Abstract: AT APPROXIMATELY 1:30 PM ON FEBRUARY 3, 1986, EMPLOYEE #1 WAS MAKING REPAIRS ON ONE OF THE HYDRAULIC CYLINDERS ON THE "CLAMSHELL" AT THE CLACKAMAS TRANSFER AND RECYCLING CENTER. THE CLAMSHELL IS LOCATED AT FLOOR LEVEL, ADJACENT TO TO THE EDGE OF A TRUCK PIT USED TO LOAD SEMITRAILERS WITH GARBAGE. ON THE NORTH SIDE OF THE CLAMSHELL THERE IS A SMALL SHEET METAL COVER WHICH PROTECTS THE MAIN CROSS MEMBER OF THE TRAILERS WHILE THE CLAMSHELL IS USED TO PACK THE GARBAGE INTO THE TRAILERS. THE SHEET METAL COVER IS APPROXIMATELY 24 INCHES WIDE AND 8 FEET LONG. THE COVER IS ALSO USED TO WALK ACROSS FROM THE CLAMSHELL PIVOT POINT TO THE MAIN FLOOR LEVEL, WHERE GARBAGE IS STORED, THEN TRANSFERED TO THE TRUCKS IN THE PIT. THE ACCIDENT HAPPENED WHEN EMPLOYEE #1 WAS MAKING SOME REPAIRS TO ONE OF THE HYDRAULIC CYLINDERS WHILE STANDING ON THE COVER. EMPLOYEE #1 WAS LOOSENING ONE OF THE FITTINGS WHEN THE WRENCH SLIPPED OR THE FITTING GAVE WAY. EMPLOYEE #1 LOST HIS BALANCE AND FELL INTO THE TRUCK PIT, SUFFERING SEVERE INTERNAL INJURIES. THE TRUCK PIT IS ABOUT 17 TO 18 FEET DEEP.