Hesperian Health Guides

Safe Disposal of Chemical Waste

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HealthWiki > A Community Guide to Environmental Health > Chapter 19: Health Care Waste > Safe Disposal of Chemical Waste

Most health centers, small or large, end up creating chemical wastes that need to be disposed of safely. Larger centers may also have waste from x-rays, chemotherapy, and laboratories. We do not include ways to dispose of these kinds of waste in this book because they are too complicated. (For information on handling these wastes, see Other Environmental Health Resources.)

Chemicals used to clean and disinfect

Bleach can be diluted and then dumped into a leaching pit. Hydrogen peroxide solutions can be disposed of with no special treatment. You can safely pour them down the drain of a sink or into a toilet.

A man wears boots, gloves and a mask while pouring liquid from one container into another.
When preparing liquid chemical wastes for disposal, wear protective gear, and be careful not to splash.

Glutaraldehyde and formaldehyde can cause cancer and death. But if your center uses these chemicals for disinfecting and cleaning, there are ways to get rid of them safely. To treat glutaraldehyde or formaldehyde for disposal, add caustic soda (sodium hydroxide) solution to change the acidity (pH). Measure the pH with litmus paper or a pH meter. Bring the pH to 12 and stay at that pH for at least 8 hours. After 8 hours, bring the pH to a neutral level (pH 7) by adding hydrochloric acid (HCl). If you do not have the proper materials to make glutaraldehyde or formaldehyde safe for disposal, do not use them — they are that dangerous. After processing, it is safe to pour them into a leach pit.

Carbolic acid, used to sterilize sheets, causes breathing and skin problems. A worker should wear protective clothing including eye protection and a mask when using or disposing of carbolic acid. The wastewater should be added to a solution of sodium hydroxide, then poured into a leach pit.


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Mercury is the silver liquid inside a thermometer. It is also used in other medical equipment, such as the meters attached to old blood pressure cuffs, as well as in batteries and lamps.

Mercury is a very toxic heavy metal. Absorbing it through the skin or breathing in even a very small amount of mercury can damage the nerves, kidneys, lungs, brain, and cause birth defects.

Mercury is not destroyed by burning. In fact, burning mercury turns it into even more harmful gas.

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The best way to reduce harm from mercury is to use as few mercury-containing items as possible. If possible, keep equipment with mercury on metal trays, so if it breaks the mercury will not soak into wood surfaces like tables or floors. Use non-mercury thermometers if they are available in your area (see Other Environmental Health Resources).

How to clean up a mercury spill

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When a thermometer or other item containing mercury breaks, the mercury scatters as small pieces. Keep people and animals away from the spill area. Turn off any heaters, fans, or air conditioners, and open windows to let air in. To clean up the spill you will need gloves, an eyedropper, 2 pieces of stiff paper or cardboard, 2 plastic bags, sticky tape, a flashlight, and a glass container with water in it.

To collect the mercury safely:

  1. Do not touch the mercury. Open windows or doors.
  2. Remove watches and jewelry. Mercury sticks to other metals.
  3. Shine a flashlight on the area to make the mercury easier to see, even during the daytime.
  4. Wear chemical resistant gloves if possible. If you have only latex gloves, wear at least 2 pairs.
  5. Use small pieces of stiff paper or cardboard to gather the mercury into a small pile.
  6. Use an eyedropper to suction up the mercury beads, and put the mercury in a glass container with water.
  7. Pick up any mercury that is left using sticky tape.
  8. Place sticky tape, eyedropper, gloves, and cardboard in a plastic bag.
  9. Label the bag “mercury waste” and put the bag in the glass container with the water in it.
  10. Seal and mark the container. Put it inside another plastic bag.
  11. Dispose of it as toxic waste.

Antibiotics and other medicines

Old medicines are another kind of chemical waste that need to be disposed of safely. Getting rid of antibiotics and other medicines safely means keeping them out of water sources and away from people who handle waste. Unfortunately, health centers, pharmacies, and drug companies often get rid of old medicines unsafely, in open dump sites, waterways, or down the drain.

When antibiotics are dumped into the environment, they can cause antibiotic resistance in people, animals, and even germs that come into contact with them. This means that when people take antibiotics to fight infections, the medicines will be less effective because fewer germs will be killed by them.

Buy and use fewer antibiotics

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Do not use antibiotics for health problems they cannot cure. (For more information about how to use antibiotics, see Where There Is No Doctor, pages 55 to 58, and Helping Health Workers Learn, Chapter 19.) When your health center buys only the amount of antibiotics it needs, then fewer drugs will need to be dumped because they are old.

Return expired medicines to the manufacturer

The drug companies that make medicines have the equipment to safely dispose of expired antibiotics and other medicines, and they should do this. But if you are unable to return medicines to the company that made them, there are ways you can dispose of them safely.

How to dispose of medicines safely

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  1. Wear gloves, safety glasses, and a dust mask.

  2. Mix pills with dry cement powder.

  3. Add water and form cement into solid balls.

  4. Bury these cement balls in a sealed waste pit.