One person still was reported missing at midday Monday and seven people were injured after an oil and natural gas storage transfer platform exploded Sunday night in Lake Pontchartrain near Kenner, LA.

The platform, owned by New Orleans-based Clovelly Oil Co. based in New Orleans, is a collection point, also known as a co-mingling facility, for oil and natural gas that is pulled from several wells, the company said.

A natural gas well was feeding the tank at the time of the explosion, which occurred during maintenance activities, according to Clovelly. The platform, in an unincorporated area of Jefferson Parish, “does service both oil and natural gas,” according to authorities.

“This is a tremendous effort by all of the agencies involved,” said Jefferson Parish President Michael Yenni. “Search and rescue was conducted throughout the night, and [Monday] morning we were able to learn more about what happened on that rig...We certainly have the families of the victims in our thoughts during this difficult time.”

Preliminary findings pointed to a tank exploding on the third floor of the platform, which includes a dining hall and live-in quarters. The City of Kenner said in a Facebook post “cleaning chemicals ignited on the surface of the oil rig platform.”

The U.S. Coast Guard and other authorities were investigating the cause of the explosion, which was first was reported around 7:15 p.m. Sunday. A natural gas fire was still burning early Monday, but 95% of the structure had been searched by midday.

A supply boat on the scene rescued seven people, and five were transported to the University Medical Center in New Orleans. Two other people were taken to a hospital in Metairie and discharged overnight.

Three of the injured people were Clovelly employees. Five of the victims, including the missing man, are contract workers.

The Coast Guard was being aided by St. John and St. Charles parishes, Louisiana Wildlife and Fisheries, the City of Kenner, the Jefferson Parish East Bank Consolidated Fire Department and East Jefferson Hospital.

The Louisiana Department of Environmental Quality was on scene conducting water quality testing; no oil sheen was seen on the waters in preliminary tests. Air quality monitors also were being checked because of the windy conditions.

No other rigs on the lake were at risk of igniting, according to authorities.