A coalition of Connecticut Democrats, including Gov. Ned Lamont and top legislative leaders, announced Thursday they have reached consensus on legislation that could lead to a public health insurance option for people and small businesses by 2022.

Called the "Connecticut Option," premiums for the yet-to-be designed plan are expected to cost 20% less than current average market premium costs, according to proponents. The wide-ranging bill also includes other components aimed at driving down the price of insurance and expanding access to health coverage.

"This is a problem of great magnitude, not just in our state, but in this entire country," said Democratic Rep. Sean Scanlon, of Guilford, referring to the high cost of health insurance. "And today, we are taking a very bold step toward a transformational bill that will change the lives of Connecticut residents."

Connecticut-based insurers, a key industry in the state, immediately voiced their opposition to the bill, predicting it puts Connecticut on the path toward government-run health insurance.

"As the Insurance Capital of the World, we should be embracing the growth of the health plan jobs here," said Susan Halprin, head of the Association of Connecticut Health Plans. She urged the General Assembly to instead examine "all cost drivers" in the health care system when trying to reduce rates.

Lawmakers in at least eight other states have proposed their own public option measures this year. Earlier this month, Washington Gov. Jay Inslee, a Democrat, signed a bill putting his state on track to create the first public option health insurance program in the country, using a hybrid system where private insurers would offer state-defined plans.

Democratic Sen. Matt Lesser of Middletown, however, said Connecticut's wide-ranging bill would be the "most ambitious" health care bill proposed by any state this year. Besides the Connecticut Option, which would be designed partly by the state's Office of Health Strategy and offered by private health insurers both inside and outside the state's health insurance exchange, the bill seeks federal permission to import lower-cost prescription drugs from Canada.

It also reinstates Medicaid coverage for 26,000 parents that was cut in 2016; restores on a statewide basis a program under the federal Affordable Care Act designed to stabilize insurance rates; and provides subsidies to people currently ineligible for premium relief.

There's also a plan to closely monitor health care spending growth in the state, a move proponents hope will help curb prices.

To pay for all these things, the bill calls for reinstating the ACA's "individual mandate" a financial penalty for those who choose not to buy health insurance. It also imposes a tax on prescription opioid manufacturers and a surcharge paid by insurance companies.

News of the bill took Republicans, the minority party in the General Assembly, by surprise. It comes about two weeks before the June 5 legislative adjournment deadline. Senate Republican Leader Len Fasano, of North Haven, said unveiling such a wide-ranging bill so late in the session was an example of the Democrats' arrogance. The party now holds a stronger majority in the General Assembly compared with last year.

"Not once, not once, had the Republicans even known this was going on or that a bill of this magnitude was being discussed," he said. "We found out from lobbyists last night."

Fasano questioned how there will be enough time to vote on such a consequential bill that "hasn't had one day of sunlight," noting there hasn't been a public hearing devoted to the proposal, which originated as a proposal to allow people to receive coverage through the state employee health insurance program.

Scanlon said he's hopeful lawmakers might vote on the bill sometime next week, after the Memorial Day holiday weekend.