EE WAS CHECKING A PUMP SYSTEM OUT FOR OPERATION AND NOTICED PRODUCT LEAKING FROM GASKET ON MAIN AERATION NOZZLE. HE KNEELED AND TURNED SIDEWAYS AND WAS LEANING AGAINST THE AIR MANIFOLD WHILE TIGHTENING A BOLT WITH SOME STRAIN WHEN HE FELT A POP IN HIS LEFT SIDE WHICH TOOK HIS BREATH AWAY AND SENT A SPASM THROUGH HIS BODY.