Final answer:
The international biohazard symbol indicates the presence of biohazardous materials. It is used in lab settings to promote safety by warning against potential hazards such as skin punctures, mucous membrane exposure, and ingestion of infectious material.
Step-by-step explanation:
The sign that indicates biohazardous materials are present is known as the international biohazard symbol. This symbol is universally recognized and is used to alert people to the presence of substances that are biologically hazardous, such as potentially infectious agents like bacteria, viruses, or other microorganisms.
In a laboratory setting, particularly a Microbiology laboratory, it is mandatory to use these signs to label areas, containers, and fridges where biohazardous materials are stored or used. The signage serves as a warning to use caution and follow proper protocols to avoid accidental skin punctures, mucous membrane exposure, or ingestion of infectious material, which are primary hazards in BSL 1 or BSL 2 labs (Biosafety Levels 1 and 2). Proper disposal of biohazard waste, such as a bacterial culture grown on an agar plate, also requires adherence to specific safety guidelines, including sterilization before disposal to prevent any hazard to the environment or public health.