We responded for a report of a warehouse fire. Upon arrival we did find a large mixed use warehouse with 50% plus involvement. My Engine went to the exposure structure to the East of the fire building, with the exposure starting to smoke, no fire yet. While operating a 2.5″ line at this position my partner and I heard a 5 second blast of what sounded like a pressure relief valve releasing. This one got our attention and perked us up, not sure if it really was what we thought it was. Within 15 to 30 seconds later we heard the same sound again and knew for sure we had an issue with some sort of pressurized tanks in our area of operations. With the 2nd blast I told my partner we are backing up and we did. Our Division command was told of the situation and he gave an Emergency transmission for crews to back away from the building. Shortly after backing to a safe distance, about a minute or two after hearing the 2nd release, tanks began exploding in the area we had been operating at. Crews on the Alpha side of the building reported some were actually launched into the air. Once the explosions stopped we were able to relocate to the area again to try and save the exposure, but it was too late with the 2nd building now well involved with fast moving fire.
Stay alert and be aware of your surroundings. Don’t get tunnel vision on one area and block everything else out. Most importantly, trust your instincts and don’t be afraid to make a call to pull back. I was pretty sure what I was hearing and it turned out to be what I thought it was. Had I been afraid to make the call to back up, my partner and I most likely would have been seriously injured.