General view of an employee operating an apparatus used to study ammonia at the Bureau of Chemistry's Nitrogen Laboratory. Part of the U.S. Department of Agriculture, the Nitrogen Laboratory conducted investigations into substances, including nitrogen, hydrogen, and carbon, formed due to the decomposition of food, as well as analyzed the nitrogen content of assorted foods, fertilizers, and cattle feeds.

The Bureau of Chemistry was established in 1901 through Congressional appropriations as a successor to the U.S.D.A. Division of Chemistry and significantly built upon the work of its predecessor, which researched the adulteration and misbranding of food and drugs on the American market. The 1906 Food and Drug Act notably increased the Bureau’s regulatory powers and led to the establishment of laboratories for testing the purity and composition of foods and drugs. In 1927, the Bureau of Chemistry effectively disbanded when its powers were reorganized under a new U.S.D.A. body, the Food, Drug, and Insecticide Organization (later the Food and Drug Administration).