Throwing aerosol cans into a fire is dangerous because: 1) The high heat can cause the compressed gas inside to rapidly expand, which may cause the can to explode like a projectile. 2) The explosion could send flaming or molten fragments flying in all directions, posing burn and impact risks. 3) The contents of the aerosol can, such as propellants or solvents, may ignite or intensify the fire when exposed to high heat.