CBS News reported on Tuesday that it has found evidence of construction problems on the southern leg of the Keystone XL pipeline. The news agengy “obtained warning letters written over the past two months to TransCanada from the federal agency that regulates pipelines. A September 10 letter warned TransCanada it was ‘not following their Construction Specifications’ because ‘dents on the pipe’ were found at dig sites with ‘rocky terrain.'”

Watchdog group Public Citizen on Tuesday released a report documenting 125 sites where pipe was dug up. Its report notes problems like dents or patches applied to coatings to stop corrosion — issues that if not repaired can lead to leaks.

Watch the full CBS News report below: