Most conventional mattresses off-gas, harbor mildew and mold, and collect dust mites. Can an organic mattress cover make a foam mattress safer? Here’s the inside scoop on mattress wrapping to minimize VOCs and seal in bugs and bacteria, with our top picks for mattress covers.
Table of Contents
- Why it matters: The trouble with foam mattresses
- Can an organic mattress cover make a foam mattress safer?
- The Best Organic Mattress Covers
- Best for bed bugs, dust mites, etc.
- Best for blocking off-gassing
- Alternative mattress covers to prevent off-gassing
- What else can I do about my mattress off-gassing?
- Don’t forget your foundation!
Why it matters: The trouble with foam mattresses
We discuss the problems with polyfoam more in depth here. For now, though, suffice it to say that foam mattresses are made with a slew of toxic chemicals, including volatile organic compounds (VOCs) such as:
- Chemical flame retardants and stain repellents.
Many VOCs off-gas most when the mattress is new. Foam mattresses also off-gas in mid-life, however, and can start to off-gas more again as they get old and further degrade.
Even if you can no longer smell that new mattress smell, your mattress is likely still off-gassing some VOCs. Indeed, if you wrap a foam mattress effectively and then unwrap it after a few weeks, chances are you’ll be able to smell that ‘new’ mattress smell again!
Why VOCs in mattresses matter
Mattresses are a key source of VOC exposure simply because we spend so much time sleeping on them. For infants and children, the impact is greater because they sleep longer and have a higher ratio of lung surface area to body mass.
If you can, prioritize non-toxic mattresses for the most vulnerable family members first. Remember that mattress dust and off-gassing affect indoor air quality throughout your home.
Given that it’s expensive to replace all your old foam mattresses with non-toxic, eco-friendly mattresses, it’s smart to find ways to minimize off-gassing and exposure to VOCs. This is where an effective mattress cover can help.
Can an organic mattress cover make a foam mattress safer?
Yes! An organic mattress cover can make a foam mattress safer, although it depends on the kind of cover, how you use it, and your priorities for safety.
Natural fabric mattress covers
Cotton, latex, and wool are great materials for organic mattresses but are ineffective at blocking off-gassing from a foam mattress. This is because they are gas permeable (they let gases through), regardless of how tight the weave.
Some key points:
- Don’t assume a dust mite cover or mattress pad will block off-gassing. It almost certainly won’t
- Organic cotton mattress covers can block dust mites, bed bugs, and allergens, but not gases
- Organic latex and wool don’t block off-gassing from foam mattresses
- Plastic is the only current option for blocking off-gassing from foam.
If you’re less concerned about VOCs and more concerned about dust mites, bed bugs, and allergens, a tightly woven organic cotton mattress cover will be sufficient to improve safety.
Check that the cover is made with genuinely organic cotton (look for the GOTS label on the cover itself) and is free of toxic chemicals, TPU, PVC/vinyl, and polyurethane. Also, look for a mattress cover with pores no larger than about 5 microns. This means bed bugs, dust mites, and dust mite feces can’t easily get through the cover.
As for off-gassing, the only current option for effective mattress wrapping is plastic. Note, though, that a plastic mattress cover has to be made with specific kinds of plastic and be a certain thickness to prevent gas penetration.
The best plastic mattress covers for off-gassing
Ironically, many plastic mattress covers actually add VOCs, instead of reducing overall exposure.
Mattress protectors made with vinyl or, more specifically, polyvinyl chloride (PVC) are notorious for off-gassing VOCs. They’re also noisy and can disturb sleep, and are made with phthalates.
Polyethylene is the best option for a plastic mattress cover to prevent off-gassing. Low-density, food-grade polyethylene (LDPE) or high-density polyethylene (HDPE) are two of the safest, least toxic types of plastic currently available.
LDPE is a simple plastic with few chemical additives and no phthalates or other plasticizers. Unlike HDPE, LDPE is also soft and flexible, which makes it useful as a mattress cover.
In New Zealand, specially formulated sheets of LDPE were developed by a physician and then tested and marketed as crib mattress covers under the BabeSafe brand. These effectively blocked off-gassing from crib mattresses.
The BabeSafe covers were made of 125 micron internally plasticized polyethylene (AKA polythene). This inert plastic doesn’t off-gas and is free of phthalates and bisphenol A.
Unfortunately, BabeSafe is no longer in business, although some other companies offer similar mattress wraps.
What about PLA, polypropylene, and TPU?
Other safer plastics for mattress covers include polylactic acid (PLA) and polypropylene. These, like LDPE, are made with very few chemicals of high concern compared to, say, polyethylene terephthalate (PET) or PVC.
PLA isn’t produced in large quantities, however, so you’re very unlikely to find it in a thickness suitable for mattress wrapping. Polypropylene is more widely produced and may actually last longer than a polyethylene cover, but I’m yet to find a mattress cover made with polypropylene.
Polyurethane mattress protectors are also very common. Unfortunately, though, these can add to off-gassing. After all, polyurethane is the material most mattresses are made of and is the primary source of VOCs you’re trying to block!
Some polyurethane covers are better than others, though, and there is a difference between a thin layer of PU and a blown PU foam that is made with a cocktail of added chemicals.
Avocado offers one of the few GOTS certified organic waterproof mattress covers (view on Avocado), made with a very thin layer of PU (5%) sandwiched between two layers of organic cotton (95%). The Avocado cover is MadeSafe™ and Greenguard Gold certified and is formaldehyde-free and low VOC.
However, this cover is not a 360-degree mattress wrap, so is only intended for protecting the top of a mattress from spills and leaks.
Full 360-degree mattress protectors that prevent off-gassing are few and far between. Finding one that’s also non-toxic and eco-friendly is a real challenge. That said, we found one!
The Best Organic Mattress Covers
Best for bed bugs, dust mites, etc.
Highlights: GOTS certified organic cotton mattress cover with zipper. Tight weave (3.8-micron pores) and dense fabric with 280 thread count. Effective against bed bugs and dust mites.
- Made with GOTS organic cotton
- 280 thread count (very dense and durable)
- Well-placed zippers
- Pore size of 3.8 microns
- Doesn’t block off-gassing
- Nylon zipper
The Organic Lifestyle mattress cover is one of very few made with entirely GOTS certified organic cotton as a full zippered encasement. Unlike a mattress cover with elasticated sides that fits like a fitted sheet, this encasement fully encloses your mattress, making it impenetrable for bed bugs and dust mites.
The 280 thread count fabric is dense and durable without feeling overly stiff. Organic Lifestyle had the fabric tested by a third party and the average pore size was just 3.8 microns (small enough to block dust mite feces).
This encasement has a smart zipper design that starts halfway up one side, runs along the bottom of the mattress, and then halfway up the other side. This means the zipper is mostly hidden and isn’t close to the sleep surface.
Best for blocking off-gassing
Highlights: Affordable and effective waterproof mattress cover to prevent off-gassing and protect against spills, bugs, and allergens. Carries GOTS, Greenguard Gold, and OEKO-Tex certifications.
- Greenguard Gold and Oeko-Tex certified
- Made with biobased TPU and GOTS certified organic cotton
- Marketed as preventing off-gassing
- Protects against dust mites and bed bugs
- Not noisy (crinkle-free)
- Free of vinyl/PVC, phthalates, off-gassing
- Can cover a mattress up to 16-inch depth
Sleep & Beyond’s zippered mattress cover is GOTS organic certified and offers 360-degree protection. That means it’s waterproof and sealed on all six sides. This is not just a mattress cover with waterproofing on the top surface.
The cover is made of two layers of stretchy organic cotton jersey fabric with an inner layer of TPU (thermoplastic polyurethane). The TPU is 20 microns thick and has pores smaller than 3 microns. This TPU is made from corn starch and is non-GMO. It is approved by GOTS and is Oeko-Tex and Greenguard Gold certified.
Sleep & Beyond produces the cover ethically too. Specifically, it uses a Fair Trade certified factory that is Sedex and ISO certified and carries the Business Social Compliance Initiative (BSCI) seal. And the company’s U.S. fulfilment center is GOTS certified too!
The cover is available in standard mattress sizes and in 10- and 14-inch depths. Because the fabric is stretchy, the 14-inch design works for mattresses up to 16 inches deep.
The cover comes in a reusable organic cotton bag and has a 10-year warranty. You can machine wash the cover on warm and dry on low.
Alternative mattress covers to prevent off-gassing
In the absence of ready-made mattress covers to prevent off-gassing, you might want to go the DIY route. Consider, for instance, using a mattress moving and storage bag.
One top choice is this robust mattress bag (view on Amazon) made with 6 mm thick polyethylene. It has a secure zipper closure and is meant for storage and to protect a mattress during a house move. However, there’s nothing to stop you from using it to wrap a foam mattress to prevent off-gassing. What’s more, it costs just $25 for a king-size bag!
Given the thickness of the plastic, I’d suggest wrapping the mattress in this bag and then adding a (plastic-free!) natural latex, wool, or cotton mattress topper for comfort and to minimize noise.
In a pinch, you might also consider wrapping your mattress in three 2 mm thick polyethylene moving bags from UHaul (view on UHaul). However, there’s a strong chance at least one of the bags will rip, and the plastic will likely be bulkier, noisier, and harder to handle than the single thicker bag above.
What else can I do about my mattress off-gassing?
Great question! Aside from replacing your mattress and using a mattress cover, you might also consider:
- Airing out any new foam mattresses in a well-ventilated area for two weeks
- Using an effective air purifier that traps VOCs
- Opening windows and doors whenever possible.
Don’t forget your foundation!
Foam mattresses aren’t the only part of most beds that off-gas VOCs. If you have a box spring or foundation made with synthetic materials, chances are that it also contains chemical flame retardants, glues, and formaldehyde in the particle board or manufactured plywood, and other materials and chemicals that off-gas.
A solid wood bed frame is the best non-toxic, eco-friendly choice as a foundation for your mattress. A metal bed frame is also a good option, though wood is easier to assemble time and again and to fix if a piece breaks or goes missing.
Ideally, your bed frame will be made from sustainably sourced hardwood grown locally and certified by the Forest Stewardship Council (FSC). It should be free of chemical stains or paints and treated only with heat and vegetable oils or other natural oils that don’t off-gas toxic VOCs.
We highly recommend the Avocado Green Foundation (view on Avocado). This is made with solid wood and GOTS organic cotton and is Greenguard Gold certified.
Naturepedic Organic Foundation (view on Naturepedic), made with organic cotton and American-grown hardwood, with no plywood or VOCs.
In the absence of a well-made LDPE, PLA, or polypropylene mattress cover, some folks go the DIY route and make their own mattress cover using LDPE sheeting. This is often available at very low cost at hardware stores.
Be sure to find sheets that are at least 6 mm thick, however, to prevent off-gassing. And be very diligent about taping or tucking seams to seal in VOCs.
In years gone by, some enterprising folks purchased several BabeSafe crib mattress covers and then cut and taped these together to cover a larger mattress.
How well these DIY covers prevent off-gassing will depend on how effectively you manage to seal the plastic around the mattress. Note, too, that some plastic tape can also off-gas!
All plastics degrade, and they degrade faster when exposed to ultraviolet light, flexing (i.e., movement), moisture, heat, tears, and washing.
As plastic mattress covers degrade they’ll become less effective at blocking VOC off-gassing. This means it’s likely a good idea to replace a mattress cover every two or so years, or more frequently if the cover is damaged or shows serious wear and tear.