Historically, physicists created a graphical representation detailing the three elements of fire (fire triangle). In recent years, one more point has been added, creating the fire tetrahedron. The four elements needed to sustain combustion are:
fuel, oxidizer, heat and a chemical chain reaction.
To extinguish a fire, it is necessary to remove one or more of the four components of combustion. Removing any of these components of the fire tetrahedron will stop the other elements from interacting and not allow combustion to continue. Firefighters work on limiting exposures (fuel that is in jeopardy of being ignited by nearby flame or from radiant heat), containing and extinguishing fire and then overhauling charred and burned debris from the affected areas as well as extinguishing all hidden fires to prevent a rekindle.
Firefighters' goals are to save life, property and the environment. A fire can rapidly spread and endanger many lives; however, with modern firefighting techniques, catastrophe is usually avoided. To prevent fires from starting a firefighter's duties include public education and conducting fire inspections. Because firefighters are often the first responders to people in critical conditions, firefighters provide basic life support as emergency medical technicians or advanced life support as licensed paramedics.