The province says keeping the current Ontario Science Centre building open to the public even temporarily would still require the “immediate closure” of the facility along with an initial investment of $70 million in “urgent capital repairs” and another $20 to $40 million for “immediate roof repairs.”

Amid public backlash, the province is continuing to defend its decision to abruptly close the beloved Toronto tourist attraction, suggesting that it would cost “a minimum” of half a billion to keep the aging museum open long-term. 

The museum was permanently closed on June 21 after the province said a recent report from engineering firm Rimkus identified a number of roof panels that would need to be replaced or reinforced at facility.

The report was the catalyst for closing the facility last month, with Infrastructure Minister Kinga Surma calling the deteriorating roof panels a “health and safety risk.”

Staff can remain at the facility over the summer in order to decommission the site by Oct. 31, the province has said.

The engineering report commissioned by the province did provide alternatives to shutting the centre down and others, including the firm that designed the facility, said the museum could stay open and be renovated safely by cordoning off some sections of the buildings.

But in an update provided Thursday, Infrastructure Ontario dismissed that idea, indicating that the site would need to be closed regardless of the course of action that is taken. 

“What it is really, really important to be very clear about, we cannot rehabilitate this asset unless the entire buildings are vacant,” Jane Domenico, Infrastructure Ontario’s president of asset management and modernization, told reporters on Thursday.

“There is no spot repair that will be sufficient or safe.” 

She said the province isn’t even fully aware of the damage to roof panels as many were inaccessible to the engineering firm that conducted the review. Domenico noted that a total of 24,000 square feet of roof panels have not yet been investigated.

According to the province, "highly intrusive access through reinforced concrete" would be required to look into uninvestigated areas in Building A, a move they say could cause significant impacts, including vibration and structural shifting, to the existing roof panels. This, the province said, could post a "risk to occupants within the building."

Staff are also concerned with disrupting asbestos and other hazardous materials during the investigation of the remaining panels, the province said.

Infrastructure Ontario noted that a recent roof leak in Building C occurred in an area "adjacent to an uninvestigated area."

According to a business case released last year, the roof is just one of a number of things that have fallen into disrepair at the facility, including mechanical, electrical, and elevator systems, which all require significant investment.

In Building B, the province noted that there is no heating due to malfunctioning heating pipes, a situation which would need to be fixed before the winter season due fire safety risks associated with "sprinkler system freezing.”

Much of the needed repairs that have been identified are due to deferred maintenance that has been put off for years by the current and former provincial governments.

On Thursday, Domenico added that the costs associated with rehabilitating the site will likely go up as “more on-site investigation is undertaken.” 

Speaking to reporters at an unrelated news conference on Wednesday, Premier Doug Ford called the building “decrepit” and suggested that fixing it is simply too expensive.

"It's not as simple as you just saying, 'Go in there and throw some shingles down, and we're all done," Ford said when asked by reporters at the press conference.

The provincial government has issued a request for proposals for a temporary home for the science centre. A new science centre is set to be built at Ontario Place but isn’t expected to open until 2028 at the earliest. Critics have suggested that moving to a temporary site may in fact be more expensive than fixing the most critical issues to keep the site running in the short term.

The province could not provide a clear answer about what the plans are for the existing buildings after the museum is vacated in the fall and whether they will be demolished.

"We will have discussions with the City of Toronto," Surma said Thursday. "Of course there is always been discussions about having science-related programming on site. We’d like to hear from the city of Toronto on that front."

With files from CTV News Toronto’s Jon Woodward