Hamilton's public school board is conducting a review of safety procedures at an Ancaster elementary school after a four-year-old student wandered away from school half naked last month.

The boy's parents are thankful he wasn't harmed, but are imploring the board to make changes so nothing like this happens again.

The incident happened on the afternoon of Sept. 28 at Rousseau Elementary School, near McNiven Road and Mohawk Road.

That's when Michael, a junior kindergarten student, had a bathroom accident, said his father, Tony. CBC News is not using the family's last name to protect the young boy's privacy.

"First he tried to clean himself off [in the bathroom]," his father said. "I guess he decided he needed to take a bath, and then he walked home — with no pants on."

Rousseau, like many other elementary schools, has its doors locked during the school day, with a buzzer that visitors can press to be let inside. The doors can, however, be opened from the inside.

'The safety and wellbeing of our children is a top priority for us.'
- Sharon Stephanian, Hamilton-Wentworth District School Board superintendent

Neither the boy's parents nor the school board are sure just how Michael managed to get outside without anyone noticing.

The family lives on a nearby side street, so Michael "luckily" didn't have to cross any major streets, his father says. A neighbour noticed the boy pounding on the front door of his house wearing only a shirt, while crying and saying, "Daddy, let me in." No one was home at the time.

The neighbour then called the school, asking if they were missing any students.

"He was probably alone, walking home [half] naked for around ten minutes … and at that point, the school didn't even notice he was missing," Tony said.

Hamilton-Wentworth District School Board Superintendent Sharon Stephanian told CBC News that determining exactly how long the boy was gone, whether anyone had noticed he was missing, and how he managed to leave the school is all part of a "fulsome review" that the board is conducting.

"That's part of the work that we're undertaking right now," she said.

Once the school learned the boy was gone, principal John Gris tracked him down at his family's home and brought him back to the school. He cleaned him up, got him a change of clothes, and called his parents.

His father was floored when he heard the news, and came to pick him up.

"How did this happen?" he said. "If this had happened when it was – 25 C outside … he could have been really hurt."

"They need a better process so this doesn't happen a second time."

Stephanian says that the school board has been in touch with Michael's family, and are "extremely apologetic" about the incident. The board is now trying to figure out exactly what took place to ensure it doesn't happen again, she said.

"The safety and wellbeing of our children is a top priority for us," she said.