"Automated systems ... secured the facility and alerted operators to the collapsed tank. The platform remains secured," a United States Coast Guard spokesperson said.
"The collapsed tank has been removed as of 7:30 p.m." Central time on Aug. 8.
Hilcorp estimates that around 13,944 gallons of crude oil entered the water, the Coast Guard said, adding that clean-up efforts were still going on and there was no reported impact to wildlife.
The Coast Guard said it has deployed 6,200 feet of containment boom, along with three skimming vessels and five response vessels.
(Reporting by Deep Vakil and Seher Dareen in Bengaluru; Editing by Andrew Heavens and David Gregorio)