Mario Dumont has continued his charge that the Quebec Liberal government knew the Laval overpass needed repairs before it collapsed, demanding on Wednesday that the province's transport minister resign.
Five people died in the collapse last fall.
Dumont, leader of the Action democratique du Quebec, surprised Liberal Leader Jean Charest during Tuesday's televised debate, when he pulled out documents relating to the overpass.
The memos, dated from 2004 and 2005, outline problems with the overpass but also recommend against immediate repair -- a fact Dumont did not mention.
"There was a huge mistake to try to hide information in (these documents) from the people. They had a responsibility to give the people full truth about that," Dumont told reporters Wednesday in Quebec City.
During the debate, Charest denied any knowledge about the documents. But a day later, Dumont continued to press the issue, asking Transport Minister Michel Despres to resign.
"While (Despres') resignation can seem symbolic, for me it's a question of principle," said Dumont.
"We have to end this culture of camouflage that seems to be installed in Quebec."
Despres later held his own press conference in Quebec City, saying he was "very disappointed" with Dumont.
"What he did is unacceptable, irresponsible and shows his lack of maturity," he said.
Former PQ leader Pierre Marc Johnson is leading a commission into the overpass collapse, but has yet to issue a report on its findings.
Late Tuesday night, the commission released a press release asking for any documents about the overpass -- a move Dumont criticized as being suspicious in the midst of an election campaign.
"(They should) stay out of the campaign and certainly not repeat things like we saw last night, when at midnight they released a press release directly related to the leaders' debate," said Dumont.
The first memo, an internal document from the Ministry of Transport dated June 17, 2004, expresses concerns about widening cracks in the overpass's structure.
The second memo, a follow-up report dated March 1, 2005, concludes the cracks are not an urgent manner.
The overpass later collapsed on Sept. 30, 2006, killing five people, injuring six others and crushing several cars.
Saeed Mirza, an engineering professor at McGill University, said the reports only prove that the overpass was thoroughly inspected.
"This shows that they dealt with the problem in a very open and transparent manner, and copes were sent to others so the knowledge was shared," he said.
One of Dumont's own candidates, Charles Ghorayeb, has criticized his leader for using the documents during the debate.
Ghorayeb told Montreal radio station CJAD that "I didn't particularly like that and I told him that."
He added: "From a tactical standpoint it looked like, 'Where did that come from?' Yes, it was important, but I just think there is a lot of depth to these documents and the debate is not the best place to bring them out."
Parti Quebecois Leader Andre Boisclair has also called the move "irresponsible," and said Dumont should have turned over the documents.
Political analysts have said Charest lacked charisma during the debate, although no clear winner emerged.
Two polls released Wednesday had different results, and with high margins of error. One suggested Charest won the debate, while the other said Dumont came out ahead.
But Boisclair has at least one fan: former premier Jacques Parizeau, who spoke during a PQ fundraising event in Montreal.
"I am very proud of our leader," he said. "He did very well last night ... He has the makings of someone who can lead Quebec."
With reports from CTV Montreal and files from The Canadian Press
