What general step should be taken to control a flammable liquid fire?

Identifying the material involved is crucial when controlling a flammable liquid fire because different substances require different approaches for effective extinguishment. By determining the specific type of flammable liquid, fire brigade members can choose the appropriate extinguishing agent or method tailored to the chemical properties of that particular liquid. For example, some flammable liquids may respond to foam or dry chemical agents, while others might necessitate the use of specialized extinguishing agents due to their unique burning characteristics. Proper identification minimizes the risk of exacerbating the fire or causing additional hazards, thus ensuring a safer and more effective response.

The other choices do not provide a suitable or proactive method for handling such fires. Using regular water, for example, can be dangerous as it may spread the fire or lead to explosive reactions, depending on the liquid's properties. Allowing the fire to burn out is highly risky, as uncontrolled flammable liquid fires can escalate quickly and endanger lives and property. Evacuating personnel is important for safety but does not address the immediate need to control or extinguish the fire effectively. The initial step in fire response should always be identifying the material involved to guide further actions appropriately.