A new law in Massachusetts, which goes into effect January 1, requires health care providers to use electronic health records that tie into a state system.

Lawmakers passed the law in 2012 and alloted five years to implement it. But with just days to go, some providers say there’s been little discussion about how it will work.

Joel Feinman, president of Valley Medical Group, said he wasn’t even aware of the law. But he said his practice, like many others, already relies on electronic health records.

What’s unclear is what the law means when it says records must be “fully interoperable” — in other words, integrated with a statewide health exchange.

“There’s a gap between what the legislature thinks needs to happen and what’s actually possible in the industry in any given moment,” Feinman said.

Feinman added that it’s also unclear how much of an electronic record can or should be available to the patient, which is another part of the new law.

In the past, the Massachusetts Medical Society (MMS), which represents doctors, has complained that the law’s January 2017 implementation was too soon, given the expense and complexity of coordinating health record systems.

“I don’t think it’s going to be easy at all, and it might be fairly expensive, and it might be prohibitively expensive for small practices,” said MMS President James Gessner.

But Gessner said he’s expecting state regulators to spend a few years ironing out the law, depending on the technology available.

A spokesman for the Massachusetts eHealth Institute (MeHI), a quasi-state agency, said regulations for the law are still being finalized. He referred further comment to the state’s Executive Office of Health and Human Services, which did not respond to a request for comment.

Correction: The final paragraph of this story was changed at 4:26 p.m. on December 27, 2016, to clarify which state agency is responsible for issuing the regulations. Further, the original post said MeHI “oversees health technology in the state,” which overstated its charge.