I cant think of what this is called, help please?

Ok since i cant think of what its called, im gonna give the best description of it i can. Whats this thing called where like ur local police & fire department get together & do a simulation of what theyd do to help everyone in an emergency like a tornado, earthquake or wreck. And they have ppl vollenteer to be the victims. & they get the vollenteers covered in fake blood & wounds & they have to act as if they were hurt in a wreck or whatever situation. So can anyone tell me what this is called? Its driving me crazy ><