West Tisbury selectmen agreed last week to back a shared funding concept for a new Tri-town ambulance headquarters in Chilmark.

Under the proposal, the town will be asked to contribute between $531,000 and $639,000 through a 20-year lease agreement for the EMS building.

Selectmen in Aquinnah also voted earlier this month to also back the concept.

Planning for the new EMS building is well under way after Chilmark took ownership of a piece of land near the town fire station at Beetlebung Corner this fall for the facility.

Selectmen chose Daedalus Projects Inc. as the owner’s project manager last Thursday.

At a special town meeting Monday night, Chilmark voters will be asked to appropriate $440,000 for design work on the building. The spending will also need approval at the ballot box on Dec. 4.

If all that goes forward, the new headquarters for Tri-town will have cleared another step in a long process.

Currently Tri-town and its ambulance are headquartered in the West Tisbury public safety building. Relocating to Chilmark aims to allow better response time in the remote up-Island area.

Meanwhile, the three up-Island towns are in discussion about how to share construction and operating costs for the new building.

Chilmark will bear a larger share of the costs, including paying for the land and the owner’s project manager. The town is also planning to rebuild its fire station as part of a broad public safety facilities improvement project in the town center.

At a meeting last Wednesday, West Tisbury selectmen briefly debated the pros and cons of a 20-year lease that would create a legal mechanism for their town and Aquinnah to contribute to construction costs.

The proposed lease includes a graduated rebate provision in lieu of equity in the event that either of the towns decided to withdraw from the regional EMS service.

Chilmark selectman Bill Rossi attended the meeting.

Selectman Jeffrey (Skipper) Manter 3rd took some issue with the fact that Chilmark will own the building.

“My issue here, which is not a deal breaker, is that we are paying $700,000 for one-third of a building that, at the end of the day, we are going to have nothing to show for it. And I don’t mean that in a negative sense,” Mr. Manter said.

Mr. Rossi said it would be difficult for West Tisbury to have ownership in a Chilmark property.

Mr. Manter also thought the gradually increasing rebate started too low, and suggested a flat rate of 50 per cent over 20 years.

In the end selectmen voted unanimously to back the proposal, with appreciation to Chilmark.

“I would like to express my gratitude to the town of Chilmark for taking the bull by the horns, getting the purchase of the land done and being willing to pay some of the costs that otherwise we all might share,” selectman Cynthia Mitchell said. “I think it is generous.”

“We recognize the need to step up and fund public safety in Chilmark,” Mr. Rossi said. “Without a doubt.”