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 http://www.osha.gov.

June 10, 2013

Jay W. Schwall
Stephen B. Ogle & Associates III, Inc.
Post Office Box 277
Caldwell, Ohio 43724

Dear Mr. Schwall

Thank you for your letter to the Occupational Safety and Health Administration’s (OSHA’s) Directorate of Enforcement Programs. We apologize for the delay in our reply. This letter constitutes OSHA’s interpretation only of the requirements discussed and may not be applicable to any scenario or questions not delineated within your original correspondence. You had specific questions regarding the use of awareness barriers to block access to machinery. Our answers to your paraphrased questions are provided below.

Question: When are awareness barriers, such as a chain equipped with a warning sign or similar type of guarding, acceptable to satisfy the OSHA standards for machine guarding?

Reply: The machine guarding standard contemplates a physical means of preventing employee contact with the moving parts of machines. An awareness barrier serves as a notice to an employee that he or she is approaching a dangerous area and does not physically prevent an employee from contact with moving parts of machines.

OSHA would not consider an awareness barrier as guarding under Machine and Machine Guarding, 29 CFR Part 1910, Subpart O. Generally, awareness barriers are not considered adequate when exposure to the hazard exists. An awareness barrier, such as a chain equipped with a warning sign or similar type of guarding, depends largely on human behavior, and so would not provide the necessary protection. However, it may be possible for an employer to address moving parts hazards by eliminating employee access to the area in which such hazards exists.

Thank you for your interest in occupational safety and health. We hope you find this information helpful. OSHA requirements are set by statute, standards, and regulations. Our interpretations letters explain the 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. In addition, 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. If you have any further questions, please feel free to contact the Office of General Industry Enforcement at (202) 693-1850.

Sincerely,

Thomas Galassi, Director
Directorate of Enforcement Programs