A biennial tradition: Beacon Hill lawmakers’ mad scramble

David L. Ryan/Globe Staff/File

They chould change what you pay for an Airbnb. They could alter the state’s health care industry. And they could add requirements for high school students and thousands of people to Massachusetts’ voter rolls. They even might have something to say about protecting animals.

State lawmakers have less than 10 days left to finish major business this year, and they face a big to-do list before wrapping up their formal session.

Welcome to the Beacon Hill scramble!

It’s the biennial mad dash in which the state’s full-time Legislature has to debate, horse-trade, and reconcile priorities it has had a year and a half to work on, all before the clock strikes midnight July 31.

It’s on that date — in the second year of every two-year session — that the chambers’ joint rules dictate lawmakers finish all “formal business.” That deadline is approaching quickly, meaning lawmakers again find themselves staring down a mountain of legislation that, if signed by Governor Charlie Baker, could touch almost all of the state’s 6.9 million residents in one way or another.

The Legislature now has 10 closed-door conference committees, each staffed with three senators and three representatives, trying to harmonize similar bills their respective chambers passed. Their collective to-do list includes:

■  Ironing out differences in how to tax short-term rentals booked through such services as Airbnb. The Senate wants to uniformly apply the state’s 5.7 percent hotel tax to short-term rentals, while the House voted to establish a three-tiered tax rate.

■  Reaching consensus on two disparate — and controversial — health care bills, one of which (from the House) would apply $330 million in new assessments on insurers and large hospitals to funnel money toward community hospitals. The other (from the Senate) would set a “rate floor” for insurance payments to help the hospitals.

■  Negotiating a bill meant to enhance civics education. It is not nearly as contentious, but even it has differences: The Senate bill mandates a civics project for high school graduation, while the House bill would leave it up to individual school districts.

On top of those issues, legislators would also need to consider a bill to protect animals from abuse, another that authorizes roughly $2 billion in environmental spending via a bond bill, and legislation that would implement automatic voter registration and join Massachusetts with 13 other states that have passed or put in place similar measures.

Lawmakers are also trying to finalize energy legislation, a $666 million economic development bill that cleared the House just this month and was the subject of a Senate hearing last week, and sweeping opioid legislation that passed the House and just cleared the Senate on Thursday.

Buttoning up what, in some cases, are hugely complicated pieces of legislation is no small task — and some things may end up on the cutting-room floor.

“Making good policy is challenging under the best of circumstances,” said Eileen McAnneny, president of the business-backed Massachusetts Tax-payers Foundation. “Waiting until the last minute to finalize several important policy matters can lead to unintended consequences with far-reaching implications for the public.”

The end-of-session logjam isn’t a new phenomenon. Elected officials often cram an array of lawmaking into late-night and weekend sessions as July inches toward a close every two years.

But this year carries differences. The Senate also plans to finalize a transfer of power, with Senator Karen E. Spilka, its budget chief, scheduled to officially take the gavel from current Senate President Harriette L. Chandler on Thursday, months after she claimed sufficient votes to be the body’s next president.

Lawmakers were also tardy in sewing up this year’s $42 billion budget plan — no other state legislative body was later, in fact — raising concerns, including for Baker, that the delays chewed up time that could have been spent working on other priorities. (Baker this month also filed a separate, supplemental budget proposal, including more funds for school safety.)

“They have a lot of work to do,” Baker said. “There’s a big opportunity cost there.”

The largest and perhaps most important piece of legislation passed every year, the budget proposal, landed in Baker’s hands on Wednesday, 17 days after the current fiscal year started and with dozens of new policy proposals.

He has until Saturday to act on it, and, if history is a guide, he will likely sign it while vetoing a number of line items. That, too, will create more work for the Legislature, which typically has scrambled in the session’s final days to override many of the governor’s changes and insert them back into the final version of the budget.

That’s not to say Baker’s desk isn’t also crowded. As of Friday, he had 17 bills awaiting his signature, covering matters as small as a Holliston liquor license and as sweeping as raising the statewide minimum age to buy tobacco to 21.

There’s also a bill that would create a $2 fee on rental car transactions to help fund police training — a goal Baker signaled he supports but through a means that would run counter to his campaign pledge of no new fees.

“You can almost put it on your calendar that the last two weeks you have to be ready every day,” said Steven C. Panagiotakos, a former Senate budget chief and a current lobbyist. “It’s the nature of the institution now.”

But amid all the question marks about what will and won’t pass, one thing is almost certain.

“They will be at it at midnight on July 31,” Panagiotakos said.