Horse Care

What to do if a mercury thermometer just broke

When working with horses and taking their vital signs it is recommended to use digital thermometers, because they are faster and do not contain mercury.

If you’re using a glass thermometer you should determine if it contains mercury before using it.

  • Glass thermometers can contain coloured alcohol, which is not toxic.
  • Even if a thermometer contains a silver liquid, it is not necessarily mercury. If the thermometer has a “mercury-free” notice on it, it contains a non-toxic substance that looks similar to mercury.
  • If a thermometer does not have a “mercury-free” notice, assume that it contains mercury.

Never do these after a thermometer has broken:

  • Do not use a vacuum cleaner, because it will put mercury into the air and increase the exposure.
  • Do not use a broom, because it will break the mercury into smaller droplets and spread them around.
  • Do not pour mercury down the drain, because it may lodge in the plumbing and cause future problems during plumbing repairs. It can also pollute the septic tank or sewage treatment plant.
  • Do not walk around if there is a chance your shoes or clothes are contaminated with mercury, because they will spread the mercury around.

What is mercury?

Mercury is a liquid metal that is dense, shiny and fast-moving. It can break up into little silver balls that reform when pushed together.

Mercury can be toxic in certain situations. However, it is not absorbed through intact skin or from a healthy digestive tract in amounts that would cause toxicity.

Harmful effects should not be expected from touching or swallowing the small amount of mercury from a broken thermometer (about 0,5-0,6 grams). Skin irritation dermatitis may occur.

The main health risks from mercury are from the vapours. Mercury vapours are produced at room temperature and especially if mercury is heated.

An unexpected way to heat up mercury
is by using a vacuum cleaner to clean up a spill.

If a spill is not cleaned up right away, vapours will continually be produced.

They may be in low concentrations that do not cause immediate effects, but repeated long-term exposure can cause problems, such as:

  • shaking
  • weakness
  • difficulty walking
  • headaches
  • loss of appetite
  • gum inflammation
  • high blood pressure
  • rapid pulse
  • red skin
  • kidney damage
  • personality changes

Preparing to clean up a broken mercury thermometer

  1. Do not allow children to help clean up a mercury spill.
  2. Have everyone leave the affected area and do not let anyone walk through the mercury on their way out.
  3. Remove animals from the area as soon as possible and make sure that they do not trample the glass or step in the mercury.
  4. Close all doors that lead to other inside areas.
  5. Open all doors and windows that open to the outside.
  6. Mercury can easily be cleaned up from wood, linoleum, tile and other similar smooth surfaces.
  7. If a spill has occurred on a carpet, curtains, upholstery or other absorbent surfaces, the contaminated items should be thrown away as per the disposal instructions below. Only cut and remove the affected part of the contaminated carpet for proper disposal.

What you need to clean up a small mercury spill

  • 4-5 zip-locking plastic bags
  • trash bags, 2-6 millimetres thick
  • rubber, nitrile or latex gloves
  • paper towels
  • cardboard or squeegee
  • eyedropper
  • duct tape, or shaving cream and small paint brush
  • flashlight or small task light
  • optional: powdered sulfur (don’t worry if you don’t have this, sulfur binds to the mercury and makes the clean-up easier, it may be found in gardening departments of hardware stores or pharmacies).

Instructions for cleaning a mercury spill

  1. Put on protective gloves.
  2. Pick up any broken pieces of glass or other sharp objects carefully and place them on a paper towel. Fold the towel and place inside a zip-lock bag. Secure the bag and label it as directed by your local health or fire department.
  3. Locate visible mercury beads. Gently use a squeegee or piece of cardboard to coax beads into larger balls. Only use slow sweeping motions to keep the mercury from becoming uncontrollable.
  4. Take a flashlight and hold it at an angle towards the floor. With the lights off you should be able to spot the glistening mercury beads that may be sticking to a surface or have become lodged in a crack.
  5. Mercury can move surprisingly long distances on hard, flat surfaces so inspect the entire room, including cracks in the floor, when cleaning.
  6. Use an eyedropper to collect or draw up the mercury beads. Slowly and carefully squeeze the mercury out into a damp paper towel. You can also use two pieces of cardboard to gently roll the mercury onto a paper towel.
  7. Fold and place the towel with the mercury into a zip-lock bag, label and dispose of it as directed by your local health or fire department.
  8. After you have removed larger beads, put shaving cream onto a small paintbrush and gently dot the affected area to pick up smaller beads that may be harder to see.
  9. You can also use sticky tape, such as duct tape, to pick up remaining glass fragments. Peel the tape slowly from the floor to ensure that any mercury beads remain stuck to the tape.
  10. Place any items used in cleaning up the mercury in a zip-lock bag and secure it. Label the bag as directed by your local health or fire department.
  11. Optional: use commercially available powdered sulfur to absorb the beads that are too small to see. The sulfur does two things: it makes the mercury easier to see since there may be a colour change from yellow to brown, and it binds the mercury so that it can be easily removed and suppresses the vapours of any missing mercury.
  12. Note: Powdered sulfur may stain fabrics a dark colour. When using powdered sulfur, do not breathe in the powder as it can be moderately toxic. Read and understand the product information before using sulfur powder.

After cleaning up a small mercury spill

  • Place all materials used in the clean up as well as all contaminated items in a trash bag. Place the bag outside in a secure area and label it clearly as directed by your local health or fire department.
  • Contact your local health department, municipal waste authority or fire department for proper disposal in accordance with the law.
  • Keep the area where the spill occurred well ventilated to the outside for at least 24 hours after your successful clean-up.
  • Continue to keep children and animals out of the area where the spill happened.
  • If symptoms of poisoning or sickness occur, seek medical treatment immediately.
  • You can also request the services of a contractor that has monitoring equipment to screen for mercury vapours if you suspect that what you are doing is not sufficient to remove the vapours or if you are not sure that all the mercury was removed.
  • Put up notices on closed doors to the area to not enter, inform everyone using the stable that there has been a spill and what symptoms to look for.

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