Ron LaPorte, an auto mechanics teacher at Fairfax County's Groveton High School, puts on a breathing mask everytime he walks into his classroom.

LaPorte says the air makes him sick.

Ten Groveton High students who have similar complaints about the air in the school's vocational wing were suspended yesterday when they refused to enter that part of the school and staged a protest.

School officials, who deny charges that toxic gases are circulated through the vocational wing's ventilating system, say the air is not to blame for student complaints about headaches, nausea and respiratory problems.

"We've ordered inspections from the county and state health departments and both reports said that there is no significant problem with the air at Groveton," said Groveton principal R. Don Ford.

But Ford said yesterday's demonstration would "probably" result in another inspection.

The demonstration yesterday broke up when Ford ordered students, assembled across the street from the school, back in their classes or face suspension. Several mothers who were protesting with their children urged difiance of the principal's order.

Nancy Maggard, who said her daughter recently became ill and was hospitalized after spending time in the school's vocational wing, claimed that the mothers attended the demonstration to urge school officials "to clean up the air down here."

The reason for the bad air, according to auto mechanics teacher LaPorte, is that laboratories in the vocational wing produce toxic fumes. These include ammonia solutions in the drafting area, solvents in the auto painting section and assorted odors in the cosmetology area, LaPorte said.

The teacher claims the fumes are mixed in the ventilating system and recirculated withoug proper filtering.

"We've had a problem with the ventilating system here for years," LaPorte said, his voice rasping. "I lost my voice back in November. I thought it might be a cold until we left for nine days at Easter and my voice came back. It's gone again."

Susan Sunbury, a cosmetology teacher, said many of her students have experienced strange illnesses in her class.

"It's like you're being gassed," she said. "Everything is fine, then all of a sudden we experience these wierd fumes.

"I wound up in intensive care for three days last summer with something they call an upper airway obstruction," Sunbury said. "My doctor thinks it's from the air in this building and [he] made me stay out for two months this winter when I became sick again."

Sunbury, who says she can't remember more than two consecutive days of good air in four years at Groveton, claims things are getting worse with more and more students headaches after attending classes in the vocational wing.

"I have headaches every single day," says Connie Simpson, a junior who spends four hours a day in the cosmetology lab. "I went in there today and I don't know what happened, I just fell asleep. I'm so tired I go home and lie down for a few hours everyday after school."

Several teachers have notified the Fairfax Education Association about the air at Groveton High School. Dennis Friel, a spokesman for the teacher's association, says he questions the validity of the health department tests at the school. He promised an independent study of the air.

"We have one English teacher who has had a low-grade temperature all year long. The only thing she has in common with the other people is she shares the same ventilating system," Friel said. "When we have a completed study by our own industrial hygenist, we're going to take this matter to the school board."

Herman Howard, the county school administrator responsible for Groveton High, says he welcomes any independent study.

"I want more experts brought in," Howard says. "If they find we have a health hazard, I want to know which program it is and I'll stop it immediately.

"The health of the people involved is the most important thing."