I found this write-up on the Biosphere from its general website:

"The Biosphère

This way of thinking -- global and ecological before those terms had coined -- inspired Environment Canada and the City of Montreal to set up the Biosphère. Despite its undeniable advantages -- its lightweight structure, strength and elegance -- Buckminster Fuller’s dome was not suited to the Canadian climate. Inside, it was practically impossible to heat and the wide seasonal variations in temperature caused the metal tubes and acrylic outer panels to expand and contract quite considerably. Leaks were common. In fact, it was a welding operation during the maintenance of the outer covering, on May 20, 1976, that caused the spectacular fire which destroyed the entire acrylic shell in just half an hour, although the structure itself remained intact. After the fire, the dome was more or less abandoned for fifteen years, but was literally reborn from its ashes with the beginning of restoration work in 1992. The Canadian government, with the City of Montreal, invested $17.5 million to construct a unique museum and environmental observation centre dedicated to water, the St. Lawrence and Great Lakes ecosystem, and sustainable development.Quebec engineers and architects, Blouin, Faucher, Aubertin, Brodeur, Gauthier, with Desnoyer, Mercure et Associés, architects, completely redesigned the layout of the dome to suit its new vocation. For financial reasons, it was decided to restore Aerial view of the Biosphèrethe structure but not to replace the acrylic covering because of the cost of heating and air conditioning the vast inner space. The steel tubes were treated with anti-corrosive paint to protect them from the elements. A new building was erected inside the dome, incorporating three of the American pavilion’s four original platforms. The Biosphere opened on June 6, 1995, World Environment Day, and became Canada’s first Ecowatch Centre. The Biosphere’s mission, in keeping with its creator’s philosophy, is to instil in the public a responsible, action-oriented attitude towards water in general and the St. Lawrence--Great Lakes ecosystem in particular. The building was a hit with the critics right from the start. It received the 1995 Award for Excellence from the Ordre des architectes du Québec in the Architectural Conservation category."