(Adds details on earnings, share movement)
April 18 (Reuters) - Kinder Morgan Canada Ltd said on Wednesday that its Trans Mountain oil pipeline expansion project was facing "unquantifiable risk" due to the British Columbia government's continued opposition and reported a 5.1 percent drop in first-quarter earnings.
British Columbia said on Wednesday that it would file a legal challenge in the province to determine whether it has the jurisdiction to stop the C$7.4 billion ($5.9 billion) expansion, which was approved by the federal government in 2016.
Kinder Morgan Canada, which was spun off from parent Kinder Morgan Inc in May last year, reported a net income of C$44.4 million ($35.17 million) for the first quarter ended March 31, down from C$46.8 million for the same period last year.
The company, which earlier this month suspended work on its expansion of the Trans Mountain pipeline, moved 289,000 barrels per day (bbl/d) of crude and refined products through the pipeline down from 307,000 (bbl/d) a year earlier.
Texas-based Kinder Morgan separately reported net income available to common stockholders of $485 million, or 22 cents per share, in the quarter to the end of March, compared with $401 million, or 18 cents per share, a year earlier.
Shares of Kinder Morgan were up 2 percent at $16.60 in after-hours trading. Shares of Kinder Morgan Canada were not trading as Canadian shares do not trade after regular hours. ($1 = 1.2624 Canadian dollars)
Reporting by Anirban Paul in Bengaluru and Julie Gordon in Vancouver Editing by Lisa Shumaker