Allowable levels of VOCs, or volatile organic compounds, for paints and products such as aerosol air fresheners, carpets, and furniture have been toughened because VOCs contribute to ozone and smog formation and are linked to respiratory illnesses and memory impairment. And claims by many manufacturers have grown bolder as they market to an audience more familiar with and perhaps more receptive to buying green goods.

So we shook things up in this report on water-based interior paints by measuring the VOC content of finishes that makers maintain have no VOCs and several high scorers that are marketed with no special claims. We detected VOCs in every paint, though none exceeded any applicable government limits, and some paints had lower levels than others.

The top paints in our Ratings (available to subscribers) had among the highest claimed VOC levels, including Behr Premium Plus Enamel low-luster and flat and Benjamin Moore Regal semigloss. Lowering VOC levels can affect performance. "When you take out VOCs, you still need strong performance properties, but you have to find other ways to achieve them," says Carl Minchew, product-development director at Benjamin Moore. Still, some no- and low-VOC paints did well in our tests (available to subscribers).

We also made another big change in our tests. Recognizing that manufacturers tout the one-coat coverage of finishes and that you might hope to save time and money by using paints that can do a solid job with only one coat, we've modified our hiding-test score to better assess this attribute.