Christian James (C. J.) Lambertsen (1917-2011) worked as a professor of pharmacology, director of the Institute for Environmental Medicine, and the founding director of the Environmental Biomedical Stress Data Center in 1985 at the University of Pennsylvania's School of Medicine. He designed the Lambertsen Amphibious Respiratory Unit (LARU), which was the first widely used, closed-circuit Self-Contained Underwater Breathing Apparatus (SCUBA) in the United States. Types of materials include correspondence, reports, photographs, audio material, slides, lab books, lab data, experimental measures and procedures, diagrams, graphs, articles, manuscript drafts, grant proposals, newspaper clippings, and notes. Primary subjects include decompression, oxygenation, diving, decompression sickness, diving physiology, and underwater breathing apparatus. Materials range in date from 1930 to 2004.

This collection contains experiment documentation, research notes, scholarly writing, technical reports, publications, correspondence, and artifacts belonging to Christian James Lambertsen, primarily created during his tenure at the University of Pennsylvania. Primary subjects include decompression, oxygenation, diving, decompression sickness, diving physiology, and underwater breathing apparatus. Documentation from the University of Pennsylvania's Environmental Biomedical Stress Data Center and the Undersea and Hyperbaric Medical Society are also included. Numerous photographs, slides, films, and audio recordings are part of the collection, many of which need to be reformatted in order to be used. Materials range in date from 1930 to 2004, the bulk of the papers documenting Lambertsen's experiments are between 1970 and 1995.