Home Podcasts THMG026 – Decontamination, Part III

THMG026 – Decontamination, Part III


In this episode, Mike and Bob continue to discuss the various methods of decontamination.

Complete Show Notes

4:00 Disinfection

  • To clean something, especially by using a chemical substance that kills all germs and bacteria
  • Sterilization is disinfection on steroids – kills everything, including spores
  • Can be done with heat, chemicals, or time
  • Heat
    • Works great on hard metal surfaces by placing them in an oven-like device called an autoclave – heat destroys the structure of the virus, bacteria, or spore and renders them unable to reproduce
  • Chemicals
    • We perform chemical disinfection most frequently
    • When we wash our hands or bleach the back of our ambulance, we take a substance that’s reactive to the biological process – these chemicals interfere somehow and either kill an organism or render it incapable of reproducing
    • Viruses and bacteria aren’t as harmful, as they can’t reproduce
    • Make sure the disinfectant you choose will work with that organism – go above and beyond the recommended concentrations and time just to be safe
  • Time
    • Can be a great weapon when used with viruses and bacteria, as they can’t live outside a host for an extended time frame
    • This can be better than chemicals because many liquid disinfectants are subject to human error, like missing a spot or not giving enough time
  • Pros
    • Disinfection is the only way to remove an organism
  • Cons
  • We can’t really disinfect people with harsh chemicals – soap and water and mild bleach are a last resort
  • Substances may become corroded by the oxidizer strength of many chemicals
  • Apparatus and equipment may be out of service for a long time
  • Doesn’t actually kill every organism – most of the time, we’re looking to minimize the organism and reduce the chances of infection

12:50 Evaporation

  • Simply allows a material to vaporize – another method commonly used for objects and environments
  • We can use a mechanical fan to remove high-pressure liquids from people
  • Pros
    • Doesn’t require any intervention on our point because it’s a natural process
    • No equipment needed
  • Cons
    • Evaporation puts lots of product into the air, which means it can get into our lungs
    • If it’s a flammable substance, you have to be aware of ignition sources
    • Have to be conscious of where the material will travel after it evaporates
    • If it’s something that pulls heat from someone, they’ll be cold
    • Time may be an issue, as we don’t always have the luxury to sit and wait
    • This option doesn’t work well for people

15:40 Isolation and Disposal

  • Definitely meant for objects that can be fully decontaminated and disposed of
  • These objects have to be treated as waste, and you must adhere to local rules and regulations
  • Depending on the product, it may be stored at the site indefinitely, incinerated, or placed in a landfill that’s designated for hazardous materials
  • Isolation and disposal is commonly used with mercury
  • Pros
    • Not many benefits to isolation and disposal – mostly used as a last resort
  • Cons
    • You’re creating a large mass of waste – since hazmat material is done by weight, it will be very expensive
    • You can’t do this with people
    • Requires over packing of material into drums or barrels to render them safe for transport

17:45 Neutralization

  • The process of taking a corrosive and bringing it to a pH that’s considered neutral by your AHJ
  • When neutralizing, the first thing you have to do is confirm the presence of an acid or base using pH or litmus paper
  • Then, we create a weak aqueous solution on the opposite side of the pH scale (also known as a slurry)
  • Next, we take our slurry and pour it into our product in increments – test the product between pours to see how far along you’ve gotten and how much further you have to go to reach 7
  • Once you reach 7 (or the pH allowed by your AHJ), you can dispose of the now salt water as per local regulations
  • The process concludes when you neutralize the slurry
  • Pros
    • We’ve chemically altered the product to render the hazard null and void
    • Very effective for large volumes of product or very strong products
  • Cons
    • Can’t be done on people – for spills and objects only
    • Can be tedious and time-consuming, especially in hot weather when you’re in a B Level suit

24:50 Washing

  • Using soap, water, brushes, and pools to perform decontamination
  • Used for non-polar substances (unlike dilution, which is used for polar substances)
  • Surfactants – interfere with the surface tension of water, causing it to become thin and weak
  • Surfactants link polar substances (like water) to non-polar substances (like grease)
  • Think of surfactants as an adaptor – they can hold polar and non-polar substances together at the same time
  • Surfactants have to be agitated – has to mingle with water in order to help it do its job
  • Most surfactants used are either soap or detergent
  • Pros
    • Very effective way of decontamination
    • Can be used on a variety of solids, liquids, and vapors
    • Can also be used on people, places, and things
  • Cons
    • Can be very manpower intensive
    • A lot of specialized equipment and training are required to do this properly
    • It’s a slow process
    • Requires waste water to be contained and dealt with

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