What is "CONDITION ONE CHARLIE"?

[Flight ATC]

Question for the ARFF heroes: WHAT DOES "CONDITION ONE CHARLIE" MEAN?
I hear this get broadcasted over the speakers in the Fire Hall when Tower calls about an emergency inbound. Are there other codes too? What do they mean?

 

[Roichi]

That may depend on the local airport fire department SOPs. Here in Germany it is defintely different.

 

[Flight ATC]

That may depend on the local airport fire department SOPs. Here in Germany it is defintely different.

Very possibly, I hear this at some Canadian airports.