The Dow Chemical Co. yesterday accused the Environmental Protection Agency of a "flagrant misuse of statistics" and "preconceived bias" in its ban of a controversial weed-killer last week.

Claiming that the herbicide 2,4,5-T is "a safe product," Dow president David Rooke told a press conference, "It's time to take a stand... I'm sick and tired of the chemical industry being picked out as the evil of mankind."

The press conference, which followed a lawsuit filed this week to overturn EPA's decision, is the latest incident in a battle that has raged over 2,4,5-T since it was used in Agent Orange to defoliate Vietnamese jungles in the late 1960s.

More than 500 Vietnam veterans have filed disability claims with the Veterans Administration, blaming 2,4,5-T for nervous disorders and cancer. Many have also filed suit against Dow.

EPA last week banned the use of the weed-killer in U.S. pasture, forests, and power-line rights of way where it has been used extensively to control brush. Uses on rangeland and rice fields were not affected. At the same time, the agency banned sylvex, a related chemical used in home gardens.

The agency cited more than 40 animal studies showing that the weedkillers cause birth defects, miscarriages and tumors in animals. It also revealed a new study showing a significant increase in miscarriages among women around Alsea, Ore., following following forest spraying over the last six years.

Joining in the Dow suit were the American Farm Bureau Federation, the Western Timber Association, the Asplundh Tree Expert Co. and Chevron Chemical Co. Dow is the principal manufacturer of both 2,4,5-T and sylvex.

Rooke acknowledged that 2,4,5-T accounts for less than 0.2 of one percent of Dow's annual sales -- $12 million out of $6 billion, and said the company has spent more defending the chemical than it has received in profits.

However, he added, "This is only one battle in a much larger war that can affect every product industry makes. If you can wipe a product with this much proven safety off the market, then what is safe?... There is a moral question: government abuse."

Rooke said Dow, which is known as the most militant of chemical companies, "believes in fighting. We hung in on napalm when it didn't mean anything to us business-wise. The government asked us to make it and we did. We believed in the principle."

Rooke was referring to the numerous demonstrations against the company during the Vietnam war because Dow manufactured napalm, a burning substance used in bombs.

Dow official Perry Gehring yesterday said EPA's Oregon study, conducted by Colorado State University and the University of Miami, was "flimsy" because the area compared with Alsea was too different in several ways. For instance, Alsea's population doubles in the summer, possibly accounting for the June peak in miscarriages, he said. EPA pesticides chief Ed Johnson said the agency counted only permanent residents.

Gehring asserted that the June peak was insignificant and that similar peaks occur in Miami and Midland, Mich., Dow's hometown. Johnson said the Miami data include induced abortions and were not comparable. Midland, he added, is "not a good example since it has a birth defects rate three times higher than the rest of Michigan."

Gehring said that, if 2,4,5-T were so dangerous, the explosion which released a cloud of a similar chemical in Seveso, Italy, in July 1977 would have produced a birth defects increase. Johnson cited a study showing a sevenfold birth defects increase after the incident.

Dow is "posturing," Johnson said. "EPA can't take things off the market without good cause. In this case we have sound evidence, in fact we have alarming evidence."

Johnson said the 2,4,5-T ban was ordered because EPA did not want to risk more miscarriages while cancellation proceedings, initiated last April, continue for another two years. Industry will not suffer by delaying the spraying until a final decision is made on the chemical, he said.

EPA carefully considers costs and benefits in deciding whether to ban chemicals, Johnson said. He cited three potentially cancer-causing pesticides the agency is allowing because the benefits are significant: pronamide on lettuce and alfalfa, chlorobenzilate on citrus, and bam on pears.

"We're not acting like a bunch of lunatics," he said. "We are trying to be objective about risks and benefits."

Environmentalists claim EPA has dragged its feet in banning pesticides -- fewer than a dozen out of hundreds of potentially dangerous ones have been taken off the market in the last decade.

"Its shocking that it has taken EPA this long to act on 2,4,5-T," said John Stauber, a Wisconsin activist who is part of the nationwide grass-roots lobby against 2,4,5-T. "They had plenty of information 10 years ago and they closed their eyes to it because of tremendous pressure from Dow."