Dark clouds of delay may be forming in what has been considered a sunny outlook for U.S. natural gas pipeline exports to Mexico.

A recent Mizuho Securities USA LLC research note expressed concern about a Platts estimate that as many as nine pipeline project delays—averaging 350 days from original in-service dates—within Mexico could force 2018 exports to remain at the current level of about 4.3 billion cubic feet per day (Bcf/d).

“Recent reporting on the pipeline buildout within Mexico suggests bottlenecks and construction delays could prevent export growth of U.S. natural gas to Mexico via pipeline until 2019,” said the Mizuho report.