A CONTRACTOR EE WITH 2 YEARS EXPERIENCE FELL 31 FT (9.4 M) TO A STEEL STRUCTURAL BEAM WHEN THE GRATING FAILED IN THE CATWALK ON WHICH HE WAS WORKING. THE INJURED CONTRACTOR WAS RESCUED FROM T HAT POSITION BY THE PLANT'S EMERGENCY RESPONSE TEAM AND MEDEVAC'D TO A LOCAL TRAUMA CENTER.