In a Nutshell:

  • Since synthetic flame retardants like PBDEs are now known to be toxic to human health, U.S. mattress manufacturers have been looking for other ways to meet federal fire resistant standards. Putting fiberglass in mattresses is one way they do that.
  • Fiberglass is not technically a flame retardant, but it is naturally flame resistant, which is why it’s used to meet those standards.
  • Fiberglass may be either added to the mattress foam, the cover, or both. Even though CertiPUR-US certified foam bans fiberglass, it says nothing about the mattress cover. This makes it very difficult for consumers to know whether or not their mattress cover contains fiberglass.
  • Fiberglass can escape from mattresses, especially with normal wear and tear over time.
  • Fiberglass inhalation can cause a range of health concerns, including coughing, rashes, burning eyes, and exacerbation of existing issues like asthma, COPD, or eczema. Several mattress companies have been sued by consumers because they experienced symptoms like these.
  • We’ve got tips below on how you can find out whether or not your mattress contains fiberglass, and how to avoid it when when shopping.

Have you heard about the lawsuits alleging fiberglass in mattresses resulted in damage to personal health and property? You may wonder why fiberglass is even in a mattress.

Ever since 2007 when the United States Consumer Product Safety Commission (CPSC) ruled that all mattresses must have a flame retardant (FR) that passes their open flame test, companies have been searching for ways to meet the mandatory standard. After synthetic FRs like PBDEs fell in disfavor for health and environmental reasons, companies scrambled again to find a non-toxic FR that would pass public scrutiny.

In this article, complementary to our piece on non-toxic flame retardants in mattresses, fiberglass is in the spotlight. We take a close look at the flame retardant properties of fiberglass to see how it performs. But the central focus will be on how safe fiberglass is to sleep on. Is fiberglass a non-toxic flame retardant in mattresses?

What Is Fiberglass and How Is It Made?

Fiberglass is a common insulation material composed of lightweight glass fibers woven into plastic. Other names for it include:

  • Glass-reinforced plastic
  • Glass fiber-reinforced plastic
  • Reinforcement glass fiber
  • Man-made vitreous fiber
  • Glass fiber
  • Glass wool

Despite structural or chemical modifications to the glass fibers to suit them better for a wide range of applications, fiberglass starting materials remain the same: 

  • Silica sand
  • Soda ash
  • Limestone

Today, fiberglass is made with approximately 50% recycled post-consumer glass content.

To manufacture fiberglass, molten glass first goes through a spinning device’s nozzle full of tiny holes. Thin streams of wispy glass emerge that quickly harden. Then they’re chopped into tiny glass fibers, measuring 5-20 microns in diameter.

Alternatively, for certain applications, hundreds or thousands of long glass filaments could be gathered in bunches and coated with plastic serving as the glue that holds them together. The most common plastics used are polyester, vinyl, or epoxy.

Starting in the 1930s as home and building insulation, today fiberglass is used in many things such as:

  • Carpeting
  • Ceiling tiles 
  • Roofing shingles
  • Construction materials
  • Cars
  • Boats
  • Surfboards 
  • Aircraft
  • Bathtubs 
  • Orthopedic casts
  • Wind turbines
  • Electronic circuit boards

Is Fiberglass a Flame Retardant?

Technically speaking, a flame retardant (FR) is a treatment (such as the chemicals PBDEs or Tris chlorinated compounds) that’s applied to something with the intention of preventing a fire from starting or spreading. FRs work in several different ways:

  • Prevent or delay ignition
  • Slow down the rate of combustion  
  • Make a fire self-extinguishing

(It’s worth noting here that chemical flame retardants aren’t actually that effective at those things, but the point is that they were meant to be.)

The fiberglass used in mattresses has not technically been treated, so the term flame retardant is not the best way to describe what fiberglass is. However, you may see fiberglass called a flame retardant in articles or by the companies using it. When it is, the term refers to its function of preventing a fire from starting or spreading.

Fiberglass is more properly described as flame resistant. This means fiberglass does not easily catch on fire because of its inherent properties. In other words, fiberglass is naturally resistant to flames. In fact, fiberglass is one of only a few materials considered non-combustible

If it ignites, fiberglass melts (self-extinguishes) instead of fanning the flames and spreading. The melting temperature of fiberglass is 1,300℉. Materials experts describe fiberglass as scoring low on both the Flame Spread Index (FSI) and Smoke Distribution Index (SDI).

Incidentally, the average temperature in a house fire is 1,100℉ but could get as high as 2,000℉.

The big problem here though, is that although fiberglass may be able to withstand the high temperature of a house fire, the plastic woven inside it burns at much lower temperatures—approximately 500℉—even if it has been treated with a chemical FR. Most plastics melt at even lower temperatures before they ignite. When they melt, they will stick to the skin. 

When plastic burns, it releases hazardous substances such as:

  • Dioxins
  • Furans
  • Sulfur dioxide
  • Hydrochloric acid
  • Mercury
  • Lead
  • Arsenic  

Some of these substances, such as certain dioxins and furans, are potent carcinogens.

Where is Fiberglass in a Mattress?

When it’s used in mattresses, fiberglass could be in the cover, inside the foam, or both. If it’s in the foam, it’s probably in the center of the interior foam portion, wrapped in other materials. The outer wrapping is intended to keep the fiberglass intact and unable to escape.

On the other hand, over 50% of the mattress cover, could be fiberglass. Normal wear and tear causes its contents to displace. You risk disturbing the inner contents as well as the components of the cover when you move it around or are active on it. If you unzip the cover, fiberglass could easily escape into the air.

According to a recent study of mattresses certified by the mattress industry’s CertiPur-US, companies may label only what is in the foam. So, you’re left wondering what’s in the cover. The CertiPur-US standard guarantees only that the foam is free of heavy metals, PBDEs, and Tris chlorinated FRs, but says nothing about what’s in the cover. In that study, one sample revealed the presence of halogenated substances (chemical FRs) and additives (antimony trioxide), both of which are toxic.

When a mattress company, such as Zinus or Graco, markets its products as having “chemical-free foam” without stating the identity of the flame retardant, it’s more probable that fiberglass is in the foam or in the cover. If fiberglass is listed at all, it may not be on the label stating how the mattress meets CPSC standards. Instead, you may find it on a non-conspicuous label that’s easily overlooked.

Is Fiberglass Safe in Mattresses?

There is ample reason to believe that fiberglass is not safe in mattresses. For example, a search for complaints on the CPSC website for 2020 turned up 128 examples of how fiberglass in mattresses escaped and caused health or property damage. 

A growing number of reports in the popular press also reveals the hazards of fiberglass in mattresses. Vanessa Gutierrez filed a class action lawsuit against Zinus in July 2022, claiming its popular Green Tea mattress caused sores, rashes, and asthma exacerbations in her children. The escaped glass fibers also caused extensive property damage. Gutierrez is suing for $20,000 in damages. The brand is sold at many locations including Amazon, Walmart, and Target. 

Ashley and Nectar mattress brands also received similar complaints. In some cases, buyers had unzipped the mattress covers despite label warnings, unleashing glass shards into their home’s airspace. Other plaintiffs claimed miniscule glass bits escaped without opening the mattress cover.

In response to these allegations, CSPC, along with the mattress companies, maintain that as long as the mattress cover is kept zippered, fiberglass is safe. As of this writing, the lawsuit is still pending.

Gutierrez’ children experienced some of the common symptoms of fiberglass exposure:

  • Coughing
  • Sore throat
  • Skin sores
  • Rashes
  • Burning eyes 

Here is a video that tells their story:

Fiberglass exposure is known to cause or exacerbate respiratory illnesses including asthma, bronchitis, or COPD (chronic obstructive pulmonary disease). In occupational settings, long-term fiberglass exposure may result in recurrent chest infections and pulmonary fibrosis which could lead to pneumoconiosis. 

How to Avoid Buying a Fiberglass Mattress

Unfortunately, reading a label on a mattress may not actually tell you if fiberglass is in it. Even if you get a mattress that uses CertiPUR-US certified foam (which means there is no fiberglass in the foam), manufacturers aren not legally required to list mattress cover components, and often do not

Here are some tips to help you navigate mattress stores and websites successfully to avoid buying a mattress containing fiberglass.

  1. Be aware of alternate names for fiberglass. Rather than fiberglass on a label, you could see these more innocuous-sounding names: 
  • Silica
  • Mineral wool
  • Glass wool
  • Reinforced composite or resin
  • Glass fiber 
  1. Be wary of low prices. Cheaper mattresses, by definition, contain cheap components like fiberglass and polyfoam. If possible, stay away from mattresses selling for $400 or less. (This guide will help you find the most affordable non-toxic mattresses on the market.)
  2. Bypass ‘Made in China‘ or ‘Indonesia.’ Although “Made in the USA” does not always mean “better” or “safer,” it is often the case when it comes to the mattress industry. A lack of regulations makes it easy for unscrupulous companies to include fiberglass and other potentially harmful substances in their products to cut costs. Plus, without stringent quality assurance controls in place, fiberglass may not be well-sequestered inside the mattress or the cover. 
  3. Look for a “Do not remove cover” label. To be safe, if you see a warning label that says something along the lines of “Do not remove cover,” you should interpret this as an admission that fiberglass is in the cover, and a warning that it could escape if you open it. 

What If I Don’t Know If My Mattress Contains Fiberglass?

If you already own a mattress which you suspect contains fiberglass and you’re not able to replace it right away:

1. Never unzip the mattress cover. 

2. Retain all labels on the mattress as a reminder not to unzip the cover (even if they don’t mention fiberglass).

3. Cover it with a second protective layer if doing so doesn’t cause too much disruption to the mattress itself. Doing so is like added security to help prevent glass shards from escaping.

And the next time you’re in the market to purchase a safer mattress, you can save yourself some time and check out our guide to non-toxic mattress brands.

TL;DR on Fiberglass as a Flame Retardant in Mattresses

Popular as insulation in homes, fiberglass is also naturally flame resistant. In recent years, mattress manufacturers have taken advantage of this characteristic by integrating fiberglass inside their products to meet the federal standard for a flame retardant that passes its open flame test.

Unfortunately, fiberglass contains millions of tiny glass shards that can escape easily from a mattress or mattress cover, especially if it’s old, worn, or pierced. The shards are toxic in several ways. 

Fiberglass exposure can cause permanent damage to your respiratory system if inhaled. Tiny glass bits lodge deeply into lungs and may enter the circulatory system. It is impossible to remove them completely. Glass shards lead to property damage, too.

Although fiberglass has good flame retardant properties, it is damaging to health if it escapes from the mattress or mattress cover. Even if you take every precaution imaginable, you could still suffer ill effects. This high risk is not worth taking when non-toxic options exist. For most people, the best non-toxic flame retardant for mattresses is wool, although there are safer options for vegans and those will wool allergies as well.

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About Jeanne

Jeanne Yacoubou, MS is an experienced researcher and writer passionate about all things environmental. She's written extensively on renewable energy, sustainability, the environmental impacts of diet, and toxic chemicals in food, water, air, and consumer products. When she’s not tending her organic garden or hanging out with her three teens, Jeanne is blogging about the latest scientific reports on our climate crisis. Jeanne holds master’s degrees in chemistry, ethics, and education. In between her graduate work, Jeanne served as a high school science teacher in Benin, West Africa as a Peace Corps volunteer for over three years.

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