eli5 – how did the numbering system start for recycling plastics?


I realize there are several different types of plastics. Wouldn’t it have been easier to just indicate recyclable vs non-recyclable on plastic products?

In: 0

The plastics industry realized they had an image problem over plastic bottles as litter, and the lack of recycling in general, so they created the number system as a public relations campaign.

The numbers represent types of plastic. You can’t just recycle any two plastics together, they have to be chemically identical or it won’t work. The numbers are nominally to help plastics get sorted by type (since you can’t necessarily tell polyethylene from polystyrene at a glance). That makes it easy to separate them at the “recycling factory”.

In practice plastic has to be super clean to recycle anyway, and mixed stream post consumer plastic usually has food detritus, so most “recycled” plastic goes to landfills anyway.