Are pesticides safe to use on fruits and vegetables? The debate continues

Q: What is the importance of the pesticides/ herbicides that the Environmental Protection Agency recently ruled on? Are these chemicals dangerous or not? What is the real answer?

A: If I had the answer to those last two questions, I’d be wearing a lab coat and perhaps be contending for a Nobel Prize. Just like the Alar controversy of the 1980s, chlorpyrifos has been in the crosshairs of the most recent fight over pesticides, and, while it survived the latest skirmish, the battle to ban it goes on.

You remember Alar, don’t you? Manufactured by the Uniroyal Chemical Co., it was a chemical sprayed on fruit to regulate plant growth so that, for example, apples didn’t fall off the tree prematurely. Then in 1985, tests on mice and hamsters suggested it was a carcinogen. Four years later, the National Resources Defense Council issued a report that children were being put at risk from ingesting even legally permissible amounts of potentially lethal chemicals, including daminozide (Alar).

Using the NRDC report, “60 Minutes” made Alar a household word (and worry) in February 1989 when it did a segment on the product. Experts at the American Council on Science and Health and others countered that the tests that produced the Alar scare would have required children to drink 5,000 gallons of apple juice — per day. Washington apple growers sued CBS and the NRDC for $100 million, but the suit was dismissed.

Consumers Union now says Alar may cause five cases of cancer in a million. Today, Alar, which is now banned for use on food crops, is listed as a “possible” carcinogen by the International Agency for Cancer Research and a “probable” threat by the EPA, which usually takes action when a cancer risk exceeds one in a million.

The same controversy has been dogging chlorpyrifos for years. Introduced by the Dow Chemical Co. in 1965, chlorpyrifos is better known by such familiar trade names as Dursban, Lorsban, Hatchet and Warhawk. It works by attacking an insect’s central nervous system, preventing its ability to break down the neurotransmitter acetylcholine.

It apparently does its job well. By 2007, chlorpyrifos was the most commonly used organophosphate pesticide in the United States and the 14th most common pesticide overall with roughly 10 million pounds applied to crops across the nation. According to Dow, it is used in nearly 100 other countries around the world, most notably on cotton, corn, almonds and fruit trees such as oranges, bananas and apples. It also has been used on golf courses and in ant and roach baits.

But just as it affects insects, some studies indicate that chlorpyrifos affects humans, especially infants and children, whose bodies cannot detoxify the chemical as readily. In multiple human studies, exposure during pregnancy or in childhood has been linked with lower birth weight, slower motor development and attention problems. In experiments on rats, short-term, lowdose exposure produced lasting neurological effects.

Other studies have found that acute exposure or repeated low-dose exposure can produce health problems in adults. In one, it was associated with higher risks of lung cancer among those who apply it frequently compared with 49 other pesticides. In 2011, New Zealand scientists said it likely caused the death of several tourists in Thailand who developed myocarditis, but Thai researchers disputed the claim.