For years, DuPont steadfastly maintained that its fungicide Benlate was not contaminated with an herbicide. In the early 1990s, the chemical giant began settling cases, without admitting guilt and for relatively small sums, that had been brought by growers around the country who claimed that the fungicide designed to protect their plants had instead killed them.

It appeared that litigation over Benlate was winding down. But in 1994, a San Francisco attorney made a startling discovery. That discovery has resulted in scores of Benlate-related suits creeping back onto court dockets, has raised the ante by several million dollars, and may blow up the previously reached settlements.