Public domain
Conversion. Converters at one of the four butadiene units where the processing of grain alcohol to butadiene is started
From the collection of Library of Congress. Free to download, adapt and use — no permission needed.
Credit lineConversion. Converters at one of the four butadiene units where the processing of grain alcohol to butadiene is started. 1935-01-01. Farm Security Administration/Office of War Information Collection, Library of Congress. Public domain.