The city is spending in excess of $40 million on health care and other benefits for teachers and school administrators, according to a New Haven alder who called the practice, undisclosed in the city budget, unlawful.

Michael Stratton, alder for Prospect Hill and Newhallville, leveled that charge in a letter sent Wednesday to the city controller, on which he copied Mayor Toni Harp, the city’s top attorney and the superintendent of schools. In addition to the $18.3 million budgeted for the school district in the current fiscal year — slated to rise by $1.5 million under Harp’s proposed 2014-’15 budget — the city is also doling out millions of dollars for health care and workers’ compensation, as well as debt service and other functions (such as legal representation) for which the Board of Education should be paying, Stratton said.

If those contributions are being made, they are not enumerated in the city budget, which lists the line item for $65.9 million in city-funded health benefits under a “Non-Education” category.

“Someone should go to jail over this,” Stratton said Thursday. “There’s no legal permission to give anything more than the $18.3 million that’s been budgeted. It’s illegal for a mayor or her department heads to be handing over money or paying bills that haven’t been approved by law or allocated by the democratic process.”

Stratton claims the city has forked over between $40 and $100 million to the Board of Education unbeknownst to city residents and lawmakers for the past decade or more. Included in the city’s general expenditures for health benefits — and potentially workers’ compensation and debt service, as well — are specific sums of money instead going to the Board of Education, he said.

Stratton did not blame Harp, who assumed office Jan. 1, but instead accused former Mayor John DeStefano Jr. and former NHPS Superintendent Reginald Mayo of concealing the extra contribution during their simultaneous 20-year tenures at the helm of the city and the school district.

“When I discovered this, I called [Board of Alders President] Jorge Perez, and he said ‘Ah well many, many years ago, Reggie Mayo and DeStefano decided to put that health care money into the non-education side of the budget,” Stratton said. By “hiding” that money, Stratton added, the school district could “pretend it’s being underfunded” and demand additional money from the city under the minimum budget requirement that compels a certain amount of municipal education funding.

DeStefano declined to comment Thursday evening. Perez could not be reached for comment.

If the city were to withdraw those funds, Stratton said, the school district could trim its budget by consolidating schools and laying off administrators.

When asked about the allegation in a Thursday morning interview, Harp said the city is obligated to contribute money to education under the Education Cost Sharing formula that conditions state funding on the city’s contribution. She said she was “sure we do more than just medical care.”

“If it’s hidden, it’s well hidden,” Harp said. “I’m not aware that we’re hiding money in the Board of Education.”

City Controller Daryl Jones denied that the city has done anything unlawful. He said New Haven Corporation Counsel Victor Bolden will be responding to the letter.

Jones said the practice of the city paying for NHPS benefits is long-standing and not improper.

“Teachers are considered city employees, and by their contract we’re obligated to pay their health coverage,” Jones said. “It’s a contract the city entered with the teachers’ union, that we’re going to pay X, Y and Z of the health coverage. We intend to follow that.”

In fact, Jones said, Stratton was present when the Board of Alders approved that contract in January. The new contract, negotiated last fall by the Board of Education and the teachers’ union, is set to take effect in July.

Stratton said he abstained from that vote because he did not understand what authority the Board of Alders had to approve the contract.

David Cicarella, president of the New Haven Federation of Teachers, could not be reached for comment.

Jones said the Board of Education is a “department of the city.” He said the fact that the school district cannot borrow money on its own proves it’s “not separate from the city.” Ward 22 Alder Jeanette Morrison, a member of the Board’s finance committee, agreed. She called the city and the school district “one and the same.”

Stratton said otherwise — and cited state law as evidence.

“Local boards of education are not agents of the towns but creatures of the state,” according to Connecticut statute. Stratton said the city has no right to negotiate with employees of the school district, citing the 1976 Teacher Negotiation Act, which provides teachers the right to negotiate with “any employing board of education or administrative agents or representative thereof.”

According to the teachers’ contract that expires June 30, “The Board [of Education] shall cover all employees hired before the signing of this agreement … under one of three medical programs.”

Carlos Torre, president of the Board of Education, said that he does not know whether the city funds medical benefits for Board of Education employees.

Will Clark, chief operating officer for the Board of Education, did not respond to multiple requests for comment on Thursday. Bolden, the city’s top lawyer, did not return an emailed request for comment Thursday. A call to the corporation counsel’s office was not answered.

NHPS Superintendent Garth Harries ’95 released a statement that did not address the city’s monetary contribution to the school district — or Stratton’s letter — but instead touted the district’s “long, positive, collaborative relationship with the city and Board of Alders.”

The Board of Education voted last month to approve a $397 million budget proposal for the 2014-’15 fiscal year.