What to Do if You Break a Mercury Thermometer

The evolution of the thermometer begins with the Greeks, with Hero of Alexandria recognising that certain substances expand and contract dependant on temperature. At that time, it was simply a water/air interface that was more of a scientific curiosity than a piece of practical equipment. It took another 1600 years for the first device that we might recognise to be invented, however this type of thermometer designed by Giuseppe Biancani in 1617, was actually called a thermoscope.

Fast-forward another century and Dutch inventor and scientist Daniel Gabriel Fahrenheit introduces the world to the first reliable thermometer. This was the first type of thermometer to use mercury instead of water/alcohol mixtures, and it was this design that would remain in use until after the Second World War. Today, that iconic mercury-based design has all but been replaced by other types of thermometer, however, while digital now rules, in Australia, they are more prevalent than in most other western countries.

Australia still allows the sale and use of mercury thermometers, while most of Europe and USA has outlawed their use in medical facilities due to the high toxicity of the substance itself. Today, in many cases, alternative types of thermometer are used either alongside mercury-based devices or as replacements. Here, we take a look at the different types of thermometer used today and what to do if your toxic mercury thermometer breaks.

Types of Thermometer Available Today


Digital ThermometersDigital thermometers are among the fastest and most accurate. Readings can be taken from under the tongue, the rectum, or the armpit in the same way as a traditional thermometer.

Ear Thermometers – Otherwise known as tympanic thermometers, this type of thermometer uses infrared light to make temperature reading.

Non-contact Thermometers – Non-contact thermometers also work with infrared to provide readings without contacting the body. They are probably the least accurate but can be useful for children.

Glass Thermometers – Traditional glass thermometers are still available, using either mercury or another substance such as alcohol to provide a reading.

Using a Mercury Thermometer? Here’s What to do if it Breaks

The first thing to remember if you break a mercury thermometer is that the silvery substance contained within those glass tubes has the potential to be highly toxic. Of course, identifying whether it is really mercury in your thermometer is an important step, however, it is always better to be safe than sorry.

To help you identify whether the type of thermometer you are using is, in fact, mercury-based, ask yourself:

  • Is the liquid silver?

If it is not, then it is most likely to be an alcohol-based thermometer. If it is, then it may be either a mercury or a non-mercury thermometer.

  • Does the thermometer contain any warnings?

Sometimes, the paper calibration strip inside the thermometer will tell you which substance has been used. If there is no writing or warning, assume that it is mercury.

Cleaning up Mercury Spills

If your mercury thermometer breaks, then you can also identify whether the substance contained is mercury by observing its behaviour. Mercury is a liquid metal that has properties quite unique from other substances. Smaller droplets will pool together into a large sphere shape, which will break again into smaller droplets when pressure is applied. However, never touch mercury and take care not to scatter smaller droplets into hard-to-reach areas.

When cleaning up after a mercury spill, you should be careful to NEVER do the following:

NEVER use a vacuum cleaner. This will disperse the mercury into the air

NEVER use a broom. This will break the mercury into smaller droplets and disperse them.

NEVER pour mercury down the drain. This can either damage plumbing, septic tanks, or sewage treatment plants while polluting at the same time.

NEVER walk around with mercury on your shoes of clothing.

Additionally, you should prep the area where the mercury has been spilled by doing the following:

• Ask people to leave the area ensuring no one walks through the mercury as they do so. Remove any pets from the area. Open all windows and doors to the outside and close doors to other parts of the building.

• For absorbent surfaces, the contaminated items must be disposed of according to the guidelines below

• For non-absorbent surfaces, clean-up is easier

• Do not allow children or elderly people to help you clean up

Instructions on How to Clean up Mercury Spills

  1. Put on latex, rubber, or nitrile gloves.

  2. Cover the affected areas with powdered sulphur, this will make the mercury easier to see and suppress any vapours.

  3. Pick up any broken glass or other debris, fold within a paper towel and place in a labelled, Ziplock bag.

  4. Use a piece of cardboard or plastic to gather mercury beads. Use slow sweeping motions. Darken the room and hold a torch at the low angle to check for any other mercury. Inspect the entire room.

  5. Use an eyedropper to draw up the mercury. Dispense onto a damp paper towel. Place the paper towel in a labelled, Ziplock bag.

  6. Place all items, including gloves, into a trash bag. Label the bag as hazardous and containing mercury.

  7. Go to the Australian Government Department of the Environment for details on how to properly dispose of mercury.
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