During the Great Depression, photographers of the Farm Security Administration/Office of War Information began cataloging the economy’s effect across the country–and some of the rare color photos contain images of Oklahoma. They’re available for viewing through the Library of Congress’s archives.

In this photo by John Vachon, we see four employees of the Mid-Continent Refinery, which was located in West Tulsa. A few years earlier, in 1938, the refinery was the scene of one of Oklahoma’s most violent and long-lasting strike.