Mattresses contain fiberglass because it’s one of the cheapest ways for manufacturers to meet a federal fire safety law. Since 2007, every mattress sold in the United States must pass an open-flame test, and a thin layer of woven fiberglass acts as a heat-resistant barrier that keeps the mattress from going up in flames. It works well and costs very little, which is why budget and mid-range mattress brands rely on it so heavily.
The Federal Fire Safety Standard
The reason fiberglass exists in mattresses traces back to a single regulation: 16 CFR Part 1633, enforced by the Consumer Product Safety Commission (CPSC). This standard requires every mattress to survive a 30-minute open-flame test without exceeding specific heat thresholds. The peak heat release can’t go above 200 kilowatts at any point, and total heat released in the first 10 minutes can’t exceed 15 megajoules. These aren’t small numbers to hit. A mattress is essentially a large block of foam, fabric, and other combustible materials, so passing this test requires some kind of fire barrier built into the design.
Before this rule took effect, mattress fires were a leading cause of fire deaths in homes. The standard was specifically created to reduce deaths and injuries by limiting how large a fire a mattress can generate. Manufacturers needed a practical, affordable solution, and fiberglass fit the bill.
How Fiberglass Stops Fire
Fiberglass is made from extremely fine strands of melted glass. Glass doesn’t burn, and it resists heat far better than the polyester, cotton, or foam that makes up the rest of a mattress. In most designs, a thin sock of woven fiberglass wraps around the foam core, sitting just beneath the outer fabric cover. If an open flame reaches the mattress, the fiberglass layer acts as a thermal barrier, blocking heat from penetrating deeper into the foam and slowing the fire’s ability to spread and grow.
It’s essentially the same principle behind fiberglass insulation in walls. The material resists heat transfer and doesn’t combust, creating a shield between the flame and the fuel source.
Why Fiberglass Instead of Something Safer
Cost is the primary reason. Fiberglass is significantly cheaper than the alternatives. A fiberglass barrier adds very little to the manufacturing cost of a mattress, which is why it shows up most often in mattresses priced under $1,000 and in many online “bed-in-a-box” brands trying to compete on price.
Safer alternatives exist, but they all cost more. Wool is naturally flame resistant and is widely considered the best non-toxic option for meeting the federal standard. Cotton and latex mattresses can use naturally fire-resistant barrier cloth, sometimes treated with boric acid (a relatively mild compound). Kevlar and other aramid fibers also work. But wool alone can add $100 to $300 or more to the retail price of a mattress. For manufacturers selling at thin margins, fiberglass keeps the price low enough to stay competitive.
The Health Problem With Fiberglass
Fiberglass is safe when it stays sealed inside the mattress. The problem is that it doesn’t always stay sealed. If the outer cover is removed, unzipped, or damaged, microscopic glass fibers can escape into the air and spread throughout a room. Once loose, these fibers are extraordinarily difficult to contain. They embed in carpet, circulate through heating and air conditioning systems, and settle on every surface in the home.
The CPSC has received more than 100 complaints from consumers who experienced sneezing, wheezing, itching, skin rashes, and blisters after fiberglass particles leaked from their mattresses. Short-term exposure can cause lung inflammation, and the tiny shards irritate the eyes, skin, and respiratory tract on contact. Long-term exposure has been associated with lung disease. Eye contact can lead to damage, bleeding, and scarring.
Many of these complaints came from people who simply washed their mattress cover, not realizing this would release fiberglass trapped in the fabric. Others cut into covers or removed them to clean a stain. The fibers are so small that once airborne, you can inhale or touch them without seeing them.
If Fiberglass Escapes Your Mattress
Cleaning up a fiberglass contamination is a serious project. California’s Department of Public Health recommends wearing eye goggles, a nose-and-mouth mask, and loose clothing that covers your skin before starting. The mattress itself will likely need to be thrown out. Cover it before moving it through your home to avoid spreading more fibers.
For the room and any affected areas, use a vacuum with a HEPA filter. Do not sweep, because sweeping pushes glass fibers into the air and spreads them further. Wipe all hard surfaces with a damp cloth. Sheets, blankets, and clothing that came in contact with fiberglass should be washed separately from other laundry, and the washing machine should be rinsed thoroughly after each load to clear remaining fibers. In some cases, contaminated bedding and clothing may need to be discarded entirely if the fibers won’t come out.
How to Tell if Your Mattress Has Fiberglass
Check the law tag, which is the white label sewn into the mattress (usually near the foot or along a seam). Manufacturers are required to list the materials inside. Look for “glass fiber,” “glass wool,” or simply “fiberglass” in the materials list. Some tags may also list “silica” as an ingredient. If the tag says “do not remove cover” with particular emphasis, that’s often a signal that a fiberglass barrier sits just beneath.
Notably, there is no federal requirement for manufacturers to warn consumers about health risks from the fire-retardant materials they use. When the CPSC finalized the 2007 rule, it considered and rejected a labeling requirement, reasoning that the presence of a fire-retardant material alone didn’t indicate a health risk. That decision left consumers without clear warnings, even though the consequences of accidentally releasing fiberglass are significant.
Legislation Is Starting to Change
California became the first state to ban fiberglass in mattresses when Governor Newsom signed legislation in October 2023. The law prohibits the sale of mattresses and upholstered furniture containing fiberglass, with an effective date of January 1, 2027. As California goes, other states often follow, and the ban may pressure manufacturers to switch to alternative fire barriers even in states without similar laws.
If you’re shopping for a new mattress and want to avoid fiberglass entirely, look for brands that explicitly advertise fiberglass-free construction and use wool, Kevlar, or treated cotton barriers instead. Expect to pay more. A mattress built with a wool fire barrier will typically cost several hundred dollars more than a comparable fiberglass model, but it eliminates the risk of glass fiber contamination in your home.