TORONTO -- Ontario's opposition parties are calling on the province's Independent Electricity System Operator to release the names of power generators that billed millions in ineligible expenses and for it to recoup all of that money.

The IESO said Thursday that rules around commercial sensitivity prevent it from publishing those names, though an executive said they could change those rules.

Auditor general Bonnie Lysyk reported Wednesday that nine generators claimed up to $260 million in ineligible costs between 2006 and 2015, including scuba gear and raccoon traps.

The program is designed to pay power generators for fuel, maintenance and operating costs when the IESO puts them on standby to supply energy.

The IESO puts the ineligible costs at $200 million, and has recovered about $168 million. Both the Progressive Conservatives and the NDP called on them Thursday to get all of the money back for ratepayers.

"There's a lot in there that people of Ontario should be concerned about, especially some of these ineligible costs that went through," said Progressive Conservative Todd Smith. "The scuba stuff is ridiculous. The raccoon traps -- insane. I mean, these are the types of things that drive people crazy when they're struggling to pay their own hydro bills and they're seeing stuff like this ending up on their electricity bill."

The IESO's vice-president of policy, engagement and innovation said all of the more egregious costs have been recovered, but there are some costs that are more in dispute. To get full recovery, the IESO would have had to use litigation, which would bring high costs on its own, said Terry Young.

One of the nine generators is Goreway Power Station in Brampton, Ont., which has repaid nearly all of the $100 million it was found to have "gamed" the system out of, but the names of the other eight generators have not been made public.

Young said market rules mean the IESO can't disclose information from the nine audits it conducted, including the names of the generators. Goreway is publicly known because the Ontario Energy Board's market surveillance panel investigated and quietly posted a report to its website.

Young said, however, that the IESO's board could change the rules that deal with confidentiality.

"We could look at changing the rules on our own," he said. "Would we do this? I guess we could look at something like this, but to be honest we haven't gone down that path yet."

Economic Development Minister Brad Duguid said he has no problem with those names being published, but it's the IESO's process.

"My dispensation is always: everything that can and should be made public ought to be made public," he said.

The IESO has already changed some practices that would prevent some ineligible billings in the future, Young said. It also is going through a process called market renewal that is looking at fundamental changes to the electricity market.

But the opposition parties have also called that process into question, since up until Dec. 1 when he resigned, a Goreway executive was the chair of an IESO panel working on that market renewal. A second member from a chemical company has since been removed as co-chair.

As per a recommendation from the auditor general, that panel has also now added a representative for low-income ratepayers, the government said.