A Toronto school bus driver has been fired after a young disabled woman was locked inside a bus for six hours, something the school board calls "completely unacceptable" and that has angered the mother of the 19-year-old student.

The bus driver was first suspended after Laura Mastache complained about how her daughter, Wendy Mastache, was left inside it last week.

Laura Mastache told CBC Toronto that the incident has left the student "traumatized," and "she doesn't want to get in the bus."

Wendy Mastache, who has both autism and epilepsy, has difficulty communicating. She can't read or write due to developmental delays, and doesn't talk much.

Laura Mastache complained about how her daughter, Wendy Mastache, who has both autism and epilepsy was left inside a school bus for six hours last week . 0:30

Mastache said her daughter has refused to return to school since the incident happened last week.

Stock Transportation is the bus company contracted by the Toronto District School Board (TDSB).

Bus driver initially suspended, now terminated following investigation

The company released a statement, after a story by CBC News.

"The safety of our students is our top priority; our drivers are required to conduct a child check to look for students at the end of each route."

The statement continues: "In this instance, the procedure was not followed and the driver has been terminated."

'What happened during those 6 hours?'

Early Jan. 23, her mother says, a school bus driver somehow didn't see her daughter on the bus, where she was left for six hours after locking the vehicle and walking away.

"I was panicked," said Laura Mastache, her voice shaking. "What happened during those six hours? No one really knows."

A tender moment between Wendy Mastache and her mother, Laura Mastache, who has been vocal since her daughter was left in the school bus for several hours. (Paul Borkwood, CBC News)

What she does know is that at the end of the school day, she received a call that Wendy hadn't been in class all day.

Strangely, however, the girl did appear outside her school — York Humber High School, which is on Emmett Avenue near Jane Street and Eglinton Avenue West — after classes ended.

A teacher saw the student getting off the bus at that time, her mother said.

The bus driver then drove the teen home.

Student spent day alone on bus

After Wendy arrived home, her mother immediately questioned the bus driver, but said she didn't receive any answers, so she headed to the school.

She said school officials viewed security video and confirmed her daughter never entered the school that day, despite other students confirming she had been on the bus in the morning.

Every morning, the bus driver first dropped off the other students at York Humber's main doors. They are all part of the school's main programming stream.

Then, the driver would normally drive around to the back of the school to drop off Wendy Mastache for her specialized program.

But that didn't happen on Jan. 23, and the student spent the day alone on the bus, which was left parked outside a building in an industrial area.

Toronto Police found the incident was not criminal

Toronto police confirmed they initially investigated, but found that the case did not warrant criminal charges. They said the driver was in tears and apologetic. She told them she was headed to a funeral following her morning bus run and was distracted as she locked the bus.

This is the area where Laura Mastache learned her daughter spent an entire day, inside a parked school bus. (Paul Borkwood, CBC News)

The temperature was just above freezing that day, rising to a high of 4 C. Mastache said during the bus ride, her daughter wasn't wearing gloves, a hat or a scarf.

Mastache shuddered, thinking about the cold and still wondering if her daughter may have had an epileptic seizure that day. More than a week later, she has pieced together some parts of what likely went wrong, but still has questions.

"So how was my daughter in the bus? Six hours. No drinking, no eating, not going to the bathroom."

As she spoke to CBC Toronto, Mastache's daughter reached over and grabbed her mother's hand or touched her face. The teenager at one point put her head down on the kitchen table where the two sat side by side.

Concerns about 'vulnerable' students

Mastache says the school board has offered other options, such as sending a van to pick up her daughter. But Mastache says Wendy, once eager every morning to go to school, now refuses.

Her mother says she has only succeeded once since the incident in persuading Wendy to put on her school uniform, after which the teen burst into tears.

Mastache had one piece of advice for the TDSB.

She said a call to parents is needed as soon as it's noticed that a child is not in school.

Until now, board policy only resulted in an automated call for students under the age of 18.

"That's wrong," she says. "Especially because [these students] are vulnerable."

TDSB spokesman Ryan Bird says as a result of this incident, the board has now changed its policy.

Parents of all students with special needs will receive an automated call if the student does not show up for school regardless of age.

"It's unacceptable. This should not have happened,' said TDSB spokesman Ryan Bird. (CBC News)

Bird says all companies with contracts to the school board have been reminded that drivers must do a full visual check of their bus before locking it.