Biohazard sign
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About the biohazard sign
In 1966 Dow Chemical and the US National Cancer Institute set out to create a warning for biological hazards, with the engineer Charles Baldwin leading the design. They wanted a striking shape with no previous meaning, so that the only thing anyone would ever learn it meant was danger.
It looks the same whichever way up it is turned and can be painted with a stencil. It now marks biological hazards worldwide.