Large steel mills often had their own fire departments for safety reasons and these retired Mack fire trucks belonged to Bethlehem Steel at their main plant in Bethlehem PA. When this steel mill closed in 1995, the trucks were run into one of the giant buildings on the site along with other industrial leftovers and left there. I was fortunate to get special permission through a local historical group to go onto the property to shoot.
There was a lot of disarray in that large building and the other junk included a small railroad locomotive, wooden sand molds, forklifts, large metal cabinets full of blueprints, various electrical apparatus, and even old metal hard hats. It was the rump left of what was once the second largest corporation in the world.
The trucks are late fifties or early sixties Macks, which were probably made at the Mack plant that still exists in nearby Allentown. Today the property has been made into a vibrant music and arts center with the original blast furnaces standing as a backdrop. For more information, see http://www.steelstacks.org/