TransCanada said Tuesday that regulatory delays have spiked costs for its Keystone XL crude pipeline up to $8.4 billion, up from previous estimates of $5.4 billion.
The pipeline has been waiting for U.S regulator approval since 2009 and has faced vocal opposition from environmentalist groups.
TransCanada must also win approval from the Nebraska State Supreme Court and the South Dakota Public Utilities Commission.
Calgary-based TransCanada said the budget estimate had to be increased “due to continued delays in acquiring US regulatory approvals and increasing regulatory conditions.”
Earlier this year the U.S. State Department released a key assessment of the pipeline that concluded the project would have a limited environmental impact.
The State Department said that if the pipeline is not built producers would use more dangerous transportation methods to move product such as rail or tankers.
The Keystone XL pipeline would stretch 1,179-mile from Hardisty, Alberta to to Steele City, Nebraska located just north of the Cushing oil hub.
The U.S. leg of the pipeline would run 875 miles from Morgan, Montana to Steele City.
Along with transporting crude oil from Canada, the Keystone XL Pipeline would also grant American oil producers more access to refining markets in the Midwest and the U.S. Gulf Coast.