The Montgomery County Board of Education voted yesterday to ban student smoking on school grounds, starting in September.

The board acted in response to a call by Superintendent Harry Pitt to "help students . . . understand the personal health consequences and . . . break what is a very addictive habit."

The ban will prohibit students from using any form of tobacco, including snuff or chewing tobacco, on school property, and earmarks $25,000 for smoking cessation clinics and other programs to discourage smoking.

Pitt included the money in his budget proposal for the next school year.

Montgomery's current rules allow each high school to set its own policy.

Only two high schools -- Seneca Valley in Germantown and Walt Whitman in Bethesda -- ban student smoking.

The smoking prohibition at Seneca Valley was suggested by student government leaders after the school's popular football coach, Hugh McCabe, was found to have terminal lung cancer. He died in December 1986, at the age of 47.

In schools permitting student smoking, students must go outside to use tobacco.

In approving Pitt's proposal, Montgomery joins school systems in Alexandria, the District of Columbia, and Anne Arundel, Fairfax, Howard and Prince George's counties in reversing the liberal student smoking policies adopted in the late 1960s and early 1970s.

Prince William County is phasing out student smoking, with only seniors permitted to smoke.

Next year, a ban on all student smoking will be in effect in Prince William.

Montgomery school board members predicted that their vote will generate complaints of discrimination because the ban applies only to students and not to staff members.

Staff members are allowed to smoke only in staff lounges and dining rooms.

Board members, including those who support extension of the ban to staff members, said they were not yet prepared to vote on a staff ban, partly because of what Pitt called legal concerns.

Andrew Herscowitz, a senior at Winston Churchill High School in Potomac who is the board's student member, said the policy discriminates and should extend to staff members because they are "role models." Herscowitz abstained as the policy got the votes of all the other members except Peggy Slye, who was absent because of illness.

"I don't see it as two-faced," Pitt said of his proposal to apply the ban only to students. "I have a different responsibility to the students than I do for staff."

The board asked Pitt to study whether a ban on employee smoking would be legally or contractually possible. Plans must still be made to implement the student smoking policy, specifying means of enforcement and penalties for violations.

Board President Sharon DiFonzo, calling herself a smoking "addictee," said, "Punishment is not going to stop someone from smoking . . . . We need to help them deal with that addiction. That is where the challenge lies."