Unlike most of my neighbors in the Boston suburb where I once lived, I never used the services of one of those lawn-care companies that come around with tank trucks to spray customers’ yards. I was philosophically opposed to the practice, and my lawn was remarkably weed free without those questionable chemicals. So why waste the money?

I should have been more concerned. It was very likely that my neighbors’ grass was being treated with 2,4-Dichlorophenoxyacetic acid. Commonly known as 2,4-D, the herbicide is frequently found in garden products because it kills broadleaf weeds but not grasses. It is also easily transported by wind, which probably accounted for my flawless lawn.

My neighbors weren’t doing me any favors. 2,4-D was a major component of the Vietnam War-era herbicide known as Agent Orange. Today the chemical is routinely applied to athletic fields, golf courses, and farms, as well as lawns. It has been linked to cancers such as non-Hodgkins lymphoma and soft-tissue sarcoma, as well as hormonal disruptions, reproductive difficulties, and birth defects, according to the Occupational Safety and Health Administration. Considered "highly toxic" by the EPA, containers of the chemical must bear labels saying "Danger." In addition, 2,4-D can cause serious eye and skin damage and enter human milk and semen through inhalation and ingestion, as well as through contact with the skin and eyes. The EPA’s own researchers have found higher than normal rates of birth defects in wheat-growing states where 2, 4-D and related pesticides are used in large quantities.

Despite such evidence, not only is the stuff still in widespread use, but the U.S. Department of Agriculture is about to make a decision that will likely lead to a dramatic increase in the application of 2, 4-D.

Just before Christmas, the agency took steps toward final approval of a new variety of genetically modified corn created by Dow AgroSciences. This corn would survive being sprayed with the herbicide, making it possible for farmers to kill weeds in their fields without risking their crops. Pesticide control advocates fear that the use of 2,4-D will soar if Dow is allowed to market the new corn.

There’s plenty of precedent. Advocates point to the example of glyphosate, an herbicide that is marketed under the trade name Roundup. Monsanto began selling GMO corn that could withstand Roundup in the mid-1990s. Since that time, the annual use of glyphosate in the United States has soared more than tenfold, from a little under five million pounds in 2000 to nearly 60 million pounds in 2010 in states surveyed for the USDA’s Agricultural Chemical Use Report. In an interview, Gary Hirshberg, the chairman of Stonyfield Farm and a long-time crusader for organic agriculture, called the USDA’s decision to approve the use of 2,4-D, which could be finalized this spring, "diabolical."

Suing to Stop Children’s Exposure

In an effort to keep the 2,4-D genie from completely escaping its bottle, the Natural Resources Defense Council (which publishes OnEarth) filed a lawsuit today against the Environmental Protection Agency. The agency has failed to respond to a petition filed more than three years ago, asking that the EPA block the use of 2,4-D due to its environmental and health implications. NRDC is also asking EPA to prevent "2,4-D Ready" crops from being planted.

"Because 2,4-D is used in household 'weed and feed' products, it creates the potential for significant exposure to children," says Gina Solomon, a senior scientist at NRDC who is also a medical doctor. Studies have shown that the chemical is frequently tracked indoors. Outside, 2,4-D dissipates quickly, but in the home, it can linger for months or even years in carpets and dust.

In a 2007 issue of the Journal of Occupational and Environmental Hygiene, researchers investigating homes in an agricultural area of Iowa reported finding 2,4-D in dust samples from 100 percent of houses they examined, even those belonging to non-farm families. More disturbing, research has also shown that concentrations of 2,4-D can be 10 to 200 times higher inside homes than in the soil around them.

The negative health impacts have also been clearly demonstrated. As early as 1986, National Cancer Institute scientists writing in the Journal of the American Medical Association reported that farmers exposed to 2,4-D for more than 20 days per year had six times the risk of getting non-Hodgkin’s lymphoma than non-farmers. They were also much more likely to suffer from soft-tissue sarcoma, another cancer.

And as my weed-free surban lawn demonstrated, 2,4-D can "drift" -- either as wind-blown droplets or vapors from where it is sprayed -- and affect unsprayed areas. In fact, its extreme volatility makes the herbicide something of a champion drifter. Studies of homes in Iowa show that 100 percent of houses within 550 yards of sprayed fields were contaminated -- even those belonging to non-farmers. 2,4-D has also been found in surface water, where it is toxic to wildlife and wells.

Dawn of the Superweeds

The introduction of 2,4-D-resistant crops will only amplify the problems. The new GMO crops, called Encore by Dow, will be able to survive applications of the herbicide that would kill competing weeds. In a recent issue of the journal BioScience, a group of researchers led by David Mortensen of Penn State University demonstrated a 'high probability" that drift from sprayed fields would blow over to adjacent farmland. "Once an initial number of growers in a region adopts the resistant traits, the remaining growers may be compelled to follow suit in order to reduce the risk of crop injury," the paper notes -- meaning that if a lot of your neighbors grow GMO crops and spray them with 2,4-D, your crops are likely to be killed by the wind-borne chemical unless you grow resistant crops, too. Broadleaf plants such as soy, potatoes, grapes, and potatoes are all vulnerable.

It’s a marketing twist that only an agrichemical executive could love.

The absurdity doesn’t stop there. The only reason 2,4-D-resistant crops have a market at all is that in the 15 years since crops resistant to Roundup have been available (they now account for two-thirds of the corn and nearly all of the soy grown in the United States), more than 20 species of weeds have mutated in 26 states to become resistant to the popular pesticide. These "superweeds," including such noxious characters as horsetail, Palmer amaranth, and Johnson grass, render Roundup useless in many parts of the country. The agrichemical and seed companies’ response to this problem essentially is to repeat history, substituting another, more powerful herbicide for the one that has been rendered ineffective.

Although Dow scientists dispute him (no one from the company returned my telephone calls), Mortensen contends that weeds which can resist 2,4-D are right around the corner. Dow and Monsanto intend to share their genetic patents to create so-called "stacked" crops that are resistant to both 2,4-D and Roundup. But Mortensen says that this will only lead to the dawn of even stronger superweeds that resist both. So then we’ll need to develop crops resistant to even more toxic herbicides, in what Mortensen describes as GMO treadmill that keeps gaining speed.

Commonsense, Not Chemicals

But agriculture can step off of that treadmill. A specialist in weed ecology, Mortensen advocates a system called integrated weed management, in which farmers draw on a vast array of weed-control tactics -- some modern, some dating back to the day when humans first planted seeds. Instead of planting the same crops in the same fields year after year, a farmer using integrated weed management rotates his crops, and he plants cover crops that will out-compete weeds. Time-honored traditions such as hoeing and cultivation knock back weeds while crops are growing. The fields are tilled before planting. Only when all else fails does the farmer resort to judicious, targeted applications of herbicide.

These are not the rantings of some pie-in-the-sky idealist. Long-term experiments have shown that integrated weed management produces competitive yields and realizes profits that are equal to or greater than the herbicide-only group. The main input in integrated weed management is a farmer’s experience and intelligence -- commonsense, not chemicals. In one study, herbicide use was reduced by up to 94 percent.

And that’s the rub. Agrichemical companies don’t make profits from things like cover crops, tillers, and commonsense. Promoting integrated weed management and funding research to support it are not in their financial interests.

On the other hand, there’s a lot of money to be made by selling farmers herbicide-resistant crops -- Monsanto’s profits in 2011 were more than $1.6 billion, almost 50 percent higher than in 2010. When those crops are obsolete, there are yet more profits to be made by engineering another resistant crop and selling it. It’s the agricultural equivalent of built-in obsolescence. The opportunities for profits are endless, unless the government agencies charged with protecting our health and the environment act in our interests, not those of the agrichemical industry -- even if it takes a nudge from the legal system.

Image: Roger Smith