Seven Democratic U.S. senators on Thursday introduced legislation designed to slow the “revolving door” between federal agencies such as the Drug Enforcement Administration and the pharmaceutical companies they regulate.

“The pharmaceutical industry has a deep-rooted and strong influence in Washington, and a revolving door between drug companies and government cannot undermine the safety of our communities,” said Sen. Tammy Baldwin (D-Wis.), who sponsored the bill.

The legislation would impose a two-year “cooling off” period on former officials from the DEA and the Food and Drug Administration, barring them from assisting pharmaceutical companies with lobbying efforts.

The bill also expands the definition of “lobbying contact” to include taking part in activities such as strategy sessions. And it limits the issues pharmaceutical industry officials can handle if they join the federal government.

It is not unusual for corporations to hire federal employees directly from the government, nor for industry officials to join the government in high-ranking positions. Industry representatives say the pharmaceutical industry is highly specialized, and they rely upon the expertise of former government officials to help them comply with complex drug laws.

There are regulations designed to prevent potential conflicts of interest.

The current restrictions include a lifetime ban on participating “personally and substantially” on a “particular matter” that the official had handled while working for the federal government.

Government ethics experts say some of those laws are easily skirted.

“The bill could go further, but this is a nice step toward slowing the revolving door that is responsible for steering public policy in favor of the drug companies and distributors rather than in the favor of the public,” said Scott Amey, general counsel for the Project on Government Oversight, a Washington watchdog group.

The proposed legislation follows a joint Washington Post/“60 Minutes” investigation into the opioid industry and its influence in Washington. Companies that manufacture or distribute highly addictive pain pills have hired dozens of high-ranking officials from the DEA during the past decade, many of them from a division that regulates some of the same companies.

A decade ago, DEA investigators began to crack down on large drug companies they suspected of failing to report unusually large orders of painkillers, many of which were winding up in the hands of street dealers and users. Since then, drug companies and the law firms that represent them have hired at least 46 DEA officials — 32 of them directly from the agency’s division that regulates the industry.

One of those DEA officials left the agency and formed a law practice to represent opioid companies. He later helped to write a law that undercut the agency’s enforcement efforts against large companies accused of violating federal drug laws, according to government documents and a legal analysis of the law by the DEA’s chief administrative judge.

Rep. Tom Marino (R-Pa.) introduced the legislation in the House and collected nearly $100,000 from political action committees representing drug companies. In the Senate, the law’s primary sponsor was Sen. Orrin G. Hatch (R-Utah), who negotiated a final version with DEA and Justice Department officials.

In the wake of the Oct. 15 Post/“60 Minutes” investigation, Marino withdrew his nomination to be the nation’s drug czar under the Trump administration.

Several co-sponsors of the Marino bill have since come under fire from their constituents and political opponents for backing the measure at the height of the nation’s worst drug crisis. The prescription drug epidemic has claimed nearly 200,000 lives, more than three times the number of U.S. military deaths in the Vietnam War.

Baldwin said her proposed legislation would serve as a check on the power the pharmaceutical industry wields on Capitol Hill. She cited an investigation by the Associated Press and the Center for Public Integrity that found that the makers of prescription painkillers spent $880 million on campaign contributions and lobbying efforts between 2006 and 2015.

The bill is co-sponsored by Sens. Dianne Feinstein (Calif.), Kamala D. Harris (Calif.), Edward J. Markey (Mass.), Maggie Hassan (N.H.), Jeanne Shaheen (N.H.) and Tom Udall (N.M.) Baldwin said she plans to seek out Republican co-sponsors.

“Patients, families and the public need to have trust that the DEA and FDA are working for them, not powerful Washington interests,” Baldwin said.