CTV News has learned that oilsands company Suncor faces a second set of environmental charges that have never been made public.

This is the latest admission from the province as it tries to explain why close to 100 other charges of dumping sewage into the Athabasca River were kept quiet.

The environment minister said there is a policy to not disclose charges until the court has prosecuted the offender and that policy will now change.

"I've asked my staff to develop a new policy that will provide more transparency," said Rob Renner.

But the former environment minister, and MLA for the area Guy Boutilier, did not know about these charges or a policy prohibiting disclosure.

The province did publicly announce when charges were laid after an estimated 500 ducks died in a tailings pond, but Boutilier said that policy didn't seem to exist then.

The Premier said at the time of the charges he was on the campaign trail.

"The first accusation was that I was sitting on the information which is totally wrong," said Ed Stelmach.

According to Alberta Environment, Suncor faces charges for not having proper emission control equipment in place at its firebag operations north of Fort McMurray.

Suncor is scheduled to make a court appearance next month in Fort McMurray.

With files from Kevin Armstrong