Americans will spend an estimated $500 billion this year on products and services that claim to be good for the environment because they contain non-toxic ingredients or produce little pollution and waste. While some shoppers buy green to help save the planet, others are concerned about personal health and safety. Whatever their motives, eco-consumers are reshaping U.S. markets. To attract socially conscious buyers, manufacturers are designing new, green products and packaging, altering production processes and using sustainable materials. But some of these products may be wastes of money. Federal regulators are reviewing green labeling claims to see whether they mislead consumers, while some critics say that government mandates promoting environmentally preferable products distort markets and raise prices. Even if green marketing delivers on its pledges, many environmentalists say that sustainability is not a matter of buying green but of buying less.

Jennifer Weeks is a freelance writer in Watertown, Mass., who specializes in energy and environmental issues. She has written for The Washington Post, The Boston Globe Magazine, Environment, On Earth and other publications, and spent 15 years as a congressional staffer, lobbyist and public policy analyst. She holds a B.A. from Williams College and master's degrees from the University of North Carolina and Harvard University.