During a grapple yarding operation, several twisters had been applied to support a tailhold tree. After yarding was complete, a worker was sent to remove the twisters from the tailhold. He was releasing the third twister when he slipped and fell on the steep terrain. The worker lost control of the twister pole and his vest became entangled in the pole as it unwound uncontrollably.

The grapple yarder operator heard the worker's distressed breathing over the radio and alerted the hooktender, who was nearby. The worker had stopped breathing but the hooktender used his basic first aid training to resuscitate the worker before the first aid attendant arrived.

• Contact the yarder operator before installing or removing a twister.
• Use two workers to install and remove twisters if possible.
• Ensure secure footing when working with twisters.
• Install the twister cable with a minimum of two wraps (four-part line). Properly installed twister cables have to be twisted only 3 to 4 times to apply correct tension.
• Keep the twister pole as close to right angles with the twister cable as possible for greater leverage and control.
• Avoid loose clothing when working with twisters.
• Provide first aid training above the minimum requirements of the Regulation.