Dear EarthTalk: Are there healthy, green-friendly mouthwashes? I've heard that some contain formaldehyde and other nasty substances. -- Marina Sandberg, Albany, N.Y.

Many mainstream mouthwashes contain ingredients that you definitely don't want to swallow, or even put down the drain. According to the Environmental Health Association of Nova Scotia's (EHANS's) "Guide to Less Toxic Products" -- a free online resource designed to help consumers choose healthier, greener everyday products -- conventional mouthwash is often alcohol-based, with an alcohol content ranging from 18 to 26 percent.

"Products with alcohol can contribute to cancers of the mouth, tongue and throat when used regularly," the guide reports, adding that a 2009 review in the Dental Journal of Australia confirmed the link between alcohol-based mouthwashes and an increased risk of oral cancers.

And you might want to avoid mouthwashes with fluoride (aka sodium fluoride). While fluoride may help fight cavities, ingesting too much of it has been linked to neurological problems and could be a cancer trigger as well. Common mouthwash sweeteners have also been linked to health problems: Saccharin is a suspected carcinogen while sucralose may trigger migraines. Synthetic colors can also be troublesome.

Some brands contain formaldehyde (aka quanternium-15). According to the National Cancer Institute, overexposure to formaldehyde can cause a burning sensation in the eyes, nose and throat as well as coughing, wheezing, nausea and skin irritation. The U.S. Environmental Protection Agency considers formaldehyde a "probable human carcinogen" and research has shown an association between long term workplace exposure and several specific cancers, including leukemia. Few of us are exposed to as much formaldehyde as, say, morticians, but does that mean its okay to swish it around in our mouths every day?

Other problematic ingredients in many conventional mouthwashes include sodium lauryl sulfate, polysorbate, cetylpyridinium chloride and benzalkonium chloride, all which have been shown to be toxic to organisms in the aquatic environments where these chemicals end up after we spit them out.

So what's a concerned green consumer to do? EHANS recommends the following mouthwashes that do not contain alcohol, fluoride, artificial colors or sweeteners: Anarres Natural Candy Cane Mouthwash; Auromere Ayurvedic Mouthwash; Beauty with a Cause Mouthwash; Jason Natural Cosmetics Tea Tree Oil Mouthwash; Dr. Katz TheraBreath Oral Rinses; Hakeem Herbal Mouthwash; and Miessence Freshening Mouthwash. Besides these brands, the Environmental Working Group's Skin Deep Cosmetic Database also lists Tom's of Maine Natural Baking Soda Mouthwash, Healing-Scents Mouthwash and Neal's Yard Remedies Lavender and Myrrh Mouthwash as least harmful to people and the environment.

You can also make your own all-natural mouthwash at home. Eco-friendly consumer advice columnist Annie Berthold Bond recommends mixing warm water, baking soda or sea salt, and a drop of peppermint and/or tea tree oil for a refreshing and bacteria-excising rinse. Another recipe involves combining distilled or mineral water with a few dashes of fresh mint and rosemary leaves and some anise seeds; mix well and swish. A quick Internet search will yield many other down-home natural mouthwash formulas.

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Contacts: Guide to Less Toxic Products, www.lesstoxic.ca; Skin Deep Database, www.ewg.org/skindeep/; Annie Berthold Bond, www.anniebbond.com.

Dear EarthTalk: I understand that some Northeastern and Mid-Atlantic U.S. states have banded together to reduce their own greenhouse gas emissions. Can you enlighten? -- Bo Clifford, Cary, N.C.

Given the lack of federal action to curb greenhouse gas emissions in the U.S., several East Coast states joined together in 2008 to form the Regional Greenhouse Gas Initiative (RGGI), committing to a market-based system to cap carbon pollution and lower energy bills while creating more green jobs.

Under RGGI, the 10 participating states -- Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Rhode Island and Vermont -- agreed on a region-wide greenhouse gas emissions limit, enforced through the sale of pollution permits to large fossil fuel power plants there. The utilities that run the plants purchase the right (at quarterly auctions) to emit certain capped amounts of carbon dioxide (CO2). The money raised is in turn invested in local businesses throughout Northeast and Mid-Atlantic states that promote energy efficiency and renewable energy sources. RGGI's overall goal is to reduce CO2 emissions from the power sector in the states involved by 10 percent by 2018.

The program was conceived in 2008 by then New York governor George Pataki based on a similar federal program launched by President George H.W. Bush in 1990 that successfully curbed emissions of other pollutants that led to acid rain.

While RGGI had strong bipartisan support at launch, changing priorities have since forced some states to reconsider their commitments. According to RenewableEnergyWorld.com, New Jersey is likely to back out, while factions in New Hampshire and Maine have also called for a withdrawal. "The political tides have turned significantly since the program was started, and many legislatures are now dominated by a new crop of lawmakers looking to cut spending in cash-strapped states," the website reports.

Environmentalists and many business owners have banded together to try to save RGGI in the face of economic threats to its viability. Last July some 200 Northeastern and Mid-Atlantic businesses signed on to an open letter urging the governors of the 10 participating states to keep up with the program so that it can achieve its goals. "The Regional Greenhouse Gas Initiative shows that market-based programs can reduce greenhouse gas emissions while boosting our economy and improving energy security, and we encourage you to support and strengthen RGGI going forward," the letter states. The letter goes on to cite research showing a $4-6 increase in economic output for every $1 invested in energy efficiency programs in the RGGI states. "Even better, these market-driven investments create jobs in the clean tech sector--one of the most dynamic segments of our state economies."

Perhaps more important, RGGI "serves as a powerful model for what a comprehensive national energy policy should do" says the Natural Resources Defense Council (NRDC), a leading environmental group. Whether or not the economy will improve enough or climate change will become dramatic enough for Congress and the White House to take federal action to limit greenhouse gas emissions across the board is anybody's guess. In the meantime, keeping alive programs like RGGI might be the best we can hope for.

Contacts: RGGI, www.rggi.org; RenewableEnergyWorld.com, www.renewableenergyworld.com; Businesses Letter to State Governors, www.cleanenergycouncil.org/files/RGGIJuly2011Final.pdf.

EarthTalk is written and edited by Roddy Scheer and Doug Moss and is a registered trademark of E - The Environmental Magazine (www.emagazine.com). Send questions to: earthtalk@emagazine.com; subscribe: www.emagazine.com/subscribe; order a free trial issue: www.emagazine.com/trial.