1. The season's most ubiquitous warning sign makes cameos in The Hulk and T3, on the poster for 28 Days Later, and in a National Geographic TV special on the FBI.
2. Created in 1966 with the help of the Dow Chemical Co. (for containment systems at the National Cancer Institute), it's usually found in hospitals and research labs.
3. After extensive test marketing, the logo was declared more recognizable than the Texaco star and Planters' Mr. Peanut.
4. It's often bright orange (that color has been found to stand out best) and three-sided, in order to be read in any direction.
5. Cost of a novelty T-shirt bearing the biohazard symbol, available online at Buy-Tees.com: $16.99.