Inspection Detail

Inspection: 107120792 - Mclean Elevator Company

Inspection Information - Office: Bismarck Area Office

Investigation Summary

A 1,000 gallon liquefied petroleum gas tank was located about 60 feet from the office facility of a grain storage elevator complex. A liquefied gas pipeline was buried underground and connected the storage tank to a grain dryer that was located adjacent to the office facility. An underground gas line connected the storage tank to the office furnace. On Friday, May 21, 1993, after elevator employees detected propane gas smells (mercaptans), the gas company repaired several leaking fittings that were connected above ground to the tank. An underground leak in the buried pipeline, however, went undetected. On Saturday, May 22, 1993, Employees #1 and #2 arrived at work. They turned on several light fixtures in the office area and started several motors in the elevator area. Both workers returned to the office and were standing next to each other. One employee struck a match to light a cigarette and ignited the propane gas that had permeated the ground and entered the office through the septic system. The explosion destroyed the office facility; both employees were hospitalized.

Keywords: LEAK, FLAMMABLE VAPORS, EXPLOSION, LP GAS, PIPELINE