Abstract: AT APPROXIMATELY 2 PM ON JULY 10, 1986, EMPLOYEES #1 AND #2 WERE PAINTING THE TOP SECTION OF A PERMIAN ENGINEERING AND MANUFACTURING COMPANY DERRICK, MODEL 96-180-000-P, S/N 557, MOUNTED ON A COOPER MANUFACTURING CORPORATION WORKOVER RIG, CARRIER MODEL LTO, S/N A615. EMPLOYEES #1 AND #2 WERE STANDING ON THE TOP OF THE BOTTOM SECTION, PAINTING FOUR FOOT LENGTHS OF THE TOP SECTION. AS SOON AS THEY HAD FINISHED A FOUR FOOT SECTION, THE DERRICK WOULD BE RASIED ANOTHER FOUR FEET. THIS PROCEDURE PLACED THE ENTIRE WEIGHT OF THE TOP SECTION ON THE DERRICK'S HYDRAULIC SYSTEM. WHEN THE DERRICK HAD BEEN RAISED TO WITHIN THREE OR FOUR FEET OF THE SPOT WHERE THE "DOGS" WOULD SET, A FAILURE OCCURRED. THE TOP SECTION OF THE MAST DROPPED ONTO THE BOTTOM SECTION. EMPLOYEES #1 AND #2 WERE KNOCKED OFF THE DERRICK AND FELL ABOUT 60 FEET TO THE GROUND. THEY WERE KILLED. NEITHER OF THE EMPLOYEES WAS WEARING A SAFETY BELT.