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Standard Interpretations - Table of Contents
• Standard Number: 1910.94; 1910.94(c); 1910.106; 1910.106(j)(5); 1910.107; 1910.107(m); 1910.108

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

August 15, 2006

Acting Regional Administrator

Directorate of Enforcement Programs

SUBJECT: Request for a Determiniation as to the Applicability of 1910.107 to
Truck Bed Spray-On Lining Operations

This is a response to Mr. Richard Soltan's letter of August 24, 2005, requesting a determination of the applicability of 29 CFR §1910.107 to truck bed spray-on lining operations. Your paraphrased inquiries and our responses follow.

Question #1: Does the guidance in the letter dated April 1, 1991, regarding the definitions of flammable and combustible liquids in National Fire Protection Association Standard (NFPA) 33-1989, Standard for spray application using flammable or combustible materials, apply to any spray finishing operations using flammable or combustible materials that meet those definitions, regardless of their flashpoints?

Response: Section 1910.107 does not define flammable and combustible liquids but its source standard, the 1969 edition of NFPA 33, did. Therefore, the April 1, 1991, letter to Mr. James Sassaman incorrectly refers to the definitions of flammable and combustible liquids found in a later edition of NFPA 33 to determine the applicability of 29 CFR §1910.107.

While OSHA first adopted the NFPA 30-1969 definitions of flammable and combustible liquids in promulgating 29 C.F.R. §1910.106, OSHA did not carry over the virtually identical NFPA 33-1969 definitions into §1910.107. The NFPA subsequently redefined the classes of flammable and combustible liquids by lowering the flashpoint in the definition of a flammable liquid from below 140 degrees Fahrenheit to below 100 degrees Fahrenheit. Therefore, in later editions of NFPA 30 and 33, the class of flammable liquids is limited to liquids with flashpoints below 100 degrees, while liquids at or above 100 degrees are defined as combustible liquids. In 1973, OSHA effected the same change in the dividing line between flammable and combustible liquids when it amended the definitions of flammable and combustible liquids found in 29 CFR §1910.106 in order to bring their identification, classification, and control into uniformity with the Department of Transportation's hazardous materials regulations. 37 Fed. Reg. 11901 (June 15, 1972); 38 Fed. Reg. 27047 (Sept. 28, 1973).

Although the term "flammable and combustible liquids" is found in 1910.107, the 1973 rulemaking that amended the definitions for purposes of §§ 1910.106 and 1910.108 did not mention §1910.107. This is most likely because no substantive provision in §1910.107 prescribes different requirements depending on whether the liquid is flammable or combustible. Rather, all of the requirements in §1910.107 apply regardless of whether the liquid is a flammable or combustible.
1 Therefore, since the requirements of §1910.107 and of its source, the 1969 edition of NFPA 33, do not prescribe distinct requirements depending on whether the liquid is flammable or combustible, OSHA's reference in the Sassaman letter to the 1989 edition of NFPA 33, while incorrect, has no substantive effect on the application of 1910.107.

As you noted in the preface to your questions, §1910.106 exempts combustible liquids with a flashpoint of 200 degrees Fahrenheit or over from the scope of that section. This limitation is limited to §1910.106 as §1910.107 makes no such exception. Therefore, spray finishing operations using liquids that are either flammable or combustible would be covered by §1910.107.

Question #2: Is 29 CFR §1910.107 applicable to truck bed lining operations?

Response: Yes. if the operation involves spray finishing using flammable and combustible materials, then 29 CFR §1910.107 applies.

Question #3: Is 29 CFR §1910.107 applicable to spray finishing operations when the flashpoints of the materials being applied are 200 degrees Fahrenheit or over?

Response: Yes. As noted above, unlike §1910.106, §1910.107 has no exemptions based on flashpoint.

Question #4: 29 CFR §1910.107(m) requires that dual-component coatings are to be applied in a spray booth. As most truck bed spray-on linings involve multi-component coatings that fall within the scope of §1910.107(m), must truck bed spray-on operations be performed within sprinklered spray booths?

Response: By its terms, 29 CFR §1910.107(m) would require employers to conduct spray finishing operations that involve dual-component coatings (found in many, if not most, truck bed lining operations) in a sprinklered spray booth. However, since 2000 the NFPA consensus standard has included a set of requirements specifically for vehicle undercoating and body lining operations. NFPA 33-2003, Section 14.1, Miscellaneous Spray Operations.
2 Since these NFPA requirements are comprehensive, pursuant to OSHA's de minimis policy OSHA believes that compliance with these provisions would generally be an acceptable substitute for use of a sprinklered spray booth.

While complete compliance with the applicable provisions of NFPA 33-2003 would reduce the flammability and explosion hazards associated with spray finishing operations, there remains the issue of associated health hazards. The standard for ventilation of spray finishing operations, 29 CFR 1910.94(c), was derived from ANSI Z9.3-1964, Design, Construction, and Ventilation of Spray Finishing Operations. The purpose of ANSI Z9.3-1964 was to "protect the health of personnel from injurious effects of contact with gases, vapors, dusts, or solvents used in, created by, or disseminated by spray finishing operations." Therefore, 29 CFR §1910.94 and its source standard, ANSI Z9.3, have the purpose of protecting employees from health hazards associated with spray finishing operations, whereas 29 CFR §1910.107 and its source standard, NFPA 33, address the explosion and flammability hazards of these operations. As a result, if there are health hazards associated with vehicle body lining operations, such as exposure to di-isocyanates, then it is possible that, even though a spray booth or room would not be required because of an employer's compliance with NFPA 33-2003, the presence of the health hazard would still necessitate a spray booth or room as required by 29 CFR §1910.94(c).

Question #5: In light of the fact that paragraph 1910.106(j)(5) indicates that 29 CFR §1910.106 does not apply to mists, sprays, or foams, except for storage requirements for flammable aerosols, does this mean the definitions and/or coverage limitations in 29 CFR §1910.106 do not apply to spraying operations?

Response: As noted earlier, although Class IIIB liquids are exempt from the scope of 29 CFR § 1910.106, §1910.107 does not contain this exemption; therefore, Class IIIB liquids are covered under §1910.107.

It is also important to note that inspections in this industry must be conducted in accordance with CPL 02-00-051, Enforcement Exemptions and Limitations under the Appropriations Act. This may result in potential non-coverage of safety-related items under certain circumstances, necessitating the addressing of these issues during the closing conference or through a subsequent letter to the employer. If you have any questions, please do not hesitate to contact Beau Ellis of my staff, at (202) 693-2247.

1 We note that in the preamble to the proposed rule, OSHA observed that while a number of changes would be made in §§ 1910.106 and 1910.108 to replace the phrase "flammable liquid" with "Class I or Class II liquid," there would be no need to replace the phrase "flammable or combustible liquid" since this phrase would still refer to the entire range of liquids concerned. 37 Fed. Reg. 11901, 11902 (June 15, 1972). [ back to text ]

2 The source standard for §1910.107, NFPA 33-1969, did not address truck bed lining but did address auto undercoating. However, the NFPA did so only as an exception, which was brought over as §1910.107 (k) in the OSHA standard.

Standard Interpretations - Table of Contents

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