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.


September 20, 2007

Chris Cloutier
Assistant Controller
Shaw Brothers Construction, Inc.
P.O. Box 69
511 Main Street
Gorham, Maine 04038

RE: Whether "discriminating [back-up] alarms" may be used to meet the requirements of 29 CFR 1926.602(a)(9)(ii).

Dear Mr. Cloutier:

This is in response to your January 16, 2007 letter you sent to Marthe B. Kent, a Regional Administrator with the Occupational Safety and Health Administration. You inquired about the use of "discriminating" back-up alarms on material handling equipment used in construction. We apologize for the delay in responding.

We have paraphrased your question as follows:

Question: Does the use of a "discriminating alarm" meet the requirements set forth in 29 CFR 1926.602(a)(9)(ii)? In this case, "discriminating alarm" refers to a system that uses infrared light, ultrasonic waves, radar, or similar means to detect objects or persons at the rear of the equipment, and sounds an audible alarm when a person or object is detected.

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


§1926.602 Material handling equipment.
* * *
(a) Earthmoving equipment; General.
* * *
(9) Audible alarms.
* * *
(ii) 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.



A discriminating alarm as described above would fulfill the requirements of 1926.602(a)(9)(ii) as long as the alarm was consistently effective in detecting any employee who is in the path of the equipment and alerting the employee of the backing-up of the equipment. As noted in our letter entitled "Alternatives to common back-up alarms on construction motor vehicles; use of other effective technology or observers/signal persons," dated September 27, 2004, alternatives to conventional back-up alarms may be used so long as they "provide 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." A discriminating alarm that detected such employees and gave warning to them in time to avoid contact with the vehicle would therefore meet the requirements of the standard.

If you need additional information, please contact us by fax at: U.S. Department of Labor, OSHA, Directorate of Construction, Office of Construction Standards and Guidance, fax # 202-693-1689. You can also contact us by mail at the above office, Room N3468, 200 Constitution Avenue, N.W., Washington, D.C. 20210, although there will be a delay in our receiving correspondence by mail.


Steven F. Witt, Director
Directorate of Construction