Plastic bags are now fairly ubiquitous, used in retail packaging across the globe. But the inventions that lead to them being widely used are all relatively recent. Plastic is made up of polymers — chain of organic molecules — molded into useful shapes. Here is a brief time line of the history of plastic and plastic bags inventions and introductions.

1839 – Process for making usable natural rubber (something of a natural plastic) discovered by Charles Goodyear; Polystyrene discovered by accident by Eduard Simon in Germany, he does not utilize this discovery.

1855 – First marketed human-made plastic invented by Alexander Parkes. Called Parkesine by its creator and now known as celluloid, first found commercial use as billiard balls (replacing ivory), before becoming used in photography.

1872 – PVC, or vinyl, discovered by Eugen Baumann, it was not patented and did not gain a commercial application until the 1920s.

1898 – Polyethylene, the polymer family used in most plastic bags, first synthesized by the German chemist Hans von Pechmann.

1908 - Cellophane film invented by Jacques E Brandenberger. Around the same time, Belgian chemist Leo Baekeland creates Bakelite, a well-constructed universally used material now considered the first “true plastic.”

1933 – Reginald Gibson and Eric Fawcett create low-density polyethene (LDPE), the material used in plastic bags. Their experiment is replicated three years later and the material soon finds much commercial use due to wartime rubber shortages.

1957 – Plastic bags begin to gain commercial use as sandwich bags.

1965 – Swedish engineer Sten Gustaf Thulin develops a process to make easy-to-construct plastic bags out of a plastic tube. The “t-shirt bag” quickly becomes adopted by many retailers.

1974 – Retail giants Sears and J.C. Penny switch to plastic shopping bags.

1977 – The Celloplast company loses its monopoly on the production of plastic shopping bags. When the monopoly expires, new and cheaper production processes make plastic bags even more common. By the early 1980s most grocery stores offer “paper or plastic” bag options.

1990 – Consumer plastic bag recycling begins through a supermarket collection-site network. (Learn about S. Walter Packaging’s own bag recycling program here.)

2011 – Over 80% of all bags used are plastic bags.