Wood Safety

In-Woods Chipper Safety

Jimmy McCraney


The headline reads: “A supervisor with over 15 years’ experience in the logging industry loses arm, from his elbow down, and part of foot in a chipper accident.”


The supervisor noticed that the chains on the fail of the whole tree chipper had sustained much wear and needed to be replaced. Normally, this task takes three people to complete.  On this day, the supervisor ignored established maintenance procedures and proceeded with the task alone.  At the chipper, he lifted the door to gain access to the chains.  He then stepped up on the stabilizer bar and got his left foot caught between the stabilizer bar and the in-feed roller (which is approximately a two inch gap).  This caused the supervisor to lose his balance and as he was falling, he reached to catch himself and got his left arm caught between the stabilizer bar and the in-feed rollers.  This activated the residual pressure left in the hydraulic system and allowed the chain that rotates the in-feed rollers to move.  The pressure caused the rollers to turn and trapped the supervisors arm and foot between the sharp teeth of the in-feed rollers.  The resulting damage from the pressure was the amputation of the left arm, from the elbow down and his left foot.


In-woods chippers are now in wide use by logging operations to produce chips and mulch.  They are in the mobile wood processing equipment class and are very efficient, very powerful, and very dangerous to work around.  Supervisors and employees must be alert and careful when operating or conducting maintenance operations on an in-woods chipper.  Unsafe operation or maintenance practices will cause severe injury or even death.

When chipping is being done as part of a logging operation, the OSHA Logging Operations standard requires that employers ensure that all logging machinery be maintained in a serviceable condition.  To that end, the logging standard requires that all machinery to be inspected daily and any discrepancies documented and/or repaired.  Failure to correct any discrepancies that result in an employee(s) being injured could result in negligence.

The OSHA standard requires any employee that operates in-woods chipper to have mandatory training prior to using the machine.  Employees operating the chipper should be properly trained in starting and stopping procedures, machinery lockout, maintenance, and emergency safety controls.  Although the hazards associated with chipper use are generally known, awareness of these hazards and the associated safeguards must be highlighted and strictly reinforced.

In-wood chipper blades can rotate at over 2,000 revolutions per minute, so it is important that all safe guards, including doors, housing, and covers, are properly installed.  The machine should be equipped with a mechanical-feed control bar.  The bar controls the chipper’s rollers when it is activated and should including a quick-stop and reverse-feed controls.  In-wood chippers must also feature a bottom-feed stop bar and panic bar that prevents an operator from being pulled into the blades.

According to the OSHA Integrated Management Information, 39 employees were killed in chipper accidents over a 10 year period.  Of those fatalities, the vast majority (78 percent) resulted from being caught in the chipper, and most of the remainder resulted from “struck-by” debris accidents.  Do not allow your logging operation to become part of an accident statistic.  Train your employees to know the hazards associated with in-wood chippers and ensure your Supervisors enforce and adhere to established maintenance procedures.