Dear EarthTalk: I’ve heard that New York City schools are trying out “Trayless Tuesdays” in their cafeterias in order to reduce waste. Why are trays such a big issue? And how can cutting them out on one day a week really make a difference? -- Mark, Brooklyn, NY
Unlike the old days when many school cafeterias offered reusable trays that could go into big industrial dishwashers after lunchtime, the trend since the early 1990s in New York City and elsewhere across the country has been to provide students with disposable polystyrene (tradename: Styrofoam) trays that are used once—typically for less than 30 minutes—and then thrown out. From there, most of the trays end up clogging already overburdened landfills or posing a litter problem. Polystyrene, impossible to compost and difficult to recycle, is one of the predominant features of litter-filled beaches, not to mention trash-based ocean gyres hundreds of miles from shore.