In December, the Tribune revealed that the EPA approved Enlist Duo after the agency tossed aside evidence of kidney problems that Dow's own researchers said were caused by 2,4-D. Regulators ultimately decided that Dow — a company with a $1 billion product at stake — had been overly cautious in flagging those abnormalities. That cleared the way for the EPA to allow 41 times more 2,4-D into the American diet than was previously considered safe.