As a H&S Officer and Fork Lift truck Trainer, I can fully understand the issues you have. Your primary goal with this issue is to look after your own health & safety as well as your workmates. If you dont feel safe using it then tell someone. Were any of you consulted before the equipment was purchased? There seems to be a number of misconseptional purchases happening recently, where senior managment buy pieces of kit in and either think that the workforce have the necessary skills and training or think "Yes, they'll be okay using this" and not think of the bigger picture.

You are right in saying that no part of the body must be outside of the protection of the truck. (see "7 Deadly Sins" and basic flt training).