A fire broke out at the James J. Peters Department of Veterans Affairs Hospital in Kingsbridge Monday night, prompting response from 12 FDNY units and more than 60 firefighters.

Authorities say it sparked in a dumpster behind the hospital around 7 p.m.

Smoke billowed inside and spiked levels of deadly carbon monoxide -- so firefighters say they promptly ventilated the building before having to evacuate.

"I was just like, what is that? Smells like smoke," says hospital worker Dashawn Rose. "When I had that thought, that's when the alarms went off. And then we went upstairs to find out what it was. By the time we went upstairs, the fire department reacted fast, real fast."

The large facility serves hundreds of veterans. The FDNY says no one was injured.