(Updated 12:19 p.m.) Connecticut’s largest teachers’ union launched a new television advertisement Friday criticizing Gov. Dannel P. Malloy’s education bill.

The ad, paid for by the Connecticut Education Association, calls Malloy’s reform bill “a bad science experiment.”

The narrator goes on to say Malloy’s bill includes “Unproven ideas backed by special interests. Taking tax dollars away from our neighborhood schools. It’s sure to explode.”

The ad says that the legislature’s Education Committee, which changed portions of Malloy’s bill on March 26, “is getting it right and moving reform forward.”

The committee bill postponed for one year Malloy’s effort to tie a new teacher evaluation system to tenure.

“With roughly four weeks left in the legislative session, the stakes could not be higher,” CEA President Phil Apruzzese said in a press release. “There are enormous consequences to our children’s future, and decisions will determine the path of educational and economic opportunity in our state.”

Malloy seems to agree the stakes are high but he made it very clear Thursday that he won’t be supporting the bill approved by the legislature’s Education Committee. Malloy told two dozen local elected officials not to count on the $39.5 million in additional education funding for their districts if he can’t reach a compromise with the legislature.

“I think this money is very much in the lurch until we have an educational bill we can agree on,” Malloy said Thursday.

Since March 26, the day the Education Committee voted on its revised bill, Malloy’s administration and the two teachers’ unions haven’t spoken. The unions had been at the table, but Malloy canceled two previously scheduled meetings with union representatives after the committee voted on the revised bill.

The unions and their representatives have been speaking with legislative leaders, who are informally speaking with the governor about how to move forward.

Roy Occhiogrosso, Malloy’s senior communications adviser, said that when teachers hear what is actually in the proposal they’re supportive.

“The problem’s been that the leadership of CEA hasn’t been trying to represent teachers; they’ve been representing themselves,” Occhiogrosso said. “They’ve consistently misinformed their members because they’re afraid if teachers learn what’s actually in the governor’s package, they’ll be supportive.”

Occhiogrosso said it’s ironic because “many of the ideas came from CEA itself.”

“People should read the brochure they put out (A View from the Classroom) — you know, the one in which they said they believe Connecticut should ‘end tenure as we know it’ (page 13), and the one in which they urge the Legislature to pass a bill implementing the evaluation system they themselves agreed to (page 11). For reasons only they understand, the leadership of CEA is defending a status quo that is indefensible to everyone . . . except them,” he concluded.

In the meantime, Mary Loftus Levine, executive director of the CEA, said they will continue to broaden public awareness of Malloy’s “damaging” proposals.

“Too many are unproven and untested — notions that will ultimately hurt, not help, our children to succeed and close the achievement gap,” she said.