The fiberglass isn’t visible. It's hidden beneath the outer cover, placed just underneath and wrapping around the entire mattress, like a sock.  It’s an inner layer you'll never see, but it's there, and that's exactly the problem.

Fiberglass is only considered safe if it remains completely sealed inside the mattress. But the moment the outer cover is compromised through a small tear or split seam resulting from normal wear and tear, or in the case of a memory-foam mattress with a zip-on cover, if the outer cover is ever opened or removed,  millions of small fiberglass particles can be released into your home. This is extremely dangerous and can have serious negative consequences for your health.

Once airborne, those fiberglass particles don’t stay in one place. They spread everywhere,  through carpets, clothing, air vents, and furniture.  At a minimum, exposure can cause serious irritation to your skin, eyes, and respiratory system. In extreme cases, exposure can lead to a condition known as bronchiolitis, which can have lifelong consequences and even result in death. And similar to asbestos, the cleanup and removal of fiberglass contamination can be extremely expensive, with many belongings needing to be replaced entirely..

This is why so many mattress tags say: "Do not remove cover." The big mattress companies are providing a product they know can cause serious harm to consumers, and they are trying to protect themselves from liability.

How to Tell If a Mattress Contains Fiberglass

Most brands will never advertise this clearly because they know it would cost them sales. Here's what to look for instead.

First, check the mattress law tag or product description to see a detailed listing of the ingredients. Many companies will try to hide the fiberglass in their products by calling it something else,  such as “glass fiber”, “glass wool”, or most often, “silica-based fibers”.  Another common method to hide fiberglass content is to list a flammability barrier made from a blended fiber, such as “Rayon/Polyester/Silica blend”. Don't be fooled.

Other warning signs include very low price points (fiberglass is very cheap, which is why it is used so frequently), imported mattresses, and vague or incomplete material descriptions. If a brand isn’t willing to tell you exactly what's inside your mattress, that's a major red flag.

The best alternative to fiberglass? A 100% wool flammability barrier. Wool is inherently fire-resistant and naturally self-extinguishes. Plus, wool is one of nature’s best temperature regulators, as it wicks heat and moisture away from your body while you sleep.