I couldn’t believe it when I saw this valve during a recent compressed gas plant tour.  My tour guide explained that his company had purchased a large number of cylinders from the World War II era.  Made in America.  With a swastika right below that phrase.

My guide explained to me that most likely the swastika had been stamped on the valve the same way the Nazis had stamped swastikas on the shoulder of compressed gas cylinders.  His company had them stamped a square around the swastika to turn into what looked like this:

You can see it to the left of the date 6-18.  It looks like a window frame with 4 panes.

When I returned to my laboratory, one of the metallurgists disabused me of the notion that the swastika had been stamped on the valve by Nazis.  It was, he explained, forged as one piece.  The swastika included.

So, the swastika had been forged as part of the valve at the date of manufacture by American manufacturers.  Not a happy thought.