- Standard Number:
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.
January 16, 1978
Dr. George P. Cressman, Chief
National Weather Service
National Oceanic and
U.S. Department of Commerce
860 13th Street
Silver Spring, Maryland 20910
Dear Dr. Cressman:
Recently, a series of grain elevator explosions occurred which resulted in the death or injury of over 50 employees. As a result of these catastrophes, there is a need to search for probable causes, including the possibility of meteorological relationships. Therefore, this is a request for meteorological information for the times of the occurrence of certain past explosions occurring in the territorial United States and Puerto Rico. (See list enclosed).
The information will be assessed for a possible meteorologically synoptic and/or physical relationship to these explosions. If some such relationship exists that can be associated with the construction or operation of the grain elevator, it will be of immeasurable value to the Occupational Safety and Health Administration in formulating additional measures to prevent future such explosions.
Since the meteorological relationship to be sought is a physical and/or a synoptic one, the following information is requested:
A. Single station data from a contiguous station.
1. Hourly surface reports for the period of time from two hours before to one hour after the time of the explosion, to show the weather, wind, pressure, pressure tendency, temperature, humidity, and wind gusts.
2. Barograph and psychometric charts to show the pressure, its tendency, and any "pressure jumps", the temperature, and the humidity.
B. Climatic data from a contiguous station.
1. Normal, mean maximum, mean minimum, extreme maximum, and extreme minimum of temperature for the calendar day of the explosion; and the same for the relative humidity or mixing ratio or absolute humidity, whichever is available, if any.
C. Synoptic data at a contiguous time.
1. Synoptic surface maps, including any local maps, to show the general and local synoptic surface weather patterns.
2. N 1,000 MB map and constant level wind charts to 1,000 feet, including any local charts, to show the wind force and direction and horizontal wind shear lines.
3. RAOB's and Rawins or Pibals before and after the explosion to bracket as nearly as possible the time and location of the explosion, to show the lapse rates of temperature and mixing ratios, and the vertical wind shear in the first 1,000 feet. Any stability charts for the first 1,000 feet would be useful.
It would be desirable to have as much of the information listed above for each explosion on the enclosed list as can be readily made available without an undue amount of work. For convenience, it is suggested that the information be made available for review at a central location(s) of your designation.
Your anticipated assistance in this grave and important matter as a common service to employee and public well-being is gratefully appreciated. For further information or discussion you may contact Mr. Peter E. Wasko of my staff on telephone number: 202-523-8124.
John K. Barto, Chief
Division of Occupational Safety Programming