Pathological Waste; How it is Collected, Treated & Disposed

Pathological Waste; How it is Collected, Treated & Disposed

What is Pathological Waste?

Pathological waste is a subcategory of biohazardous waste which typically originates from surgical procedures or research that involves removal of organs, tissues or body parts. It can be human or animal. For the purpose of proper classification and disposal, teeth, hair and nails are not considered pathological waste in Maryland. Check with your state’s health authorities or with your medical waste disposal vendor if you need help determining what is and what isn’t pathological waste.

Pathological waste is a very common type of waste generated by numerous healthcare and medical research and testing facilities. And due to its unique qualities and challenges, it calls for different collection and disposal procedures than your typical red-bag waste.

Types of Pathological Waste

  • Amputated tissues, organs and body parts
  • Tissue samples collected for analysis
  • Animal tissues, organs, body parts or carcasses used in research
  • Surgical specimens.
  • Bodily fluids removed during surgery or autopsy.

Pathological Waste Collection

Pathological waste should be separated from the rest of the red-bag regulated medical waste. It possesses a few qualities that may warrant different disposal procedures. Consider this when developing your facility’s guidelines for pathological waste collection and disposal:

  • Pathological waste, specifically anatomical waste such as organs, can be saturated or filled with bodily fluids. Special measures, such as double-bagging or use of absorbents, may need to be taken to prevent leakage.
  • Pathological waste has to be refrigerated in order to slow down decomposition and prevent odors. It’s best to have it picked up promptly.
  • Some pathological waste may be hazardous if it was in contact with hazardous chemicals such as chemotherapy drugs. It may also be infectious or potentially infectious. In either case, it should be labeled accordingly.

Read Also: Biomedical Waste Management; Treatment & Disposal

Pathological Waste Treatment

There are some approaches to the treatment of pathological waste. Some are as follows:

  • Composting:

Just as waste food can be composted, so can pathological waste, although some people may object to treating human tissue that way. Small backyard composters operate at ambient temperatures. Large compost piles that accept material from commercial sites and entire neighborhoods are generally more efficient and operate at higher temperatures (140 degrees F or so). Sometimes worms are put in the mix in a process called vermicomposting.

Pathological waste is not usually put in composters, with the exception of placentas. Human psychological considerations prevent human body parts from being composted.


  • Irradiation:

Irradiation treatment exposes waste to electron beams, cobalt-60 or ultraviolet sources. The pathogen destruction efficacy depends on the radiation dose absorbed by the waste. Electron beams can penetrate waste bags, thereby eliminating the need for a mechanical shredding before treatment.

Ultraviolet radiation (wavelength 210 nm to 328 nm) can destroy airborne microorganisms. It is sometimes used as part of the overall treatment system, but it is rarely a main treatment unit. Unlike electron beams, UV radiation is not able to penetrate closed waste bags.

When waste management engineers incorporate irradiation into their process, they usually have to install personnel protective shielding.

  • Chemical processes:

Chemical treatment methods use disinfectants such as dissolved chlorine dioxide, bleach (sodium hypochlorite), peracetic acid, lime solution, or dry inorganic chemicals (e.g. calcium oxide).

In liquid systems, the waste may go through a dewatering section to remove and recycle the disinfectant. Besides chemical disinfectants, there are also encapsulating compounds that can solidify sharps, blood or other body fluids within a solid matrix before disposal. If done correctly, this process reduces the possibility of future leaching of hazardous materials into groundwater.

Some systems uses heated sodium hydroxide solution or calcium oxide/lime slurries to digest this waste in heated stainless-steel tanks. After the digestion/treatment, the waste is no longer recognizable as of human origin, and typically has little or no microbial activity. Further treatment (such as encapsulation or incineration) is required before final disposal.

Read Also: Patient Safety; Everything You Need to Know [An Indepth Review]

Pathological Waste Disposal

Technically, this waste falls under the umbrella of regulated medical waste. Within that category, there are two primary means of waste disposal. Depending on the type of waste, that can involve medical waste autoclaves, or it can involve a medical waste incinerator.

One of the most common medical waste steams treated through the autoclave process is anything contaminated with blood or other potentially infectious material. This type of waste is largely known as red bag medical waste.

Anything deemed pathological, however, is not suitable for the autoclave machine. Rather, this type of waste must go through medical incineration—a much hotter treatment that essentially reduces the contents to dust or ash. (On the other hand, autoclaving is merely a sterilization process. The products themselves are not reduced down in this way.)

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