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.

May 27, 2004

Mr. Richard Holmes
Safety Department Manager
Aggregate Industries
1707 Cole Boulevard, Suite 100
Golden, Colorado 80401

Dear Mr. Holmes:

This is in response to your March 16, 2004, letter to the Occupational Safety and Health Administration's (OSHA) Englewood Area Office regarding the use of a reverse alarm, which is being manufactured in the United Kingdom, on construction sites. The alarm uses "white noise" instead of the more common single-tone alarm.

We have paraphrased your question below:

Question: Does a back-up alarm that uses "white noise" instead of a single tone meet the requirements of 29 CFR 1926.601(b)(4)(i) and 1926.602(a)(9)(ii)?

OSHA is generally precluded from approving or endorsing specific products. The variable working conditions at job sites and possible alteration or misapplication of an otherwise safe piece of equipment could easily create a hazardous condition beyond the control of the equipment manufacturer. However, where appropriate, we try to give some guidance to help employers assess whether products are appropriate to use in light of OSHA requirements.

Title 29 CFR 1926.601(b)(4) states:

No employer shall use any motor vehicle equipment having an obstructed view to the rear unless:
  • (i) The vehicle has a reverse signal alarm audible above the surrounding noise level or:
  • (ii) The vehicle is backed up only when an observer signals that it is safe to do so.

Section 1926.602(a)(9)(ii) states:

No employer shall permit earthmoving or compacting equipment which has an obstructed view to the rear to be used in reverse gear unless the equipment has in operation a reverse signal alarm distinguishable from the surrounding noise level or an employee signals that it is safe to do so.

These provisions, by their terms, do not specify that a reverse signal alarm be of the single-tone type. However, we have neither the data nor the resources to evaluate whether this particular device would be "audible above the surrounding noise level" as required by the standard. If it does meet this test -- that is, provides adequate warning to workers in the path of the vehicle, and to workers walking towards the path of the vehicle in time to avoid contact -- it would comply with §1926.601(b)(4).


Russell B. Swanson, Director
Directorate of Construction