An internal investigation finds the June 13 fire and explosion at the Williams Olefins' Geismar plant was the result of a vapor cloud released after a reboiler ruptured.

The company said in a news release Thursday received by The Advocate that, once the vapor cloud was released, it ignited within seconds from an unknown heat or flame source.

Investigations by the Occupational Safety and Health Administration and the U.S. Chemical Safety Board continue. The incident killed two men and injured more than 100 others.

Traffic at the mouth of the Mississippi stopped Friday as coastal Louisiana prepares for a possible strike by Tropical Storm Karen, which is churning in the Gulf of Mexico.

Karen is forecast to hit the northern Gulf Coast over the weekend as a weak hurricane or tropical storm. A hurricane watch was in effect from Grand Isle to west of Destin, Fla. A tropical storm warning was issued from Grand Isle to the mouth of the Pearl River, including the New Orleans area.

Benteler Steel/Tube has started construction on its hot rolling steel tube mill at the Port of Caddo-Bossier. Gov. Bobby Jindal joined Benteler officials for a groundbreaking ceremony yesterday to formally kick-off the project that is slated to cost $975 million. It will be the Germany company's first factory in the United States.

The Sierra Club is leading a testing program to fight the addition of a third coal terminal in Plaquemines Parish. The state Office of Coastal Management is recommending the terminal be allowed.

John Boudreaux / Assumption Parish Office of Homeland Security and Preparedness

The Assumption Parish sinkhole, a massive opening in the earth that is believed to be the result of a collapsed salt dome used by petrochemical services company Texas Brine, underwent a sudden growth spurt around 5:30 p.m. Wednesday.

Parish officials were on hand to witness a process called a "slough-in," where the edge of the sinkhole collapses into the hole. Assumption Parish Office of Homeland Security and Emergency Preparedness director John Boudreaux took this video:

A lawsuit filed this week against dozens of companies in the oil industry has already gotten stiff political opposition. A Loyola University law professor sees a major legal battle erupting ahead for the levee board suing for wetlands repairs.

A natural gas well explosion in the Gulf of Mexico is reviving concerns about drilling safety, three years after the Deepwater Horizon explosion led to the biggest offshore oil spill in U.S. history.

Forty-four crew members were evacuated Tuesday morning after the well blew out in shallow water, some 55 miles off the coast of Louisiana.

While the cause of the blowout is still under investigation, a key safety measure failed on the rig.

Natural gas is no longer escaping from a blown-out oil rig off the Louisiana coast. Only a small flame is burning off residual gas in the pipeline.

A New Orleans-area levee district is suing 97 oil industry companies for damaging wetlands that protect the city from hurricanes. The district is seeking repairs that could cost several billion dollars.

Teams of workers are mobilizing in the Gulf of Mexico to try to stem a natural gas leak at an offshore drilling rig that exploded and caught fire Tuesday. The rig off the Louisiana coast has been partially destroyed by the out of control blaze, and firefighting boats are on the scene.