The Dow Chemical Co. announced yesterday that it will spend $3 million on independent studies to show what it already believes--that there is no danger to humans from trace levels of dioxins, poisonous byproducts of the production of some chemicals.

President Paul F. Oreffice, presiding at a heavily attended briefing in the Dow headquarters television studio, conceded that the program is aimed as much at quieting public fears as it is in producing new science.

"Our perspectives and judgments about the dioxin controversy remain unchanged," Oreffice said. "What has changed is that with all the publicity dioxin has received, the general public cannot be expected to take our word for it without corroboration. We invite and are encouraging third-party evaluation and verification of our own scientific conclusions."

Dow in recent months has been at the center of an outcry in Michigan and other parts of the country over the health effects of dioxins, compounds highly toxic to laboratory animals.

Dow's Agent Orange, a jungle defoliant used in Vietnam, and 2,4,5-T, a herbicide no longer manufactured here, generated dioxin as a byproduct. Both are the subject of potentially expensive litigation seeking to hold the company liable for health impairment allegedly caused by its products.

Oreffice and other Dow officials have maintained consistently that there is no health threat from dioxins, and have rejected allegations that the company has poisoned the soil around Midland and the water of the Tittabawassee River with its industrial processes.

Yesterday's news conference, which drew print and electronic media reporters from across the country, was part of an intensified Dow public relations campaign to allay public fears about its products and to counter charges of secrecy and corporate arrogance.

Oreffice complained that "fame breeds fame, and the spotlight on dioxin in Midland has attracted a steady stream of reporters, camera crews, government officials and others . . . . Sometimes we have been asked questions for which there are no absolute answers. For this we have been accused of equivocation or talking out of both sides of our mouth.

"When we respond unequivocally, we are accused of arrogance or self-righteousness. I guess we can accept these accusations. But what we cannot and will not accept is the level of anxiety and concern the publicity surrounding this issue has generated in the country, in this state, and for some in this community.

"We believe we have come up with an approach for addressing the understandably human concerns that people throughout the state and perhaps nationally are feeling about dioxin in Michigan."

Oreffice said Dow's $3 million investment will cover these elements:

A state and federal study of soil contamination inside the plant, in the city of Midland and other sites; an investigation of dioxin sources inside the plant; a state study of soft tissue cancer, which in Midland County exceeds national averages, and a University of Michigan research study on ways to reduce dioxin in the Dow waste water effluent stream.

Expansion of Dow's analytical laboratory, doubling its ability to detect dioxin in the regional environment, and a study by an independent scientific organization that Oreffice declined to identify to determine if trace amounts of dioxin pose a health hazard to humans.

Oreffice said he believed Dow's effort, to be completed within two years, will help answer concerns about the perils of dioxin. And he also said that Dow supports the proposed $12 million national dioxin study by the Environmental Protection Agency.

The company president, however, indicated he expected no surprises as a result of Dow's investment. He said he anticipated the studies would show "that all our science is correct and that there is no danger . . . . We will accept the results."

The company announcement was greeted skeptically by at least one of Dow's local critics. Environmentalist Andrea K. Wilson said, "I'm glad there will be more studies but we'd like to be assured there will be independent third-party review of the findings. We're thinking this may be an attempt to defuse our request for a full scale EPA investigation . . . .All of Dow's focus is on the dioxin, but there are real serious concerns here about other environmental and public health issues."