Biohazards are infectious agents or hazardous biological materials that present a risk or potential risk to the health of humans, animals ro the environment. The risk can be direct through infection or indirect through damage to the environment.

Biohazardous materials include certain types of recombinant DNA; organisms and viruses infectious to humans, animals or plants (e.g. parasites, viruses, bacteria, fungi, prions, rickettsia); and biologically active agents (i.e. toxins, allergens, venoms) that may cause disease in other living organisms or cause significant impact to the environment or community.

Biological materials you may not consider to be biohazardous maybe regulated by regulations and guidelines as biohazardous materials.