Attorney General David Eby said British Columbia will appeal the court decision that effectively killed the province's attempt to impose laws that would stop the Trans Mountain pipeline expansion.

"We believe we have the right and authority constitutionally to regulate harmful substances through B.C., however they get here," said Eby, announcing the province will appeal to the Supreme Court of Canada.

Eby was reacting to the unanimous decision handed down by the B.C. Court of Appeal on Friday morning that ruled proposed environmental legislation to limit the flow of "heavy oil" into B.C. would be in direct conflict with federal jurisdiction over interprovincial pipelines.

The judges found that, if introduced, the amendments to B.C.'s Environmental Management Act would essentially usurp the National Energy Board's role in approving projects in the national interest.

B.C. Attorney General David Eby says the cost of appealing the decision at the Supreme Court of Canada will be a 'fraction of a fraction' of the cost of a catastrophic diluted bitumen spill. 0:37

"We're disappointed with the decision," said Eby. "Our government said from the outset that we would stand up for the B.C. environment, economy and coast."

Speaking at an event in Kelowna, B.C., Premier John Horgan said the courts need to consider the question of environmental jurisdiction.

"There's always been a tug and pull in our federation between the supremacy of federal jurisdiction versus that of provincial jurisdiction. And when comes to the environment, this is an untested area," he said.

Environmental charity Ecojustice, which was an intervener in the case, also expressed disappointment in the ruling.

"The issue at the heart of this case goes far beyond a single pipeline project. What was at stake is the B.C. government's ability to step in and enact laws that will better protect communities and the environment when federal measures fall short." said Ecojustic lawyer Kegan Pepper-Smith.

It's official: Courts have unanimously ruled that B.C. has no authority to ban Alberta oil in a pipeline.<a href="https://twitter.com/JustinTrudeau?ref_src=twsrc%5Etfw">@JustinTrudeau</a>, it's time for you to do the right thing. Stand up for Alberta and all of Canada and build <a href="https://twitter.com/hashtag/TMX?src=hash&ref_src=twsrc%5Etfw">#TMX</a>, now. <a href="https://t.co/uhePPNx0qd">pic.twitter.com/uhePPNx0qd</a> —@jkenney

In Alberta, Premier Jason Kenney took to Twitter to celebrate.

"It's official: Courts have unanimously ruled that B.C. has no authority to ban Alberta oil in a pipeline," he wrote.

A spokesperson for Natural Resources Minister Amarjeet Sohi called it a welcome decision.

"It is a core responsibility of the federal government to help get Canada's natural resources to market and support good, middle-class jobs, but we know that is only possible when we earn public trust by addressing environmental, Indigenous peoples' and local concerns," said press secretary Vanessa Adams.

Attorney General David Eby says the province will appeal the decision limiting its right to control the transport of harmful substances through B.C. to the Supreme Court of Canada. (Ben Nelms/CBC)

Eby said the fact that all five judges ruled against his government would not affect the decision to take the case to the highest court in Canada.

When BC threatened to block our oil, we used the wine ban to force them to court. The result is this decision, creating investor certainty for AB.<br><br>Turns out BC's toolbox was more Fisher Price than DeWalt. This is a good day for people with toolboxes all across Canada. <a href="https://twitter.com/hashtag/ableg?src=hash&ref_src=twsrc%5Etfw">#ableg</a> <a href="https://t.co/dCFc1OL8Nd">https://t.co/dCFc1OL8Nd</a> —@RachelNotley

"The Supreme Court of Canada has overturned unanimous decisions by the B.C. Court of Appeal in the past," he said. "For reference questions like this, provinces have the right to appeal."

According to Section 36 of the Supreme Court Act, the appeal is automatic and does not require leave.

When asked about the financial price tag of the appeal, Eby said it would be a "fraction of a fraction of the cost of a catastrophic diluted bitumen spill."