sentences:  In these cases the training and registration may follow the same requirements as for other professional divers, or may include training standards specifically intended for scientific diving.In other cases, where the divers are in full control of their own diving operation, including planning and safety, diving as volunteers, the occupational health and safety regulations may not apply.Where scientific diving is exempt from commercial diving regulation, training requirements may differ considerably, and in some cases basic scientific diver training and certification may not differ much from entry level recreational diver training.