A letter from a paid researcher working for Yale’s labor unions has one city legislator up in arms over the tax status of the Yale Golf Course.

Tuesday night, Ward 17 Alderman Matt Naclerio asked a committee of the Board of Aldermen to re-evaluate the city’s 1990 tax assessment of the 491-acre course, which is located in Ward 26, about three miles west of Yale’s central campus in Ward 26.

After he received a copy of a letter that union researcher Antony Dugdale sent to City Assessor William O’Brien, Naclerio sent a letter of his own to the board’s Tax Abatement Committee requesting an investigation into the status of the golf course.

Naclerio said Tuesday night he believes the city might not be collecting its due in taxes on the property.

“I would like to know if our good neighbor — who always tells us how good they are — are actually doing what they say they’re doing,” Naclerio said, referring to Yale.

The golf course, which was once completely tax-exempt, is currently assessed as two separate parcels — one commercial and taxable, the other designated as an open-space nature preserve.

Under a 1990 memorandum of understanding between Yale and former Mayor John Daniels, the city agreed to change the tax assessments of several Yale properties and ceded the deeds of other properties to the University completely.

In the memorandum, Yale agreed to allow the course to be taxed.

Naclerio alleged Tuesday night that by dividing the land into two parcels with separate taxation schemes, the city and Yale breached the agreement.

City Assessor William O’Brien said he did not believe the agreement had been breached. Regardless, he said, the city is better off under the current system than it would be if the land was assessed as a single parcel.

The University currently pays taxes on 287 of the golf course’s roughly 491 acres, but New Haven also receives money on the other 203 acres from the state of Connecticut under the Payment in Lieu of Taxes, or PILOT, program.

The taxable parcel is currently assessed at roughly $39,700 per acre; the city receives money under PILOT on the other parcel as if it were assessed at $35,000 per acre.

But if the land were reassessed as a single parcel without PILOT, Yale could argue that the entire course be classified as open space, as have the owners of many golf courses throughout Connecticut and especially in Fairfield County, O’Brien said.

Open space in Connecticut can be assessed at as little as $160 per acre.

The point, O’Brien said last night, is that the city is getting far more money from the two parcels under the current agreement than it would if the city reassessed the property.

Under current Connecticut state law, Yale does not have to pay taxes on any property it can prove is being used for educational purposes, and state courts have traditionally given the University wide latitude in allowing it to claim such exemptions.

State law also grants city assessors the exclusive ability to grant tax exemptions and designate land as open space.