Old clothes or stored items treated with naphthalene or paradichlorobenzene are why your house smells like mothballs. These chemicals release a strong, persistent odor that clings to fabrics and circulates through your home’s air vents. Most of the time, the scent comes from a specific box or closet rather than the entire structure. If you find a container with a chemical smell, move it outdoors immediately to stop the gas from spreading further.
Why your house smells like mothballs
| Cause | How common | How to confirm it | Fix it yourself? |
|---|---|---|---|
| Stored seasonal clothing | Very common | Check storage bins | Yes |
| Antique furniture drawers | Common | Smell inside wooden units | Yes |
| Dead rodents in walls | Occasional | Look for entry points | No |
| Improper chemical disposal | Rare | Check trash storage | Yes |
| Moldy crawl space | Rare | Inspect under floors | No |
| Gas leak (mercaptan) | Very rare | Check gas appliances | No |
Musty odors in seasonal bins often stem from trapped humidity. If fabrics feel damp to the touch, you must wash them with a cup of white vinegar to neutralize the mildew spores.
Antique wood odors are usually caused by decades of absorbed oils. You can fix this by lining the drawers with cedar paper or placing a bowl of activated charcoal inside for forty-eight hours.
If you suspect a dead rodent, look for dark, greasy rub marks along baseboards. Don’t attempt to remove the carcass yourself if it’s behind drywall; the risk of structural damage or secondary pest infestation is high.
If you smell rotten eggs, prioritize safety over investigation. Leave the home immediately and call your utility provider from outside. Never flip a light switch or use a phone indoors, as a single spark can ignite the concentrated gas. If the smell persists after a professional inspection, check your floor drain traps for dried-out water seals.
Stored items and seasonal clothing
Old boxes or suitcases packed with wool sweaters and blankets are the primary source of this issue. Mothballs are solid pesticides that turn into gas over time, a process called sublimation. This gas settles into the fibers of the stored items. When you open a container that has been sealed for months or years, the concentrated fumes escape into the room.
To confirm this is your problem, open your storage areas one by one and smell the contents. If the odor is much stronger inside a specific box, you have found the source. Move these items to a garage or an outdoor shed immediately. Since these chemicals are designed to be toxic to insects, the United States Environmental Protection Agency warns that breathing these vapors over long periods can cause health issues for humans.
If you decide to keep the items, hang them outside in direct sunlight and fresh air for at least 48 hours. If the smell remains, you may need to wash the items repeatedly or have them professionally cleaned.
Antique furniture and wooden storage
Older wooden dressers or cedar chests often trap chemical odors from years of past use. If a previous owner used mothballs in these drawers, the wood absorbs the chemicals deep into its grain. This creates a lingering smell that persists even after you remove the original mothballs.
You can tell this apart from the first cause because the smell stays in the furniture itself, even when the drawers are empty. Check the corners of the drawers for any white, crystalline residue. If you find nothing but the smell remains, the wood is likely saturated. Wipe down the interior surfaces with a mixture of vinegar and water. Leave the drawers open in a well-ventilated room for several days to allow the trapped gases to escape.
This isn’t for someone who owns delicate, antique finishes that might be damaged by moisture. If the smell is faint, activated charcoal or baking soda placed in a bowl inside the drawer can help absorb the remaining scent over time. If the smell is overwhelming after a week of airing out, the wood may be too damaged to save.
Potential household hazards
Rodents sometimes die inside wall cavities or crawl spaces, and their decay can create a sharp, chemical-like odor that homeowners often mistake for mothballs. You can tell this isn’t mothballs if the smell is localized to one specific wall or floor area and seems to get worse over a few days.
If you suspect this, look for small holes in your baseboards or signs of scratching noises. This is a job for a professional pest control service. Don’t attempt to seal walls yourself if you suspect a dead animal, as this can lead to sanitation issues.
Another rare cause is a natural gas leak, which smells like rotten eggs or chemicals. If you ever feel dizzy, get a headache, or suspect a gas leak, evacuate your home immediately and call your utility company from outside. Never try to fix a gas leak yourself.
Professional help for persistent odors
Determining if you need a professional depends on whether the source is hidden or airborne. If the smell comes from a specific item you can move outside, you can handle it yourself. However, if the smell persists throughout the entire house despite removing all stored items, you need an expert.
A professional HVAC cleaner can tell you if the chemicals have settled into your ventilation ducts. They use specialized air scrubbers to pull particles out of the air. The cost depends on the size of your duct system and how long the chemicals have been circulating.
Ask for a quote based on your home’s total square footage. Before you hire someone, check their license and ensure they have experience with chemical remediation. If the smell is coming from a crawl space, you’ll need a contractor who specializes in moisture and air quality control.
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Frequently asked questions
Can I just use air fresheners to hide the smell?
No, air fresheners only mask the scent and don’t remove the toxic gas. You must find the source and remove it to stop the chemical reaction. Using fragrances in a room with high levels of mothball gas can actually make the air quality worse for your lungs.
How long does the smell last after removing the source?
The odor typically fades within one to two weeks if you provide good ventilation. If the items were heavily saturated, it may take longer. You can speed up the process by using fans to circulate fresh outdoor air through the room where the items were stored.
Is it safe to stay in the house while it smells like this?
No, you shouldn’t stay in a room with a strong chemical odor. Exposure to mothball vapors can cause headaches, nausea, and eye irritation. Open all windows immediately to dilute the gas and move to a different part of the home until the air is clear.
Does the smell mean I have a moth infestation?
No, the smell means someone used pesticides in the past, not that you currently have moths. People often place these chemicals in storage as a precaution. If you don’t see actual insects, the smell is likely just the chemical residue from old storage practices.
What happens if I wash clothes that smell like mothballs?
Washing helps, but you must keep the items separate from your clean laundry. Use a heavy-duty detergent and the hottest water setting the fabric allows. If the smell is still present after one cycle, wash the items again or keep them outside for a few more days.
How do I stop the smell from coming back?
You prevent the return by never using mothballs again. Use alternative methods like cedar blocks, lavender sachets, or vacuum-sealed plastic bags for long-term storage. These methods keep your items safe from pests without leaving behind toxic chemical gases that are difficult to remove from your home.
Conclusion
If the sharp scent lingers after you’ve cleared the source, open your windows wide to let fresh air circulate for a few days. You shouldn’t have to live with that heavy chemical smell forever. Once the house feels airy again, you’ll finally be able to enjoy your home’s natural, clean atmosphere.