That new mattress smell—what is it and is it harmful?

Picture this: You buy a new mattress online, and it arrives at your door in a matter of days. You unroll it on your bed frame, let it expand, and make the bed, excited for your first blissful night. Night falls, you go about your evening routine, and lie down to curl up and catch some zzz’s, and pee-yew, a pungent chemical odor wafts up into your face.

As the sleep writer at Reviewed, I’ve experienced the “new-mattress smell” a couple of times and, to be frank, it’s unpleasant. I even slept on a mattress with an odor so strong that for the first few mornings after sleeping on it, my hair smelled like it.

My experiences with mattresses (and my hair) stinking made me wonder, what is causing the stench? Sure, it’s gross, but is it actually bad for your health? Many mattresses in a box recommend letting the bed air out for at least 24 hours after you free it from the plastic wrap and before you sleep on it. Does that imply the odor is straight-up unhealthy?

In short, the answer is: You shouldn’t worry. In all likelihood, it won’t harm you. But allow me to explain.

What causes that new-mattress smell?

There’s a technical explanation for the process that new products, from mattresses to car interiors, go through that causes the “new” smell: off-gassing of “volatile organic compounds,” or VOCs. VOCs are gaseous byproducts of the manufacturing process that largely dissipate over time. In mattresses that contain foam, the foam itself is the most likely culprit of off-gassing. However resins, adhesives, and other materials used to make mattresses can also off-gas, as can flame retardants applied to the mattress so it meets government mandated standards in the event of a fire.

All of this can be true of conventional mattresses, as well as upholstered furniture, which can contain many of the same materials and components. But there’s a reason this “new-mattress smell” recently came to my attention, and maybe yours. The popular mattresses-in-a-box, wherein a bed that’s compressed to a fraction of its actual size appears at your door, relies on super-tight plastic wrapping that prevents the mattress from prematurely expanding (and, for example, busting out of its packaging on the delivery truck). But immediately encasing a newly made mattress in air-tight packaging can cause VOCs that would otherwise dissipate to remain trapped until you unseal it, says Kevin Stewart, the director of environmental health at the American Lung Association. In brick-and-mortar stores, mattresses aren’t always so tightly packaged, and may sit in a back room for some period prior to sale, allowing time for VOCs to release, he says.

What are VOCs and SVOCs?

Volatile organic compounds (VOCs) are molecules that “volatilize,” or evaporate and disperse, into the air at or near room temperature. Not all VOCs are inherently bad: “When you smell a flower, you are smelling a naturally occurring VOC,” Stewart says. “But many chemicals in our homes are human-made.” And don’t let the word “organic” in this context mislead you. “Organic” means the compounds contain carbon.

Semi-volatile organic compounds, or SVOCs, are a sub-group of VOCs that can also be released by mattresses and other furnishings with foam components. SVOCs are characterized by a higher boiling point, which means it takes more heat and ‘oomph’ for them to vaporize, Stewart says.

In the context of mattresses, SVOCs are often byproducts of flame retardants that are added to the foam or mattress fabric (called “ticking”) to meet requirements set by the Consumer Product Safety Comission (CPSC), says Heather Stapleton, a researcher at Duke University who studies environmental health and serves as the deputy director of the Duke Superfund Research Center. There are two main types of flame retardants: additive and reactive. Additive retardants are more prone to leaching out of products due to the way they’re added, Stapleton says. She uses cookies as an example. Eggs and flour are well incorporated, but something like raisins won’t be added until the very end, making them more prone to separating from the cookie. Additive flame retardants are thrown in at the end of the manufacturing process, and are not chemically bonded to the base material. This makes them more prone to easy release despite the higher boiling point, Stapleton says.

Should I be concerned about off-gassing from a new mattress?

Most healthy adults won’t experience side effects from VOCs and SVOCs from mattresses, Stewart says. Plus the simple step of letting a new mattress air out in a room where you don’t spend much time for at least a day before you move it into your bedroom has major benefits.

Many VOCs, and especially SVOCs, are still being researched for exposure concerns related to human health. But others have already been deemed “known carcinogens”—though research thus far indicates that their carcinogenic effects are linked only with exposure to high concentrations, nowhere near the levels you find in consumer products. As it stands, VOCs and SVOCs from mattresses could leave you with eye and throat irritation, or headaches, but these effects often quickly subside once you’re away from the bed.

Regardless, even at a low level, “chemicals are an additional burden to the body, [they’re] something the body has to deal with. Most people are able to deal with a small level of exposure without having health problems,” Stewart says. But it’s not about completely eliminating these chemicals, which is almost impossible, rather decreasing their presence to the best of your ability, he says. When you get a new bed containing foam, pay attention to your body and the signals it’s sending you. Just being mindful is often enough to know whether a mattress and off-gassing VOCs irritate you as an individual, he says.

In addition, while you may notice a smell for at least a couple of days, it depends on your sensitivity and the individual mattress. What’s more, humans have to deal with “olfactory fatigue,” which happens when our smell receptors become temporarily desensitized due to ongoing exposure to a scent. Also bear in mind that even older foam products can continue to off-gas low levels of VOCs, some of which are odorless in the first place. So pay attention to whether you experience other symptoms, such as headache when you first wake up, because you can’t rely on your nose alone to detect off-gassing.

People with certain pre-existing conditions, including asthma and chronic lung disease, can face greater risk or side effects from exposure to VOCs, and may need to be more cognizant of off-gassing and thoughtful about the mattress they purchase, Stewart says. One way to do this is give any newly purchased mattress ample time to off-gas, preferably somewhere away from you. Whether that be in a room you don’t frequent as much or your garage depends on your circumstances.

Babies and children are also more sensitive to these chemicals than adults because of their developmental stage, so it’s especially important to limit their exposure, Stapleton says. “If a baby isn’t being held, it’s on a bed, or play mat, or even a car seat,” she says. All these products can contain foam so being mindful while shopping for this group is essential.

Of course, manufacturers aim to keep consumers safe and happy. As such, high levels of chemicals, and chemicals that trigger immediate and acute health concerns—as in, you get one whiff of something and feel nauseous—can’t be readily found in consumer products. “It’s just not a sustainable business plan if a product is obviously and immediately harmful,” Stewart says.

How can I buy a safer mattress?

Fortunately, there are still steps you can take to choose a mattress with lower VOC emissions. Various independent companies offer certifications that ensure the bed foam is “low-toxin,” low-VOC, or that it contains fabric components that are made from organically grown fibers.

Well-known third-party certifiers, such as Okeo-Tex, which issues the Okeo-Tex Standard 100 and the Global Organic Textile Standard (GOTS), are a good place to start. These groups only certify products after they meet a number of criteria that can include lab testing that’s completed by independent entities and production requirements.

GOTS and Okeo-Tex focus on textiles, and can certify the fabric covers used on mattresses. For polyurethane foam beds, a category that encompasses nearly all foam mattresses including memory foam and hybrid foam-spring beds, there’s one certifier that comes up again and again: CertiPUR-US.

A certification from CertiPUR-US indicates the foam used in a flexible polyurethane mattress meets a number of chemical and environmental criteria. The organization's testing criteria were based on federal, state, and local level authorities, says Helen Sullivan, a spokesperson for CertiPUR-US. To qualify for CertiPUR-US certification, foam used in a mattress:

• Can’t emit high levels of VOCs. The manufacturing process makes it difficult to completely eliminate VOCs from products, so CertiPUR-US certification means that a foam doesn’t release more than 0.5 parts per million (ppm). To scale how small 0.5ppm is consider cutting a pie into a million slices. Only half of one of the million slices would contain VOCs. This is well below standards set by the U.S. Department of Labor Occupational Health Safety and Health Administration for common VOCs.

• Must pass an emissions test specifically for formaldehyde, a common VOC that’s considered a “probable human carcinogen,” which can also be found in mattress ticking, according to the EPA.

• Can’t be produced with phthalates, a group of chemicals sometimes used to soften plastics that can cause respiratory issues or disrupt the endocrine system, which includes the thyroid and regulates hormones and metabolism, among other things.

• Must be manufactured without ozone depleters, or chlorofluorocarbons (CFCs), a group of chemicals that harm human health and the environment. You’ve probably heard “ozone” in one context or another. Ozone is complex because in the layer of atmosphere closest to earth’s surface, the troposphere, it’s a pollutant. But in the next layer up, the stratosphere, it helps shield the earth’s surface from harmful UV rays. CFCs drift into the stratosphere where UV causes them to break apart and release chlorine, which destroys ozone molecules. While they affect the atmosphere, they can also harm our health and cause a range of symptoms, including headaches and even tremors at high concentrations. The chemicals’ use is heavily restricted in the U.S., but it’s still used overseas.

• Cannot contain mercury, lead or other heavy metals. These metals are not very common in mattresses, but they found their way into a variety of other household and personal items, from cadmium in vintage toys, to lead in paint, and even cosmetics. Excessive exposure to these metals can cause poisoning.

In the past, a handful of mattress companies have certified themselves, so it’s best to opt for a prominent organization that’s not involved with manufacturing, like CertiPUR-US or Okeo-Tex.

Okeo-Tex and CertiPUR-US certifications are voluntary. Mattress flammability standards set by the CPSC, on the other hand, aren’t optional. The agency’s strict regulations on mattress flammability were implemented in 2006 to reduce how quickly and to what extent a mattress exposed to fire would ignite and become engulfed. Mattresses contain flammable components, and were among the first household objects to ignite in thousands of residential fires prior to the regulation. Open flames, like candles, lighters, and smoldering cigarettes have caused beds to go up in flames.

Fortunately, mattress companies can meet the requirements without using additive chemicals. Stapleton encourages people on the market for a mattress to seek out and purchase products that are free of these chemicals whenever possible, to help limit your potential exposure to SVOCs. Luckily, finding a mattress that’s safer all around isn’t too difficult, if you know how to shop smarter. Mattress companies often advertise if their beds don’t contain flame retardant chemicals in product descriptions or online FAQ sections, but you can still go deeper. Look for mattress fabrics made of fibers that naturally have flame-retardant properties, like wool. The Leesa Legend Mattress, for example, has a cover made of a wool and cotton blend.

In addition, internal components, like foam, can be made with reactive flame retardants rather than additive ones. Avocado is one mattress retailer that manufactures without relying on flame retardants. If a mattress you’re considering isn’t abundantly clear on how they meet flammability requirements, call or chat with its customer service and ask if the mattress or its components are made with additive chemical flame retardants.

Can I get rid of the new mattress smell?

Regardless of certifications and “chemical-free” claims, mattresses can still smell. What’s more, off-gassing isn’t a one-size fits all scenario. In fact, the levels of chemicals can vary from one batch of a brand’s mattresses to another, Stapleton says. To compound things further, brand new mattresses, as in the mattress was manufactured and at your door within 10 days, will be more likely to produce an odor than a mattress with older components, or one that was exposed to more open air, Sullivan says.

VOCs and SVOCs from foam and other man-made products have an easier time sticking around indoors because there is often less ventilation to disperse them, Stewart says. That said, you may not like the idea of leaving your brand-new, unprotected bed outside in the yard, so do your best to let a new mattress off-gas in a well-ventilated space that you don’t spend a lot of time in (whenever possible—I know the difficulty of airing out a new bed in an apartment firsthand).

When a mattress is first off-gassing, you can use higher temperatures to your advantage. Heat makes these volatile compounds air out more quickly, says Patty Davis, a spokesperson for the U.S. Consumer Product Safety Commission, so letting them breathe in an un-air-conditioned space during the dead of summer may help, just so long as it’s not in the living room.

Nonetheless, airing out a mattress for one to two weeks is generally a good idea, Stewart says. He warns that some beds could need longer, depending on a variety of factors. Plus, odorless chemicals can still be off-gassing without you realizing it, so even if a new bed stops smelling within a day or two, more time won’t hurt.

In the end, don’t let VOCs keep you up at night. If you’re healthy, it’s very unlikely you’ll experience any issues other than maybe a wrinkled nose and raised eyebrows from your new bed. I’ve aired out and slept on new foam or foam hybrid mattresses a few times in a small apartment, and I’ve yet to run into a problem (stinky morning hair aside).

If all else fails, many online mattress retailers offer a satisfaction guarantee. If you discover you’re sensitive to a new bed’s smell even after a week or two, or that the bed’s just not filling the bill for how you like to sleep, don’t sweat it—coordinate with the retailer to send it back.

The product experts at Reviewed have all your shopping needs covered. Follow Reviewed on Facebook, Twitter, and Instagram for the latest deals, product reviews, and more.