Repair of RS Conv 99% complete w/severe storm minutes away. 2 riggers supplied by Edwards, Inc on catwalk loading tools on deck of hyd. manlift supplied by Hanson Agg. 1 rigger thrust a heavy steel pinch bar on deck of manlift & it slid across deck, under entrance w/no kick plate, fell onto conv. carriage, glanced toward EE who threw rt arm up as shield, hit his arm & broke it.