Mothballs: What's in Them, and Calmer Ways to Store Clothes
Mothballs are made almost entirely of one pesticide that slowly turns into vapour, so the smell in a closet is the chemical itself drifting into the air you breathe.
What mothballs actually are
A mothball is a small pesticide block made almost entirely of a single active ingredient: usually naphthalene or paradichlorobenzene (PDB, also written 1,4-dichlorobenzene). What makes them unusual is that they are solids that slowly turn straight into vapour without melting first. That is why an open jar gives off such a strong, lasting smell.
According to the US National Pesticide Information Center, when you can smell mothballs you are breathing in the pesticide. The same two chemicals show up beyond the closet, too: paradichlorobenzene is common in solid 'deodoriser' or 'air freshener' blocks for cupboards, bins, and toilets, where the heavy lingering scent is reused to mask odours.
Because the front of a package may just say 'deodoriser,' the reliable move is to read the active-ingredient line and look for naphthalene or paradichlorobenzene rather than trusting the marketing name.
- Naphthalene — the classic mothball ingredient
- Paradichlorobenzene / 1,4-dichlorobenzene / PDB — common in deodoriser and toilet blocks
- Older product names: moth flakes, moth crystals, moth cakes, white tar, tar camphor
What the evidence suggests about health
The clearest, best-documented concern is red blood cells. The US EPA's hazard summary states that short-term naphthalene exposure may cause cataracts and haemolytic anaemia in people, and published case reports link mothball ingestion to severe haemolysis in children with G6PD deficiency, an inherited trait that is more common in some Mediterranean, African, and South and East Asian backgrounds.
On cancer, the EPA classifies both naphthalene and paradichlorobenzene as Group C, possible human carcinogens, and the International Agency for Research on Cancer lists both as possibly carcinogenic to humans (Group 2B). 'Possible' here means the evidence is suggestive but not proven, and these classifications largely reflect higher, sustained exposures rather than a brief whiff from a stored coat.
There is a practical reason to keep perspective and still act: naphthalene and PDB can cross the placenta, and a US pregnancy-cohort analysis (the ECHO PATHWAYS study) found a small association between higher maternal levels of a naphthalene breakdown product and slightly shorter gestation and lower birth weight. Many things affect those outcomes, so this does not prove cause, but it is part of why reducing exposure during pregnancy is sensible.
A single mothball can look like a sweet to a small child, and the NPIC notes one mothball can cause serious harm if eaten by a young child. If you keep any mothball product, it must stay sealed in an airtight container, never loose, and well out of reach.
Who is most sensitive
Most of the documented risk concentrates in a few groups rather than across healthy adults. Babies and young children are the group of greatest concern: hospitals have reported many cases of haemolytic anaemia in infants and children who swallowed naphthalene mothballs, or were in close contact with clothing and blankets stored in them.
Anyone with G6PD deficiency, at any age, is more sensitive, because even modest naphthalene exposure can trigger a haemolytic episode. A baby born with G6PD deficiency can also be especially sensitive in the days right after birth. For a healthy adult, by contrast, a brief whiff from a stored garment is a low-level concern, and the risk rises mainly with enclosed, ongoing exposure in a small closet or bathroom.
Calmer ways to store clothes
This is one of the easier exposures to set down, because the alternatives cost about the same and do the same job without the fumes. The first step is simply to walk through your closets, storage boxes, and bathroom cupboards, remove any mothballs, moth flakes, or solid deodoriser blocks, bag them to dispose of per the label, and open a window or run a fan to air the space out.
Moths are drawn to body oils and food residue, not clean fabric, so the real protection is keeping garments clean and sealed rather than gassing them. If you have stored baby clothes or hand-me-downs that smell of mothballs, wash and air them before anyone wears them.
- Cedar blocks, balls, or a cedar-lined chest — refresh the scent occasionally by sanding lightly
- Sealed airtight bins or vacuum bags for off-season clothes, so moths cannot reach them in the first place
- Wash or dry-clean wool and natural fabrics before storing them away
- For bathroom odours, use ventilation and ordinary cleaning instead of solid PDB blocks
Keeping it in proportion
None of this is about fear. The honest read is that mothballs are an optional product with well-established replacements, the strongest concern is red-blood-cell damage in babies and children, and cedar plus sealed airtight storage work just as well. The aim is to use these products only as the label directs and keep them out of the rooms where your family breathes, sleeps, and plays.
One unrelated note, because it comes up alongside chemical worries: when you are reducing avoidable exposures, sunscreen is not the place to cut back. Mineral options are available — never stop using sunscreen. The goal throughout is to reduce avoidable exposure, not to add anxiety to your day.
Your one small step
Pick a single closet, wardrobe, or storage box and check it for mothballs or solid deodoriser blocks. If you find any, bag them to dispose of per the label and let the space air out. Swapping to a couple of cedar blocks or a sealed bin takes a few minutes and removes the vapour entirely.
Common questions
If a closet smells of mothballs but I cannot find any, is that a problem?
The smell means naphthalene or paradichlorobenzene vapour is present, and it can soak into stored fabrics, so a blanket or bag of hand-me-downs can carry it long after the mothballs are gone. Air the space out with a window or fan, and wash and air any clothes or bedding that smell of it before anyone wears them, especially babies.
Are the solid blocks in toilets and bins the same chemical?
Often, yes. Many solid toilet, urinal, and bin deodoriser blocks use paradichlorobenzene, one of the two main mothball ingredients. For bathroom odours, ventilation and ordinary cleaning do the job without releasing the vapour, so these blocks are an easy thing to skip.
Does cedar actually keep moths away?
Cedar repels clothes moths with a scent that is far less concerning than mothball vapour, and you can refresh it by sanding lightly. Even more reliable is removing the food source: moths are drawn to body oils and stains, so washing wool before storing it in sealed airtight bins or vacuum bags is the strongest protection.
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Micro Detox is an educational exposure reduction guide. It is not medical advice and does not diagnose, treat, prevent, or cure any condition. If you are pregnant, trying to conceive, or managing symptoms, speak with a qualified health professional.
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