Unless it also contains sodium hypochlorite, bleach is not considered flammable. It also contains chemicals that can fuel a fire by acting as oxidizers. For instance, if you use bleach to clean several surfaces in your house and a fire starts, the chemicals in the bleach will cause the fire to spread more quickly. Despite not being flammable, bleach can still explode. The other chemicals oxidize and explode when bleach is combined with ammonia and acetylene.