The Montgomery County school board voted yesterday to investigate the possibility of closing Montgomery Blair High School in Silver Spring, a school never mentioned publicly for closing during nearly a year of debate on the county's schools.

At the same time, the board agreed to look into possible changes in attendance boundaries for Blair, the school with the highest enrollment of minority and foreign students in the county, and to consider a third choice that would establish a special performing arts program to attract outside students to the school.

"The solution for Blair High is not to close," said Blair Advisory Council chairman Barbara Cantor, who attended yesterday's board meeting. "We are upset that at the end of the whole procedure the board is coming up with a scheme to close Blair. It is in violation of their policy."

Board member Joseph R. Barse suggested in a memo last week that the board consider closing Blair. He said then that such a plan would help save money and would improve integration by sending Blair students into schools with lower minority enrollments.

Yesterday the board instructed Superintendent Edward Andrews to look into Barse's proposal, but because of a motion by board member Elizabeth W. Spencer, the superintendent must also investigate ways of changing the school's boundaries to keep it open and to reduce the concentration of minority students. With roughly 58 percent minority enrollment, Blair is now close to violating a board guideline that sets a ceiling on the acceptable percentage of minority students in any school.

The board's new president, Eleanor D. Zappone, who was elected yesterday, had proposed last month that the board consider a special performing arts program at Blair, and that option will also be studied.

Outgoing board president Carol F. Wallace noted during yesterday's meeting that there would be "a lot of apprehension raised" in the Blair community if the closing proposal alone were investigated.

The board will not take any action on the school until Andrews completes the feasibility studies, which he must do within 45 days.

Board member Blair G. Ewing, who lives in the Blair area, said the board's actions "send a clear message that the Blair High community should expect in all probability that the school will be closed."

He said that Blair High School parents would prefer "a solid academic program" to the special performing arts program that Zappone recommended.

Andrews has said that he believes there must be a high school in the Blair area because it serves as an anchor in that section of the county.

The discussion of Blair High came at the end of a testy meeting that began with the election of two members of the board's conservative faction as president and vice president.

Suzanne Peyser, the new vice president who with Zappone is a close ally of conservative member Marian Greenblatt, took the opportunity of her election to dispute charges that recent board decisions to close schools would affect housing patterns and integration in the county.

"Our responsibility is education," Peyser said, adding that the county executive and County Council were responsible for zoning and housing plans.

Greenblatt echoed Peyser later, saying that "the school board did not establish housing patterns or high minority schools."

"I think we should stop using the red herring of 'local control,' " Greenblatt said. "This is getting to a point of rhetoric that is completely ridiculous."