A 15-year-old boy is in hospital after falling through a hole inside the long-abandoned Canada Malting factory Monday in St. Henri.

The building at 205 Riverside St. has been vacant since 1989 but people in the area say trespassing is all too common.

City councillor Craig Sauvé said urban explorers often film themselves going inside despite the risk of parts of the building collapsing.

"It's an extremely dangerous building to be trespassing in, doing any urban exploration. I highly discourage it. The borough highly discourages it," said Sauvé.

"We know that there are places in this building that are structurally unsound so it's really a bad idea."

Three teenagers entered the building and climbed up the inside.

One fell through a hole and plunged five metres before striking a piece of wood, injuring his arms, legs, and collarbone.

The fire department rescued the three boys, having to enter through a window and then descending to lift the boy out.

Brendon Roy lives near the silo, and he frequently sees people inside the building.

"It's sad to hear that for sure. I mean unfortunately there are a lot of people that tend to try and climb up. I guess it's an adventure for them," said Roy.

Vincent Claremont-Leduc has lived right across the street from the Canada Malting site for three years.

"I see people go in there almost every day, especially in the evening. People of all ages," he said.

While he has been inside, he is not going to return.

"I went in about 10 years go. It was a disaster then. I can't imagine what it would be like now," said Claremont-Leduc.

Roy said the building needs to be secured with regular patrols.

"What we do is we make sure as best we can with our inspectors that the building is barricaded. It is a private building so when we see there are holes or fences that aren't done we send a notice to the owner," said Sauvé.

City and borough officials are analyzing a report in order to determine the current state of the building. Previous reports have shown that the vast majority of it is not salvageable.