The Biohazard reference article from the English Wikipedia on 24-Apr-2004
(provided by Fixed Reference: snapshots of Wikipedia from wikipedia.org)

Biohazard

Sponsor with the world's largest charity for orphans
biohazard symbol
Biohazard is a shorthand term for "biological hazard". It refers to biological substances that pose a threat to (primarily) human beings. This can include medical waste, samples of a virus or bacterium that can affect humans, and so forth. It is generally used as a warning, so that those potentially exposed to the substances will know to take precautions.

In Unicode, the biohazard sign is U+2623 (☣).