The Environmental Defense Fund and E.I. du Pont deNemours Inc. have hardly been close political allies in Virginia.

The fund's clamor over mercury contamination from a Du Pont plant fueled the push for a $1.98 million settlement by the chemical giant. Yet state officials say that an alliance between an official of the fund in Virginia and a Du Pont executive was key to the recent appointment of that Du Pont executive, Richard L. Cook, 55, to the state's top environmental post.

As deputy secretary of commerce and resources, Cook, who managed health and environmental affairs at a Du Pont plant near Richmond, will guide Virginia's environmental policy while maintaining ties to the chemical company under an unsual appointment by Gov Charles S. Robb. While earning $65,000 a year in the state job, Cook will be permitted to receive health, dental and insurance benefits from Du Pont, where he will return to work after a year in state government.

The arrangement raised complaints from national environmental groups, but none from similar groups in Virginia, including those whose officials have tangled with the chemical industry. The Virginians have nothing but praise for Cook.

"I think it's really terrific that the administration has been able to get someone of his caliber," said David S. Bailey, director of the Virginia office of the Environmental Defense Fund.

"I don't see any problems there in terms of a conflict of interest," said Timothy G. Hayes, the former director of the Environmental Fund's Virginia office. "It may be I trust Dick implictly and I know him well."

"He's got integrity. He shoots straight," said Gerald P. McCarthy, executive director of the Virginia Environmental Endowment. "He's a real joy to work with."

"Obviously, we'd love to get someone with an environmental background," said Bud Watson, staff attorney for the Virginia office of the Chesapeake Bay Foundation. "But I think it's unrealistic to think that would happen in Virginia at this point. Virginia traditionally has had a very proindustry leaning. It's simply a fact of life in Virginia."

"I feel very strongly that people in industry should share what they can with the state," said Cook. He said he will avoid issues in which Du Pont has been active. He said he plans to concentrate on such projects as the Chesapeake Bay.

For some Virginia environmentalists, their association with Cook began after a chance meeting between Cook and the fund's Hayes four years ago. Both were attending a conference on hazardous wastes.

Hayes said he noticed Cook because he was one of the few other Virginians and one of the few industry people there. "A lot of local environmental activists sort of got on his case," said Hayes.

Hayes and Cook went to dinner that night and talked about the "almost automatic" antagonism between industry and environmentalists. The Virginia Toxic Roundtable evolved out of those and other discussions.

"We realized that industry and environmentalists have a lot of common goals," said Cook.

In the roundtable, environmentalists and industry attempt to find solutions to waste problems, avoiding court battles.

Cook and other roundtable participants rallied the chemical industry to comply with state waste management reporting requirements, after the fund threatened to go to court. Many firms in the state said they were unaware that the state regulations were in force, because similar federal rules had been suspended.

Hayes, who left the fund in August to join the Alexandria law firm of Thomas and Fiske, said that before he and Cook formed the roundtable, "industry just assumed that environmental groups were the enemy."