The Physical Form of Medical Waste


Barches of waste - or streams of waste - can have different natures. Common ones are:

  • Dry solid
  • Wet solid
  • Slurry
  • Gel
  • Liguid-liquid colloid

Solid waste is the easiest to control and poses less of a spread/distribution risk than liquid or vapor. The disposal risk for a solid largely depends on how friable it is. A piece of metal isn’t likely to split unless great force is applied while a graham cracker will produce crumbs.

If your waste more resembles a graham cracker than a bar of metal, it is more likely to cause a disposal risk.

Liquid waste causes concerns for waste managers because of the risk of aerosols forming.

Liquid waste can splash and run when out of the container, but the biggest risk is if it is converted to tiny droplets that become airborne. An aerosol can travel long distances and can enter the respiratory systems of humans and animals.

Gaseous or vapor waste is usually less of a worry than liquid waste. Gases themselves disperse in the atmosphere and fall to low concentrations quickly. Unless they are toxic, they turn into a low hazard. A mist, however, can be dangerous, as it carried drops of higher density liquid. Further, biohazards can be carried on vapor streams.

How Hard to Mitigate Hazards


Attribute How Hard Method
pH liquid easy Add alkaline or weak acid solution
pH colloid or slurry medium Add alkaline or weak acid solution
Flammable (liquid) hard Combustion/incineration
Corrosive (liquid) medium Chemical treatment
Corrosive slurry/colloid medium Chemical treatment
biohazard hard Heat or liquid disinfectant
radioactive hard Immobilization
Generates gas when exposed to water or air hard
sharps medium Heat disinfection followed by griding to eliminate sharp edges