Is PET plastic?

What PET actually is

Polyethylene terephthalate: a polyester, clear, strong and gas-tight, which is why it took over the beverage industry. Earth Action attributes roughly a third of all packaging-related microplastic exposure to PET bottles alone. It is also the most recycled plastic, which is a separate virtue and does not change what the bottle does while it holds your drink.

Where you find it

What PET releases, and when

The bottle wall sheds into the contents across the whole shelf life, and there is more of it than anyone realised until Raman-based methods could see below a micron. UV exposure can raise release up to a hundredfold, which is why a case left in a car or a sunny warehouse is a different product from one kept cool. Refilling makes it worse: mechanical stress measurably increases release from PET bottles.

Graded A. This exact product, or an item identical to it, has been measured for particle release in a peer-reviewed study. The number is anchored to a laboratory result rather than to a material. How evidence grades work →

How to tell you're holding it

• A 1 in the recycling triangle

• Glass-clear and rigid, with a small moulding dot in the centre of the base

• Makes a sharp crackle when squeezed

• Every standard single-use water and soda bottle

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Products we've scored involving PET

Each with its own 0–100 exposure score, evidence grade and sources.

Packaging formats made of it

Sources

1. PNAS 2024 (Qian) — Counted roughly 240,000 plastic particles per litre in bottled water, about 90% of them nanoplastics that earlier optical methods could not see at all.

   Limitation: Three unnamed US brands, small sample. It measured particles, not absorption or any health outcome, and the brands were not disclosed — so it cannot be attributed to a specific label.

2. Mason 2018 — 93% of 259 bottles across 11 international brands contained microplastic; an average of 325 particles per litre across all size classes.

   Limitation: Nile-red staining and optical microscopy only reliably resolve particles above ~100 μm, so its counts are a floor, not a total. Lower numbers here do not mean less plastic than the 2024 study — they mean a less sensitive method.

3. Schymanski 2018 — Compared formats head to head: single-use PET averaged 14 particles/L, returnable PET 118/L, glass bottles 50/L and beverage cartons 11/L.

   Limitation: The glass result is the one people skip. Glass was not zero — particles came from the cap and the filling line, not the bottle wall. Small sample per format.

4. Winkler 2019 — Refilling and mechanically stressing PET bottles measurably increased particle release compared with first use.

   Limitation: A laboratory stress protocol rather than observed household reuse. It establishes direction — reuse of single-use PET makes things worse — more firmly than magnitude.

5. Earth Action 2026 — Estimated roughly 1,000 tonnes of microplastics migrate from packaging into food and drink annually — about 130 mg per person per year — with PET bottles responsible for around a third, and found UV exposure can raise release up to 100×.

   Limitation: An industry-funded modelling exercise, not a laboratory study, and not peer-reviewed. We use it for the relative ranking of formats rather than for any absolute number.

Related materials

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