Chiron is a biotechnology firm based in Emeryville, California. It was founded in 1981. In mid-2003, Chiron employed 2,225 people in the United States, and 1,819 outside of the United States. Chiron's business and research is focused on vaccines, infectious diseases, and cancer treatment.

On August 27, 2003 two bombs exploded at Chiron's headquarters in Emeryville. [1] A group calling itself Revolutionary Cells of the Animal Liberation Brigade E-mailed a statement to reporters taking credit for the bombing.