Washing new clothes before wearing them removes some chemicals completely and reduces others, but it does not strip out every chemical finish applied during manufacturing. The results depend heavily on which chemical you’re dealing with. Formaldehyde, one of the most common concerns, washes out entirely in a single cycle. Flame retardants, on the other hand, barely budge.
What Chemicals Are in New Clothes
Clothing goes through a surprising number of chemical treatments before it reaches you. Wrinkle-resistant and “easy care” fabrics are typically treated with formaldehyde. Waterproof jackets and outdoor gear rely on per- and polyfluoroalkyl substances (PFAS). Flame-resistant clothing, especially children’s sleepwear, contains brominated, chlorinated, or phosphorus-based flame retardants. The dyeing process can introduce heavy metals like lead, cadmium, chromium, and mercury, along with azo and disperse dyes that cause skin reactions in some people.
Beyond these, you’ll find anti-microbial finishes using phenols or silver compounds, anti-static treatments with silicone, and various other coatings depending on the garment’s intended performance. The total chemical load varies by fabric type, country of manufacture, and how many “features” the clothing is marketed to have.
Formaldehyde Washes Out Almost Completely
If formaldehyde is your main concern, the news is good. A study published in the journal Toxics tested 20 garments with some of the highest formaldehyde concentrations found in clothing, including jeans, leggings, and underwear. After a single wash, none of the 20 items had detectable levels of formaldehyde remaining. The researchers noted that this held true regardless of how much formaldehyde was present before washing. Because formaldehyde is a volatile organic compound that dissolves easily in water, a standard wash cycle is enough to flush it out.
This is particularly relevant for anyone with sensitive skin or chemical sensitivities. Formaldehyde is one of the most common causes of contact dermatitis from clothing, and a single pre-wear wash eliminates the risk.
Flame Retardants Mostly Stay Put
Flame retardants are a different story. Research published in Environmental Science & Technology found that less than 10% of brominated flame retardants accumulated in fabric were released into laundry water during washing. More than 90% of the chemical mass remained on the laundered cotton and polyester. These compounds are designed to bond tightly to fibers, which makes them effective at their job but also very difficult to wash away.
The study tested a standard 30-minute wash cycle. The researchers did not test whether hotter water, longer agitation, or repeated cycles would improve removal, but the stubborn retention rate suggests that home laundering is not an effective strategy for stripping flame retardants from treated fabrics. If you want to avoid these chemicals, choosing untreated garments is more effective than trying to wash them out.
PFAS Removal Is Complicated
Waterproof and stain-resistant clothing treated with PFAS presents the most complex picture. Washing does reduce the concentration of some PFAS compounds, and the effect increases with more cycles. After five wash-and-tumble-dry cycles, extractable PFAS levels dropped across all coated fabrics tested. After ten cycles, concentrations dropped further still.
But there’s a catch. Washing can also increase the detectable concentration of certain volatile PFAS in the fabric. This happens because the mechanical action of washing breaks down larger PFAS molecules into smaller, more extractable ones, or releases compounds that were previously locked into the fabric’s structure. In one case, a specific PFAS compound increased from 87 micrograms per kilogram to 430 micrograms per kilogram after washing. The combination of aging (normal wear over time) and washing made this effect even stronger.
So while repeated laundering reduces the total PFAS burden over time, it can temporarily increase your exposure to certain breakdown products. The chemicals don’t simply rinse away cleanly.
Volatile Compounds and Off-Gassing
New clothes often have a distinct chemical smell. That’s volatile organic compounds off-gassing from the fabric. Washing reduces these emissions meaningfully. Testing shows that laundered clothes produce roughly 20% fewer volatile emissions compared to soiled or unworn garments when exposed to normal indoor conditions. While that study focused on skin oils interacting with ozone rather than factory-applied chemicals specifically, the principle holds: washing reduces the volatile chemical load on fabric surfaces.
For people who notice a strong chemical odor on new purchases, washing before wearing is a simple way to reduce that initial burst of off-gassing. Hanging clothes outdoors to air out before the first wash can help too, since many of these compounds evaporate on their own given time and airflow.
Washing Can Add Chemicals Too
It’s worth noting that the wash cycle itself introduces new chemicals to your clothing. After a standard laundry cycle, residual components left on fabric can include surfactants, synthetic fragrances, dyes, enzymes, preservatives, and optical brighteners from the detergent. For most people these residues are harmless, but they can trigger skin irritation or allergic reactions in sensitive individuals.
If you’re washing clothes specifically to reduce chemical exposure, using a fragrance-free, dye-free detergent and running an extra rinse cycle helps minimize the chemicals you’re adding back in.
Cross-Contamination Between Garments
Chemical residues can transfer between items in the same wash load. Research from Montana State University on pesticide-contaminated work clothing found that tossing contaminated garments in with regular laundry transferred residues to the other clothes, and from there to other family members. The recommendation for heavily contaminated items is to wash them separately, in small loads, and to group items with the same type of contamination together.
For everyday clothing, this is less of a concern. But if you work with industrial chemicals, pesticides, or other hazardous substances, keeping those garments out of the family laundry is important. Use a disposable plastic bag rather than a cloth hamper to store them before washing.
Which Chemicals Washing Removes Best
- Formaldehyde: Effectively eliminated in one wash. Water-soluble and volatile, it rinses out almost completely.
- Surface dye residues and loose colorants: Partially removed, especially in the first few washes. This is why new dark clothes bleed color.
- Volatile organic compounds: Reduced by washing and air drying, though not fully eliminated in a single cycle.
- PFAS (waterproofing chemicals): Partially reduced over many washes, but some breakdown products can temporarily increase. Not reliably removed by home laundering.
- Flame retardants: Largely resistant to washing. Over 90% remains on fabric after laundering.
- Heavy metals from dyes: Some leaching occurs during washing, but these are bound into the fiber structure and are not fully removable through normal laundry cycles.
Practical Takeaways
Washing new clothes before wearing them is a genuinely effective step for the chemicals that matter most for skin contact, particularly formaldehyde and loose dye residues. A single wash with a mild detergent handles those well. For deeper concerns about flame retardants or PFAS, washing helps at the margins but won’t solve the problem. The more effective approach is choosing clothing that wasn’t treated with those chemicals in the first place.
Hot water generally dissolves chemical finishes more effectively than cold water, since most textile treatments are more soluble at higher temperatures. If your goal is maximum chemical removal on that first wash, a warm or hot cycle (fabric permitting) will outperform a cold one. Adding an extra rinse cycle also helps flush out what the first rinse loosened.