Two views of the No. 2 furnace and stock piles at a U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory plant. The stock piles likely contained a mix of raw material, including greensand, leucite, coke, and limestone, used in the experimental blast furnace. According to notations accompanying the photographs, the first photograph was taken when the furnace's precipitator was on, while the second photograph was taken when the precipitator was off.

The Fixed Nitrogen Research Laboratory (F.N.R.L.) was established at American University in 1919 under the directorship of Arthur B. Lamb. Initially part of the War Department, the F.N.R.L. was the successor to several wartime initiatives to develop a secure domestic supply of nitrate compounds necessary for the manufacture of explosives during World War I. With a staff of about 110 individuals, including 35 to 50 chemists, the F.N.R.L. focused on the manufacture, production, and development of products of atmospheric nitrogen, including munitions and fertilizers.