By Nia Williams
(Reuters) -The government of Canada's main oil-producing province Alberta has filed for intervener status in a legal challenge to the federal government's move to list plastics as toxic substances, Alberta Premier Jason Kenney said on Thursday.
It is the latest in a string of disputes between Prime Minister Justin Trudeau's Liberal government and the western province, which also brought legal cases against Ottawa's carbon price policy and legislation governing environmental assessments for major infrastructure projects.
"Labelling plastics as toxic substances is already having an impact on Alberta's responsible and growing petchem (petrochemical) industry by creating uncertainty for those investors," Kenney said.
Ottawa is aiming to cut plastic pollution and last year added plastic manufactured items to its list of toxic substances under the Canadian Environmental Protection Act.
In response, industry group the Responsible Plastic Use Coalition, whose members include Dow Inc and Imperial Oil, filed a legal challenge in the Federal Court of Canada, arguing the move was unconstitutional and unreasonable.
Alberta has the largest petrochemical sector in Canada, which Kenney said was facing a massive expansion.
"What the federal government is doing with this listing presents a serious threat to our economic interests," he said, adding a provincial government analysis estimated C$30 billion ($22.87 billion) in investment could be at risk.
($1 = 1.3119 Canadian dollars)
(Reporting by Nia Williams; Editing by Aurora Ellis)