Anthrax spray. Computer artwork of an aerosol can spraying out anthrax spores. Anthrax is a biological warfare agent. It is a naturally occurring disease of plant eating animals and is caused by Bacillus anthracis bacteria. The inhalation of anthrax spores is fatal if the victim is not treated prior to the onset of symptoms. The spores can be delivered by spraying devices from crop duster aeroplanes to household spraying equipment such as aerosol cans. Anthrax is easy to produce in large quantities with equipment similar to that for home-brewing beer.