ST. JOHN’S, N.L. – The interior floors collapsed in a vacant heritage building that caught fire Friday in St. John’s, N.L., sending large plumes of smoke spewing over the port city.

Platoon chief Rick Mackey of the St. John’s fire department said the fire was under control but still burning after being reported at about 4 a.m. local time. About 30 firefighters had been on the scene to battle the blaze.

“There’s still a fair amount of smoke,” he said. “The interior floors have pancaked and the actual exterior is still standing.”

Two schools near the building, which dates back to the 1800s, were closed.

The downtown structure used to be the Medical Care Plan Building and was once part of the Belvedere Orphanage, a girls facility that closed decades ago.

Mackey said the fire had consumed much of the interior and was too intense for crews to go inside.

Heavy smoke spewed over the city and people were asked to steer clear of the area.

Mackey said it wasn’t clear what caused the fire, but it was under investigation.