The injured employee was working in the platform of an aerial lift approximately 40 feet above the ground. Another employee was extending the boom of a telehandler with an iron girder truss attached to the forks. As the telehandler operator was lifting the iron girder truss, he simultaneously lifted the left-side outrigger. The length and weight of the girder truss caused the telehandler to tip on its side, striking a support beam. The support beam broke from the anchor bolts, causing the support beam along with an attached iron girder truss to fall backward and strike the aerial lift. The aerial lift fell and the employee was ejected from the platform, resulting in lacerations to the face and multiple lost teeth.