EMPLOYEE DROPPED A SIEVE CLEANING BRUSH ON THE FLOOR OF LAB. BRUSH LANDED BEHIND COOLING RACK. SHE GOT ON HER HANDS AND KNEES TO TRY TO RETRIEVE BRUSH. AFTER RETRIEVING BRUSH, SHE STOOD UP AND WHEN SHE DID, SHE FELT SEVERE PAIN IN HER BACK AND WAS UNABLE TO STAND UP STRAIGHT.