All it took to send the EPA’s draft assessment to the National Academy of Sciences for a review was for a congressman to slip one paragraph into in a 221-page spending bill. When Heath asked Simpson about the paragraph, he said he worried about small communities not being able to meet drinking water standards.

Such stealth maneuvers are not uncommon in Congress. A senator, for example, can anonymously put a hold on legislation, completely blocking it. Committee members can insert language written by lobbyists directly into a large spending bill before anyone has adequate time to review it. As Chellie Pingree, a Democrat from Maine, bemoaned to Center for Public Integrity reporter David Heath in June 2014: “It’s happening more and more in this Congress that we see less and less of what goes on behind the scenes, that members aren’t informed until the last minute. So things like this, major policy changes like this, can happen somewhat in the dark of the night with very little information to the public.”

When confronted by a reporter, Simpson said he didn’t know that the paragraph inserted into the spending bill kept a weed killer containing arsenic on the market, and he said he had “no idea” that Grizzle had donated to his campaigns.

Delays continued in subsequent years as industry-funded scientists presented their views to the Academy, sometimes without disclosing their financial ties. (The Center for Public Integrity reported that one such scientist suggested that an arsenic dose even higher than the current drinking water standard doesn’t cause cancer.) The result: in 2015, seven years after the EPA’s draft assessment that arsenic is considerably more dangerous than previously thought, many public health experts said the federal government was continuing to allow too much arsenic in our water and in products like weed killers.