Page updated 30 April 2007
Mercury Spillages
The equipment required (which can be obtained from Medical Physics and/or Bioengineering in your hospital) is as follows:
For a mercury thermometer:
- Pair of gloves
- Mercury collector
- Bag labelled "Hazard" for returning these items to Medical Physics
- A copy of these instructions
For a mercury sphygmomanometer (maximum 5ml mercury):
- Gloves, masks
- Mercury collector
- Syringe
- Wooden spatulas
- A container of calcium hydroxide
- A container of calcium hydroxide
- A container of sulphur
- Bag labelled "Hazard" for returning these items to Medical Physics
- A copy of these instructions
Action
To prevent and further spreading of the mercury and to minimise exposure to mercury vapour:
- Instruct others to keep away
- Do not allow people to walk over the spillage.
- Open windows and close doors adjoining rooms or corridors.
Send immediately for the equipment which will be labelled "Equipment for dealing with minor spillages from thermometers only". Or "Equipment for dealing with major Mercury spillages from Sphygmomanometers" as above.
When the equipment arrives, put on the gloves and mask (for larger spillages).
Thermometers
- Discard the empty thermometer in a Sharps Container, unscrew the cup of the mercury collector and dab the foam pad on the globules of mercury until all the mercury has been collected.
- Place foam back on the collector and screw the cap back on so as to be airtight.
- Wipe the affected area with a damp cloth and place the cloth and the gloves in a yellow plastic bag bag. Seal the top for disposal by incineration.
Sphygmomanometers
- Place broken manometer into the pastic bag provided.
- Use the mop with the disposable duster head to sweep slowly in straight lines over the affected area, so that mercury drops gather in one place.
- Unscrew the cap of the mercury collector and, using the syringe and a wooden spatula, transfer as much of the mercury as possible into the collector.
- To collect the remnants, dab the foam on the mercury droplets then screw the cap firmly on the collector. A mesh inside the collector squeezes the mercury out of the pad, permitting the process to be repeated until all the mercury has been collected.
- If tiny amounts remain in cracks, treat with a dry mixture of sulphur and calcium chloride.
- If spillage is on an absorbent surface, it can be treated liberally with a paste of sulphur and calcium chloride. The resulting amalgam and can then be wiped up with a damp cloth. Drying takes a few hours but in the amalgam, mercury is not volatile.
- When the procedure is complete, the area should be wiped with a damp cloth. Place all the mercury contaminated items, including the mop head in the labelled Hazard polythene bag and seal the top.
Call Medical Physics to announce the equipment has been used. Send the sealed bag, the spare instructions and the mercury collector back to Medical Physics. If necessary, Medical Physics will inspect the spillage area for consistent results and deal with any remnants in cracks or absorbent surfaces. In general, Medical Physics staff will carry out the whole procedure or, on arrival, will check for consistent and safe results.
General Notes on Mercury Spillages
- A mesh inside the mercury collector squeezes mercury out of the foam pad, making it immediately available for repeated use.
- If spillage is on a carpet, get advice from Medical Physics. It is likely that the carpet will have to be destroyed, so it is wise to use aneroid instruments (which are notoriously inaccurate) or have the sphygmomanometer securely fixed to the wall.
- If mercury comes into contact with skin, wash well with soap and water.
- Keep mercury off jewellery, it will amalgam with gold.
References
BDH Hazard Data Sheets Compendium, 1990
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