In explaining the litany of accusations, Revenue Quebec said Wednesday that he and his former companies filed false declarations and invoices while claiming unwarranted tax credits and refunds.
Accurso was the dominant player in a construction empire that included companies now targeted by Revenue Quebec: Simard-Beaudry Construction Inc., Louisbourg Construction Ltd., Louisbourg Simard-Beaudry Construction Inc. and Marton Construction (a division of Louisbourg).
He has withdrawn from his businesses amid a mounting pile of scandals and legal woes. Now added to that mountain of troubles are new charges against him and his firms — 470 of which directly name him as an individual or company administrator.
"Prison sentences will also be sought for the presumed cases of tax fraud in the construction industry," said a statement Wednesday from the revenue agency and Quebec's anti-corruption unit.
The statement said the $8.5 million amount was only the minimum fine. And it said 14 other charges had been laid last month against Accurso in relation to another one of his companies, Hyperscon Inc.
Accurso was not arrested Wednesday but has been ordered to appear before a judge on Sept. 25.
The tax investigation was code-named Project Touch, a play on the name of the now-infamous luxury yacht where Accurso entertained municipal officials and union bosses.
The accusations stem from the period between June 1, 2005 and March 31, 2010.
The 928 charges announced Wednesday are almost all against Accurso and his former companies. In addition, one of Accurso's right-hand men, Frank Minicucci, is also facing six charges of filing false returns for the same period.
"It was a scheme that was elaborate and well-planned," said Revenue Quebec spokesman Stephane Dion.
A large part of Accurso's construction empire was sold earlier this year to a consortium, Hexagon Investments, which includes two of his sons as shareholders.
The firms mentioned Wednesday are not part of that sale, the head of the new company said.
"We knew that there was trouble with the tax authorities and there were search warrants, but we did our homework," said Joel Gauthier, head of Hexagon.
In October 2012, Accurso announced his retirement.
He had emerged by then as a central figure in Quebec's corruption scandals. He faces a wide range of charges stemming from other cases.
One witness at Quebec's corruption inquiry, Lino Zambito, says that when he tried to bid against Accurso for a big job he was called to a meeting in the presence of Vito Rizzuto — reputedly the most powerful mobster in Canada.
Accurso has denied that claim.
He has been arrested three times in two different municipal corruption cases — one in Laval and one in Mascouche.
In December 2010, Constructions Louisbourg Ltd. and Simard-Beaudry Construction Inc., two of the firms under his empire, pleaded guilty to tax evasion following a Canada Revenue Agency investigation.
They admitted to improperly claiming $19 million in business expenses between 2003 and 2008, and failing to pay $4 million in taxes as a result.
- with files from Magdaline Boutros
Note to readers: This is a corrected story. An earlier version said the charges were under the Criminal Code.