This series of photographs depicts the aftermath of a fire that swept through the National Technical Laboratories building in South Pasadena. Most are unattributed, but Hank Hoag is identified as the photographer in one case. Some photographs are numbered or stamped May 5, 1950. One image includes an account on the fire on the reverse.
Hoag, Hank. “National Technical Laboratories, South Pasadena Building Fire,” May 1950. Beckman Historical Collection, Box 56, Folder 29. Science History Institute. Philadelphia. https://digital.sciencehistory.org/works/rf55z808j.