biohazard symbol

You may be familiar with the biohazard image but did you know that the design has a rather fascinating history behind it?

Symbol design

The biohazard symbol was created in 1966 by Charles Baldwin, an environmental health engineer at the Dow Chemical Company (US).  He designed it as a way to clearly communicate the dangers of biological materials, such as bacteria and viruses, in a way that was easily recognisable and universally understood.

Rather than trying to represent biological threats in an abstract way, it was designed as a symbol that would be completely devoid of any obvious meaning, then crowd-tested it to make sure it didn’t carry any unwanted associations.  According to Baldwin, the team wanted something “memorable but meaningless”.

Without an obvious way to graphically connect the symbol to invisible biological matter, the design had to avoid creating accidental associations with things people can see.  Why?  Well, biohazards are frequently odourless, tasteless and invisible, making them hard to symbolise in any tangible way.


The symbol is a three-sided trefoil – a graphic form composed of the outline of three overlapping rings – often used in architecture and Christian symbolism to represent the holy trinity.

There is no right way up, no matter how it’s placed so there’s no mistakes when affixing it to hazardous materials and the symbol is usually found on a yellow triangle, but this was not part of the original design.

The symbol was officially adopted by the International Organisation for Standardisation in 1986 and has since become a widely used warning sign in laboratory settings, medical facilities, and zombie apocalypses.


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