EMPLOYEE WAS ROCK DUSTING WITH THE SCOOP BLADE DUSTER. HE WAS USING A CHEATER PIPE TO LOOSEN ONE OF THE TWO BOOMERS THAT WAS HOLDING THE DUSTER INTO THE END OF THE BUCKET. HE HAD INSTALLED THE CHAINS WITH A GOOD AMOUNT OF TENSION ON THEM TOHOLD THE DUSTER IN PLACE TO PREVENT MOVEMENT AS HE WAS PULLING THE PIPE TOWARD HIM THE BOOMER RELEASED AND THE PIPE CAME OFF THE BOOMER HANDLE.