Thumbnail: The biohazard symbol was developed by the Dow Chemical Company in 1966 for their containment products. It is used in the labeling of biological materials that carry a significant health ris...Thumbnail: The biohazard symbol was developed by the Dow Chemical Company in 1966 for their containment products. It is used in the labeling of biological materials that carry a significant health risk. Image used with permission (Public Domain; Silsor).