For the second time in less than two years, falling glass has forced the closure of the Thunder Bay Centennial Conservatory.

The city said in a news release that shards of glass fell into the safety neeting in the Tropical House viewing area late Friday afternoon.

General manager of Infrastucture and Operations Darrell Matson said it was caused by a malfunction in a roof vent.

"We've contacted the contractor that is responsible under a city contract for repairing or replacing glass panels. They are there this afternoon or late this afternoon assessing what is needed and they actually expect to have repairs done early part of next week," Matson said.

Matson said no one was hurt in the incident.

During the temporary closure, city staff will take safety precautions while they work at the Conservatory to maintain the plants.

In February, 2012 the Conservatory was shut down for about a year as a result of falling glass.