we have a 24/7 operation so the trucks are refuelled 3 times a day and the cylinders are fixed on to the truck. we have a service and supply contract from a large UK supplier and part of this contract is an annual cylinder inspection plus the cylinder and fittings are part of the pre shift check. These cylinders are designed to be filled on the truck and are not much different to a car that is fitted with an lpg tank. If the correct method is used and protective clothing worn, there shouldnt be a problem. We do include the refilling the truck as part of the initial training and as part of the 3 year refresher training. You can never guarantee that an operator will always follow the rules but you can have sanctions in place if they do. It would be considered a major breach in safety procedure and leaves the operator open to instant dismissal if they dont follow the rules.