Biological hazards (biohazards) are substances that are biological in nature and pose a threat to the health of living organisms. Sources of biological hazards include bacteria, viruses, insects, plants, birds, animals, and humans. These sources can cause a variety of health effects ranging from skin irritation and allergies to infections (e.g., tuberculosis, AIDS), cancer, and so on. Infections from biological agents can be caused by bacteria, viruses, rickettsia, chlamydia, and fungi. Parasites include protozoa, helminths, and arthropods. Toxic and allergenic substances include bites from animals or “sticks” from plants.

Biological hazards have become a leading cause of concern in the workplace. The Occupational Safety and Health Administration (OSHA) implemented the Blood-Borne Pathogen Standard (29 CFR 1910.1030) to reduce the potential for occupational illnesses related to biological hazards. In this chapter, we will discuss the more common biological illnesses of occupational concern and the means to prevent injuries and illnesses related to them.