The Paper Caddy Liner
“Your council's "compostable" liner is 60–70% petroleum plastic. Its degradation products are more toxic than the intact polymer. Paper composts in weeks. That liner doesn't exist to our standard. Yet.”
The Problem
Terephthalic acid disrupts the endocrine system. 1,4-butanediol accumulates in soil at 1.6 mg/kg in thirty days — with no clearance. These are not contaminants. They are the degradation products of the "compostable" caddy liner your council posted through your letterbox.
The liner is a petroleum copolyester. Sixty to seventy percent of it is PBAT — a polymer derived from crude oil, owned by an oil supermajor, marketed as vegetable starch. When it breaks down in your garden compost, it doesn't disappear. It becomes something worse. The very process sold as the benefit — biodegradation — is the mechanism producing the harm. That is the toxicity inversion.
It gets more absurd. The certification on the box — EN 13432 — requires 58°C. Your local treatment plant runs at 35–40°C. It doesn't matter. Both paper liners and bioplastic liners are screened out at the plant gates and incinerated. The certification describes a destination your liner never reaches.
The one place the material actually matters is your garden compost bin. And in your garden compost bin, that liner persists for years while leaching endocrine disruptors into the soil you grow food in.
The Gap
Paper caddy liners exist. We checked every UK supplier. Not one meets the standard: fully disclosed waterproofing chemistry, no bioplastic products anywhere in their range, standard UK caddy sizes. They either won't say what waterproofs the paper, or they sell the petroleum liner alongside the paper one. The technology is proven. The product to this specification is not.
What Should Exist
A paper caddy liner that holds wet food waste for a week, tells you exactly what's in it, and comes from a company that doesn't also profit from the problem.
- 100% paper construction — unbleached kraft, FSC-certified, no bioplastic lining or petroleum-derived coating of any kind
- Waterproofing fully named — starch-based, plant-wax, or mechanical double-ply. The specific agent disclosed on the packaging. Not "waterproofed." Not "natural resin."
- Home compostable by material property — degrades in garden compost at UK ambient temperatures within weeks. No industrial certification required because no industrial conditions required.
- Standard UK sizes — 5L countertop, 7L kerbside insert, 23L outdoor. Fits the caddies councils actually issue.
- Full bill of materials — paper, waterproofing, adhesive, ink. Every component named.
The Honest Position
Paper liners may wet through faster than bioplastic under heavy loads. They tear more easily when overfilled. They cost a few pence more per bag. These are real trade-offs — and they matter less than you think. Your council incinerates both liners identically. The only place the material makes a difference is your garden. Paper has been composting in gardens for four thousand years. The petroleum liner has been composting in gardens for zero.
The Investigation: The Caddy Liner — how a petroleum copolyester became the default "compostable" liner for 27 million English households.