The Prince George's County Board of Education voted unanimously last night, over the objections of several parents, to close Lanham Vocational School and send its 38 students to three other schools.

Superintendent John A. Murphy recommended closing the 16-year-old vocational program because of aging and inadequate facilities, low enrollment and questions about the effectiveness of the program. The school, which enrolls mostly students who suffer from mental or emotional handicaps, offers only limited programs for girls and does not meet state standards for vocational facilities, according to school officials. Also, absenteeism at the school is higher than other schools, according to a report presented to the school board.

The students will be sent to Tall Oaks and Croom vocational high schools or a new vocational program at Bladensburg High School. School staff said these facilities will expose the students to nonhandicapped youngsters and offer more modern facilities.

The change was greeted with protest from a group of parents, four of whom argued to the board that their children had thrived at Lanham and would suffer setbacks in a larger school with nonhandicapped students.

"It's unfair," said Marcia Lacey, whose 15-year-old son John attends Lanham. She said her son had difficulties at a regular school but since he's been at Lanham, "I've had a year of peace and quiet."

Lester Purkey, 16, a Lanham student, said he had made poor grades and had poor attendance as a student at Bladensburg High School. "I just couldn't make it at Bladensburg . . . Lanham school is the best thing that has happened to me."

Several board members expressed reservations about closing the school.

"My primary concern," said board member Angelo Castelli, "is that the students involved in the program will be getting the same if not better treatment."

Board member Sarah Johnson said, "I have some ambivalence as a parent and a board member . . . but these are students who need to begin to interact with all their peers," including nonhandicapped students.

Board members Lesley Kreimer and Norman H. Saunders were not present.