Mercury (Hg): hazardous material guidance

Mercury (Hg) appears on UW System campuses for two primary uses: as a stock chemical in laboratories for instruction and research purposes; or as part of a device or piece of equipment. Standard health and safety information is available from many sources — this guidance concentrates on the following aspects of this material with which we have frequently assisted UW System campuses.mercury_med_drop

Fluorescent lamps

Mercury is used in fluorescent lamps because of its ability to increase efficient operation and life expectancy. Depending on the style and manufacturer, a lamp can contain from 1 milligram (mg) to about 100 mg of mercury. This includes both compact fluorescent lamps (CFLs) and “green cap” lamps. According to the National Electrical Manufacturers Association (NEMA), about half of the fluorescent lamps manufactured by their members and sold in the U.S. contain 5 to 10 mg of mercury; while a quarter contain 10 to 50 mg.

If a Small Number of Bulbs Break (guidance for custodial or maintenance staff)

  • Carefully scoop up glass pieces and powder using stiff paper or cardboard and place them in a lamp box
  • Use sticky tape, such as duct tape, to pick up any remaining small glass fragments and powder.
  • Wipe the area clean with damp paper towels or disposable wet wipes. Place tape and towels in the box.
  • Do not use a vacuum or broom to clean up the broken bulb on hard surfaces.
  • If a large number of bulbs break or elemental “liquid” mercury spills, cleanup and disposal are more complicated. Contact your Environmental Officer for advice and assistance.


mercury small drops


Mercury spills rarely present an imminent health hazard, unless it is in an area with very poor ventilation. The main exposure route of mercury is via vapor inhalation. If metallic mercury is not cleaned up adequately, the tiny droplets remaining in surface cracks and crevices may yield toxic vapors for years.

Keep in mind that mercury can spread easily if the spill is walked on. It will adhere to footwear and can be deposited in smaller amounts over a much larger area. This can lead to a much costlier cleanup, temporary closure of affected areas, and disruption of operations. Therefore, it is critical that when a mercury spill occurs, first cordon off the spill area to prevent people from inadvertently tracking the contamination.

Generally, a special mercury vacuum cleaner provides the best method of mercury spill cleanup. DO NOT use a regular vacuum cleaner; it will disperse toxic vapors into the air, contaminate the vacuum cleaner, and potential cause a much greater health hazard. If a special mercury vacuum is not available, first use an appropriate suction device to collect the big droplets, then use a special absorbent (available from most laboratory supply vendors) to amalgamate smaller mercury droplets.

What Never to Do with a Mercury Spill

  • Never use a vacuum cleaner to clean up mercury. The vacuum will put mercury into the air and increase exposure.
  • Never use a broom to clean up mercury. It will break the mercury into smaller droplets and spread them.
  • Never pour mercury down a drain. It may lodge in the plumbing and cause future problems during plumbing repairs. If discharged, it can cause pollution of the septic tank or sewage treatment plant.
  • Never wash clothing or other items that have come in direct contact with mercury in a washing machine, because mercury may contaminate the machine and/or pollute sewage. Clothing that has come into direct contact with mercury should be discarded. By “direct contact,” we mean that mercury was (or has been) spilled directly on the clothing.
  • Never walk around if your shoes might be contaminated with mercury. Contaminated clothing can also spread mercury around.

Mercury spill cleanup: examples of training and employee information


Laboratory Safety Guide: Chapter 5, Emergency Procedures. Section 5.7 covers mercury spills.

University of California at Berkeley

mercury big drop

Cleaning Up a Small Mercury Spill (video)

University of Georgia

How to Clean Up Elemental Mercury Spills

University of Washington

Mercury Spills (webpage)


Fluorescent lamps and mercury thermostats can be disposed under the universal waste regulations. UW System campuses must dispose of these through the State of Wisconsin Contract for Waste Lamp and Ballast Recycling, and PCB Waste Disposal Services.

Wisconsin ban on mercury-containing products

Wisconsin Act 44 went into effect Monday, November 1, 2010.

There are three sections to the law:

Section 1 amends Stat 118 GENERAL SCHOOL OPERATIONS and doesn’t apply to UW System institutions.

Section 2, which amends Stat 299 GENERAL ENVIRONMENTAL PROVISIONS does apply to UW System institutions, but bans sale only of the items containing elemental mercury that are enumerated in Section 2:

  • mercury switches
  • thermometers
  • manometers
  • mercury-added thermostats
  • barometers
  • esophageal dilatorsmanometer
  • bougie tubes
  • gastrointestinal tube
  • flowmeters
  • hydrometers
  • hygrometers
  • psychrometers
  • pyrometers
  • sphygmomanometer

Section 3 describes the effective date.

Mercury salts and other compounds are not be banned for sale to a University of Wisconsin campus under Act 44. There are provisions for requesting exemptions. See your Environmental Manager.

Reference material, files, and websites

IMERC Fact Sheet: Mercury Use in Lighting – NEWMOA, Northeast Waste Management Officials’ Association

Guide for Chemical Spill Response Planning in Laboratories — Prepared by the American Chemical Society’s CEI/CCS Task Force on Laboratory Waste Management American Chemical Society, Washington, DC 1995

WIDNR Mercury Pollutant Minimization Program Guidance Manual For Municipalities

NIST Mercury Thermometer Alternatives

NIST Poster -Measurement Uncertainties in Organic Liquid-in-Glass Thermometers

EPA – Recommended Management and Disposal Options for Mercury-Containing Products





This publication was prepared for environmental, health and safety staff at University of Wisconsin System campuses, to assist in finding resources and information for regulatory compliance. It is not intended to render legal advice.

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