Excerpts from the report: Although chloropicrin has been used as a grain fumigant for many years, published data on its distribution in large grain masses are nearly nonexistent. These studies were planned to determine the distributional characteristics and effectiveness of selected dosages of chloropicrin used alone or mixed with carbon tetrachloride and carbon disulfide for the fumigation of bulk wheat and sorghum. Chloropicrin concentrations throughout the entire grain mass were recorded to establish the value and limitations of chloropicrin as a grain fumigant. The gravity-penetration method was tested in 3,250-bushel metal circular bins. The closed-recirculation method was tested in 3,250-bushel bins, 6,000-bushel bins, and a large flat storage of 100,000-bushel capacity.