A Canadian firetruck responding with lights and sirens to a weekend fire in Rouses Point, New York, was stopped at the U.S. border for about eight minutes, U.S. border officials said Tuesday.
http://www.cnn.com/2007/US/11/14/bor...uck/index.html
If the fire station is that close to the border, then it seems to me that some kind of protocol should have been established ahead of time with the Us customs so that the border patrol knows the fire crew and they are pre-screened.