Blue Denim work clothing was adopted as Standard by the Army on 11 June 1919, replacing brown work clothing used before. The top was a jumper style pullover, the trousers had five pockets -- two front, two hip, and a watch pocket. In 1933 a one-piece work suit (coveralls) was adopted in blue denim for use by mechanics, drivers, machinists, and others in similar roles. This was in addition to and did not replace the two piece work uniform. These blue denim coveralls were used until replaced by herringbone twill (HBT) one piece coverall in 1938.

The Army Blue Denim Work Uniform of 1940

In 1940, after field complaints about pullovers ripped down the front, the jacket style of blue denim work uniform was adopted. It had two large front pockets toward to bottom of the garment and buttoned up the front. It was made to be closed at the collar.

At the same time in 1940, the blue denim trousers were improved by using a style made from the same pattern as the khaki summer uniform trousers, with the front pockets moved to the side. The M-1937 "Daisy Mae" style hat was also provided in blue denim (with white stitching visible) to complete the uniform, as seen in the photo at left, made in 1940. These blue denim garments were used until replaced by the HBT two piece field uniforms in 1941.

Although the replacement was standardized, the blue denim uniforms continued in use for a few more years as supplies were used up. Since the great increases in supplies for World War II came after the HBT uniforms had been adopted, blue denim garments were relatively rare and are not much associated with the Army in World War II.