THE EE WAS WORKING AT STARGO CANYON LEACH FIELD, ATTEMPTING TO ASSEMBLE AN 8-INCH PIPE AND COUPLING. HE PUSHED ON THE PIPE WITH HIS LEFT FOOT AND LOST HIS BALANCE WHEN THE PIPE SLIPPED INTO TH E COUPLING. HE FELL STRAIGHT TOT THE GROUND. EE DID NOT GO RESTRICTED DUTY UNTIL 5-31-02.