Do you know the origin of the radiation warning symbol?

It was conceived at the University of California at the Berkeley radiation lab in mid-1946 by a small group of people. At first, its impression was magenta on blue and the image was spreading throughout the United States.

However, using blue as a background was not a good choice, as color is not recommended for use in warning signs and the like, as the color deteriorates over time, especially if used outdoors.

It is estimated that the use of yellow as a background was probably standardized by the Oak Ridge National Laboratory in early 1948, and modifications in the original design were made in the early 1950s. For example, straight or undulating arrows have been added between or within the propeller thrusters.

The current version was finalized by ANSI standard and federal regulations in the mid 1950s.