When used safely and properly, a propane hibachi grill is a very safe piece of BBQing equipment. However, just like any other propane grill, they pose a fire risk if a gas valve is left on. Leaving the valve on can cause the gas to build up and be ignited by a flame.
To ensure optimum safety on a propane hibachi grill, temperatures should not exceed 320°F. Temperatures over this heat can increase the pressure inside the grill tank, exceeding and overpowering the safety release valve, leading to explosion.
You should also regularly check hoses and valves for leaks. You can do this by applying a soap solution to the hose and valve exterior then switching on the gas. Any bubbles that appear indicate a leak that needs to be repaired.