Never Say Never?
DEPARTMENTS
EDITOR’S OPINION
Let’s consider a hypothetical situation: A two-story, frame house has been burning for more than 30 minutes and is fully involved on our arrival. Two firefighters carry a 35-foot portable ladder from the apparatus toward the inferno. As the ladder is raised in preparation to being positioned against the severely fire stressed structure, a sudden “whoosh” announces the expected collapse of the dwelling. The two firefighters are critically injured.
After much critiquing and data gathering, a national authority announces that portable ladders should never be used at frame dwelling fires, as that procedure was found to be futile and unsafe in the above mentioned incident.
Sound like overkill? Sure.
But this scenario parallels an actual incident and resulting alert issued by the National Institute for Occupational Safety and Health (NIOSH). The alert followed a year-long critique of the “empty” toluene tank disaster in Phoenix, AZ. While cutting into the base of the tank with a metal cutting, rotary power saw, sparks ignited the residual gases, which were made explosive by the steady inrush of air (oxygen) to a rich flammable vapor atmosphere. The explosion caused the death of a firefighter and the unconscious worker he was trying to reach inside the tank.
All of us who mourned the loss, who listened to the circumstances surrounding the actions taken before the tank exploded, or who watched the videotapes made available to us by a significant safety communication gesture by Chief Alan V. Brunacini and his Phoenix Fire Department, shared access to the major basic lesson, NEVER cut into an empty storage tank.
The NIOSH alert bulletin, however, chose a different lesson. It questions mitigation tactics using hand-held water spray (fog) streams at all flammable atmosphere emergencies. NIOSHs findings showed that the combination of water spray applications to the interior and exterior of the tank and the increasing opening made in the side of the tank by the cutting blade diluted the flammable vapor mixture with oxygen down to its explosive range. The sparks thrown into the tank then provided the ignition source necessary for the explosion.
Although NIOSH’s alert is generally acceptable for the example addressed, to suggest that the application of fog streams is unsafe at all flammable vapor incidents is questionable.
The alert is in response to a request for assistance. I think that the request for assistance should be from NIOSH to the fire and emergency response personnel. Accurate field use data should be gathered and forwarded to the NIOSH office so they may review the successes as well as the failures in mitigating flammable atmosphere emergencies.
You may request copies of the NIOSH alert together with the address for data collection by writing for DHHS (NIOSH) Publication No. 85-112 to: Publications Dissemination, DSDTT, National Institute for Occupational Safety and Health, 4676 Columbia Parkway, Cincinnati, OH 45226; or telephone (513) 841-4287.
