My question involves personal property located in the State of: Massachusetts
While working on a job site (landscaping) I place one of the weed whackers next to the trailer, underneath the side door, which was facing the road.
A while later, my boss got into the truck and attempted to drive away, running over the weed whacker in the process. The handle on the tool broke but it was otherwise usable. I left the job after the fact and have now been told that the weed whacker ultimately fell apart. My boss admits that he tried to fix it and took it apart to find that the metal support has broken in 2. He is attempting to get me to pay the full price for the weed whacker (300 dollars).
Who is ultimately liable for the destruction of the property and should I pay any money?

