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• Standard Number: 1910.178; 1910.178(c)(2)(ii)(a)


This letter constitutes OSHA's interpretation only of the requirements discussed and may not be applicable to any situation not delineated within the original correspondence.


November 23, 2004

Mr. Arthur G. Sapper
McDermott, Will & Emery
600 Thirteenth Street, N.W.
Washington, D.C. 20005-3096

Dear Mr. Sapper:

Thank you for your August 5, 2004 letter on behalf of the International Carbon Black Association to the Occupational Safety and Health Administration's (OSHA) Directorate of Enforcement Programs (DEP). Your letter has been referred to DEP's Office of General Industry Enforcement for an answer to your question regarding treatment of carbon black under 29 CFR 1910.178(c)(2)(ii)(a). Your background and question has been restated below for clarity.

Background:

29 CFR 1910.178(c)(2)(ii)(a) states:
Power-operated industrial trucks shall not be used in atmospheres containing hazardous concentrations of metal dust, including aluminum, magnesium, and their commercial alloys, other metals of similarly hazardous characteristics, or in atmospheres containing carbon black, coal or coke dust except approved power-operated industrial trucks designated as EX may be used in such atmospheres.
Paragraph (c)(2)(ii)(a) of §1910.178 was adopted in 1971 under Section 6(a) from §202(a) of NFPA 505-1969, entitled "Powered Industrial Trucks". Section 202(a) of NFPA 505-1969 states:
Power-operated industrial trucks shall not be used in atmospheres containing hazardous concentrations of metal dust, including aluminum, magnesium, and their commercial alloys, other metals of similarly hazardous characteristics, or in atmospheres containing carbon black, coal or coke dust, except approved power-operated industrial trucks designated as EX may be used in such atmospheres subject to special investigation by the authority having jurisdiction. In atmospheres where dust of magnesium, aluminum or aluminum bronze may be present, fuses, switches, motor controllers and circuit breakers of trucks shall have enclosures specifically approved for such locations.
The corresponding provision in the most recent version of that national consensus standard (NFPA 505-2002) states as follows:
4.2.5 Class II, Division 1, Group F.

4.2.5.1 Approved power-operated industrial trucks designated as Type DX or Type EX (classified for Class II Group F locations) shall be used in either of the following locations:
(1) Where Group F dust is in suspension or can be in suspension under normal operating conditions in quantities sufficient to produce explosive or ignitable mixtures[;]

(2) Where mechanical failure or abnormal operation of machinery or equipment can cause such mixtures to be produced[.]

4.2.5.2 Class II, Division 1, Group F areas shall include locations containing either of the following:
(1) Carbon black, charcoal, coal, and coke dusts that have more than 8 percent total volatile material [Emphasis added]

(2) Atmospheres containing the dusts described in (1) that are sensitized by other materials so that they present an explosion hazard[.]
Question: Would a violation of the prohibition in 29 CFR 1910.178(c)(2)(ii)(a) against the use of powered industrial trucks not designated EX in atmospheres containing carbon black be de minimis if, as permitted by the current version of the national consensus standard, the carbon black contains eight percent or less volatile material?

Reply: NFPA 505 - 2002 indicates that, under certain conditions, carbon black presents no explosion hazard when the volatile content is eight percent or less. In these circumstances i.e., where there is no explosion hazard, OSHA would consider the use of a truck not designated EX to be de minimis. However, an employer that chooses to comply with the current NFPA 505 must meet all of the criteria contained in NFPA 505, 4.2.5.2. Paragraph (2) includes atmospheres containing the dusts described in (1) (i.e., carbon black, charcoal, coal, and coke dusts) that are sensitized by other materials so that they present an explosion hazard as a Class II, Division 1, Group F location.

Therefore, atmospheres that have carbon black containing less than eight percent total volatile material in combination with any sensitizing material would be considered a Class II, Division 1, Group F location. A prudent employer that uses a combination of these materials must assess its workplace to assure that an explosion hazard does not exist and not solely rely on the fact that the carbon black it uses contains less than eight percent total volatile material. In addition, operators of powered industrial trucks must be informed that a combination of carbon black containing less than eight percent total volatile material and a sensitizing material could be explosive. If it is determined that an explosion hazard does exist, the employer would be required to have the appropriate listing and labeling for the equipment in that hazardous location.

Thank you for your interest in occupational safety and health. We hope you find this information helpful. OSHA requirements are set by statute, standards, and regulations. Our interpretations letters explain the 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. In addition, 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
www.osha.gov. If you have any further questions, please feel free to contact the Office of General Industry Enforcement at (202)693-1850.

Sincerely,



Richard E. Fairfax, Director
Directorate of Enforcement Programs


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