GET your plastic grocery bags while you can. By Earth Day, that is, Tuesday, the national chain Whole Foods Market will no longer offer shoppers plastic bags – leaving consumers who don’t want reusable canvas bags one choice: paper.

Unfortunately, paper has its own drawbacks, such as: it’s preferred by cockroaches – like those contributing to New York City’s asthma epidemic.

Like other Earth Day initiatives, this move by Whole Foods reeks of a phenomenon known as “greenwashing” – when companies make lofty claims in an effort to profit from “environmentally concerned” shoppers.

Whole Foods insists that the decision to take away the plastic option is wildly popular with consumers. When pressed on why consumers would be happy about having fewer choices, Whole Foods spokeswoman Kate Lowery insists that the “emphasis is on reusable canvas bags.” Why not let customers have the choice?

The company claims on its Web site that it isn’t “trying to settle the ‘paper vs. plastic’ debate.” But by no longer offering plastic, it sure sounds like Whole Foods has chosen paper.

Unfortunately, so have cockroaches.

Entymologists, including Coby Schal of North Carolina State University, have observed that cockroaches prefer paper to plastic. “They really like to live in the creases found in paper bags,” said Schal, the nation’s top expert on cockroaches. Many cockroach species chew into paper bags to lay their eggs – something they don’t do with plastic.

This is a problem beyond just the yuck factor. Darryl Zeldin, a senior scientist with the National Institute of Environmental Health Sciences, says: “Cockroaches significantly increase asthma symptoms in allergic individuals. And while a third of inner-city residents are cockroach-sensitive, sensitivity to cockroach exposure is widespread in our nation – not just in the inner cities.”

If Whole Foods’ “green” move starts a trend among food stores, it may contribute to New York’s asthma epidemic.

It gets worse. The move flies in the face of the enviro mantra to “reduce, reuse and recycle” – in that order. Almost everyone keeps a stash of plastic bags. We reuse them to line garbage cans, bring lunch to work and clean up after the dog – try doing that with paper. Plastic bags are easier to reuse and more efficient to recycle than paper. In fact, starting this summer, New York City will require large stores to offer shoppers recycling bins. (Maybe the city’s overbearing emphasis on public health resulted in something positive, this time.)

That makes a lot more environmental sense than San Francisco’s governmental greenwash: an outright plastic-bag ban. If you are worried about the environment, reusing plastic bags is a better choice than paper bags, which rarely get reused.

Too many mindlessly follow green initiatives and bask in how good it feels – without recognizing the unintended consequences. Magicians Penn and Teller have a video posted on YouTube in which hundreds of naive greens at a rally happily sign a petition to ban a “chemical found in reservoirs and lakes” and used in pesticides and nuclear energy that is finding its way into grocery stores and baby food.

The chemical the people signing the petition want banned? Dihydrogen monoxide – water.

Blindly following environmental extremists might make you feel good, but there is a dark side. Recall the millions of unnecessary malaria deaths that have resulted from Rachel Carson’s “green” effort to ban DDT. Next time you are asked “paper or plastic,” do something the water-petition-signers didn’t do. Think.

Jeff Stier is an associate director of the American Council on Science and Health.