"Biodegradable" detergents. Seventh Generation Automatic Dishwashing Gel is said to break down in the environment. But the claim broke down when we found that the product contains a petroleum-derived agent that doesn't readily biodegrade. A spokeswoman said the company would remove the claim and review its product line and labeling. Biodegradability of two other detergents--Earth Friendly Product's Wave automatic dishwasher gel and Planet Ultra Dishwashing Liquid--was certified by reputable independent groups.

"Green" paper towels. Green Forest paper towels claim to be "soft on nature." As proof, the company pointed to an assessment of the product's recycled content by the Natural Resources Defense Council. The council stated that the paper is 100 percent recycled and that 40 percent is "post-consumer," meaning that it had already been used and would otherwise have been dumped. The rest is recycled manufacturer scraps and other paper that never reached the consumer. That's better than most paper towels, an NRDC official says. But other brands listed on the NRDC's Web site (www.nrdc.org) have even more post-consumer content, and so go further in encouraging municipal recycling.

"Environmentally friendly" foil. The maker of If You Care 100% Recycled aluminum foil claims to use 5 percent of the energy needed to make regular foil, and research bears that out. As for the claim that If You Care "can be recycled again," any clean foil can be recycled in most towns that recycle aluminum.

"Gentle on the earth" laundry detergent. Biokleen powder says it has "no negative effects on rivers, streams, plants, or wildlife." Indeed, it received a logo from the U.S. Environmental Protection Agency for its "environmentally preferable" chemistry. Although we found an "acute" hazard listed on the product's chemical disclosure form, a company official told us the listing was wrong and has been corrected.