Molecular Miracle Workers

Green chemist Paul Anastas on making the world less toxic and more convenient

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Yale professor Paul Anastas is considered the father of green chemistry, a field he defines as 'the design of chemical products and processes that reduce or eliminate the use and generation of hazardous substances.' He talks about the innovations in this burgeoning field and why chemists have a special responsibility to the environment.

Many people assume chemists are evil--they inevitably cause pollution.

People don't know we have the option of doing things green. They think that in order to have cars, computers, and other modern conveniences, we need to generate all kinds of nasty poisons. Green chemistry is disproving that myth every day.

What's really new about it?

We're touching on something that historically has not been done, which is to design molecules with an eye to consequences right from the start. If you just try to deal with a particular hazardous outcome--cancer or poisoning or explosions--then you're addressing things piecemeal. If you go back down to the molecular architecture, you can address a wide range of issues.

Has green chemistry actually taken hold anywhere?

I could give you hundreds of examples of award-winning technologies--used by companies in the United States, the United Kingdom, Japan, Italy--that have eliminated literally billions of pounds of hazardous substances. It goes from the way we make pharmaceuticals or electronics to the way we raise crops or paint the bottoms of boats. That said, for every one process or product that uses green chemistry, there may be a hundred or more that have yet to be considered.

Give me a few examples of things we're using now, or will be using soon.

Polylactic acid is a plastic whose molecule is made from potatoes, corn, and other plant sources. Wal-Mart put in multimillion-pound orders a year ago for cups, soup containers, food packaging--it's just getting going. There's also supercritical carbon dioxide--that is, CO2 put under high pressure so that it becomes a fluid [a form in which it does not contribute to greenhouse gas emissions]. It's now used in many processes that previously used some fairly toxic solvents. That includes decaffeinating coffee, which historically used methylene chloride, a cancer-causing suspect that is also used for stripping paint. CO2 is also used in dry cleaning, which up to now has typically used a toxic chemical called PCE.

So why aren't more businesses using these new techniques?

The replacement cost of machinery is a big part of the equation. Take dry cleaning, for example. CO2 itself is vastly cheaper than PCE, but a new machine costs somewhere around $40,000. Most dry cleaners are mom-and-pop shops, and they can't afford to throw away a 'perfectly good' machine. There should be a whole portfolio of incentives for industries to overcome this.

Once we retool, can green chemistry make economic sense on its own?

If you're in business, your interest is to make money, so if somebody came up with a green-chemistry solution that made no economic sense, I'd say, Go back to the drawing board. The idea is to meet environmental and economic goals simultaneously.

Is there a place for green chemistry in the developing world, where people are trying to rapidly advance their economies, often at the expense of the environment?

In the developing world, they're often starting from scratch. So when they build new plants, they can build at the state of the art--and green chemistry is state of the art. In China, they have big new green-chemistry plants making polycarbonate, the clear plastic you see in things like Plexiglas. Here, we're still making it using phosgene, a chemical-warfare agent. In India, the minister of science and technology just decreed that every chemistry student has to take a year of green chemistry. They're looking to grow through innovation.

How did you get started in this field?

Ah! I grew up outside Boston, in Quincy, Massachusetts, on a little hill overlooking the most beautiful wetland you've ever seen. And one day when I was 8 or 9 years old, the bulldozers arrived and filled it with banks and insurance companies. My father was a biology teacher, and he knew how much this upset me. He said, If you really care about something, you should learn about it. I decided to pursue chemistry. It touches everything we see, feel, hear, and touch.

Makes me think of my 6-year-old daughter--I just gave her her first chemistry set. Any advice for her?

Oh, yeah! It's a great time to be a chemist. A friend of mine once asked, tongue in cheek, why there's no green astronomy, no green geology. The answer is serious: Unlike other science, which seeks to understand the world as it is, chemistry introduces new things into the world, and because of that we have the responsibility for the consequences. Science and technology won't be able to achieve sustainability alone. But I don't know of a pathway to sustainability that isn't going to require science and technology.


Reprinted from OnEarth (Spring 2007). Subscriptions: $15/yr. (4 issues), including Natural Resources Defense Council membership, from 40 W. 20th St., New York, NY 10011; www.nrdc.org/onearth.