I am aware of only one incident involving a fire during a rotors running refuel offshore on the North Sea. It was early 80's and involved a hose bursting while refuelling a S61. There was a brief fire caused by fuel from the ruptured hose spraying into the engine exhaust but it was quickly extinguished. The oil company concerned immediately banned all rotors running refuels but eventually returned to allowing them when it created so much inconvenience and reduction in payloads. It was subsequently discovered that the hose was well past its sell-by date.
As to Crab's assertion of lack of helideck crew "professionalism", I think that is just down to not understanding the difference between military and civilian procedures. On the North Sea, the civilian standard does not require a specific clearance for each ground crew member to enter the disk area. Once the anti collision light is extinguished after landing then ground crew can move around the deck as necessary to fulfill their duties. There are occasional lapses in standards, getting too close to the tail rotor for instance, which should be picked up on very quickly, if not by the HLO, by the helicopter crew member supervising the turn round. This would normally always be followed up by a safety report which would be fed back through the helideck operator's SMS.