University of Texas Study Lists Common Chemicals in Crib Mattresses to Avoid

In the first year alone, babies sleep for a total of around 228 days!

But don’t be lulled into thinking they’re just sleeping; that little body is busy building a robust immune system and nervous system and is growing rapidly. And, whenever rapid growth happens, there’s a greater potential for things to go awry, especially in the presence of toxic chemicals in crib mattresses that adversely affect development.

Why prioritize the crib mattress?

Well, even though your baby may spend a good amount of time being rocked, bounced, and sung to sleep in your arms, eventually they’ll sleep in their crib for hours at a time. 

Looking for our top crib mattress picks? Check out these posts:

• The best eco-friendly and non-toxic crib mattresses
• The best sustainably made cribs
• The best climate friendly disposable diapers

University of Texas Crib Mattress Study

Crib mattresses may be a significant source of volatile organic compounds (VOCs), with the air space immediately surrounding the mattress showing the highest concentration of all, according to researchers from the University of Texas.

These researchers looked at 20 new and used crib mattresses made with either polyurethane foam or polyester foam. They simulated sleeping conditions for an infant by creating a bedroom-sized chamber with a heated cylinder to imitate body heat generated by a baby. They then measured VOCs within the room (at 10 feet away from the crib) and in the breathing zone (determined as 2.5 cm or 1 inch above the mattress) to give area-specific emission rates (SERs).

All mattress samples emitted VOCs, with the mean total VOC SERs 56 microgram per meter squared per hour (μg/m²h) at 23 degrees Celsius and 139 μg/m²h at 36 C. More than 30 VOCs were found in the tests, with new mattresses releasing four times as many VOCs as older mattresses, on average. Polyurethane foam mattresses emitted a greater diversity of VOCs compared to polyester foam mattresses. 

VOC concentrations were significantly higher in the breathing zone and in the interior pore air of the mattress compared to elsewhere in the room, by a factor of 1.8-2.4 and 7.5-21 respectively. 

The VOCs found in the mattress samples in this study included:

• Phenol
• Isooctanol
• Neodecanoic acid
• Heaxnoic acid, 2-ethyl-
• 1-Heptanol, 3-methyl-
• D-Limonene
• Propanenitrile, 2,2′-azobis[2-methyl-
• 2-propanol, 1,3-dichloro-
• (S)-3-Ethyl-4-methylpentanol
• Linalyl acetate
• Cyclopropane, pentyl-
• -Hexanol, 2-ethyl-
• 2,6-Bis(1,1-dimethylethyl)-4-(1-oxopropyl)phenol
• 2-(2-Dimethylaminoethyl)isothiourea
• Dimethylfornamide
• Oxalic acid, bis(2-ethylhexyl) ester
• 1-Decene, 3,4-dimethyl-
• Ethanol, 2-(2-butoxyethooxy)-
• Phenol, 2-(1-methylethyl)-
• Hexanal
• Pentanoic acid
• Nonanal
• Decanal
• Benzoic acid, 2-ethylhexyl ester
• Isopropyl Myristate
• Palmitic acid
• Propanoic acid, 2-methyl-, 1-(1,1-dimethylethyl)-, 2-methyl-1,3-propanediyl ester
• Homosalate
• Octane, 1,1′-oxybis-
• Isopropyl Palmitate

Some of the VOCs found are classified as environmental pollutants and developmental disruptors. In fact, the CDC addresses concern over VOCs and indoor air quality on this page of its website, even going so far as to suggest “removing products that release formaldehyde in the indoor air from the home.”

Volatile organic compounds (VOCs) in crib mattresses come from resins, catalysts, adhesives (glues), solvents, and other products used in manufacturing the mattress. These may be present initially as residues that off-gas in a few days to weeks to month or may be intended to stay in a mattress during use to confer specific qualities. Such chemicals may act as stain repellants, flame retardants, antimicrobial agents, or water resistance treatments.

As with all chemicals, it’s the dose that makes the poison. And, unfortunately, it’s very difficult to quantify cumulative exposure to VOCs and other chemicals from all of the products we come into contact with each day. Testing just one product and finding low VOC emissions does not, therefore, offer much assurance of safety if this is just one of the sources in a household, daycare, school, or work environment.

Polyurethane foam crib mattresses

Polyurethane foam is the most common filling material used to make crib mattresses. In addition to being made from fossil fuels and requiring a lot of energy to make, polyurethane foam is highly flammable and releases horribly toxic chemicals when it burns. This means that it is almost always treated with flame retardant chemicals in order to comply with fire safety regulations. 

Looking for more information on mattresses? Check out these posts:

• The best organic mattresses
• The best Vegan mattresses
• Toxins in mattresses – what to look for
• Does it matter that my mattress has metal springs?

What about CertiPur foam mattresses?

I’ve seen quite a few round-ups of eco-friendly, non-toxic crib mattresses that include products made with CertiPur certified foam. This is rather irritating, given that CertiPur is a certification dreamt up by manufacturers with a vested interest in trying to greenwash polyurethane foam. Sure, some foam products are less problematic than others, but if you’re looking for a truly safe and eco-friendly mattress, avoiding polyurethane and polyester foam is the way to go.

The CertiPur-US™ logo does offer some assurance that the foam component of the pillow is free from polybrominated diphenyl ethers (PBDEs) and some of the most egregious flame retardants, and that levels of formaldehyde and other chemicals including ozone depleting substances, mercury, lead, and other heavy metals, and hormone-disrupting phthalates are low. However, foam is still resource-hungry, synthetic, and emits VOCs, so it is best avoided. 

Indeed, CertiPur standards are far less robust than the Ecolabel requirements used in the EU (for certain substances). Products certified by CertiPur are only tested for 72 hours, compared to 7 or 28 days for Ecolabel. Emission standards for VOCs, including formaldehyde, toluene, styrene and other chemicals are also significantly more robust for Ecolabel compared to CertiPur.

If your choice is between a CertiPur certified foam mattress and a foam mattress not certified by CertiPur or Ecolabel, it probably is best to pick the CertiPur product. If you have the choice of a non-foam mattress, however, this is likely to be far healthier overall. 

Waterproof covers

If you’ve ever had to deal with a wailing infant following a 2 am poop explosion, you’ll know that a waterproof mattress pad or cover is a must. 

See also:

• Cloth vs. disposable diapers: which is better for the planet?
• The best non-toxic infant car seats

In a 2016 study of foam mattresses randomly selected in a hospital setting, researchers found that of 77 samples, 44 showed bacterial growth (R). They concluded that mattresses support the growth of microbes that could cause infection, although the samples in this study were mercifully negative for Staphylococcus aureus, including methicillin-resistant S. aureus. In another study, however, S. aureus  was found in used foam crib mattresses and the researchers, who simulated the movement of a newborn’s head on the mattress, noted that these microbes became airborne and could be breathed in by an infant sleeping on a contaminated mattress (R).

Any tear or opening in a waterproof mattress cover (or a mattress without any cover at all) will allow bodily fluids to enter and contaminate the mattress. Given the likelihood of poop, pee, spit-up, and other bodily fluids being present in or around a baby’s crib, a waterproof crib mattress and/or mattress cover seems smart to me.

Unfortunately, most crib mattresses have a waterproof cover made with polyvinyl chloride (PVC) made with phthalates, chlorine, and flame retardants. PVC is one of the most environmentally unfriendly plastics around, with a variety of harmful chemicals like chlorine gas, ethylene dichloride, vinyl chloride, mercury, and dioxins, used in its manufacture, which are then released into the environment.

According to TreeHugger.com, every kilogram of PVC requires roughly 17 kg of abiotic materials, mostly petrochemicals, to produce, and uses around 680 liters of water in its manufacture. A kg of PVC also requires 11.6 kg of air, which becomes greenhouse gases and other gases. Add to that the energy involved in shipping the raw materials (petroleum) around the world and shipping the mattress to you, and an organic cotton and wool crib mattress made in the US from locally produced raw materials starts to look even better. All in all, PVC is pretty bad news, especially for a product that will be mere millimeters away from your baby’s face. 

The Leaf Score Verdict? Avoid crib mattresses or waterproof mattress pads that are made with phthalates, polyurethane, or PVC, where possible. Instead, choose a mattress with a polyethylene cover that can be wiped clean and use a wool puddle pad or additional polyethylene mattress pad that you can remove quickly for middle of the night clean-up.

The two best options I can find are Holy Lamb and Home of wool.

Antimicrobial treatments for crib mattresses

Antimicrobial treatments for crib mattresses and sheets may make it sound like you won’t need to wash bedding as often, but that’s just not true. Babies are messy in ways you can’t even begin to imagine until you’re in the thick of it. 

The Leaf Score verdict? Avoid any crib mattress (or sheets) that have an antimicrobial coating or treatment. It’s a waste of money and potentially harmful, with no real benefit.

Conventional cotton and pesticides

As we discuss in our post on sustainable denim, Conventionally grown cotton is resource-hungry and involves the use of pesticides and other chemicals that damage the environment and are bad for human health. Given that you can’t wash a crib mattress to get rid of any residues of these pesticides, I’d definitely avoid buying a crib mattress made with conventional cotton.

See also:

• Why it might be time to break up with avocados
• The best organic maternity wear

Fortunately, we can limit exposure to pesticides by choosing products made with organic cotton that is grown and processed without pesticides, formaldehyde, or other harmful chemicals. Organic cotton is natural, non-toxic, firm, and nowhere near as flammable as petroleum-based foam. Nor does it release toxic fumes if it does somehow catch on fire.

How to minimize risk and choose a healthier, safer crib mattress

There’s clearly a lot at stake when choosing a crib mattress. It certainly makes me anxious to think that my choices could have anything but a beneficial effect on my baby’s health, but being overly anxious is also problematic. My feeling, then, is that it’s smart to avoid or minimize avoidable risks wherever doing so doesn’t create a more significant risk.

As an example, if you’re worried about a petroleum-based foam mattress catching fire easily, don’t buy a mattress treated with flame retardant chemicals that may themselves pose a health risk (and that may be ineffective, according to recent research). Instead, opt for a crib mattress made with organic cotton and wool as a natural fire barrier that meets safety standards without the need for any added chemicals. With the foam, at best you’re just swapping one potential risk for another potential risk and at worse you’re adding one risk to another with no benefit.

Not everyone has the luxury to spend weeks tracking down and reading material data safety sheets, poring over scientific studies, re-running statistics, and then stumping up a load of cash for a product that may be slightly safer than something that costs a lot less. 

The bottom line

As the Australian Red Nose Society note on their website, as parents and care givers, we want the best for our babies, but it can be hard to make decisions on what to buy for the nursery, given that “There are many items available for sale, but unfortunately, many are simply not safe”. As in the US and elsewhere, “there is currently no explicit market-wide requirement under the Australian Consumer Law for manufacturers or retailers to proactively ensure that the products they sell are safe”. Companies can sell potentially dangerous products without any requirement to act unless a product causes serious injuries. The same is true in the US.

It’s important, then, to acknowledge your limits. Driving yourself up the wall with worry can also be detrimental to health and happiness for the whole family. This means I try to be forgiving to myself and others where limited knowledge, education, finances, and such mean there’s a limited capacity to avoid risks. 

In general, my advice for buying a crib mattress is to:

1. Avoid foam crib mattresses where possible
2. Use an effective waterproof barrier to avoid mattress contamination
3. Don’t reuse a mattress if possible (due to sagging and possible contamination)
4. Make sure the mattress fits snugly in the crib with no gaps
5. Make sure the crib mattress is firm and doesn’t sag or compress excessively
6. Favor crib mattresses made with organic cotton, wool, flax, hemp, and well-wrapped natural latex
7. Avoid crib mattresses made using chemical flame retardants, stain repellants, antimicrobial treatments, spray on PFC waterproofing, and other unnecessary chemicals
8. Look for a mattress with a polyethylene waterproof barrier and use a puddle pad or another polyethylene cover on top of the mattress (just don’t machine wash polyethylene pads)