Clearing saw operator partially severs two fingers while removing jammed brush

Thursday, June 07, 2007

What happened?

A clearing saw operator with more than 10 years experience was doing pre-commercial thinning, a silviculture technique in which space is created for the growth of young trees by removing less valuable trees. During normal operation of the clearing saw, brush became caught between the blade and the blade guard. While reaching to clear the jam, the operator slipped on bedrock. While trying to regain his balance he inadvertently engaged the saw throttle, causing the saw blade to spin and cut his hand. Two fingers of his left hand were partially severed.

Why did it happen?

The operator did not shut off the clearing saw before reaching to clear the jam. The bedrock he was standing on had been made slick by rain, causing the operator to lose his balance and hit the throttle control.

How can it be prevented?

Among the personal protective equipment used by operators of clearing saws are a hardhat with face shield and hearing protection, safety shoes or boots, high-visibility clothing and gloves. In this case, the fact that the operator was wearing gloves may have saved his fingers from being completely severed when his hand came into contact with the spinning saw blade.

But personal protective equipment alone can’t completely guard the clearing saw operator from injury. A number of safety features are built into the saw itself. One of the most effective of these safety features is the STOP switch. The operator’s manual for one of the leading brands of clearing saw includes the following warning: “Neither the user of the tool or anyone else may attempt to remove the cut material while the engine is running or with the blade rotating as this can result in serious injury.”

The manufacturer’s warning sounds like simple common sense, but accumulated work experience sometimes seems to contradict common sense, such as when dangerous shortcuts are taken dozens or even hundreds of times with no unpleasant consequences. Taking a shortcut such as not shutting off a clearing saw before trying to clear a jam is dangerous every time it’s done, but a particular combination of circumstances – unforeseen and unnoticed – can dramatically raise the odds of being injured or maimed.

In this incident, the clearing saw operator was standing on wet bedrock as he tried to clear the brush that was jamming his saw. When he lost his footing, he set off a chain of events that confirmed the wisdom of the warning in the operator’s manual.