Pipeline operator TransCanada has voiced its disappointment over the latest delay in the decision regarding the proposed construction of the Keystone XL pipeline.

The decision on whether construction of the pipeline will be permitted has been pending for months. The U.S. Department of State announced on April 18 that there would be another process delay, due to the fact that eight more federal agencies had been asked to weigh in on the matter.

Russ Girling, president and chief executive officer of Calgary, Alberta-based TransCanada, issued a statement revealing that the company was "extremely disappointed and frustrated" with the latest delay. He called the decision "inexplicable" and pointed out that the two sections of Keystone XL have been treated in completely different ways by U.S. regulators. The first leg of the pipeline, which has been shipping oil since 2010, is about the same length and has a similar capacity to the second leg. However, the first leg only took 21 months to be approved, while the second one has been pending approval for more than 2,000 days, he noted.

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Girling also pointed out that the recent Final Supplemental Environmental Impact Statement by the State Department found that turning down the Keystone XL project would have a negative effect on greenhouse gas emissions and would close opportunities for jobs and a stronger economy. "Not building Keystone XL is a lose, lose, lose scenario any way you look at it," he concluded.