EE FINISHED FUELING A SMALL DIESEL TANK & WAS DESCENDING A 10' LADDER WITH THE 1 1/2"" FEL HOSE IN HIS RIGHT HAND. HE SLIPPED 1/2 WAY DOWN, FALLING 5' TWISTING HIS RIGHT ANKLE. HE DID NOT HAVE 3 POINT CONTACT ON THE LADDER WITH HOSE IN RIGHT HAND. PROCEDURE IS TO ATTACH A LINE TO HOSE AND PULL UP TO TOP OF TANK & LOWER SAME WAY.