Save the Fish
Face mask: how long does it take to break down in the sea?
Estimated time to break down in the sea: > 450 years. Source: Ville d'Osny (osny.fr). This figure comes from a French town council's guidance, not from a study, and it is not specific to the sea.
Face mask: why is it harmful to the sea?
Polypropylene sheds microfibres; ear loops tangle birds and turtles.
Face mask: does it really disappear?
No. A mask's polypropylene layers are plastic: they break into microfibres and microplastics.
Face mask: how harmful is it compared with other trash?
Harm score 8 out of 10: lasts 4/4, toxic 1/3, wildlife 3/3. It ranks 4 of 31 on our list. This score is our own simple scale for comparing items in the game. It is not an official index.
Face mask: what is it made of?
Material: Polypropylene, a plastic. A typical one is about 17.5 cm long and weighs about 3 g.
Face mask: what can I do?
Small litter still counts: put it in a bin, never on the beach, in a drain or down the toilet.
Face mask: what lasts longer, and what breaks down sooner?
Lasts longer: Plastic bottle, Toothbrush, Bottle cap. Breaks down sooner: Disposable diaper, Plastic cups and plates, Plastic straw.
Face mask: where does this figure come from?
From “Masques jetables : dans la poubelle uniquement !”, Ville d'Osny (French municipal government). Checked on 2026-10-25.
The source says“Leur durée de décomposition est d’environ 450 ans.”The source's limits (in English): Town-hall guidance in French, not a study, and not sea-specific: 'Leur durée de décomposition est d’environ 450 ans' (about 450 years).