Dry ice

I work at a Genetic research institute as I think most of you know. It is built in the grounds of an old stately pile and the grounds are very nicely maintained. Most Lunch breaks I go for a walk to give my back a stretch and my eyes a break from the computer. The other day I was walking on one of the paths past a laboratory where a lorry was filling up a nitrogen tank. However a lot of it was leaking so we had a strange mist escaping all over the place. It was like being in a musical with all the dry ice on the ground. I'm assuming it wasn't dangerous as the man controlling the tank didn't seem to have any protective clothing. However I'm sure that is the same stuff that chemistry teacher's used to dunk a banana in which then went brittle.