Pallet jacks are a common tool for moving palletized material. They are inexpensive and easy to operate. Therein lies the danger: there is often a direct relationship between the perception that material handling equipment is easy to operate and their involvement in incidents.
If an object is too heavy to lift by hand and an overhead hoist, crane, forklift, or pallet jack is used to lift it, a safety hazard is created. The load is heavy; maneuvering it creates dynamic forces that are not always obvious. Manually-propelled pallet jacks have no brakes; if a heavy load is moving it will take some time to stop it using only body weight. During this time the load will have traveled some distance and can trap an operator against an object. The load can also turn over when making a quick turn due to centrifugal force.
The person in this video had no idea what he was doing. He never lowered the lift gate to the floor (which is why it is there). The lift gate raises and lowers loads to and from the truck bed. Once the load was pulled off the edge of the lift gate, he should have let go of the pallet jack handle. There was literally no physical way he was going to be able to stop the load from falling. We hope this person suffered no serious injuries from this incident.