OPENING DOOR TO #1 STOCKHOUSE BETWEEN PUMPS AND COMPRESSOR. STEEL PANEL TO RIGHT OF DOOR WAS LOOSE AND FELL ON HER RIGHT SHOULDER, KNOCKING HER TO THE GROUND. BOLTS TO REATTACH PANEL TO DOOR N OT DONE AFTER WORK DONE TO ADJUST PANEL. AFTER INCIDENT, PANEL BOLTED TO DOOR FRAME.