TORONTO -- Municipal politicians in a region of Ontario that is home to one of the world's largest nuclear power plants violated provincial law by holding secret meetings over the storage of radioactive waste, an outside investigation has found.

The probe followed complaints about years of undocumented discussions between the mayors who sit on Bruce County council and nuclear-waste representatives searching for a permanent storage site.

An investigator with a company that helps Ontario municipalities with closed-meeting procedure investigations concluded the mayors had breached the Municipal Act, which requires open meetings.

"There was no notice of these council meetings given to the public ... no clerk or designate was present to take minutes, nor were any taken," wrote Nigel Bellchamber of London, Ont.-based Amberley Gavel.

"The public was unaware of, and in no case attended, any of these meetings; nor was there any resolution to close them."

At issue were numerous meetings of the "community consultation" advisory group -- comprising the mayors and representatives of the Nuclear Waste Management Organization and Ontario Power Generation -- that began in 2005.

Some of the mayors argued the meetings were simply information sessions at which they passed no motions.

That explanation didn't impress Bellchamber, who concluded the discussions had a marked influence on the mayors' decisions regarding the radioactive-waste project. He also urged councillors and municipal staff to be "more sensitive" to potentially breaching the act when getting together for what might appear to be informal gatherings.

Ontario Power Generation is proposing to build a massive underground nuclear-waste site at the Bruce nuclear power plant on the shores of Lake Huron near Kincardine, Ont., a plan that has drawn opposition from environmentalists and aboriginal groups.

The Southampton Residents Association and Save our Saugeen Shores, which lodged the meetings complaint in May last year, saw skullduggery in the highly charged search for the storage site.

The groups alleged the discussions were kept secret because the politicians feared damaging their electoral fortunes and pointed to informal notes from one meeting in February 2010 that showed a mayor fretting about "a negative backlash at the polls."

However, Bellchamber concluded the officials did not contravene the Municipal Act deliberately.

Jim Henning, president of the Southampton Residents Association, said he found it hard to believe the contravention was inadvertent.

"It seems to me that if you get a whole bunch of mayors together for over eight years for regular meetings, one of them should know something about the Municipal Act -- if not all of them," Henning said in an interview Thursday.

The results of the investigation amounted to a "moral" victory given that the legislation provides no penalty, Henning said.

County officials, who sent the report to corporate services for review, are expected to discuss it at a council meeting next month. They did not respond to a request for comment on Thursday.

Jill Taylor, president of Save Our Saugeen Shores, called the outcome a victory for those who expect "transparency" in government. She also called it "disturbing" that neither the politicians nor administrators demanded compliance with the Municipal Act.

"Citizens should be able to trust that their mayors will follow the law, even and especially if faced with pressures from powerful industrial interests," Taylor said in a statement.