A Mercury Thermometer Broke: EPA's Cleanup Steps and the Four Things Never to Do

When a glass thermometer breaks, your first instinct is usually to grab the vacuum or the broom, and that’s the mistake to avoid. EPA says a vacuum puts mercury into the air and increases exposure, and a broom breaks the mercury into smaller droplets and spreads them. This guide covers how to tell whether the liquid is mercury, what not to do, how to prepare the room, and how to get rid of the waste legally.

Check whether the liquid is mercury

Many glass thermometers don’t contain mercury. According to EPA, newer non-digital fever thermometers often use alcohol or a non-toxic compound that looks similar to mercury. If the liquid is any color other than silver, it is most likely alcohol. If it’s silver, look for a paper calibration strip inside the glass. If the strip says “mercury free,” the liquid isn’t mercury. If you do NOT see the words “mercury free,” then assume that the liquid is mercury.

It also helps to know how much mercury you’re dealing with. EPA puts oral/rectal/baby thermometers at about 0.61 grams of mercury. Basal temperature thermometers, which track small changes in body temperature, hold about 2.25 grams. This matters because EPA’s steps are written for spills of that size. They apply to spills from other sources if the amount spilled is less than or similar to the amount in a thermometer. For anything bigger, EPA has a separate page, What to Do if You Spill More Mercury than the Amount in a Thermometer.

Four things EPA says never to do

Mercury behaves unlike most household spills. EPA explains that small droplets will combine into a larger sphere shape, which will roll on a flat surface and break back into smaller droplets if dropped or if pressure is applied. Each rule below exists to avoid scattering it.

Never	EPA’s reason
Use a vacuum cleaner	Puts mercury in the air, raises exposure
Use a broom	Breaks and spreads smaller droplets
Pour it down a drain	Lodges in plumbing; can pollute septic/sewer
Walk around in contaminated shoes	Spreads mercury; clothing can too

The drain rule has consequences after the spill itself. EPA warns that mercury may lodge in the plumbing and cause future problems during plumbing repairs, and that if it’s discharged, it can cause pollution of the septic tank or sewage treatment plant.

Step-by-step: prepare the room, then clean up

1. Clear the area. Have everyone else leave the area; don’t let anyone walk through the mercury on their way out. Get pets out too.

2. Ventilate the room and seal it off from the house. Open all windows and doors to the outside; shut all doors to other parts of the house.

3. Do the cleanup yourself. EPA puts it bluntly: DO NOT allow children to help you clean up the spill.

4. Check the surface. Mercury can be cleaned up easily from wood, linoleum, tile and any similarly smooth surfaces. Carpet, curtains and upholstery are another matter. EPA says contaminated absorbent items should be thrown away, and for carpet you should only cut and remove the affected portion rather than pull up the whole room.

5. Gather the supplies, then clean up in EPA’s order. EPA’s list for a small mercury spill: zip locking plastic bags, trash bags (2 to 6 mils thick), rubber, nitrile or latex gloves, paper towels, cardboard or a squeegee, an eyedropper, duct tape or shaving cream and a small paint brush, and a flashlight. Then:

   • Put on gloves. Pick up any broken glass with care, place it on a paper towel, fold the towel and seal it in a zip locking bag.
   • Gather the visible beads with a squeegee or cardboard, using slow sweeping motions to keep mercury from becoming uncontrollable.
   • Darken the room and hold a flashlight at a low angle close to the floor to spot more glistening beads. EPA warns that mercury can move surprising distances on hard-flat surfaces, so check the whole room, including cracks in the floor.
   • Draw the beads up with the eyedropper, squeeze them slowly onto a damp paper towel, and seal the towel in a zip locking bag.
   • For smaller, hard-to-see beads, gently dot the area with shaving cream on a small paint brush, or use duct tape and peel it up very slowly. Bag the brush or tape too.
   • Put everything used in the cleanup, gloves included, into a trash bag with the beads, and place the trash bag outside in a secured area, labeled as your local health or fire department directs.

   The never-list applies the whole time: if your shoes might have mercury on them, don’t walk around in them.

6. Keep ventilating afterward. Keep the area well ventilated to the outside (i.e., windows open and fans in exterior windows running) for at least 24 hours after your successful cleanup. During that time, continue to keep pets and children out of cleanup area.

If anyone feels sick at any point, EPA’s guidance is to seek medical attention immediately.

Getting the waste out of your house

EPA tells households to contact your local health department, municipal waste authority or your local fire department for proper disposal in accordance with local, state and federal laws.

While you wait to hear back, package the waste the way EPA describes for household mercury:

• Put it in a larger container with a tight fitting lid.
• Surround it with kitty litter or oil-absorbent matter to protect it from breaking or sudden shocks.
• Clearly label storage container as “Mercury - DO NOT OPEN.”
• Store it out of reach of children and pets until the collection date.
• Bring it to a household hazardous collection center in a cardboard box, secured so it can’t tip. Carry it in the trunk or a pickup bed. If it has to ride in the passenger compartment, make sure there is adequate ventilation.

Rules differ depending on where you live. Federally, households are exempt from the universal waste regulations that cover businesses. However, some states are stricter: Vermont bans all mercury-containing waste from landfills, including mercury-containing waste generated by households. Don’t assume your regular trash can is legal. Ask your local agency, and look into the collection/exchange programs for mercury-containing devices such as thermometers that many states and counties run.

When to call for help

If you have questions about health effects, EPA directs you to your physician or your local poison control center at 1 (800) 222-1222.

Once the cleanup is done, look for any other mercury thermometers in the house. EPA notes that a thermometer that is improperly disposed of will release mercury vapors that are harmful to human and ecological health. Taking it to a collection program now is easier than cleaning it off the floor later. EPA recommends that consumers use mercury-free thermometers but doesn’t endorse any particular brand.

Sources

• epa.gov – “What to Do if a Mercury Thermometer Breaks”
• epa.gov – “Storing, Transporting and Disposing of Mercury | US EPA”
• epa.gov – “Mercury Thermometers | US EPA”