General view of an unidentified chemist handling radioactive material at an unidentified U.S. Department of Agriculture facility. The U.S.D.A. commonly used radioactive material for a variety of research and testing,…

General view of a Stokes Tablet Press at the U.S. Department of Agriculture's Agricultural Engineering Laboratory facility. A tablet press is a mechanical device that compresses granulated material into tablets or…

General view of a variety of tools used to handle radioactive substances and other materials at U.S. Department of Agriculture facilities. The tools are labelled with numbers, presumably corresponding to an…

General view of an unidentified apparatus at an unidentified U.S. Department of Agriculture facility.

General view of an unidentified apparatus at a U.S. Department of Agriculture facility. A radioactive materials sign and protective glass panel are visible to the right of the apparatus. The U.S.D.A. commonly used…

Close-up view of the interior of an apparatus likely used for the manufacture and/or testing of fertilizer at an unidentified U.S. Department of Agriculture facility.

Component parts, likely of a drillability apparatus, used at an unidentified U.S. Department of Agriculture facility.

View of chemist William A. Jackson using a Gieger counter to examine a package at an unidentified U.S. Department of Agriculture facility. The U.S.D.A. commonly used radioactive material for a variety of research and…

View of chemist George Wieczorek removing a vessel from a Pereco kiln at an unidentified U.S. Department of Agriculture facility.

General view of assorted containers and components used to house radioactive materials. The jar labels include space to record the isotope, amount, and date. These containers are believed to have been used as part of…

Close-up view of the handling of radioactive material at an U.S. Department of Agriculture facility. The U.S.D.A. commonly used radioactive material for a variety of research and testing, including the study of…

George Wieczorek (right) and two unidentified chemists handling radioactive material at an U.S. Department of Agriculture facility. The U.S.D.A. commonly used radioactive material for a variety of research and testing,…

View of chemist George Wieczorek (right) using a Geiger counter to measure ionizing radiation in an unknown substance, likely soil or fertilizer, at an unidentified U.S. Department of Agriculture facility.

General view of granulation equipment used at the U.S. Department of Agriculture's Agricultural Engineering Laboratory located in Beltsville, Maryland. This equipment is believed to have been used by chemist John O.…

Overhead view of the Ingalls Shipbuilding Corporation's Mid-South Big N barge showing several tankers and unidentified workers. This barge may have been used to transfer ammonia fertilizer between storage terminals.

General view of the Shell Corporation's oceanic barge, known as "Ammonia Mariner." The barge was used to transport approximately 50,000 tons of ammonia fertilizer each year from Pittsburg, California to storage…

General view of fertilizer storage piles supported between uprights at the U.S. Department of Agriculture's Agricultural Engineering Laboratory. Text accompanying the photograph notes that each row contained a full set…

General view of small-scale continuous granulation equipment used at the U.S. Department of Agriculture's Agricultural Engineering Laboratory.

General view of an unidentified room at the U.S. Department of Agriculture's Agricultural Engineering Laboratory showing a drillability apparatus with fertilizer hoppers, a starwheel, and rotating plate mechanism.

General view of the trays used to expose fertilizer to humidity in the Air Control Room at the U.S. Department of Agriculture's Agricultural Engineering Laboratory.

General view of the drillability machine at the U.S. Department of Agriculture's Agricultural Engineering Laboratory showing the distribution of wet granular fertilizer as deposited by the Grether hopper.

General view of the Air Control Room at the U.S. Department of Agriculture's Agricultural Engineering Laboratory showing three bags of fertilizer in storage under three bags of sand.

General view of an International Fertilizer Distributor (No. 49 Machine) in use at the U.S. Department of Agriculture's Plant Industry Station facility in Beltsville, Maryland. This machine was used to determine the…

General view of an unidentified worker sorting raw material, possibly ore or phosphate, at a Fixed Nitrogen Research Laboratory plant. The Fixed Nitrogen Research Laboratory (F.N.R.L.) was established at American…

General view of an unidentified apparatus, possibly a pump or compressor, used at the U.S. Department of Agriculture's Fixed Nitrogen Research Laboratory located in Washington, D.C.

The Fixed Nitrogen Research…