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KENNER – Investigators have determined that the explosion on an oil and natural gas rig in Lake Pontchartrain that injured seven workers originated in a large tank on the third floor of the rig.

The blast, which rattled homes and businesses throughout Kenner shortly after 7 p.m. on October 15, heavily damaged the rig and left one worker unaccounted for.

“We still have an active investigation, an active fire and more importantly an active search and rescue mission,” said Jefferson Parish Sheriff Joe Lopinto, “The weather is inhibiting it because we have 4 and 5 foot seas out there, but we have the tools in place to get done what we need to get done.”

Search crews from multiple agencies, including St. John Parish, Louisiana Wildlife and Fisheries, St. Charles Parish, the City of Kenner, the Jefferson Parish East Bank Consolidated Fire Department, and East Jefferson Hospital, have been assisting the Coast Guard in the search and rescue effort.

“This is a tremendous effort by all of the agencies involved,” Jefferson Parish President Michael Yenni said. “Search and rescue was conducted throughout the night and this morning we were able to learn more about what happened on that rig. I want to thank all of the agencies that have been a part of this operation and even the good Samaritans who helped with the rescue efforts last night. We certainly have the families of the victims in our thoughts during this difficult time.”

Louisiana Department of Environmental Quality officials are on the scene of the explosion to monitor any environmental impacts of the explosion and resulting fire, according to Jefferson Parish officials.

A two-inch natural gas line ignited and burned throughout the night, but Jefferson Parish Sheriff Joe Lopinto said at an 8 a.m. press conference that the line has been shut off.

The remaining gas in the line is under low pressure and is burning itself out, a process which Lopinto said could take some time.

It is unclear what caused the tank to explode.

Crews have searched 95 percent of the rig so far, according to parish officials.