What happens to synthetic bedding after the last night
Necati Yesil
Mostly, it is buried or burned. Americans throw away an estimated 18 to 20 million mattresses a year, and fewer than one in ten is recovered. Memory foam is polyurethane, a cross-linked plastic that cannot be melted down and remade and is among the most stubborn materials there are to break down. Polyester sheds plastic microfibers every time it is washed. Wool is a protein: in composting and seawater tests it breaks down where polyester, nylon and polypropylene barely change. The lowest-impact topper is the one you buy once, keep for decades and can return to the soil at the end.
Where old mattresses and toppers end up
Nobody counts toppers separately, so mattresses are the best guide. The Mattress Recycling Council estimates that Americans discard 18 to 20 million mattresses a year, around 50,000 a day, and the EPA estimates that fewer than 10% of them are recovered for reuse or recycling. In the EPA’s own waste figures, furniture and furnishings, the category mattresses fall under, came to 12.1 million tons in 2018: 80% went to landfill, almost all of the rest was burned, and well under 1% was recycled.
It does not have to be that way. California, Connecticut and Rhode Island run mattress recycling programs, and between them they have taken apart more than 15 million mattresses; in Connecticut the recycling rate went from under 9% to over 60% in the program’s first year. Steel springs, wood and cotton all have real second lives. Foam is the hard part.
Why foam is the hard part
Memory foam is polyurethane. It is made by reacting two petrochemical ingredients, a polyol and an isocyanate, into one continuous cross-linked network, and that network is what lets the foam sink slowly and spring back. It is also a one-way street. Polyurethane foam is a thermoset: unlike a water bottle, it cannot be melted down and made into something new, which is why so much of it ends up in a landfill or an incinerator.
What recycling there is, is downcycling. Shredded foam is glued into the spongy underlay that goes under carpet, or stuffed into pet beds. That buys it one more product life, and then it goes to the landfill anyway. Chemical recycling, which breaks foam back down into its ingredients, is an active field of research with pilot plants; it is not what happens to a topper left on the curb today.
Nor does it rot. A 2023 review of the microbes that can attack polyurethane sums up the problem: plastics, and polyurethane especially, are highly resistant to breaking down in the environment, and can persist in a landfill for a very long time.
What polyester sheds
Polyester is the usual filling in inexpensive duvets, pillows and fiber toppers, and the usual cover on foam ones. It is a plastic too, and it sheds. When researchers at the University of Plymouth washed polyester fabric in a domestic machine, a single 6 kg load released an estimated 496,000 microfibers: tiny strands of plastic that leave with the rinse water. They tested clothing fabric, not bedding, but a polyester duvet in the same machine is the same material doing the same thing.
Once those fibers reach the sea, they stay. In a 2024 study that held fabrics in natural seawater for 90 days, polyester broke down by about 2.5%, and nylon and polypropylene by less than 1%.
What wool does instead
Wool is a protein, keratin, the same family of material as your hair, and the microbes in compost, soil and seawater can feed on it. In a 2024 study run to the international standard for composting tests (ISO 14855), wool fabrics broke down by about half to two-thirds in six months, depending on how the wool had been treated. Over the same six months, polyester, nylon and polypropylene barely changed.
In seawater, the same researchers found wool broke down several times faster than polyester and far faster than nylon or polypropylene, and concluded that wool is very unlikely to add to microplastic pollution in the sea.
| Composting, 6 months | Seawater, 90 days | |
|---|---|---|
| Wool, untreated | 48% | 8% |
| Wool, machine-washable | 68% | 27% |
| Polyester | 0% | 2.5% |
| Nylon | 2% | 0.3% |
| Polypropylene | 1.5% | 0.7% |
| Cellulose (the reference) | 88% | 40% |
The figures are the share of each fabric’s carbon that microbes turned back into carbon dioxide, the standard measure of biodegradation. Cotton was not in these tests, but cotton is cellulose, the reference material that did best in both.
You should know who paid: both studies were funded by Australian Wool Innovation, the wool growers’ research body, and carried out by New Zealand’s AgResearch. They were peer-reviewed and published in mainstream journals, and the synthetic fabrics were tested side by side under the same conditions.
What “biodegradable” does and does not mean
Biodegradable is a word that gets stretched, so here is the fine print. Microbes need air and moisture to do their work. A modern landfill is built to keep both out, and inside one almost nothing breaks down quickly, wool included. So we will not tell you that a wool topper simply vanishes in the trash.
The difference shows up wherever bedding can break down: a composting facility that takes natural textiles, a garden bed, or, for the fibers that wash out in the laundry, rivers and the sea. There, wool goes back to carbon dioxide, water and nutrients, and polyester and foam stay what they are.
The lowest-impact topper is the one you keep
Nothing we make is free of impact. Sheep are ruminants and produce methane, and wool has to be washed, carded, sewn and shipped like anything else. The biggest lever any of us has is how often a thing gets replaced. A foam topper softens and holds body impressions within a few years. A wool topper recovers its loft with a fluff and lasts for decades, and if it develops a fault in its first five years, our warranty repairs it.
Buying one topper instead of several is the largest difference between the two, long before the end of its life comes into it.
When yours is finally done
- First, think reuse: a worn wool topper makes a good dog bed, a kneeling pad for the garden or extra insulation in a shed.
- If it has to go, cut off the four elastic corner straps and the label; they are not wool or cotton.
- Cut the rest into pieces. The wool and cotton can go to a composting facility that accepts natural textiles, or into the garden: gardeners use wool as a mulch, and as it breaks down it feeds nitrogen back into the soil.
And before any of that, email us. If something has failed, the 5-year warranty covers it, and a repair keeps a topper out of the bin for years.
It’s time to Woolify.
Questions people ask
Is memory foam recyclable?
Only partly. Some foam is shredded and bonded into carpet underlay, and chemical recycling is being developed, but foam cannot be melted and remade like a plastic bottle, and most of the foam in discarded mattresses is landfilled or burned.
Is a wool topper biodegradable?
Its wool and its cotton shell are: in composting and seawater tests wool breaks down where synthetic fibers barely change. A sealed landfill stops almost everything from breaking down, wool included, so the better plans are reuse, composting or the garden. Cut the elastic straps and the label off first.
Is plant-based memory foam better?
Some foams replace part of the petroleum polyol with one made from plant oil. That trims the fossil content, but the result is still a cross-linked polyurethane with the same end-of-life problem.
Does wool shed microplastics?
No. Wool sheds fibers like any fabric, but they are protein, not plastic, and microbes in seawater break them down; the researchers concluded that wool is very unlikely to contribute to microplastic pollution in the sea.
Sources
- Massachusetts Department of Environmental Protection (prepared by GreenerU), Background document for policy recommendation on mattresses, 2025, citing the Mattress Recycling Council and the EPA.
- U.S. Environmental Protection Agency, Durable goods: product-specific data, furniture and furnishings, 2018.
- Hosgor E. et al., Polyurethane depolymerization by dialkyl carbonates: toward sustainable chemical recycling, Green Chemistry, 2025.
- Bhavsar P., Bhave M., Webb H.K., Solving the plastic dilemma: the fungal and bacterial biodegradability of polyurethanes, World Journal of Microbiology and Biotechnology 39:122, 2023.
- Napper I.E., Thompson R.C., Release of synthetic microplastic plastic fibres from domestic washing machines, Marine Pollution Bulletin 112:39–45, 2016.
- Collie S., Brorens P., Hassan M.M., Fowler I., Biodegradation behavior of wool and other textile fibers in aerobic composting conditions, International Journal of Environmental Science and Technology, 2024. Funded by Australian Wool Innovation.
- Collie S., Brorens P., Hassan M.M., Fowler I., Marine biodegradation behavior of wool and other textile fibers, Water, Air, & Soil Pollution 235:283, 2024. Funded by Australian Wool Innovation.
