Questions and Answers:These Q's and A's apply only to NIH facilities unless otherwise indicated.Thermometers or Sphygmomanometers
Mercury Waste and Disposal
Mercury Contamination - I suspect there might have been a past spill of mercury from a broken thermometer in my lab. I don't see any mercury in the area. What should I do?
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top of pageI broke a mercury thermometer. What should I do?
DO NOT ATTEMPT TO CLEAN UP MERCURY SPILLS REGARDLESS OF THEIR SIZE. Elemental mercury (metallic) has a significant vapor pressure and can therefore easily vaporize and become a potentially serious inhalation hazard. It can also be absorbed through intact skin. When a glass mercury thermometer breaks and the droplets are not cleaned up quickly, personnel working in the area can be exposed to the vapor from the metallic mercury.
- Prevent the spread of mercury. The droplets can roll around and adhere to the sides of the laboratory casework. The area should be secured and normal activities stopped until the area has been decontaminated. This will keep the mercury from being tracked around.
- Do not move any of the broken pieces of the thermometer. The hazardous material (HAZMAT) emergency responder who responds to the spill will use the location of the broken glass to determine the extent of the mercury spill.
- Immediately notify the hazardous material (HAZMAT) emergency responder for your facility (911)
- Give the responder the location of the mercury spill, your name and telephone number. HAZMAT emergency responders have the cleanup material and personal protective equipment that are specifically suited for cleaning up the mercury. Additionally, they have an analytical instrument that can detect minute quantities of mercury vapor and determine the effectiveness of the cleanup.
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top of page Why do we have to keep mercury wastes separate from all other chemical wastes?
With appropriate precautions, pure mercury is easy and economical to recycle. On the other hand, solid and liquid wastes contaminated with mercury are difficult to treat and very expensive to dispose of. The presence of even trace amounts of mercury - as little as 0.2 milligrams per kilogram (parts per million) requires the entire quantity of waste to have to be managed as hazardous waste. Technology to completely separate mercury from certain common types of waste such as organic solvents is not available.
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Where can I find replacements for mercury thermometers?
Alternative, non-mercury thermometers are found in the NIH Supply Catalog.
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top of page Are there accuracy standards for non-mercury thermometers?
Yes. Mercury thermometers and alternative non-mercury liquid-in-glass thermometers used in laboratories should be calibrated using an approved method such those issued by the American Society for Testing and Materials (ASTM) or the International Standards Organization (ISO), and traceable to the National Institute of Standards and Technology (NIST) or other recognized standard setting organization. The reference cited below provides guidance on how to choose, use, calibrate and maintain calibration and traceability records for both glass standard thermometers and working liquid-in-glass thermometers and a listing of applicable ASTM, ISO and NIST publications.
Emory DN. Liquid-in-glass thermometers in the ISO-certified laboratory. American Laboratory News Edition 30(25):9-14 (1998).
Information on thermometers for clinical applications is available in this NIST publication:
Mangum BW, Wise JA. Standard Reference Materials: Description and use of a precision thermometer for the clinical laboratory. SRM934, NIST Special Publication 260-113, Washington DC: National Institute of Standards and Technology.
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top of page I suspect there might have been a past spill of mercury from a broken thermometer in my lab. I don't see any mercury in the area. What should I do?
Report the potentially hazardous situation to the Division of Safety by calling 301-496-3457, or by calling the Emergency Communication Center after hours at 301-496-5685. When mercury is spilled it usually splatters into small droplets, many too small to see. These can cling to objects - even vertical surfaces. Liquid mercury often collects in cracks, crevices and other areas that are hard to observe. Even small amounts of mercury can contaminate indoor air to unsafe levels.
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top of page I have mercury thermometers in my lab. How should I dispose of them?
Place them in a break resistant, leak proof container such as a plastic bottle. Fill out and attach a NIH Chemical Waste tag and call the NIH Chemical Waste Disposal Service at 301-496-4710 for pick-up and recycling. Please do not package mercury wastes in water; this increases the total quantity of material that must be treated as hazardous waste.
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top of page I have mercury-containing equipment that I will be turning in as surplus property. What should I do about the mercury?
Do not move the equipment or attempt to remove the mercury yourself. Call the NIH Chemical Waste Service at 301-496-4710 for assistance. The chemical waste personnel will remove the mercury and dispose of it appropriately. After the equipment has been drained, complete and attach a “Certification that Property is Free from Hazards" tag (NIH Form 2683) ![]()
. On the line for chemical hazards, indicate that the item previously contained mercury. Then dispose of the item in accordance with NIH procedures for surplus property. NIH Policy Manual. 26101-25-2 - PERSONAL PROPERTY MANAGEMENT GUIDE
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The literature indicates that mercury thermometers or sphygmomanometers are the most accurate/reliable method in my clinical/research application. Do I have to switch to non-mercury units?
No, if the needs of patient diagnosis, treatment or research are better served, continue to use the mercury-based unit with appropriate precautions. We recommend that you check with the safety specialist of your IC. Some ICs may have policies requiring use of non-mercury units or administrative approval to procure or continue use of mercury devices.
In most cases the health, safety and environmental hazards outweigh the potential benefits of continuing use of mercury devices. Generally, non-mercury units provide satisfactory results if the equipment is appropriate for the application, calibrated properly, and the users have been trained on its use. Major healthcare and research facilities are now mercury free. Legislative actions are pending in some areas that may ban mercury thermometers.
If you must continue using mercury thermometers, consider using Teflon coated or armored thermometers. These resist breakage and contain the mercury if they are broken.
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