The San Francisco Fire Department is one of the last remaining departments that still uses wooden ladders in all of its operations. It is also the only city department that builds its own ladders. Wooden ladders are used for a number of reasons. The main reason being that wooden ladders don't conduct electricity, which is very important when your has lots of exposed high voltage power lines. Wooden ladders are also heavier, making them more stable in the heavy San Fran winds. They also handle heat better and don't fail catastrophically like aluminum ladders can. Wood may be much more expensive than aluminum, but the city actually saves money using the wooden ladders, because unlike metal ones they can easily be repaired, something the department also does in house. Some ladders that are still in use date back to as early as 1919.