AN OIL RIG HAS EXPLODED in the Gulf of Mexico, just west of the site of April’s Deepwater Horizon explosion which caused a massive oil spill.

AP reports that a commercial helicopter company reported the explosion at around 9.30am today.

Thirteen people were blown into the water by the force of the explosion. The platform is still on fire, but was not producing either oil or gas, according to the BBC.

The 13 workers have been accounted for, and one is reported injured. The coastguard is focusing on their rescue.

“Right now we’re focused on search and rescue and then, ultimately, as this thing progresses we’re going to be looking into the cause,” one official told the BBC.

Early reports suggesting that the rig was not leaking oil now appear to be incorrect. The Telegraph reports that the coastguard confirmed that an oil slick up to a mile long has come from the rig.

The coastguard said that the oil platform is owned by Mariner Energy.

Shares in the company fell 5% after reports of the explosion broke, according to Reuters. Shares in a company expected to buy Mariner Energy, Apache Corp, also fell, by just under 2%.

In April, an explosion on BP’s Deepwater Horizon rig killed 11 employees and resulted in 5m barrels of oil gushing into the sea. The Mariner rig is located in shallow waters, and is not believed to be as large or as deep as the Deepwater Horizon rig.