What is considered to be a biohazard?

A biohazard is defined as any material that poses a risk to human health or the environment, particularly when it is contaminated with potentially infectious substances. In this context, something that is contaminated with blood secretions qualifies as a biohazard because blood can carry pathogens that are capable of causing disease in humans. Therefore, surfaces or materials that have been in contact with blood or other bodily fluids must be handled with care and treated as hazardous waste to prevent the spread of infection.

The other choices depict conditions that do not pose a similar risk. A clean surface and a surface free of microbes indicate a lack of contamination and, thus, do not present any biohazard risk. Additionally, a non-toxic substance does not meet the criteria for being a biohazard since it lacks the potential to cause harm or infection. Only materials contaminated with biohazardous substances, such as blood secretions, require special handling and disposal procedures due to their infectious nature.