The cleaners' job is to remove any sign of what happened at the location they have been employed to clean, and to deal with and any biohazards that result from such an incident. As US Federal regulations deem all bodily fluids to be biohazards, any blood or tissue at a crime scene is considered a potential source of infection.

Crime scene cleaners need specialist knowledge to handle biohazardous material safely and to know what to look for at the scene. They also need permits to transport and dispose of biohazardous waste.