Tobacco industry whistleblower Jeffrey Wigand conceded some “technical inaccuracies” in prior testimony but insisted cigarette makers had knowingly produced an unsafe product as he testified on Monday in the government’s $280 billion racketeering suit.

Wigand, chief scientist at Brown & Williamson from 1989 to 1993, said some of his testimony in earlier lawsuits was “technically inaccurate” in describing chemicals he charges were used to flavor tobacco or enhance the effects of nicotine.

In written testimony for the government case, Wigand said Brown & Williamson executives often acknowledged they were in the “nicotine delivery business” and discussed plans to develop a high-nicotine tobacco.

Brown & Williamson lawyer David Bernick tried to discredit Wigand’s testimony, repeatedly questioning him about whether he gave false testimony in the past.

“It may have been in some ways technically misleading,” said Wigand, who first went public with allegations about industry wrongdoing in a 1995 CBS interview. “I don’t believe it was false,” he told U.S. District Judge Gladys Kessler.

Brown & Williamson was bought by R.J. Reynolds last year from British American Tobacco Plc.

The U.S. government suit, filed in 1999, targets Altria Group Inc. and its Philip Morris unit; Loews’ Lorillard Tobacco unit, which has a tracking stock, Carolina Group; Vector Group Ltd.‘s Liggett Group; Reynolds American Inc.‘s R.J. Reynolds Tobacco; and British American Tobacco Plc unit British American Tobacco Investments Ltd.

The Justice Department wants the industry to give up $280 billion in past profits and is seeking tougher rules on marketing, advertising and warnings on tobacco products.

Tobacco companies deny they conspired to promote smoking and say the government has no grounds to pursue them after they drastically changed marketing practices as part of a 1998 settlement with state attorneys general.

Bernick played two video clips of Wigand’s taped depositions in a 1995 trial in Mississippi.

In one clip, Wigand was asked if rat poison was found in cigarettes. He answered “yes,” saying that coumarin, an ingredient in some tobaccos, was also in rat poison.

But Wigand on Monday said that he should have testified that a related compound, coumadin, was found in rat poison.

The second clip showed Wigand testifying that acetaldehyde was added to Sir Walter Raleigh Aromatic Pipe Tobacco.

On the stand Monday, Wigand said while acetaldehyde was not a “direct additive,” the tobacco companies knowingly added sugars that turned into the chemical when burned. Acetaldehyde can enhance tobacco flavor, he said, but it also can increase nicotine’s effect on the brain.

Wigand said he agreed to go to work for Brown & Williamson in part because officials told him he would help to design a less toxic cigarette.

But the firm refused to research possible safer cigarettes in the United States because findings could be subject to lawsuit investigations and could imply “that ‘safer’ meant everything else was unsafe,” he said in court on Monday.

Wigand’s story was chronicled in the movie “The Insider.” He runs a non-profit group called Smoke-free Kids and delivers anti-tobacco speeches.