Oct. 15, 1936. Washington, D.C. “Protection against that dreaded disease Silicosis is assured underground workers with this new sand-blasting helmet developed by William P. Biggs, Safety Engineer of the Navy Department. Weighing only 43 ounces, the helmet has been tested for nearly a year in various naval stations throughout the country.” Harris & Ewing glass negative.

(taken from http://www.shorpy.com/node/15321)