The fastest way to check is to read the law tag on your mattress, the white label usually stitched near the head or foot of the bed. If the materials list includes “glass fiber,” “glass wool,” or “fiberglass,” your mattress contains it. But not every mattress tag is straightforward, and some don’t list fiberglass at all even when it’s present. Here’s how to investigate further and what to do if you find it.
Check the Law Tag First
Every mattress sold in the United States has a law tag listing its filling materials. Look for the tag sewn into a seam, usually along the bottom edge. The key term to search for is “glass fiber,” which is the most common way fiberglass appears on labels. You may also see it listed simply as “fiberglass.” If neither term shows up, check for vague language like “fiber barrier” or “fire-resistant barrier” without specifying the material, which can sometimes indicate fiberglass.
The California Department of Public Health warns that some mattress labels don’t list fiberglass even when it’s inside the mattress. In one documented case involving a Graco crib mattress, fiberglass wasn’t mentioned on the label at all. So a clean tag doesn’t guarantee a fiberglass-free mattress, especially with older or budget models.
Look for “Do Not Remove Cover” Warnings
A strong clue is a prominent warning telling you never to unzip or remove the outer cover. While many mattresses have removable, washable covers, mattresses with fiberglass fire barriers typically warn against this because the fiberglass layer sits just beneath the cover fabric. Removing or unzipping it releases tiny glass fibers into the air and onto surrounding surfaces. If your mattress has an unusually emphatic warning about the cover, fiberglass is likely the reason.
Why Fiberglass Is in Mattresses
Federal safety standards require every mattress to resist open-flame ignition. Under the regulation known as 16 CFR Part 1633, a mattress must keep its peak heat release below 200 kilowatts during a 30-minute burn test and its total heat release below 15 megajoules in the first 10 minutes. Manufacturers can meet this standard however they choose. Fiberglass is one of the cheapest options: a woven or knitted sock of glass fiber wrapped around the foam layers acts as an effective flame barrier at very low cost.
The standard doesn’t require fiberglass specifically. Manufacturers can use wool, treated rayon, aramid fibers, or other materials instead. But fiberglass keeps production costs down, which is why it shows up most often in budget and mid-range mattresses sold online or through big-box retailers.
Which Brands Have Used Fiberglass
An analysis of 348 mattresses by the sleep research site NapLab found that about 10% contained fiberglass, while roughly 87% were confirmed fiberglass-free. Brands that have used fiberglass in at least some models include several Casper mattresses (including the Original and Nova Hybrid, both now discontinued), multiple Ashley Sleep models, and several Tempur-Pedic lines including the TEMPUR-Adapt, TEMPUR-Breeze, and TEMPUR-Cloud.
Some brands have phased it out in recent years. Leesa stopped using fiberglass in late 2023, meaning any Leesa mattress made before that date could still contain it. Zinus transitioned to a carbon-rayon fire barrier in early 2025. Siena switched to fiberglass-free construction in 2024 after being acquired by Ashley Sleep. Novaform mattresses have historically contained fiberglass, though the newer Nue by Novaform line sold at Walmart and similar retailers reportedly does not.
If your mattress is from any of these brands and was purchased before the switch date, it likely still has fiberglass inside regardless of what the current product listing says.
Signs of Fiberglass Exposure
If your mattress cover has been unzipped, torn, or washed (which can break down the fabric barrier), fiberglass may have already escaped. The fibers are extremely fine and can spread through an entire room or even through HVAC systems.
Physical symptoms of exposure include itchy skin, irritated eyes, coughing, and wheezing. These symptoms are typically temporary but can be persistent if fibers remain on surfaces you touch or in the air you breathe. People with asthma or chronic bronchitis may experience more serious aggravation. The fibers can embed in bedding, clothing, carpet, and upholstered furniture, making them difficult to fully remove once released.
A visual clue: fiberglass particles often look like tiny, shiny threads or a fine glittery dust on sheets, pillowcases, and nearby surfaces. If you notice an unexplained shimmer on your bedding combined with skin irritation that gets worse at night, fiberglass contamination is a strong possibility.
What to Do if Fiberglass Has Escaped
If you’ve already opened the cover or suspect a tear has released fibers, the California Department of Public Health recommends keeping the area well-ventilated and using a vacuum equipped with a HEPA filter to clean all affected surfaces. Standard vacuums can push the fine particles back into the air. Wipe hard surfaces with damp cloths rather than dry dusting, which also disperses fibers.
Wash all bedding and any clothing that may have been exposed. If the contamination is widespread (fibers visible on walls, in carpet, or circulating through vents), replacing the mattress and professionally cleaning the room may be necessary. A mattress cover with a tear that can’t be sealed should be discarded along with the mattress.
If your mattress cover is still intact and you’ve confirmed the mattress contains fiberglass, the simplest step is to leave it zipped and undisturbed. The fiberglass is not a hazard as long as it stays enclosed.
Fiberglass-Free Alternatives
If you’re shopping for a replacement, several materials serve as effective flame barriers without the risks of loose glass fiber. Wool is one of the most common alternatives. It’s naturally fire-resistant because of its high nitrogen and moisture content, requiring temperatures above 1,000°F to ignite, and it tends to self-extinguish. Cashmere and mohair share similar properties.
Rayon treated with silica is another option. When exposed to flame, the silica creates a charred barrier that stops fire from spreading. This silica treatment can also be applied to other fabrics. Some manufacturers use aramid fibers (the same material in Kevlar) or treated cotton and polyester blends. Mattresses using these alternatives typically cost more, but they eliminate the risk of glass fiber contamination entirely.
When shopping, look for mattresses that explicitly state “fiberglass-free” or “no glass fiber” and confirm this on the law tag after purchase. Brands that have recently reformulated their fire barriers are worth checking carefully, since older inventory may still contain fiberglass even if the current product description says otherwise.