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Plastic coupling guards as a de minimis alternative

Summary A guard manufacturer asked whether a nonmetal coupling guard met OSHA's mechanical power-transmission rule. OSHA said it did not approve products, but suitable substantial nonmetal guards were treated as a de minimis violation rather than cited under its then-current policy. The posted letter has no printed issue date.
Document
Federal opinion letter
Agency
Occupational Safety and Health Administration (OSHA)
Document number
1999-02-08
Date issued
February 8, 1999
Status
Unknown
The letter describes a de minimis enforcement approach for nonmetal guards; its page does not establish whether that approach remains current.
Status last verified October 9, 2026

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The current status of this document is unclear
The letter describes a de minimis enforcement approach for nonmetal guards; its page does not establish whether that approach remains current. It may no longer reflect the agency's current position. Treat this page as historical context, not current guidance, and verify current law before relying on anything here.
About this page: The full text below is the official document from Occupational Safety and Health Administration (OSHA). Ezel adds the plain-English summary and tracks the document's status. The official source linked on this page is authoritative for any reliance.

Mr. Stephen Wilson
Flowserve
Corporate Director of Safety,
Health and Environmental Affairs
[Recipient address omitted]

Dear Mr. Wilson:

This is in response to your letter of October 16, 1998, in regard to the Occupational Safety and Health Administration's (OSHA's) standard, 29 CFR 1910.219 as it relates to plastic shaft guarding and your company's new non-metallic coupling guard.

We have reviewed your letter and attachments. As you may be aware, OSHA does not approve, endorse or promote any products or test results.

As your letter acknowledges, OSHA has taken the position that guards constructed of any substantial material may be an acceptable alternative to the metal construction required by the standard at 29 CFR 1910.219(m). Until such time as the standard is modified, we are not in a position to deviate from that interpretation, and OSHA will continue to regard the use of suitable materials other than metal as a de minimis violation but will not be cited.

In this regard, we would like to suggest that you contact the American National Safety Institute (ANSI) and submit your test data for evaluation and review by a third party; to be considered in the future for the purpose of modifying OSHA's standard.

Thank you for your inquiry. If you have questions regarding the preceding, please contact Alcmene Haloftis of my staff at 202-693-1850.

Sincerely,

Richard E. Fairfax, Director
Directorate of Compliance Programs

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