A dangle-head processor was cutting a log when the chain broke at the top of the saw bar. A tooth flew off the chain, and this "chain shot" penetrated the 5/16-inch-thick steel plate at the side of the cab. The operator in the cab was not injured.

The processor was fitted with a chain catcher and guard. In addition, the operator had angled the saw bar away from the cab — a safe work practice the company was using as a result of a WorkSafeBC hazard alert in 2004. However, the window of the cab was only half-inch polycarbonate. If the bar had been directly in line with the cab, the chain shot could have gone through the window and hit the operator.

• Never operate a log processor with the saw bar directly in line with the cab window. Position the saw bar at an angle to the window.
• Consider installing a chain catcher and chain shot guard to minimize the risk of chain shot hitting a worker. (However, a chain catcher and chain shot guard will not completely eliminate the hazard, especially if the chain breaks at the top of the bar.)
• Consider upgrading the cab's front window from ½-inch polycarbonate (which will not stop all chain shot) to 1¼-inch laminated polycarbonate or its equivalent.
• Follow the manufacturer's instructions for chain speed, chain tension, and for maintenance of the chain, bar, and sprocket.
• Do not repair chains with used parts.
• Keep ground workers at least 70 metres (230 feet) away from a working processor.

Watch a slide show on the 2004 chain shot incident:
View the slide show "Broken chain link almost kills worker" on WorkSafeBC.com (see Publications, Multimedia).