While performing morning equipment checks a fire fighter was running a gas powered cut-off saw with carbide tipped demolition blade installed on the saw. While throttling the saw to its maximum rated speed the fire fighter observed that the saw didn't sound like it was running correctly, at that moment the carbide tipped demolition blade came off the saw, came out of the blade guard, spun across the concrete station ramp at time becoming airbourne before striking a vehicle traveling in the roadway approximately 100 feet away causing property damage to the vehicle.

The Investigation:

All carbide tipped demolition blades were removed from service pending investigation into the cause of the incident. On examining the saw there was no apparent damage to the saw. The bolt that secures the blade to the saw was found to not be damaged. There was a nylon spacer found on the arbor to adjust the arbor size of the blade to the saw. I made contacted with Mr. Solomon Nutt, the Stihl representative for this area via phone and discussed briefly the incident. He without hesitation stated that Stihl does not stand behind the use of demolition blades as I had described to him on their saws, he was quick to inform me that there is a warning written in the owner’s manual and displayed on the saw. During our discussion of the event and the potential for injury during fire ground operations Mr. Nutt noted that the fire service is the only group still using carbide tipped demolition blades. The private sector is not permitted to us these blades due to injuries caused by them. Other areas of concern with the use of these blades on rotary saws include no retractable blade guard, no blade brake, lack of proper blade installation (not torque), and the type of bushings being used to correct the arbor size. On August 17, 2009, I contacted Lynn Cleek the District Manager of construction products for Husqvarna/Partner. During our conversation about the carbide tipped demolition blade and the use of Partner/ Husqvarna saw to power the blade Mr. Cleeks stated that they do not support the use of carbide tipped demolition blades on rotary saws. He went on to say the fire service is the only group still using these blades. Mr Cleek also offered to look at the saw and blade to evaluate and provide insight into the incident. On Wednesday August 26 Mr. Cleek examined the blade and we discussed safety issues related to blades of this nature. During our conversation he made me aware of a OSHA standards that apply to operation of the saw, they are standards 1910.243(a)(1)(i), 1910.212, 1910.213(r)(4). On November 15, 1999 a Standard Interpretations was prepared addressing fire department use of carbide tipped saw blades. The link to this document is Guarding/hazards of using woodcutting sawblades on a cut-off machine.[1910.243(a)(1)(i); 1910.212; 1910.213(r)(4)]. I also reviewed three other saw manufactures for their guidelines for blade usage, not one of the three recommends the use of carbide tipped demolition type blades on their cut-off saws. Factors leading to the incident: •  

The use of carbide tipped demolition blades on our rotary cut-off saws. •          

Not maintaining equipment as required by the manufacture. • 

Using an improper type of spacer for the blade being used (solid core blades require metal spacers). •           

Not properly training all operators of power equipment on the manufactures recommended procedures.

Recommendations: The overwhelming body of evidence indicates that all carbide tipped demolition blades should be removed from service to provide for a safe working environment for our personnel. Replace the saw blades with blades that have been approved for use by fire and rescue organizations. Improve our wood cutting capabilities by replacing the present bars on our chain saws with bars with guards that limit the exposed chain during ventilation operations. Properly train all operators of power equipment on the manufactures recommended procedures. Properly maintain equipment as required by the manufacture. Insure the proper size blade in installed Insure when wood is cut it is with a saw that has a retractable blade guard, the saw has a braking device to stop/ slow the blade when the source of power is removed. Make every attempt to use saw blades that have the proper size arbor for the saw that is being used. If this is not possible use the proper type of spacer for the blade being used (solid core blade equals metal spacer).