Standard Interpretations - Table of Contents
• Standard Number: 1926.602; 1926.602(a); 1926.602(a)(9); 1926.602(a)(9)(ii)

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

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 sound