Note: this post was originally written by Daniel DiClerico and posted to Consumer Reports News on April 28th, 2008

At my local home center, I’m seeing more interior paints whose cans say that the finishes have few or no VOCs. What are VOCs, and what do the numbers mean?

The seal has definitely been broken on the issue of VOCs, or volatile organic compounds, in paint. You can expect to see more brands touting their virtuous VOC content.

VOCs are solvents that get released into the air as the paint dries. Other products also emit solvents, including adhesives, cleaning supplies, and even some home furnishings. VOCs can cause acute symptoms, including headaches and dizziness. The long-term effects are less certain, but according to the U.S. Environmental Protection Agency, some VOCs are suspected carcinogens.

The federal government caps the VOC content in paint at 250 grams per liter (g/l) for flat finishes and 380 g/l for other finishes, including low-luster, semi gloss, etc. However, some manufacturers have opted to comply with more stringent limits 50 g/l for all finishes set by California s South Coast Air Quality Management District. These products include Benjamin Moore Aura, True Value Easy Care, and Glidden Evermore. In the past, low-VOC paints have performed poorly in our tests, but these products all got high marks in our latest tests of low-luster interior paints.

The Ozone Transport Commission, a multistate organization created under the Clean Air Act, also has a model rule that limits flat coatings to 100 g/l and non-flat coatings to 150 g/l. It has been adopted by the District of Columbia and Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, Pennsylvania, Rhode Island, Vermont, and Virginia. Any paint sold in these places must be OTC-compliant.

A handful of paints whose manufacturers claim they contain zero VOCs are now on the market. One is Mythic, which sells for $35 to $45 per gallon at independent dealers nationwide. If you’re a reader of shelter magazines, you’ve probably seen the print ads for Mythic. Another zero-VOC paint is Freshaire Choice, a Home Depot exclusive that sells for $35 to $38 a gallon. Freshaire has adopted a more wholesome marketing approach: It’s good for your family and better for our world.

The base of other paints might also be free of VOCs, but when any pigment is added at the point of sale, the VOC level climbs as high as 150 g/l, according to ICI Paints, which manufacturers Freshaire Choice. But the makers of Mythic and Freshaire Choice both say that the color pigments used in their finishes contain no VOCs.

Mythic and Freshaire Choice use a VOC-free color additive that is supposed to eliminate not only harmful solvents but also the telltale odor of a freshly painted room, according to their manufacturers. Carl E. Smith, CEO of the Greenguard Environmental Institute, argues that measuring emissions is as important as identifying the VOC level in a paint. You can have a low count on VOC, but still have high emissions, says Smith. That’s why Greenguard, which describes itself as an industry-independent, third-party testing organization, makes emissions central to its certification process. Currently, Freshaire Choice earns the Greenguard seal, as does Benjamin Moore Aura, whose low-luster and flat paints scored an excellent and a very good overall score, respectively. Mythic has not yet been tested by Greenguard.

Consumer Reports has not yet tested Mythic or Freshaire Choice, but both will be considered for our 2009 report of interior paints. We don’t know whether these finishes will endure our typical hiding, fading, and stain resistance tests.

Remember, even though a paint might have low or no VOCs, it doesn’t do you any good if it needs constant touch-ups or reapplying.