What are the origins and significance of the components of the biohazard symbol?
The symbol was designed by Dow Chemical. Scientists at Dow found that many labs had warning labels but no standardization and decided to take on the project. Scientists and marketing people came up with a symbol that could be easily stencilled, easily remembered, and easily recognized even when upside-down.
For more on the origins see this New York Times Magazine article.
—The Fact Monster