One of the early assignments Parks undertook on behalf of Standard Oil was to photograph a grease workers’ plant in Pittsburgh. The plant’s grimy interiors gave Parks the opportunity to render dramatic contrasts of light and dark in his pictures, visible on machines and barrels and on the faces of the workers who handled them. Among the most notable images from the series are those of a Black worker in the cooper’s room, where a spectral steam rises around the barrels and drums he is reconditioning.