A fire in a storage unit at U-Store Self Storage, 620 Mitchell Ave. in Woodland, was quickly contained on Saturday morning.Crews from Clark County Fire & Rescue, Clark County Fire District 6, the Cowlitz Fire District in Kalama and the Vancouver Fire Department all responded to a 911 call at 11:22 a.m.They found one storage unit completely on fire — and heard what sounded like stored ammunition exploding inside, according to division chief Tim Dawdy. “They knew it was a serious fire,” he said. (Dawdy added that ammunition stored properly may burst open in a fire, but if the ammunition is stored inside a weapon, it may behave like a projectile. That’s another excellent reason never to keep guns loaded, he said.)Fortunately, Dawdy said, one wall of the unit was a firewall, so the fire couldn’t spread in that direction. Firefighters were able to stop the fire from spreading in the other direction and there was only minor smoke damage to two adjacent units, Dawdy said. No one was injured.