What is the recommended action to take in order to stop a liquid petroleum leak?

The recommended action to stop a liquid petroleum leak is to turn off the valve and shut off the tank. This approach directly addresses the source of the leak by halting the flow of petroleum, which is crucial in preventing further spillage and reducing the risk of fire or explosion. By controlling the tank's valve, you effectively contain the leak, making it safer for responders to manage the situation.

While covering the leak with a blanket might seem to offer a temporary solution, it does not stop the leak itself and could lead to further hazards if the blanket becomes flammable. Using a chemical absorbent is useful for cleaning up petroleum spills after the leak has been stopped, but it does not address the immediate containment of the leak. Evacuating the area is a safety measure but does not fix the source of the leak, which is the immediate priority in managing a hazardous situation involving liquid petroleum.