It’s About Apples, and Growers’ Attempt to Make Them Redder

WASHINGTON —  Daminozide is a pesticide that the Environmental Protection Agency wanted to take off the market but couldn’t. It makes apples redder and makes them last longer in storage. And, it provides a perfect case study of how hard it is to make sensible decisions about useful chemicals whose safety is questioned.

You may not know daminozide but your grocer does. Safeway, the country’s largest grocery chain, has announced that it will stop buying apples treated with the chemical, which is sold under the trade name Alar. So did the Giant chain in Maryland, Virginia and the District of Columbia. The supermarkets acted after prompting from Ralph Nader and other consumer activists.

Nonetheless, these stores are doing something almost unheard of in the food industry: shunning chemically treated crops even when government regulations do not demand it.

Cite Cancer Threat

Environmentalists argue that daminozide causes cancer and serves chiefly to make apples more appealing to customers. Farmers and the Agriculture Department say it is harmless and essential to growers’ prosperity.

The manufacturer, Uniroyal Chemical Co., convinced the EPA’s independent Scientific Advisory Panel for pesticides that the EPA had not made its case for banning the chemical. In January, the EPA backed down.

Daminozide is a growth regulator that results in apples getting redder on the tree, preventing premature drop and extending storage life of some varieties for two or three months, thus making them available year-round.

In the early 1960s, Uniroyal, searching for something that would produce dwarf apple trees, found that the chemical could slow the growth of greenhouse flowers. Federal approval for sale on flowers came in 1963.

Paul Bohne Jr., company horticulturist, then applied it to apple trees in his own orchard near Bennington, Vt.--50 acres where 30 varieties, mostly McIntosh, are cultivated by his two sons.

“We were really dumbfounded,” Bohne recalled. At harvest, there were only four or five apples on the ground under the treated trees, but the usual 25% or 30% fell from untreated sections.

Approved in 1969

Uniroyal submitted rat feeding studies to the Agriculture Department, then in charge of pesticide regulation. The rats were healthy--no tumors--and daminozide was approved in 1969 for food under the trade name Alar.

That test does not meet today’s standards. Too few rats, only 37, were tested against a control group of the same size.

Alar was an instant hit. About 908,000 pounds are used each year on 267,000 acres, about a quarter of the apple crop. About 40% of the popular Red and Golden Delicious, McIntosh and Stayman varieties are treated. The EPA says $31 million of growers’ profits depend on the chemicals, a figure the Agriculture Department says is far too low.

Nothing else provides the same combination of benefits, growers say.

“They suggest that I could grow Granny Smiths,” Roscoe Crist, who grows apples in New York’s Hudson River Valley, told a meeting of the pesticide advisory panel last fall. “If I, in New York, tried to grow Granny Smiths. . . . I would be beating my head against the wall. It is a long-season variety; (it) will mature by Thanksgiving Day.”

Alar has other food applications--peanut plants, tart cherries, grapes, peaches, nectarines, pears and tomatoes--but none is anywhere near as important as its use on apples.

The EPA says that these other crops do not need it or can use substitutes. Indeed, Uniroyal gave up selling it for cantaloupes, peppers, plums and Brussels sprouts.

Tumors Found in Mice

In 1977, a researcher at the Eppley Institute in Omaha published a report showing blood vessel tumors in 73% of mice fed daminozide in water, but in only 6% of a control group.

Two National Cancer Institute tests of daminozide in feed in 1979 were equivocal. There were statistically significant liver tumors in male mice, but the EPA did not consider them of biological significance because the particular mouse strain is prone to that tumor.

There were uterine tumors in female mice--not statistically significant, but biologically significant, according to the agency, because of their rarity.

Daminozide breaks down into another chemical, unsymmetrical dymethyl hydrazine, or UDMH, a rocket fuel. The EPA thinks this may also cause cancer.

There were no blood vessel tumors in the NCI studies; the EPA thinks this is because the dose was lower and the chemical was in food, giving less UDMH breakdown product.

Eppley Institute feeding tests showed UDMH caused various tumors in mice and hamsters. An Air Force inhalation study showed lung and pancreas tumors in rats, but nothing in dogs or hamsters.

The upshot: The EPA said in 1980 that it would hold a special review of daminozide.

But the review did not begin until 1984.

Key Information Lacking

“We lacked two key pieces of information: what were the exposure levels for applicators and in the diet?” said Paul Lapsley, head of the EPA’s special review branch.

According to Uniroyal’s toxicology manager Ray Cardona, “it took us a couple of years” to develop a method to detect UDMH in food.

The EPA cannot simply ban a pesticide shown to cause cancer. It must determine that the risks outweigh the benefits.

There turns out to be not much risk for the people applying the chemical. But the EPA calculated the increased risk of getting cancer from daminozide in the average diet as probably, at most, about one in 10,000 over a lifetime, a risk the agency said outweighed the benefits. This would mean about 800 cancers a year, it said.

A lifetime risk of one in 10,000 is about the risk a frequent flyer faces of being in a crash in which someone, not necessarily that person, is killed.

Cancer of all forms causes more than 400,000 deaths a year. Your chances of dying of cancer are about one in five.

The EPA strenuously avoids numerical rules for taking action. Nonetheless, several observers and officials have said that the agency rarely sits still and does nothing if a lifetime risk appears greater than about one in 100,000, or one in 10,000 for an on-the-job risk.

Last September, the EPA proposed to cancel all food uses of daminozide.

Studies Faulted

According to Uniroyal, something was seriously wrong with all five studies the EPA relied upon.

Both sides seem to agree that the 1977 study was the key. Without it, said Ernest Hodgson, professor of toxicology at North Carolina State University and chairman of the advisory panel, the other studies would not justify action.

It was not designed to estimate risk. The test animals got only a single massive dose, well above the “maximum tolerated dose,” the company argued.

This problem must be distinguished from the old argument that “the rat drank the equivalent of 8,000 cans of soda pop; no human can drink that much; therefore, the chemical (whatever it is) is safe.”

Most toxicologists agree that doses must be high to maximize the chance of detecting cancer-causing power if it is there, but not so high that the animal’s metabolism is changed. Below that point, it does not matter whether the dose is the human equivalent of eight or 8,000 cans.

Uniroyal’s toxicologists said the mice died at half their normal life span and appear to have been dehydrated, thus possibly drinking extra daminozide-dosed water. The EPA auditors concluded that the maximum tolerated dose was indeed exceeded, but they also concluded that the EPA scientists nonetheless probably were underestimating the potency of daminozide.

Risk Calculation Hit

Other company objections were based on the risk calculation. In these calculations, the EPA’s policy is to use conservative assumptions in trying to answer the question: Just how many cans of soda pop--here, how many apples--did the rats get anyway?

These are some of the company’s points:

- The EPA adjusted the rat dose to equivalent human dose according to the ratio of rat skin area to human skin area. If it had used the ratio of rat weight to human weight, the human risk would appear to be only about one-tenth as large.

Some government agencies, notably the Food and Drug Administration, use the weight ratio. In the absence of further information, toxicologists split on which is more appropriate.

- The EPA simply made some wrong calculations in the rat-to-human conversion, particularly by using the lifetimes of the longest-lived rats instead of the average lifetimes. This makes to much depend on when just two rats happen to die, Uniroyal argued, and in this case inflated the risk by a factor of four.

- The EPA assumed that 100% of all fresh apples are treated with daminozide, but actually only 22% are treated. The agency assumed, in the absence of data, that meat, milk and eggs are contaminated with daminozide up to the legal limit, further inflating exposure.

- If daminozide is as potent as the EPA says it is, animals in the original 1966 test should have gotten cancer--which did not happen--and virtually all rocket fuel workers should have gotten cancer--which did not happen.

Uses ‘Minimal’ Measure

For these and other reasons, Uniroyal calculated the extra risk of cancer at about a “minimal” one in a million from daminozide, only 1% of the EPA’s calculation, and maybe even only one in 10 million.

At the scientific advisory panel hearing last September, Lapsley, of the EPA, defended the agency: “I think what they are bringing out is that it is very difficult to have a perfect study, and I am sure that any study that we look at will have some deficiencies; so what we have are five studies that, taken together here provide the weight-of-the evidence conclusion that I believe is compelling--that it is biologically active, and our comment on the (potency estimate) is that regardless of which of these studies were used” the number would be roughly similar.

The panel was unconvinced. Its formal report said that while the Eppley studies gave grounds for concern, “the data available are inadequate to perform a qualitative risk assessment” and “quantitative risk assessments cannot be appropriately carried out until adequate data become available.”

It took the EPA four months to decide what to do.

During that period, Steve Schatzow, then director of the office of pesticide programs, said: “My belief is we did not make as good a presentation as we could have. . . . We should have been more open in discussing the weaknesses of the data.

“I think the panel overreacted” to those weaknesses, he said.

Lapsley admitted that it would be difficult to proceed in the face of objections from the advisory group. But he added: “We’re talking about another four years to make a decision. Is it prudent to expose the public for another four years?”

Cites Major Problems

Lawrie Mott, of the Natural Resources Defense Council, which supports a ban, said: “I tend to agree that the studies have major problems and probably are not adequate for quantitative risk assessment. I disagree with the notion that we have to have reams of data” to decide that the chemical should be banned.

The EPA in January told Uniroyal that it could continue selling Alar pending new rat studies and new dietary exposure studies but that it had to reduce the application rate from four pounds per acre to three. The agency said it would establish lower tolerances for residues.

The agency said it had made “new exposure estimates using the actual percentage of crops treated with daminozide” and concluded that “exposure to daminozide will be only 10%-15% of the levels the agency used in issuing its notice of intent to propose the cancellation of this product.”

Mott and her colleagues had asked the EPA to establish zero tolerances for daminozide and UDMH.

The chemical’s chief benefits, the group wrote, are “to improve the cosmetic appearance of crops and promote ease of harvesting . . . . With consumer education, the public could learn to accept less than perfect-looking fruit.”

The scientific panel chairman, Hodgson, said daminozide is not an unusual case: “By the time something gets to the scientific advisory panel, it’s never an easy question. . . . These hard questions aren’t going to go away.”

And, the man who introduced it, Bohne, said: “It was embarrassing for the EPA people.” The agency should wait for the new studies and “if it’s a carcinogen, I’d say pull the damned stuff.”