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.

October 22, 1984

MEMORANDUM FOR:     BYRON R. CHADWICK
                    Regional Administrator

FROM:               JOHN B. MILES, JR., Director 
                    Directorate of Field Operations

SUBJECT:            Redrilling Seismic Shotholes For The Purpose of Plugging
                    the Hole to Protect Groundwater

This is in response to your memorandum requesting clarification on the above subject. We are of the opinion that a drill using a remote operator at a safe distance where there would be no exposure to any employees would be appropriate.

This would allow the proper plugging of these holes to the underground water from being contaminated.

The redrilling of any holes which have contained explosives cannot be allowed or recommended by OSHA, where employees could be exposed to a hazard.