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.

July 22, 1985

Mr. L. A. Jennings
Department 608
John Deere Dubuque Works
P.O. Box 538
Dubuque, Iowa 52001

Dear Mr. Jennings:

This is in response to your letter of May 31, 1985, addressed to Mr. Barry J. White, concerning our requirements for mesh size on protective canopies for mobile equipment.

29 CFR 1926.604(a)(2)(ii) does require that the opening in the rear of the canopy structure shall be covered with not less than 1/4-inch woven wire mesh with openings no greater than one inch. However, the Occupational Safety and Health Administration's Field Operations Manual in chapter IV on page 29, defines a De Minimis violation of a standard as "violations of standards which have no direct or immediate relationship to safety or health." The 1.75 inch mesh opening complies with the consensus standard rather than with the standard in effect at the time of an inspection when the employer's action provides equal or greater employee safety, and therefore meets our De Minimis criteria. De Minimis violations need not be abated and penalties are not proposed.

Machines equipped with an open mesh material on the rear of the canopy with openings no greater than 1.75 inch would provide acceptable protection for use in site clearing, and meet with the intent of 29 CFR 1926.604(a)(2)(ii).

If we can be of further assistance, please let us know.


John B. Miles, Jr., Director
Directorate of Field Operations