Bloodborne pathogens are microorganisms found in human blood that can infect and cause disease in people who are exposed to blood containing the pathogen. The precise risk of bloodborne pathogen transmission during exposure to open wounds or mucous membranes such as eyes, ears, nose, and mouth is not fully known. However, scientific evidence suggests the chance of exposure may be extremely low but not zero. The good news is that precautions can be taken to ensure that no bloodborne pathogen transmission occurs. The guidelines outlined in this article are important for avoiding contact with bloodborne pathogens during high school laboratory or field work.