Why Do Some Memory Foam Mattresses Smell? All About Off-Gassing

Why Do Some Memory Foam Mattresses Smell? All About Off-Gassing

A common complaint people have with memory foam mattresses is something known as "off-gassing" or more colloquially, “memory foam smell.” Off-gassing refers to the chemical odor emitted when you first take a memory foam bed out of the box - some compare it to the smell of a freshly painted room or the "new car smell." We’ll explore what causes the foam to smell, best practices letting your mattress air out, and things you can do to minimize off-gassing.

What Causes Memory Foam to Smell?

We'll save you the full chemistry lesson, but as you're probably aware, memory foam doesn't grow on trees. The base for all memory foams is a polymer called Polyurethane. You've probably heard of it before – it’s used in hundreds of applications you encounter every day, including clothes, furniture, paint, dry cleaning, and much more in addition to foam. Polyurethane foam, like all of these other products with polyurethane experience off-gassing which is caused by volatile organic compounds (VOCs) breaking down into a gaseous form, thus the term “off-gassing”. Now, it’s worth noting that the degree to which each of these products off gases is variable based on the presence of VOCs.  With memory foam mattresses, most every brand of mattress is made of a slightly different "recipe" of Polyurethane mixed with other components such as water & flame retardants, so they will have differing amounts of VOCs and hence levels of off-gassing.

Air It Out: Off Gassing and Unboxing A Foam Mattress

When a foam mattress is enclosed in air-tight packaging, low levels of gas can build up from the compression. When the mattress is let out of its packaging and reforms, the gas is released producing an off-gassing effect. Most memory foam mattress manufacturers offer a guideline for how long you should wait for your mattress to fully reform which is also a good guideline for airing your mattress out.

Are Memory Foam Mattresses Safe?

View our full blog on this topic here Fortunately, memory foam smell / off-gassing is not harmful, and usually subsides fairly quickly. According to mattress review site, Sleep Like The Dead, the vast majority of memory foam bed customers reported the smell subsiding within hours to 3 days of unboxing the mattress. While it may sound scary, research has confirmed that the vast majority of memory foam produced in the U.S. is completely safe & non-toxic (barring any specific allergies you might have). Even though you smell them, there is not a high enough level of vapor to affect your health. A very small percentage of people who are naturally more sensitive or allergic to certain chemical fumes have reported minor irritation or headaches until the off-gassing subsides.

How Can You Avoid Memory Foam Smell and Off-Gassing?

While completely chemical-free mattresses don’t exist, if you have concerns about the safety of your bed, there are characteristics to look for to make sure your bed meets safety standards & is non-toxic when you’re shopping for a mattress:

  • Independent Certification: Check if the foam has been approved by a U.S. foam testing authority. We recommend only buying a bed that has been certified under CertiPUR-US® standards. CertiPUR-US® is an independent, U.S.-based foam testing & certification agency, which ensures all foams it certifies meet a rigorous set of content, emissions and durability standards, including lower levels of flame retardants & VOCs, which ensure they made without ozone depleters, formaldehyde, heavy metals, and more. 
  • Check Reviews: Does the mattress you're looking at buying have reviews notating a smell that lasts longer than 24-48 hours?

Once You Have the Bed: What Can You Do About Off-Gassing?

As we said, any smell usually subsides fairly quickly on its own. However, if is bothering you, there are some simple steps you can take to minimize the effects of off-gassing. As soon as you receive your bed, you should take it out of its packaging and take off any mattress covers allowing it to air out. If there are any fans in the room, you should run them to increase circulation - another option is putting your bed somewhere safe & off the ground outside. If possible, let the bed air out for a day or two until the off-gassing subsides before you put on any sheets or mattress covers back onto it.

Updated: 09/13/2019