An attempt was made to use the flat-top gas grill located underneath the tiki umbrella area. At the point of starting the grill, the tubing from the propane tank was not properly fastened/connected to the grill therefore it came apart causing a fire with multiple small explosions as propane was being emitted into the surrounding area. If the property and all equipment would have been inspected properly, this could have been prevented. Also, as the fire extinguisher was attempting to be engaged, it did not work. It was empty. At this point a realization was made that the fire department needed to be called & they came out to extinguish the fire. After they were called, one guest thought to close the valve on the propane tank. He put his own life in danger by entering the area of the fire to close the valve on the tank. He reached in and closed it. This is when the fire calmed down. The fire department then arrived to ensure that the scene was safe. After an assessment, the fireman explained the tubing was faulty. They explained: the tube that was disconnected to the grill was previously damaged & should have been caught by the property manager upon inspection. They also showed the gauge on the fire extinguisher & obviously showed that the fire extinguisher was empty. When the owner, Martha, was contacted about the incident, her response was, "I was not aware as I have not gone to the property. Were there any damages?" She did not even ask if everyone was okay! Wow, heartless.