Why can't you put water over a chip pan?

If there is a chip pan which is on fire, the correct way to deal with this is to wet a tea towel, ring it out and then lay it over the top of the burning pan (this excludes the air from the fire) then turn off the heat under the pan and leave it to cool.

You must not throw water into the pan because the fat in the pan is hotter than the boiling point of water and this causes the water to boil and explode, throwing burning fat all over you and the room. Water over a chip pan turns a small, controllable fire into an uncontrollable inferno.