The following information is NOT printed on this postcard: The Biohazard Sign was developed by the Dow Chemical Company in 1966 for their containment products. According to Charles Baldwin, an environmental-health engineer who contributed to its development: "We wanted something that was memorable but meaningless, so we could educate people as to what it means." In an article in Science in 1967, the symbol was presented as the new standard for all biological hazards ("biohazards").

It is used in the labeling of biological materials that carry a significant health risk, including viral samples and used hypodermic needles. It was also somewhat famous for being the "insignia" for the 2002 horror film, 28 Days Later. A tattoo of the biohazard sign is recognized within the gay community to indicate the wearer is living with HIV. The origins for this practice aren't clear, but they range from a response to William F. Buckley's call for the tattooing of HIV positive individuals to a few activists within ACT UP. The biohazard symbol was created to identify hazardous substances back in the 60's but is now part of popular culture. As a tattoo it was popularized by the band Biohazard.