In recent years there have been numerous construction accidents because companies were either not aware of fire hazards or did not have safe practice policies and employee training in place. On October 7, 2007, five men were killed and three injured from a flammable vapor fire in a penstock tube at Cabin Creek Reservoir outside Georgetown, Colorado. On June 9, 2009, 4 people were killed and 67 injured in a natural gas explosion at the ConAgra Slim Jim facility in Garner, North Carolina. On February 7, 2010, six people were killed and fifty injured in a natural gas explosion at Kleen Energy in Middleton, Connecticut.
The Cabin Creek incident involved the use of highly flammable methyl ethyl ketone inside a confined space. There was no air monitoring for LEL in use, the equipment was not grounded and bonded, and there was no fire extinguisher immediately available (the nearest was over 1400 feet away).
The ConAgra and Kleen Energy incidents both occurred from using natural gas in planned work to blow down newly installed piping. In the case of the Kleen Energy blowdown, initial calculations by the CSB investigators revealed that approximately 480,000 standard cubic feet of natural gas were released outdoors near the building in the final 10 minutes before the blast. Just over 2 million standard cubic feet of natural gas were released in total over the course of the morning.
In all three cases employees were creating large flammable gas or vapor clouds that only needed an ignition source to have a catastrophic accident. Company practices and policies allowed for the conditions that led up to all three incidents. Training for employees did not fully recognize the hazards involved. In the case of Kleen Energy there were numerous personnel present that were not even involved in the blowdown. In the case of ConAgra most plant personnel were not even aware of the blowdown being conducted.
The natural gas blowdowns had created catastrophic accidents previously, yet were still in use. All three examples were hazardous operations, yet adequate safety precautions were not observed. In two cases personnel not involved in the hazardous operations were allowed to be present and were killed as a result. “Minimum personnel, for the minimum amount of time, exposed to the least possible amount of explosive material” is the cardinal rule for actual explosives operations, yet in the case of the natural gas blowdowns apparently no own conducting the operations really considered the explosive hazard.
If you are conducting work that involves the use of flammable gasses or liquids, a thorough job hazard analysis, strict use of safety procedures, and restrictions about the number of personnel exposed can reduce the level of risk. But as long as highly flammable materials are in use the risk is never going to be zero. Have you thought about safer materials or safer processes? None of my three examples needed to happen. There were and are safety procedures, safer materials and methods available to have prevented all three accidents.