By Ken Robinson
FireRescue1 Associate Editor
ST. ANNA, Wis. — Using water and foam to fight a combustible metal fire caused an explosion that killed a Wisconsin firefighter last year, NIOSH investigators concluded.
St. Anna Volunteer Firefighter Steven Koeser, 33, was killed and nine other firefighters were injured in the December 29 blast.
A lack of hazardous awareness training, no documented site preplan and insufficient scene size-up and risk assessment also contributed to the death, a report released Wednesday said.
The crew was responding to a reported dumpster fire at a rural foundry and arrived to find blue-green flames about two feet high coming out of the bin.
Firefighters also reported seeing a ten-inch red-orange glow at the bottom of the dumpster.
Using a ladder, the incident commander surveyed the contents of the dumpster, which included aluminum shavings, foundry floor sweepings, and a 55-gallon drum.
Firefighters used approximately 700 gallons of water and 100 gallons of foam solution on the fire with no effect for four minutes until the contents of the dumpster started sparking and exploded, propelling shrapnel and barrels through the air.
The report says the initial fire may have been caused by “a thermite reaction started from aluminum shavings and particles mixed with metal oxides or silicon oxides (wet sand) which generated enough energy to ignite the aluminum shavings and particles,” the NIOSH report said.
Investigators say firefighting efforts then led to the explosion — a conclusion the state fire marshal arrived at.
“The addition of wet extinguishing agent (in this case, water and a foam solution) on the fire most likely generated hydrogen gas, due to the volatile reaction with the aluminum, which exploded.”
As a result of the incident, NIOSH recommends departments preplan for similar foundries, mills, plants and other high-risk sites by having every potentially responding department conduct a walkthrough.
“In this incident, the fire department had walked through the facility 2 years prior to the incident but there was no documentation and the hazards associated with the outside disposal area were not indentified or considered at that time,” the report said.
The report also stresses the importance of specialized training for unique hazards like combustible metals.
In this case, the department should have used a bulk dry extinguishing agent such as dry sand, dry soda ash, or dry sodium chloride to avoid accelerating the fire and adding the explosive gas that can come from a liquid reaction with aluminum, the report said.
NIOSH also recommends manufacturers that use combustible metals implement measures such as limited access disposal sites and container labeling to help protect firefighters.
In addition, manufacturers should have a bulk dry extinguishing storage and delivery system for the fire department and establish a specially trained fire crew, investigators said.
The report also recommends fire departments avoid similar incidents by:
- Ensuring that standard operating guidelines are developed, implemented and enforced
- Ensuring a proper scene size-up and risk assessment when responding to high risk occupancies such as foundries, mills, processing plants, etc.
- Ensuring a documented junior firefighter program that addresses junior fire fighters being outside the hazard zone.
- Fire departments should ensure all firefighters who may operate in or near a hazard zone, prior to approaching, have donned the full complement of personal protective equipment, i.e., self-contained breathing apparatus and turnout gear.