UPDATE (3/4/13, 3:25 PM): NBCNews.com issued a correction acknowledging that its report “misstated the State Department's projection of the number of construction jobs the Keystone XL pipeline project would create.” It noted that 3,900 workers are expected to be “directly employed in construction activities,” and that when construction is completed the project “would generate 35 permanent and 15 temporary jobs, primarily for routine inspections, maintenance and repairs.”

NBCNews.com falsely claimed that a recent report by the State Department found that the Keystone XL pipeline would create “as many as 42,000 new construction jobs.” In fact, the report found that the pipeline would create less than 4,000 construction jobs and only 35 permanent jobs.

Late Friday, the State Department issued a draft Supplementary Environmental Impact Assessment of the proposed Keystone XL pipeline that was largely supportive of the project, which will inform President Barack Obama's decision later this year. The report found that “Including direct, indirect, and induced effects, the proposed Project would potentially support approximately 42,100 average annual jobs across the United States over a 1-to 2-year construction period.” Those jobs encompass everything from food service to health care to finance, which the report estimates would be temporary ripple effects from the “approximately 3,900” annual construction jobs created for the 1- to 2-year construction period.

NBCNews.com not only inflated the number of construction jobs anticipated, but it failed to mention that the long-term economic impact of the project would be minimal contrary to persistent conservative claims. The State Department found that “Operation of the proposed Project would generate 35 permanent and 15 temporary jobs, primarily for routine inspections, maintenance, and repairs. Based on this estimate, routine operation of the proposed Pipeline would have negligible socioeconomic impacts.”

Knowing the true economic impact of the pipeline is critical to weighing the benefits and costs of another infrastructure project facilitating catastrophic climate change.