Westport is a concerned spectator as Bristol County Agricultural High School in Dighton pushes forward with plans for $104 million worth of improvements to its aging facility.

Thursday evening, the project cleared an important hurdle when it won the approval of the 20 Bristol County towns that send students and pay tuition there.

Thirteen towns voted yes, two (Seekonk and Freetown) voted no, and four did not vote, Westport among them.

Days prior to that vote, Westport Town Administrator Tim King brought the pending vote to the attention of the Board of Selectmen at last Monday’s meeting. The vote as actually a re-vote of a January 6 vote — one town then complained of a lack of proper notice.

Several board members said they were caught off guard by late word of this vote, adding that they were not sure what to think.

Westport, which now sends 33 students to Bristol Aggie, pays $75,000 per year in tuition costs — just under $2,300 per student (well less than the $10,000-plus per student cost in the Westport public schools).

But if the $104 million project moves forward, costs will be shared by the community towns on a per-student basis.

Westport’s $75,000 annual bill would initially leap by $150,000 to around $225,000 per year, board member Shana Shufelt said. In later years of the duration of the loan that per-student cost would decrease somewhat.

“And that is out of our operating budget.”

That’s a considerable impact, Ms. Shufelt said, although “I’m not saying (the project) doesn’t have merit.”

Board members talked about having one of them attend Thursday’s vote (Brian Valcourt volunteered) but then said they weren’t sure how Westport ought to vote.

Bristol Aggie certainly needs the improvements yet the local impact is considerable, several said.

“We are uninformed about this in a lot of ways,” Ms. Shufelt said.

What’s more, Mr. King said, Fall River’s Diman Regional Vocational High School, to which Westport also sends tuition students, is making progress toward a costly project as well.

The Massachusetts School Building Authority (which would pay 40 percent of the cost of the new Westport middle-high school), has already agreed to pay $50.5 million of the Bristol Aggie project. The remaining $53.2 million would be paid by Bristol County towns including Westport by way of long-term borrowing.

The Bristol Aggie project includes construction of a new building to house classes for small and large animal science, natural resource classes and other science classes.

Gilbert Hall, now the main academic and administration building, would be revamped to provide bigger classrooms and laboratories to meet present day school standards.

The school now takes 450 students from county towns but has long had a waiting list. The expansion would enable it to increase enrollment to around 640 students.