An air and water Search And Rescue continued on Monday for a missing worker around Lake Pontchartrain, after a Louisiana Oil Rig exploded on Sunday. The power of the explosion was felt by residents living more than one mile away, in what some say resembled a sonic boom.

Speaking to ABC News at the scene, Jefferson Parish Sherriff Joe Lopinto said the search would continue as long it took, to find the missing worker, who was a contractor. Lopinto added that he was in contact with the missing worker's family since the explosion occurred on Sunday.

The Sherriff declined to identify the missing worker or the family until the search was complete and the fate of the worker was communicated to the family.

Oil rig explosion

According to authorities, the explosion occurred on Sunday evening at approximately 7.15pm, during routine maintenance of the oil rig structure. Kenner residents called 911 after they heard and felt the explosion which shook their houses and sent a huge fireball into the sky, with some saying that the air was filled with the smell of burning rubber.

The rig -- which is owned by Clovelly Oil Company in New Orleans -- is situated around one and a half miles north of Kenner, Louisiana. The cause of the explosion is still not clear and Sheriff Lopinto said an investigation was underway to establish what may have caused the accident. Company officials also stated that the cause was still unknown.

Situation under control

Rescue workers and firefighters managed to access the rig, which was still smoldering, and shut off the main gas line. Sherriff Lopinto confirmed that the authorities now had the situation "under control" -- according to ABC News.

Clovelly Oil Company released a statement which said that immediately after the explosion, three oil wells located near the platform were shut off, leaving one gas well still active, which was then shut off by rescue workers.

According to the company spokesperson, Tim O'Leary, oil and gas from a number of wells is stored in the platform, which is basically an underwater tank. Once the tank is full, the oil or gas is then pumped into a barge, ready for transportation.

Number of injured

A total of seven people were injured in the blast, with one person missing.

Three are in critical condition and receiving treatment, while two were admitted to the burn unit of a Baton Rouge hospital, ABC News reported.

Tests on the lake still have to be conducted by authorities to establish if the explosion leaked oil or gas, causing pollution. Authorities have assured residents that their drinking water is safe, as it comes from a different source, the Mississipi River.