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.