A fire on a Brooklyn ship yesterday had a potentially deadly radiation leak yesterday. But New York's Bravest were so calm that the worst thing that happened was a broken water hose.

The fire, the radiation and the casualties aboard a merchant ship docked in Red Hook were a simulated joint training exercise between the Marine Corps and the FDNY.

Working with 90 Marines from the Chemical Biological Incident Response Force (C-BIRF), over 100 Brooklyn firefighters ran through a nearly three hour drill that included extracting victims, testing air quality and practicing decontamination techniques.

The drill was a way for Marines and firefighters to learn from each other. In the event of an actual radiation leak, the FDNY would know how to respond appropiately. But the 500-man C-BIRF team, based in Maryland, could also arrive within hours to support New York's first responders, officials said. The drill was a success, officials proclaimed.

"I'm very pleased that it went very well," Fire Commissioner Nicholas Scopetta said.

"It was, I think, a seamless integration of Marines reinforcing the Fire Department of New York," Col. Michael Campbell said.

The drill was the fourth joint training exercise between the FDNY and the Marine Corps since 1996.