Coke and Pepsi's plant-based bottles still damage the environment.

They should also commit to using recycled material in their packaging. In 2001, Coca-Cola pledged to use 10 percent recycled plastic in their PET bottles by 2005. It achieved that goal, promptly dropped its commitment to using recycled content, and now evades precise accounting with statements like, "We are working to advance technologies that allow us to use greater amounts of recycled materials in our packaging." The bottles currently produced by major bottling companies use about 4 percent recycled content, according to Susan Collins, executive director of the Container Recycling Institute.

There's no question that setting up collection facilities and integrating recycled material into the production stream is expensive. But several companies are already doing it, Collins says. Naked Juice, Naya Water, Eldorado Water, and Rainbow Light Nutritional Systems, for example, are all using 100 percent recycled plastic in their bottles. Meanwhile, Coke and Pepsi are spending millions on a plant-based version of the same old packaging and touting it as an environmental leap forward. Don't be fooled: It's a sidestep at best.

Correction, June 15, 2011: This article incorrectly suggested that bisphenol A and pthalates are commonly used as additives to PET and HDPE plastics. (Return to the corrected sentence.)