Demetra Ashley, acting assistant administrator of the Drug Enforcement Administration, testifies before the Senate Judiciary Committee that the Ensuring Patient Access and Effective Drug Enforcement Act should be revised. (Melina Mara/Washington D.C.)

The head of the Drug Enforcement Administration office that regulates pharmaceutical opioids told senators Tuesday that a 2016 law has made enforcement more difficult in urgent circumstances and should be revised.

Demetra Ashley, who leads the agency's Diversion Control Division, said Congress should choose between repealing and amending the law. But she said the DEA agrees with the Justice Department that it should be altered to help curb the ongoing opioid epidemic.

Since passage of the law, Ashley said, DEA investigators have faced a greater challenge showing that a company's conduct poses an immediate danger of death or harm to shut down shipments of painkillers from a distributor to a pharmacy. That burden has moved the agency away from its traditional posture of preventing harm, she said.

"The DEA, along with the Department of Justice, believes that has to change," she said.

During an oversight hearing, Ashley told members of the Senate Judiciary Committee that the agency continues to do its job, relying on tools other than the "immediate suspension orders" reserved for the most egregious cases.

Those tools include forcing doctors, pharmacists and others to surrender their DEA licenses, bringing them to hearings and seeking civil penalties.

Senators broke down largely — but not completely — along party lines about whether changes are needed. "In my view, this bill has done harm," said Sen. Dianne Feinstein (Calif.), the committee's ranking Democrat. "It seems to me that we should look very closely at repeal."

But Sen. Orrin G. Hatch (R-Utah), who led negotiations over the law in the Senate, was openly skeptical of what he called a rush to "rewrite history" in the wake of reports by The Washington Post and "60 Minutes" that highlighted the legislation's effect.

"This wasn't some effort to help drug companies kill people. Give me a break," Hatch said. "This was an effort to ensure that DEA's efforts . . . didn't end up hurting legitimate patients."

The Post and "60 Minutes" reported in October that a small group of lawmakers allied with drug companies pushed the Ensuring Patient Access and Effective Drug Enforcement Act through Congress. The measure curbed the DEA's powers to use its most potent weapons against drug companies that do not report suspicious orders of prescription painkillers from pharmacies.

The reports revealed that an early version of the legislation was written by a drug company lawyer and shepherded through Congress by Rep. Tom Marino (R-Pa.) in the House and Hatch in the Senate.

By amending the Controlled Substances Act of 1970, the new law made it almost impossible for the DEA to use immediate suspension orders against drug distributors, according to a law review article written by the DEA's chief administrative law judge.

The orders had allowed the DEA to instantly stop shipments of controlled substances to drugstores suspected of diverting prescription narcotics to the black market. Another provision of the new law allows companies to submit "corrective action plans" that the DEA must consider before bringing sanctions.

Ashley called that provision "redundant and unnecessary" because the DEA holds lengthy discussions with drug distributors before it decides to penalize them.

Hatch and others, however, have said the law does not weaken the DEA, noting that it was passed by unanimous consent in both houses of Congress and signed by President Barack Obama.

Some lawmakers and officials in the Obama White House said they were not made aware of the legislation's import before they approved it. Overdoses of prescription drugs killed nearly 200,000 people between 2000 and 2016.

Two days after the reports, Marino withdrew his nomination to become the nation's drug czar. Since then, Democratic lawmakers, 44 state attorneys general and U.S. Attorney General Jeff Sessions have called for repealing or amending the law to restore some of the DEA's authority.

On Tuesday, one of those attorneys general, Brian E. Frosh of Maryland, told the panel that the new law "handcuffs" the DEA. Challenged by Hatch to offer data to support that assertion, Frosh acknowledged that it is too early to prove the law's impact numerically.

But he said that Republican and Democratic attorneys general had analyzed the new standard for immediate suspension orders and found that the DEA must now meet an "extraordinarily" high threshold to use that tool.

"Any lawyer can tell you it makes a big difference," Frosh said.

Hatch, committee Chairman Charles E. Grassley (R-Iowa) and others pointed to a sharp drop in immediate suspension orders between fiscal 2011 and 2015 as proof that the 2016 law could not be responsible for loss of that authority.

However, The Post and "60 Minutes" reported that the decline stemmed from a separate, voluntary slowdown in the use of immediate suspension orders by DEA attorneys, who imposed a strict new standard of proof on investigators during that period, even as the opioid crisis mushroomed.