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.

August 26, 1981

MEMORANDUM FOR:   DAVID H. RHONE
                 REGIONAL ADMINISTRATOR

THRU:             JOHN B. MILES FIELD COORDINATOR

FROM:             BRUCE HILLENBRAND
                 DEPUTY DIRECTOR,
                 FEDERAL COMPLIANCE AND STATE PROGRAMS

SUBJECT:          Blasting and Use of Explosives Relative to
                 29 CFR 1926.905(h) and (k)

REFERENCE:        Your memorandum dated July 22, 1981.

The requirement in 29 CFR 1926.905(h) "that equipment shall not be operated within 50 feet of loaded holes" does not include equipment such as a backhoe used in the placement of blasting mats. 29 CFR 1926.905(k) requires that no drilling be performed within 50 feet of a loaded hole where the explosives have failed to detonate. The regulations do not apply to holes which have been filled with explosive in the initial loading.

Because 29 CFR 1926.905 does not regulate the distance between a loaded hole and the drilling of the next hole, CSHO's will have to cite as a recognized hazard section 5(a)(1) of the Act for drilling performed too close to a loaded hole. For guidance in this matter, the Mine Safety and Health Administration requires in Subchapter N-55.6-107 "Mandatory. Holes shall not be drilled where there is danger of intersecting a charged or misfired hole".