Rep. Tom Marino of Pennsylvania. AP A joint investigation by The Washington Post and CBS's "60 Minutes" found that members of Congress alongside the pharmaceutical industry helped fuel the opioid crisis.

Drug distributors — the three biggest of which are Cardinal Health, AmerisourceBergen, and McKesson — are in charge of shipping drugs to pharmacies and hospitals around the US.

In recent years, the Drug Enforcement Administration has cracked down on distributors that send too many opioids to a particular location. The distributors then pay a fine and keep on doing business.

But in 2016, Congress passed a law that made it harder for the DEA to impose those fines, the investigation found.

"The drug industry, the manufacturers, wholesalers, distributors and chain drugstores, have an influence over Congress that has never been seen before," Joseph Rannazzisi, the former chief of the DEA's Office of Diversion Control, told The Post.

The Ensuring Patient Access and Effective Drug Enforcement Act aimed to improve enforcement around prescription-drug abuse and diversion. But it also raised the standard of proof that the DEA needed to crack down on a drug company's pain-pill distribution, making it more difficult for the agency to enforce fines against the companies.

The chief architect of the law, the investigation found, was Rep. Tom Marino of Pennsylvania, a Republican whom President Donald Trump nominated to lead the White House's Office of National Drug Control Policy, a position commonly referred to as the nation's "drug czar." Marino on Tuesday withdrew his name from consideration, Trump tweeted, adding that Marino was "a fine man and a great Congressman."

Marino introduced the bill in 2014, after which it went through two years of back-and-forth, delays, and opposition from the DEA. By the time it became law, neither the DEA nor the Justice Department objected to the bill, though the DEA had for years fought against it.

The Post called it "the crowning achievement of a multifaceted campaign by the drug industry to weaken aggressive DEA enforcement efforts against drug distribution companies that were supplying corrupt doctors and pharmacists who peddled narcotics to the black market."

Lobbying groups — including those representing drugmakers, retail pharmacies, and drug distributors — spent more than $102 million in support of the bill, The Post reported.

The report says the Pharmaceutical Research and Manufacturers of America, which represents drugmakers, spent more than $40 million lobbying for the bill, but the group says that is "unequivocally false."

A revolving door from DEA to industry

The joint investigation also found that top DEA officials often moved to the drug industry.

For example, Linden Barber, who was an associate chief counsel in the DEA, is now a senior vice president at Cardinal Health. Barber, who left the DEA in 2011 to work at a law firm representing drug companies, was key in crafting the bill Marino ushered through Congress, The Post reported, and he testified in favor of the legislation.

Barber wasn't the only one to move from government to industry — a move that former colleagues say troubles them.

"Some of the best and the brightest former DEA attorneys are now on the other side and know all of the weak points," Jonathan Novak, a former DEA attorney, told CBS. "Their fingerprints are on memos and policy and emails going out where you see this concoction of what they might argue in the future."

In response to the investigation, Democratic Sen. Claire McCaskill of Missouri introduced a bill on Monday aiming to repeal the 2016 law.

This post has been updated to include that Rep. Tom Marino has withdrawn his name from consideration for the drug czar position.