Environmental Close-Up: The Alar Controversy
In 1989, U.S. consumers experienced a public-health scare concerning the pesticide Alar (daminozide), a plant growth regulator that was used on apples to postpone fruit drop, enhance the fruit’s color and shape, and extend storage life. The scare was raised by several scientists and covered extensively by the media.
The public was alarmed to the point of panic. Worried mothers dumped apple juice down the drain, despite EPA’s repeated assurances that such measures were unnecessary. Apples were banished from school cafeterias. With each new event reported by the media, consumers were further unsettled and confused as points of disagreement between the EPA and outside groups were raised on the risks of Alar.
The initial panic concerning Alar has subsided somewhat, but an uneasy confusion remains, and consumers have been left with a lingering doubt about the safety of their food. In general, the public has limited patience with extended deliberations by scientists and regulators over a chemical’s potential harmful effects. While scientists and regulatory officials are concerned with questions of scientific uncertainty and statistical risk assessment, consumers, who generally do not speak the language of risk assessment, tend to ask very direct questions: Is it safe to eat apples? Is it safe for my child to consume apple products? Does Alar cause cancer?
Two questions are implicit in the questions: Does Alar cause cancer? First, is Alar a known human carcinogen? The answer is no; scientists do not have direct evidence in humans that traces actual cancer cases to Alar exposure. In fact, comparatively few chemicals in the world have been demonstrated beyond doubt, on the basis of epidemiological data, to cause cancer in humans.
Second, does Alar cause cancer in laboratory animals? The answer is yes; Alar and its breakdown product, called unsymmetrical dimethylhydrazine (UDMH), have increased the incidence of malignant tumors in mice.
It is difficult to understand cancer risks, or any kind of risk, without a meaningful frame of reference. For perspective, one of the key phrases consumers should keep in mind in the Alar case, and generally in cases of chemicals said to pose cancer risks, is “long term.” In evaluating the risks of pesticides to consumers, the EPA uses the working assumption that dietary exposure to the pesticide occurs over a lifetime (70 years). This is just one of many assumptions that the EPA factors into its chemical risk analysis.
The truth, however, is that hard evidence on the effects of pesticides is generally limited to cases where short-term, highly concentrated exposure has caused acute toxic poisoning in humans or killed important nontarget organisms in significant numbers. Such acute toxic effects are immediately apparent.
Most risk scenarios are not so easy to access, and this is especially true of chronic or delayed health effects, such as cancer, reproductive dysfunctions, or effects on the newborn. Such chronic or delayed effects do not become apparent for a long time, and when they do occur, it is almost always impossible to trace them with certainty to exposures to specific chemicals. Instead, the evidence at hand consists of the raw materials of risk assessment: animal data tabulations, cancer potency estimates based on animal study results, food consumption statistics, and exposure estimates. As the Alar case demonstrated, such data may be used selectively and inappropriately to make calculations that misrepresent pesticide risks.
Consumer education and risk communication will become increasingly necessary if pesticide decision making is to take place in an atmosphere that is relatively free of fear, confusion, and unnecessary economic disruption.