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• Standard Number: 1926.651

November 19, 1991

Mr. George Kennedy, C.S.P.
Director of Safety
National Utility Contractors Association
1235 Jefferson Davis Highway, Suite 606
Arlington, Virginia 22202-3283

Dear Mr. Kennedy:

This is in response to your September 25 request for an interpretation of the Occupational Safety and Health Administration's excavation standards addressing air sampling in trenches.

Air sampling required by 29 CFR 1926.651(g) does not have to be performed in all trenches over four feet in depth. This paragraph addresses excavations over four feet deep where oxygen deficiency or other "hazardous atmosphere exists or could reasonably be expected to exist", such as in excavations in landfill areas or in areas where hazardous substances are stored nearby. It is the responsibility of a competent person to determine if air monitoring needs to be performed before employees enter each excavation.

If we can be of any further assistance, please contact Roy F. Gurnham or Dale Cavanaugh of my staff in the Office of Construction and Maritime Compliance Assistance at (202) 523-8136.

Sincerely,



Patricia K. Clark, Director
Directorate of Compliance Programs

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