A man was killed while using a wood chipper to trim trees in Richfield, Minn., May 16.

Bill Pipes, a 51-year-old employee of Victory Tree Service was completing a two-day tree removal job in a neighborhood when a metal piece of the wood shredder he was using flew off and hit him in the back of the head, Fox 9 reported. According to witnesses, while the crew was putting parts of the tree into the chipper, it became clogged. As one worker tried to unclog the machine, a piece of metal came loose and hit Pipes, killing him instantly, ABC 5 News reported.

"Apparently something blew up today, one of the knives came out and hit that shroud, which hit him in the back of the head, which killed him," said Tom Pipes, Bill's brother.

"I heard the noise the machine made when the accident happened and I turned and saw him on the ground," said Christian Abraham, Pipes' coworker. "My heart is broken right now."

Pipes is survived by his six children.