There are normally two types of fog machines, chemical (glycol based) and water atomizing. But this one is not a fog machine. It's LN2 and steam. The vapor is drawn off of the liguid in the liquid nitrogen tank. The same effect is in front of the falling building. The LN2 gives it the fog and the steam carries it. It's the same thing used at T2, MIB, Sinbad and Posiedon.
Hope that helps..
[This message was edited by Earl on 01-31-01 at 11:25 PM.]