If a mercury thermometer, thermostat, or compact fluorescent bulb breaks in your home, you can safely clean up the spill yourself as long as the amount is small (roughly the volume of a thermometer or less). The key is to never vacuum, sweep, or mop the spill. Mercury is a liquid metal that evaporates at room temperature, releasing invisible vapor you can inhale. The cleanup method is slow and deliberate, using simple household items to gather every tiny bead before it spreads or vaporizes further.
Why Vacuuming and Sweeping Make It Worse
Your first instinct with a spill is to grab a vacuum or broom. With mercury, that instinct can turn a minor incident into a serious hazard. A vacuum cleaner’s motor generates heat, which accelerates mercury evaporation and pumps concentrated vapor into the air you’re breathing. The exhaust then spreads contaminated air throughout the room. A broom or mop fractures mercury into smaller and smaller droplets, scattering them across a wider area and into cracks where they become nearly impossible to retrieve. Worse, the vacuum, broom, or mop itself becomes permanently contaminated and would need to be discarded as hazardous waste.
Pouring mercury down a drain is equally dangerous. It can lodge in your plumbing, creating a long-term vapor source inside your walls and contaminating sewage systems downstream.
Before You Start Cleaning
Get everyone out of the room, including pets. Don’t let anyone walk through the spill area on their way out. Children should not help with cleanup. Close the doors to the rest of the house so vapor doesn’t drift into other rooms, and open all windows and exterior doors in the spill room to get fresh air flowing through.
Gather these supplies before you approach the spill:
- Rubber or latex gloves
- Stiff cardboard (two pieces, or a squeegee)
- An eyedropper
- Duct tape or sticky tape
- A flashlight
- Zip-lock bags
- Damp paper towels
- A small paint brush and shaving cream (optional, for tiny beads)
- A trash bag
Step-by-Step Cleanup on Hard Floors
Put on your gloves first. If the broken thermometer or bulb left glass shards, carefully pick those up and place them on a paper towel. Fold the towel around them and seal it in a labeled zip-lock bag.
Now look for the mercury itself. The beads are shiny, silvery, and surprisingly mobile. Use two pieces of cardboard or a squeegee to slowly herd the beads together into larger balls. Work with gentle, deliberate motions. Quick sweeping movements will send tiny droplets rolling in every direction.
Once you’ve gathered the beads, use an eyedropper to suction them up one at a time. Squeeze them out onto a damp paper towel, then seal the towel in a zip-lock bag. If you don’t have an eyedropper, you can roll the beads onto the paper towel using the cardboard.
Here’s the step most people skip: darken the room and hold a flashlight at a low angle, close to the floor. Mercury beads catch the light and glisten, making even tiny droplets visible against tile, wood, or linoleum. Check cracks, seams, and edges where beads tend to settle.
For the smallest remaining beads, dab the area with shaving cream spread on a small paint brush, or press strips of duct tape slowly against the floor and peel them back. The beads will stick. Seal the brush or tape in another zip-lock bag.
Finally, place all your cleanup materials (gloves, cardboard, eyedropper, bags, everything) into a single trash bag. Seal it, label it “Contains Mercury,” and set it outside in a secure spot away from children and animals.
What to Do About Carpet and Fabric
Mercury on carpet is a much harder problem. The beads sink between fibers and embed themselves in the padding, where you can’t see or reach them. You cannot vacuum carpet to retrieve mercury, and manually picking beads out of fibers is unreliable. If mercury spills on carpet, clothing, curtains, or upholstered furniture, the contaminated section or item generally needs to be cut out and discarded as hazardous waste. For items like shoes or clothing where the mercury isn’t visible, hang them outside to air out for at least 24 hours before deciding whether to keep or discard them.
If the spill on carpet is anything more than a bead or two, contact your local health department or fire department for guidance. A professional environmental cleanup may be necessary.
Ventilating the Room Afterward
Even after you’ve collected every visible bead, trace amounts of mercury can continue to release vapor. Keep the windows open and air flowing through the room for at least 24 hours after a thermometer-sized spill. If weather permits, 48 hours is better. Keep the room’s doors to the rest of the house closed during this time, and keep children and pets out of the space while it ventilates.
If you want to confirm that vapor levels have returned to safe levels, professional mercury vapor analyzers exist, but they’re industrial equipment, not consumer products. Your local health department can often test air quality after a spill, or direct you to an environmental services company that can.
How to Dispose of Collected Mercury
Mercury is classified as hazardous waste. You cannot throw it in your regular trash or recycling bin. Many counties and cities run household hazardous waste collection programs, and some have specific exchange or drop-off programs for mercury-containing items like thermometers and thermostats. Contact your local municipal waste authority, health department, or fire department to find the nearest option. You can also search Earth911.com by ZIP code to locate a collection site.
For transport, place all your sealed bags inside a larger container with a tight-fitting lid. Surround them with kitty litter or other absorbent material to cushion against breakage. Label the container “Mercury – DO NOT OPEN.” Carry it in your car’s trunk or the bed of a pickup truck rather than the passenger compartment, and make sure it’s secured so it won’t tip during turns or stops. Some states, like Vermont, ban all mercury waste from landfills regardless of the source, so checking your local rules matters.
Health Risks of Mercury Vapor Exposure
A single broken thermometer in a well-ventilated room is unlikely to cause serious harm if you clean it up promptly. The danger increases when mercury sits unnoticed in a warm, enclosed space, or when someone vacuums it and sends a concentrated burst of vapor into the air.
Acute mercury vapor exposure follows a recognizable pattern. In the first few days, it mimics a flu: chills, fever, muscle aches, headache, and dryness in the mouth and throat. Within one to two weeks, more serious symptoms can develop, including persistent cough, chest pain, nausea, vomiting, difficulty breathing, and confusion or disorientation. These intermediate symptoms can affect the lungs, kidneys, digestive system, and nervous system. In the late phase, other organ symptoms resolve but neurological effects can linger.
If anyone in your household develops flu-like symptoms after a mercury spill, especially one that wasn’t cleaned up right away, that exposure history is critical information for a doctor to have.
When the Spill Is Too Big for DIY
The guidelines above apply to small household spills: a thermometer, a single fluorescent bulb, a small thermostat switch. If the amount of mercury is larger than that, if it has spread across a wide area, if it has gotten into your heating ducts, or if you simply can’t find all of it, call your local fire department or health department. They can deploy a hazmat response or connect you with a professional environmental cleanup company equipped with vapor detection instruments that can locate hidden mercury deposits in cracks, under baseboards, and inside ventilation systems.