Cross-Contamination Risks in Crime Scene Cleaning and How to Avoid Them

Crime scenes are delicate environments that must be treated with care. Investigators need them to be kept in pristine condition for as long as possible. 

Safety procedures and processes do not end with the investigation itself, as professionals whose job it is to clean the scenes must also follow strict protocols to eliminate cross-contamination risks such as the spread of bloodborne pathogens, bodily fluids, or other hazardous materials. The safety of the individual is paramount in these hazardous work environments. This blog will examine the risks faced by crime scene cleaners and how they avoid cross-contamination.

De-contamination zone

The setting up of this safe zone is one of the first things to happen at a crime scene. It is a designated area where cleaning equipment is kept away from the scene of the crime to avoid the risk of cross-contamination. It is also used by professionals to ensure their PPE is worn correctly before they enter the scene. For example, ensuring their boots are free from contaminants and their hair is adequately covered, as the accidental transferral of liquid from their boot soles or DNA in stray hairs could destroy or disrupt potentially valuable evidence. 

Finally, at the end of an investigation, the decontamination zone is used to remove, clean, and safely discard PPE.


Crime scene cleaners are equipped with a range of personal protective equipment to avoid cross-contamination, for their own safety as well as other members of the team on-site. Standard issue equipment is disposable gloves, masks, and overalls. Safety goggles with side shields are also used to avoid cleaning products or bodily fluids splashing into the eyes.

Professional cleaners must pay special attention to their boots as these are most likely to contaminate evidence on the floor by bringing in liquids or dirt from outside the secure zone. Disposable plastic boot covers are the most common preventative used but some companies will provide bodysuits with integrated foot pads for use in scenes with higher risks of bloodborne pathogens.

More complex crime scenes require more specialist equipment, such as respirators and HazMat suits. Below is a list of the range of PPE available to a crime scene cleaner.

  • Disposable gloves
  • Disposable face masks
  • Goggles/ Glasses with side shields
  • Shoe covers
  • Overalls/ Jumpsuits
  • Respirators
  • HazMat suits
  • Suits with integrated foot pads.

Insufficient or improper use of PPE can lead to direct contact with contaminants, so regular and effective training should be provided by companies as the highest priority.

Procedures and protocols

Using incorrect cleaning agents or methods may not effectively eliminate contamination from hazardous liquids such as blood or bodily fluids, leading to the spread of pathogens. This is why it is imperative for law enforcement agencies and cleaning companies to enforce strict procedures, which should cover everything from the initial assessment to the final stages of cleaning and decontamination.

There are three assessments that cleaners must make before beginning the sanitation process:

  1. Are there any hazardous fluids present such as blood?
  2. Are there any sharp objects such as needles containing toxins?
  3. Are there any objects that could be used as a weapon against personnel?

The specialized cleaning products that are used to effectively remove dangerous substances must be logged and documented. This information is included in the records kept by the cleaning companies in the event they are needed for review in legal proceedings.

Tools and equipment

Crime scene cleaners often use a variety of equipment. If these items are not properly decontaminated between uses, they can become vectors for cross-contamination. Thorough cleaning and sterilization of tools are key to reducing the risk of cross-contamination.

As always, correctly used personal protective equipment is the most important item in a crime-scene cleaners’ toolkit, but that is only the first step. Specialized vacuum cleaners and containers are also used to clean crime scenes, post-investigation.

Biohazard containment – Bodily fluids such as blood can be difficult to remove completely, but the job must be done right. They can be stored in specially designed containers with tight-fitting lids to be transported elsewhere for analysis or disposal. The same containers are used for body parts and other sensitive organic materials.

When handling biohazardous materials, PPE must be worn properly to reduce the risk of spreading pathogens. The use of cleaning agents such as bleach and hydrogen peroxide reduces this risk significantly.

Hazardous waste – If a crime scene has disturbed volatile substances such as asbestos, specialist vacuum cleaners are used to remove airborne fibers. Cleaning companies are vigilant in ensuring that these tools are free of contaminants before being used at the scene of a crime.


Proper disposal of items gathered from crime scenes is one of the most important responsibilities of a cleaner. As different types of waste require different methods of disposal, it is important to know this before even starting a clean-up job.

Cleaning companies will have established disposal protocols that their staff will be aware of. This will include gathering, packaging, labeling, and transporting items that could be dangerous or contain potential pathogens. These processes are in place to eliminate any risk of dangerous substances or fluids coming into contact with the public or contaminating the local water supply.

The most common process for disposing of crime scene waste is through incineration or, depending on local guidelines, burial.

Avoiding cross-contamination during a crime scene clean-up

Face masks, gloves, and overalls are a must for any person entering a crime scene, not just the cleaners.

Secondly, it is important to follow protocols and procedures to the letter. Make sure everything is documented. Remember, these records could be requested by a court.

And thirdly, make sure the equipment brought into the crime scene is disinfected and fit for purpose.
Aftercare is an established crime scene clean-up company. Visit our website to explore the range of Virginia crime scene clean-up services we provide.