Paper, Plastic Or Neither

Steven Stein likes to trail garbage trucks. "As long as my girlfriend's not with me, I follow them," the Maryland resident says. "It's hard to resist." Stein's odd habit makes sense when you consider that he's an environmental scientist who studies how to reduce litter, including stuff that falls off garbage trucks as they barrel down the road. What is even more interesting is that one of Stein's current gigs is defending an industry behind a notorious source of trash: the disposable plastic shopping bag.

Americans use more than 100 billion thin film plastic bags every year. So many end up...