In a year during which Montgomery County principals have taken strong stances against underage drinking, the interim superintendent last week overruled one principal who banished a group of seniors from graduation ceremonies after concluding that they drank alcohol on prom night.

For months, Bethesda-Chevy Chase High School Principal Donna Redmond Jones warned that students who violated efforts to keep prom alcohol-free would not be allowed to participate in commencement. On May 6, the day of the prom, Jones reemphasized in an email that “significant school consequences” awaited those who consumed alcohol or drugs before or during prom or at the after-party.

Six students were disciplined, according to school officials who would not describe the punishment. Students said several of them are seniors.

In a letter sent Friday to parents, school district chief Larry A. Bowers announced that he had reversed the graduation ban, triggering outrage from some community members who have supported the principal’s campaign against substance abuse.

Although the students “consumed alcohol during prom activities,” Bowers said, he had examined the circumstances of each case and decided the seniors could walk across the stage to receive their diplomas during the ceremony on Wednesday, June 1.

“I did not reach this decision lightly,” Bowers said in the letter. He said he supports the work the school is “doing to promote student safety and healthy decision-making,” but looked at circumstances and board policy in reaching a different conclusion. He ­noted that the students “received appropriate consequences under our discipline policy.”

District policy generally prohibits schools from using exclusion from graduation as a part of their disciplinary standards and procedures, Bowers said in his letter. Still, principals have the authority to exclude students from commencements “for cause, on a case-by-case basis.” In the B-CC case, it appears to have made a difference that the principal took a blanket approach.

In recent years, Maryland education officials have taken steps against zero-tolerance policies in student discipline, saying that school systems should consider cases individually. District officials declined to elaborate Saturday about the policy, saying they had no comment beyond Bowers’s letter.

Jones could not be reached for comment.

School board member Patricia O’Neill said that she did not know the details of the B-CC situation but that other principals have issued warnings against drinking at prom in the past and other students have had to skip graduation ceremonies. She said she worries about the message the reversal sends to students about rules.

“If there are no consequences to dangerous and risky behaviors, we may have a total drunken-fest on our hands” in future proms, she said, emphasizing that underage drinking is illegal.

The decision comes at a time when principals in Montgomery County and beyond are combating pervasive underage substance abuse among students. B-CC has brought in medical professionals as speakers and held assemblies to raise awareness.

“How else do we change the culture? Do we just wait until someone dies?” said Deb Ford, a parent of two students and president of the school’s PTSA, who said she was speaking for herself and not for the organization. “I think it would be a travesty if our community only took this seriously after we experienced a student death.”

Jones started at the school in the summer of 2015, around the same time that two recent Wootton High School graduates were killed in an alcohol-related crash. That crash heightened concerns about a culture of underage drinking.

It happens often enough that it drove Whitman High Principal Alan Goodwin to send a strongly worded email to parents urging them to stop hosting parties where minors are allowed to drink alcohol. Police, too, have targeted these parties and shut down at least 30 in the past year.

PTSA member Missy Reingruber, who has chaperoned B-CC’s after-prom party for three years, said most parents have no idea how bad things can get.

Jones’s directive was strong enough to make a difference in students’ behavior, she said.

For the first time in years, staff did not have to call any ambulances at the after-prom party, and fewer parents had to pick up their students. She said chaperones weren’t pulling bottles of booze away, mopping up vomit or managing alcohol-fueled drama — as they had done in the past.

“It was surreal. The kids did a great job because they knew there was a boundary they shouldn’t cross,” Reingruber said. “When it’s overruled, it makes it all meaningless, and that is disappointing.”

But some parents said banning students from graduation was overly harsh for the offense of drinking — something that is not unusual.

School officials did not comment on the type of discipline the students received, but Bowers said in his letter that he met with students.

B-CC graduating senior Alec Cohen said those involved don’t recognize the harm they are wreaking: “Missing graduation is a minor consequence,” he said, compared with what could happen to a underage student who drinks in excess. “They knew what they were getting themselves into, and it’s hard to feel bad for them.”

Bowers’s decision had broad implications in that it not only undermines Jones but also tells younger students that prom rules are all “bark and no bite,” said Jeanne Rossomme, a mother of two B-CC students, a senior and a sophomore.

“If there was a problem with her policy, why was it not brought up before?” she said.