Massachusetts legislators are demanding that the Healey administration tighten its oversight of nursing homes, after a Boston Globe Spotlight report found that nearly one in five of the state’s homes had changed hands since the pandemic, many of them bought by out-of-state companies with poor records elsewhere.

The Globe report focused on Eli Mirlis, a New Jersey businessman whose RegalCare chain bought homes in Massachusetts even though he owned nursing homes in Connecticut with dismal quality ratings. Care at the RegalCare homes deteriorated almost immediately after he bought them, the Globe found, yet regulators allowed three more purchases in the last six months alone, in Sudbury, Whitinsville and Wakefield. The report also examined eight other out-of-state companies, mostly from New York and New Jersey.

Within hours of publication, the administration moved on the point that most angered lawmakers: its failure to put in effect a 2024 law giving the Department of Public Health broader power to investigate buyers’ out-of-state performance, finances and other records before granting licenses. Mr. Healey’s staff said on Monday that regulations carrying out the law would be adopted at last. The Public Health Council is scheduled to vote on the rules on Oct. 14.

Dr. Robbie Goldstein, the public health commissioner, acknowledged to the Globe that he had been aware of RegalCare’s poor performance even as it kept acquiring homes. But he said his powers were limited because state law did not expressly let regulators examine an applicant’s broader national record. The Globe’s review found that the department was never prohibited from looking at out-of-state records, and that it has not denied an application to buy a nursing home in at least seven years.

Gov. Maura Healey, in an interview with the Globe on Wednesday, stood by her commissioner. “I have total confidence in Commissioner Goldstein in this moment, in particular, where healthcare is being ripped away from millions of Americans,” she said after an event at MIT. “We are so fortunate to have Robbie Goldstein here in Massachusetts to protect people.”

Senator Patricia Jehlen is requesting a meeting with Dr. Goldstein about the oversight. Representative Marjorie Decker, a Cambridge Democrat who chairs the Joint Committee on Public Health, said she was sending him a letter with a long list of questions about why the department never used the legal tools it already had. “If it’s not private equity, are we clearly looking at these owners who are using these acquisitions to extract more money?” she said. All nine chains the Globe examined reported on federal disclosures that they had no private-equity backing.

“We have predatory providers who are fleecing the public purse and providing unacceptable care to the residents living in their facilities,” said Senator Julian Cyr, a Provincetown Democrat who co-sponsored the 2024 law. Representative Thomas Stanley, a Waltham Democrat and the law’s other sponsor, said regulators had been given “all sorts of tools” but showed “a lack of urgency” in using them.

Mike Minogue, the Republican nominee for governor and former chief executive of Abiomed, a medical device company, called the report more evidence of what he termed Ms. Healey’s “failed leadership” and said outside auditors should police the health department if he is elected. “We can get rid of the people that are the bad actors, that are costing us more money, wasting our tax dollars, and most important, not giving great care to our vulnerable older people,” he said in an interview.

Mr. Mirlis did not respond to most of the Globe’s questions, including evidence that he fabricated educational credentials, and would not discuss his finances beyond denying he had private-equity funding. He said RegalCare strives for the highest level of care and works with the health department to correct problems. The Spotlight findings are detailed in two earlier reports on the buying spree and on RegalCare’s rise in Massachusetts.