Mattresses contain a fire barrier. Federal law requires it. But the material brands use for that barrier is rarely printed on the label, and for millions of budget mattresses sold in the last decade, the answer is chopped fiberglass.
Most consumers find out the same way: they unzip or wash the mattress cover, and microscopic glass fibers spread across the bedroom, the carpet, the closet, and sometimes the entire house. Cleanup costs have run as high as $20,000 per household, documented in class-action filings.
The good news: the industry has been moving away from fiberglass quickly. A 2026 census by NapLab covering 395 mattresses found 89.1% were fiberglass-free, up sharply from earlier in the decade. The problem is now concentrated in the sub-$500 tier, which still reaches millions of shoppers every year.
This explainer covers why fiberglass ends up in mattresses, how to check whether yours contains it, and which major brands have confirmed they use it versus those that have eliminated it.
Why fiberglass is in there
Every mattress sold in the United States must pass the federal open-flame standard, 16 CFR 1633, which went into effect in 2007. The rule requires that a mattress resist an open flame long enough to allow a person to escape a fire. Manufacturers need a fire-barrier layer between the cover fabric and the foam inside.
Wool is the cleanest solution: it is inherently flame-resistant without any added chemistry, and brands that use it can say so plainly. But wool adds $30 to $100 or more to the cost of a finished mattress, depending on layer thickness.
Chopped fiberglass (also called glass fiber or glass filament) costs a fraction of that. It does not burn. It can be sewn into an inner sock or knitted into the fabric just below the outer cover, and it passes 16 CFR 1633 without any chemical treatment. For a $200 mattress, that cost difference is decisive.
The catch: fiberglass is not prominently labeled. Brands are not required to disclose what material they use as a fire barrier in consumer-facing materials. The law tag sewn into every mattress lists fill percentages, but the fire-barrier layer is not subject to separate mandatory disclosure. Shoppers have no reliable way to know what is in the barrier unless the brand publishes it voluntarily.
The contamination problem
Fiberglass inside a mattress is harmless as long as the cover stays on and isn't damaged. The problem starts when it doesn't.
Most fiberglass mattresses hold the glass fiber in a zippered inner cover, or in a sock sewn around the foam core. The outer cover looks like normal mattress fabric and is designed to unzip for cleaning. When a consumer does that, the inner sock is exposed and glass fibers go airborne.
Once airborne, they're nearly impossible to remove with household tools. They settle into carpet fibers, stick to upholstery, embed in clothing, and cause skin and eye irritation with prolonged contact. The California Department of Public Health identified this as the central problem in its investigation of fiberglass mattress complaints.
Zinus, one of the largest mattress sellers on Amazon, faced a federal class-action lawsuit over this issue. Plaintiffs described fibers spreading through their homes after removing or washing covers, with cleanup costs documented in case filings as high as $20,000. The lawsuit focused on how the brand disclosed the fiberglass barrier to buyers before purchase.
The Environmental Working Group called fiberglass a hidden mattress hazard. Its reporting pointed to a key gap in 16 CFR 1633: the standard requires flame testing but doesn't require brands to tell buyers what material they used as the barrier.
89.1%
of 395 mattresses tested
fiberglass-free in 2026, per NapLab census
sub-$500
price tier
where fiberglass use remains concentrated
$20,000
cleanup costs
documented in Zinus class-action filings
How to check your mattress
Do not remove the cover first. If you do not already know whether your mattress contains fiberglass, leave the outer cover on. Removing it without knowing is the most common way fibers get loose.
Read the law tag. The law tag sewn into a corner of every mattress lists fill materials by percentage. If you see "glass fiber," "glass filament," or "fiberglass" in any percentage, your mattress contains it. The absence of these terms is not a guarantee of fiberglass-free, because some brands list the fire-barrier layer separately or not at all.
Search the brand's website. Most fiberglass-free brands now say so prominently, because it has become a competitive differentiator. Search the brand's own site for "fiberglass," "fire barrier," or "fire sock." Look for a direct statement: "We do not use fiberglass" or "Our fire barrier is wool." Vague claims like "safe materials" or "non-toxic cover" do not address the barrier.
Search "[brand name] fiberglass" on Reddit. Consumer reports are often more current than brand marketing pages. The r/Mattress subreddit maintains running discussion of known fiberglass brands, and contamination incidents surface there within days.
Warning signs of fiberglass exposure: unexplained skin prickling in bed, eye irritation on waking, glinting fibers visible on the mattress surface or bedding, or itching that follows contact with the mattress. These warrant a careful inspection of the law tag and, if fiberglass is confirmed, stopping use of the mattress until you have a containment or replacement plan.
Brand status table
The table below reflects publicly available information as of mid-2026. Mattress formulations change. Always confirm directly with the brand before buying, especially on older models.
| Brand | Fiberglass status | Notes |
|---|---|---|
| Zinus | Uses fiberglass | Documented in class-action filings and NapLab testing; fire sock design |
| Linenspa | Uses fiberglass | Confirmed across product line in NapLab census |
| Sweetnight | Uses fiberglass | Confirmed in budget models; NapLab census |
| Signature Sleep (Ashley) | Uses fiberglass | Entry-level models; NapLab census |
| Avocado | Fiberglass-free | Wool fire barrier; GOLS organic latex; GOTS certified cover |
| Saatva | Fiberglass-free | Organic cotton cover; FR-free construction |
| Purple | Fiberglass-free | Proprietary polymer grid design; no inner fire sock |
| Nectar | Fiberglass-free | Confirmed by brand FAQ |
| Casper | Fiberglass-free | Confirmed by brand materials page |
| Helix | Fiberglass-free | Confirmed by brand FAQ |
| WinkBed | Fiberglass-free | Wool fire barrier; confirmed on brand specs page |
| Bear | Fiberglass-free | Confirmed by brand materials page |
| Leesa | Fiberglass-free | Confirmed by brand FAQ |
Brands not listed here: ask before buying. The direct question is: "What material do you use as the 16 CFR 1633 fire barrier, and does it contain fiberglass or glass fiber?" A brand that cannot answer that question directly is one where the risk is unconfirmed.
What to do if your mattress has fiberglass
Leave the cover on. The outer cover is a containment layer. If fibers have not yet become airborne, keeping the cover on and undamaged is your primary protection.
Add a zippered mattress encasement. A waterproof, fully zippered encasement (not an open-corner pad or protector) creates a second containment layer. This is a short-term measure while you plan replacement.
If contamination has already occurred: do not use a household vacuum. Standard vacuum filters pass fiberglass fibers, spreading them through the exhaust. Contact a professional textile or hazmat remediation service that specifically handles glass fiber. Bag contaminated bedding and clothing separately. Washing them in a home machine spreads fibers through the drum, the gasket, and the drain.
Plan for replacement. A mattress that has already released fiberglass into the room is unlikely to be cleaned up in place. Once fibers are in the underlying foam and the fabric, encasement slows further release but does not stop it. Most households end up replacing the mattress and having the room's soft surfaces professionally cleaned.
The NapLab 2026 finding is the right frame for this: most of the market has moved. Fiberglass-free options now exist at most price points. The brands at the top of the market eliminated fiberglass years ago.
For a curated list of vetted mattresses that are confirmed fiberglass-free, use wool or another non-fiberglass fire barrier, and have been checked against our full disqualifier list: see our picks for fiberglass-free beds.
Cover image: via Unsplash (Unsplash License). Source photo.
