The oil producers whose facilities are impacted include W&T Energy VI, Occidental Petroleum, Walter Oil and Gas, Cantium, Arena Offshore and Talos Energy Ventures, the Coast Guard said, citing the U.S. Interior Department's Bureau of Safety and Environmental Enforcement.

The pipeline was closed by Third Coast's Main Pass Oil Gathering Co (MPOG) on Thursday morning after crude oil was spotted around 19 miles (30 km) offshore of the Mississippi River delta, near Plaquemines Parish, southeast of New Orleans.

Remotely operated devices and divers had surveyed more than 23 miles (37 km) of the 67-mile-long (108 km) pipeline to find the leak's source, the Coast Guard said in its latest update, adding that no impact was observed on wildlife and the shoreline.

While the exact volume of discharged oil was not known, the Coast Guard, which was leading the clean-up, said initial calculations placed the volume of the leak at 1.1 million gallons or 26,190 barrels.

Officials said during a press briefing on Tuesday that it had not yet been established whether Third Coast was responsible for the spill, as oil recovery efforts continued.

There were no reported injuries so far, and the waterway remains open to all commercial and recreational vessel traffic, officials added.

The U.S. Environmental Protection Agency has said that the Coast Guard was coordinating with 15 federal entities in charge of responding to oil pollution incidents, while the National Transportation Safety Board was investigating the cause of the leak.

(Reporting by Deep Vakil and Daksh Grover in Bengaluru; editing by Jonathan Oatis, Will Dunham and David Gregorio)