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Ken Cook, 57 and Nneka Leiba, 28
Co-founder, Environmental Working Group (EWG.org ), and Nneka Leiba, 28, an environmental health researcher for the group's Skin Deep website (CosmeticsDatabase.com), Washington, D.C.

How It Started: Since 1993 EWG has used computer investigations to protect the environment and public health. In 2000 we learned that a study by the CDC found a chemical—dibutyl phthalate—in the blood of several women and suggested it may have come from personal care products. We downloaded ingredient lists and used regulatory databases to match them against toxic properties. Now we have over 41,000 products up. — Ken

How It Works: We score products for toxicity on scale of 0 to 10: 0 to 2 is "green," a low hazard; above 7 is pretty high. If a product isn't on our site, you can type in the ingredients and how it's used (say, "rubbed in") and the site generates a score. — Nneka

Biggest Mistake: At first, we focused on media instead of individuals. Our e-mail list had only 6,000 people in 2006. Today we have 480,000. When we e-mail them, tens of thousands take action. — Ken

Is It a Drag That Polar Bears Get All the Press? I'm all about charismatic mega-fauna. I like polar bears, organic cows, pandas. We're comrades in arms. — Ken

Just One Thing You Can Do: Don't use bottled water. Our study of 10 brands found an average of eight contaminants in each. Also, it has to be transported, which produces emissions. — Nneka 

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