There’s no such thing as a styrofoam cup

And you have never used a styrofoam plate or take-out box.

Many moons ago, right after graduate school, I had a job researching and writing entries for a materials encyclopedia. I became the queen of arcane trivia about everything from wood and glass to elastomeric polymers and cementitious materials. I was SO fun at cocktail parties!

Years later and one of my most enduring takeaways from that project is this: There are no such things as cement walls and styrofoam cups. Cement is just one ingredient in concrete, so what we have are concrete walls. The story of styrofoam, or Styrofoam™ Brand Insulation, to be specific, is a little more nuanced.

“Styrofoam” is the brand name of insulation board manufactured by DuPont. It was discovered by Dow in 1941. It is extruded polystyrene (XPS), and a different animal from expanded polystyrene (EP), which is used to make foam cups, take-out containers, and packaging. Styrofoam is used mostly in construction and is almost always blue.

Now of course some may maintain that this is a case of a genericized trademark. Aspirin, band-aid, and kleenex, for example, were all once trademark names that have become generic terms for the same class of products made by different companies. But while both XPS and EP are made with polystyrene plastic, they use different technologies and they have markedly different uses – so the genericized trademark argument doesn't work very well here.

So why does this even matter? Am I just being an annoying pedant? (Well, I may be, but that's not the point.) And I am not being a Styrofoam apologist – or a Dupont or Dow apologist, while we are at it. But the fight against single-use foam cups and containers is real. It is important. And in the era of BANS ON PLASTIC BANS and dizzying disinformation campaigns, it feels crucial to be informed, educated, and to get the facts right. When activists and journalist go around fighting against something of which they don't know the correct name, it's harder for those arguments to be taken seriously.

So there you have it. There are no such things as styrofoam cups – and you certainly can't put a styrofoam cup on a cement wall. And now you too can be the life of a cocktail party!

And you have never used a styrofoam plate or take-out box.