Thirteen of the 19 students expelled from Burbank Unified schools during the past academic year were because of drug or alcohol use, officials reported.
Other students were expelled for possessing a weapon, committing sexual battery or assaulting a teacher.
When school officials expel any student, it is considered the last resort, said Lee Strong, interim director of student services for Burbank Unified.
"It's not something you do willy-nilly," he said. "It's a very serious thing and we take it very seriously."
The student's principal must make the first recommendation to expel, which leads to a hearing with the student, his or her parents, and a panel of educators who work at another campus to weigh in on the case.
Of the 21 hearings that took place over the last year, in two cases, officials did not recommend expulsion.
In most cases, the panel suggested expulsion and the decision fell on the Burbank Unified school board, which has the final say.
Expulsions can last from one semester to a full academic year, and during that time, students attend the district's Community Day School, where they receive personalized instruction, said Emilio Urioste, the district's director of secondary education.
"It's very much a monitored setting," he said.
With every expulsion comes a recommendation for students to participate in a rehabilitation program or counseling, and parents work with educators to decide on the kind of support the student needs, such as therapy or a drug abuse program the parents then pay for.
School board member Larry Applebaum said the district also offers programs for students to turn to before they face expulsion.
"It's always tragic when we do [expel students] because there's usually circumstances that I find that, if there was a little bit more intervention, or a little bit more attention, sometimes we could have intervened before it got to that point," he said.