Decontamination removes radioactive dust from people, clothing, equipment and ground by taking off outer clothing first and then washing gently with soap and water, moving the material to a controlled place rather than destroying it. It helps only against contamination: a person who was merely irradiated has nothing on them to wash off, and washing does not reduce a dose already absorbed.
Part of Radiation Safety
Decontamination is the removal of radioactive material from where it is unwanted, which concentrates and relocates the hazard but does not remove its radioactivity.
Contamination Only: Check Which Problem You Have
Decontamination applies to contamination and is useless against irradiation; see Contamination vs Irradiation. If a person arrived from a fallout area, assume contamination. If they were near a distant source and never in dust, there is nothing to wash, but washing does no harm. Decontamination should not delay treating life-threatening injuries, since the risk to a helper wearing gloves and covering skin is far lower than the risk of delay.
People: Clothes First, Then Water
The parent article, Nuclear Safety, says to remove all clothing and wash the whole body with soap and water, paying attention to hair, skin folds and under the nails, and not to use conditioner on hair because it binds contaminants. Removing outer clothing carefully removes much of the material. Order the work from the head down and from the dirty side to the clean side:
- Outdoors or at an entry point, remove outer clothing without shaking it, rolling the dirty surface inward, and bag it.
- Protect wounds. Rinse a contaminated wound gently with clean water and dress it before washing the skin around it, so wash water does not run into it; see Wound Cleaning.
- Wash with lukewarm water and soap, gently. Do not scrub the skin raw: broken skin lets material in. Use water that can be collected. General practice, recalled, not from the corpus.
- Wash hair, then skin folds, ears and nails. Wash hands thoroughly, see Hand Washing.
- Dress in clean clothes from a clean place.
- Wash the helper last, the same way.
Equipment And Surfaces
Hard, smooth things wash well with soap, water and a brush; porous things such as wood, fabric and unsealed concrete hold material and may not come clean. Dry sweeping lifts dust into the air; wet it first. Remove the top layer of soil only if you have somewhere to put it. The aim is to remove material, so decide beforehand where the waste goes.
Where The Waste Goes
Wash water, wipes and soil now carry the contamination. Collect wash water in a container and dispose of it in a pit far from wells, springs and streams, downslope of them, and cover it; bag clothes and wipes and store them away from living areas. A plan is easier than a clean-up of what ran into a well; see Ground Sources. Do not burn contaminated material: smoke carries it.
Worked Example: Why Order Matters
Hypothetical: a person arrives with grey dust all over. If the first step is a bath, the dust is washed into the water and onto every surface in the bath area; removing the dusty clothes outdoors first leaves little for the water to do, in line with the parent article’s order. The numbers are not needed: the order is the method.
Common Mistakes
- Washing before undressing.
- Using conditioner, as the parent article warns.
- Scrubbing hard with abrasives.
- Tipping wash water into a ditch or well.
- Decontaminating an irradiated person and thinking it cleared the dose.
Safety
Protect the helper and the water supply first
Wear gloves, cover skin, cover nose and mouth, and wash afterwards; do not eat, drink or smoke. Keep wash water away from every water source; see Personal Protection. If a person is carrying a solid object they cannot identify, such as a capsule or a heavy metal piece, have them put it down where it is, then move everyone away from it and do not handle it.
What’s Next
- Learn next: Personal Protection — preventing contamination in the first place
- Combine with: Wound Cleaning — treating contaminated wounds