Archive Notice - OSHA Archive

NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy. It is presented here as historical content, for research and review purposes only.

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

January 6, 1978

Mr. Jack Thompson
Safety Coordinator
Houston Fire Department
410 Bagby Street
Houston, Texas 77002

Dear Mr. Thompson:

Confirming our telephone conversation this date, I am enclosing available information on grain elevator explosions over the past five years. To some extent, our information is fragmentary and incomplete, however, as it is refined, you will be kept advised.

Your observation that the barometric pressure changed noticeably at the time of three of the recent explosions is most interesting. As indicated, our tentative finding that the relative humidity and amount of precipitation at the time of the explosions may be a factor worthy of further investigation all ties in together.

Our investigation of the entire spectrum of climatic conditions will continue to ascertain if there appears to be any relationship, and if so, explore feasible corrective actions to preclude future incidents.

As our interest in this matter is mutual and our goals identical, our close cooperation can only work for the benefit of all persons exposed to hazards at grain elevator sites.


John K. Barto, Chief
Division of Occupational
Safety Programming