Pesticide Ban Urged; Firm Partly Agrees

WASHINGTON — Environmental groups Wednesday urged that a pesticide widely used on cotton crops be banned as a potential cause of cancer in humans. And, in an unusual turn, a leading producer has agreed that its pesticide should be prohibited under some circumstances.

A report published by the Natural Resources Defense Council said that animal tests dating from the mid-1970s show “conclusively” that the insecticide chlordimeform is a carcinogen and should be banned from manufacture and sale worldwide.

Coalition Joins in Call

The resources council was joined in its call by the Pesticide Action Network, which describes itself as a coalition of 300 public interest groups in the United States and abroad.

An estimated 500,000 pounds of chlordimeform are used annually in the United States, including 34,000 pounds--a relatively small amount--sprayed on California cotton fields in 1984, the last year for which figures are available.

The U.S. manufacturer, the Ciba-Geigy Corp., said that declining sales in California recently led it to withdraw the pesticide from that state’s market, although it is still widely used in other cotton states against bollworm and tobacco budworm.

Peril Acknowledged

In a letter to the coalition commenting on the resource council’s report, Ciba-Geigy Corp., which is based in Switzerland, acknowledged that the insecticide is “potentially hazardous,” but only to workers who fail to follow instructions for its use, which include donning protective clothing and goggles.

Douglas G. McKinney, of the Environmental Protection Agency’s Office of Pesticide Programs, said he expects the agency to issue a “proposed decision,” or tentative conclusion, on the need for further restrictions on the pesticide this spring. But he said no final action on chlordimeform is likely until next year.

The environmental scientist who prepared the resource council’s report on chlordimeform said that it was made possible by an unusual degree of cooperation from Ciba-Geigy. Dr. A. Karim Ahmed said in a telephone interview from New York that the company’s agricultural chemicals division in Greensboro, N.C., gave him free access to its unpublished studies of the pesticide’s effects on laboratory animals, which he said showed that it is “clearly a potential human carcinogen.”

In its letter, the company said that it agreed to cooperate with environmental groups seeking to ban its product in the hope that the two sides’ differences could be eliminated.

Rare Tumors Produced

Ahmed said the company’s data shows that tests carried out from 1976 to 1978 produced unusual numbers of a rare malignant tumor called a hemangioendothelioma in the blood vessels of two strains of laboratory mice fed large amounts of the pesticide and one of its breakdown products.