CALGARY -- The B.C. government is creating more uncertainty around Kinder Morgan Inc.'s Trans Mountain expansion project with a proposal to restrict any increase in diluted bitumen shipments until it conducts more spill response studies.

"The people of B.C. need to know that there is effective spill management across the province and, in particular, for our most environmentally sensitive areas, including coastlines," Environment Minister George Heyman said in a statement.

"We believe spills should not happen. But if hazardous pollutants have potential to spill, our government will ensure that spillers must be prepared and able to fully mitigate the environmental damage before they proceed."

The government said it will establish an independent scientific advisory panel to make recommendations to the minister on whether, and how, heavy oils can be safely transported and cleaned up if spilled.

It will also seek input from First Nations, industry, local governments, and environmental groups, as well as the general public over the coming months.

Kinder Morgan said in a statement that it would actively participate in the engagement and feedback process, while pointing out that the Trans Mountain expansion project was already thoroughly studied before it secured approval.

"The expansion project's approval by the Government of Canada followed a rigorous and lengthy regulatory process that included a thorough examination of the pipeline and products being shipped."

The restriction creates more uncertainty for the already delayed Trans Mountain expansion project, which is planned to nearly triple the capacity of the current pipeline system to 890,000 barrels a day.

While the long-term implications of the proposed ban are not yet clear, environmental groups have cheered it as a victory.

"Today's announcement is a major blow to Kinder Morgan. The province is proposing what is, in essence, a temporary moratorium on new bitumen exports," said Greenpeace Canada campaigner Mike Hudema in a statement.

"We know bitumen and water don't mix; when the scientific panel comes to the same conclusion, Kinder Morgan will be the owner of a brand new pipeline with no `on' switch."