Seven energy companies in the US have reportedly been affected by an oil discharge near the pipeline system of Main Pass Oil Gathering (MPOG) in the US Gulf of Mexico.

The incident is estimated to have resulted in the release of over a million gallons of crude oil, according to US officials.

MPOG shut down the 108km long pipeline last week. This was after crude oil was observed approximately 30.5km off the coast of the Mississippi River delta, in the vicinity of Plaquemines Parish, to the southeast of New Orleans.

During a briefing to the press, Bryan Domangue from the Bureau of Safety and Environmental Enforcement said that seven producers were impacted and that they have currently shut down operations.

Officials said that vessel traffic remains unaffected, and the waterway is open for both commercial and recreational activities.

Although the precise volume of discharged oil is unknown, the Coast Guard, which is overseeing the cleanup of the oil spill, estimated the leak at 1.1 million gallons or 26,190 barrels.

Coast Guard New Orleans sector Deputy Commander Captain Kelly Denning told the media that: “We’re not saying that was the exact amount. We are not going to know the exact amount of oil that was discharged into the Gulf of Mexico until we find the source.”

MPOG is a fully-owned subsidiary of Third Coast Infrastructure, a Houston-based offshore focused midstream company.

Authorities said that it has not been determined whether Third Coast Infrastructure is accountable for the spill.

Denning said: “They’re suspected responsible party but we won’t know until we find the source which is why we keep referring to them as the responding party.”

In its most recent update on the oil spill incident dubbed MPOG 11015, the US Coast Guard stated that remotely operated vehicles and divers have examined over 37km of the pipeline.

The federal law enforcement agency further said that overflights have revealed no new visible sheens, and assessments of wildlife and shorelines have found no evidence of oiled wildlife, shoreline oiling, or oil on the water.