Squeezing and flexing containers
Moderate impactMechanical stress is a documented, repeatable driver of release.
The short answer
Research on plastic bottles has directly linked mechanical stress — squeezing, shaking, repeated opening, temperature cycling — to increased particle release. Squeeze bottles are the only format where you deliberately deform the wall at every single use, which is why oil in a squeeze bottle is a worse choice than oil in a glass bottle you pour from.
Why it happens
- Deformation creates and propagates micro-cracks in the wall
- Every flex works those cracks further open
- Force increases as a bottle empties, so late use is the worst
- Shaking a carbonated bottle adds internal pressure to the same stress
The fix, easiest first
- Pour rather than squeeze — glass bottle with a spout
- Decant from a tin into a small glass bottle for daily use
- Do not shake plastic bottles of carbonated drinks
- Buy sizes you will finish, so you are not squeezing the dregs for weeks
Packaging this applies to
Plastic squeeze bottle
LDPE or PET, flexible wall
PET plastic bottle
Polyethylene terephthalate, PET (#1)
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Get my exposure scoreFrequently Asked Questions
Does squeezing a plastic bottle release microplastics?
Research on plastic bottles has directly linked mechanical stress — squeezing, shaking, repeated opening, temperature cycling — to increased particle release. Squeeze bottles are the only format where you deliberately deform the wall at every single use, which is why oil in a squeeze bottle is a worse choice than oil in a glass bottle you pour from.
Why does this happen?
Deformation creates and propagates micro-cracks in the wall. Every flex works those cracks further open. Force increases as a bottle empties, so late use is the worst. Shaking a carbonated bottle adds internal pressure to the same stress.
What should I do instead?
Pour rather than squeeze — glass bottle with a spout. Decant from a tin into a small glass bottle for daily use. Do not shake plastic bottles of carbonated drinks. Buy sizes you will finish, so you are not squeezing the dregs for weeks.
Sources
- Earth Action with rePurpose Global (2026). Microplastic migration from food and beverage packaging (reported May 2026). Forbes.
- Qian N, Gao X, Lang X, et al. (2024). Rapid single-particle chemical imaging of nanoplastics by SRS microscopy. Proceedings of the National Academy of Sciences (PNAS).
- Winkler A, Santo N, Ortenzi MA, et al. (2022). Does mechanical stress cause microplastic release from plastic water bottles?. Water Research.
- Hernandez LM, Xu EG, Larsson HCE, et al. (2019). Plastic teabags release billions of microparticles and nanoparticles into tea. Environmental Science & Technology.