerely,

Bruce Hillenbrand
Acting Director, Federal Compliance
and State Programs



December 2, 1994

Mr. Glynn Reentry
Aerospace Industries Association of America, Inc.
1250 Eye Street, N.W.
Washington, D.C. 20005-3922

Dear Mr. Reentry:

This is in response to your May 25 letter, requesting that the Occupational Safety and Health Administration (OSHA) revisit current OSHA interpretations issued previously on the applicability of the Process Safety Management standard, 29 CFR 1910.119 to the manufacture of explosive devices. Please accept our apology for the delay in responding.

The paragraph (k)-Scope of the Explosives and Blasting Agents standard, 29 CFR 1910.109 was revised by adding paragraph (k)(2). By (k)(2), the manufacture of explosives as defined in 1910.109(a)(3) must meet the requirements in 1910.119. This revision was published as a final rule, a copy of which is enclosed for your use. Explosive is defined in 1910.109(a)(3) as "any chemical compound, mixture, or device, the primary or common purpose of which is to function by explosion, i.e., with substantially instantaneous release of gas and heat, unless such compound, mixture, or device is otherwise specifically classified by the U.S. Department of Transportation; see 49 CFR Chapter I..." A copy of 1910.109(a)(3) is also enclosed for your use.

Interpretations on whether the PSM standard applies to the manufacturing of explosives at work sites are predicated on the aforementioned 1910.109 regulations. Explosive manufacturing covered by the PSM standard is discussed in the preamble to the enclosed final rule. (See page 6367, middle of the third column). The 1910.109 standard did not address the hazards associated with the manufactures of explosives before this final rule. The PSM standard is intended to apply to the explosive manufacturing process to address this gap and to address the explosive potential for producing a major accident during manufacturing.

In your letter you referenced an interpretation issued previously by OSHA (See paragraph 3 of the enclosed letter). This interpretation was intended to clarify that the manufacturing of certain explosive devices, as defined in 1910.109, would be covered by the PSM standard. This interpretation follows:

"The term explosives includes all materials which were formally classified as Class A, Class B. and Class C explosives by DOT and are now classified by number designations. See the 49 CFR 173.53 table (enclosed) which compares old and new designations. Additionally, OSHA considers the manufacture of explosives to mean: mixing, blending, extruding, synthesizing, assembling, disassembling, and other activities involved in the making of a product or device which is intended to explode or contains DOT classified explosive materials as described above.

The phrase with which you expressed particular concern in your letter, "or contains DOT-classified explosive materials was intended to apply to the manufacturing of explosive devices which are intended to explode. OSHA did not intend that the PSM standard apply to the installation of explosive devices, such as, explosive bolts, detonating cords, explosive actuator, squibs, heating pellets, thermal batteries, ejection seat rocket motors and similar small explosive devices (described in your letter as commonplace in the Aerospace Industry) into larger finished products or devices that are not intended to explode. The preceding installation is considered a handling activity covered by 1910.109.

We appreciate your interest in employee safely and health. If we can be of further assistance, please contact the Office of General Industry Compliance Assistance, Ron Davies on 202-219-8031 ext. 110.

Sincerely,

John B. Miles, Jr., Director
Directorate of Compliance Programs