Napoleonville - Gov. Bobby Jindal declared a state of emergency Friday in Assumption Parish after officials ordered an immediate evacuation of the Bayou Corne area because a slurry area appeared to be expanding.

"The fear of the unknown prompted the evacuation order," said John Boudreaux, director of the parish's Office of Homeland Security and Emergency Preparedness. "The fear of it possibly compromising either the nearby pipelines or cavern storage areas, that could cause a risk to the community."

Boudreaux said about 150 homes are affected by the order. He was unsure how long it would remain in effect. The governor's emergency proclamation extends through Sept. 2 unless terminated earlier.

Boudreaux initially estimated the area was about 200 feet by 200 feet. He said it's on private land near the Texas Brine Co. LLC facility. Police Jury President Marty Triche said that in speaking with the Louisiana Department of Natural Resources and the Governor's Office, he was advised there was a risk that the slurry area could grow to a size of about 2,000 feet across.

Triche told The Advocate that authorities are concerned that if the slurry area expands to that extent, it could affect natural gas, water and other wells working the nearby Napoleonville salt dome.

Sheriff's deputies would not force residents to move, Triche said, but he was issuing the mandatory evacuation order similar to one that would go out if a hurricane threatened the area.

The police jury said the Office of Emergency Preparedness is working with the Red Cross to open a shelter at 8 a.m. Saturday.

The parish president said the evacuation area extends from a point just west of Bayou Corne and La. 70 eastward to the point where La. 69 intersects La. 70.

He added that La. 70 would remain open to vehicular traffic.

A large "slurry area" that has toppled trees formed overnight Thursday in the swamps of northern Assumption Parish below La. 70 where unexplained gas bubbles have been rising from nearby bayous and tremors have been felt for more than two months, parish officials said.

The area's formation - which parish officials initially described as a sinkhole - was also accompanied early Friday by a slight diesel smell in the area that has since dissipated, parish officials said.

The odor prompted parish officials to call in a variety of state agencies Friday morning.

Bob Gresser, a spokesman for Houston-based Texas Brine, said employees detected a hydrocarbon smell resembling diesel in the vicinity of a plugged well tied to a salt cavern around 6:30 a.m.

Gresser said company officials do not believe the smell was emanating from the well, which has been out of service for two years. He said they believe it was coming from the "slurry area," although that is still under investigation.

He said the brine facility is operating normally and the company is cooperating with authorities.

A brine facility mines salt from the Napoleonville dome and then stores hydrocarbons such as natural gas in the caverns that remain after mining is completed.

Natural gas has been seeping up from Bayou Corne and Grand Bayou, which run below and along the side of the reported "slurry area." A suspected water well in the same area has also been venting natural gas.

Residents have also reported contemporaneous tremors in the area, which has a known fault and a salt dome that is mined for brine and used for storage of natural gas and other hydrocarbons.

Federal, state and parish official have been unable so far to pin down the cause of the earthquakes or the source of the natural gas releases, despite of battery of tests on the oil, gas and brine production infrastructure in the area.

The American Red Cross issued this press release Friday night on shelter for evacuated residents:
The American Red Cross is opening a shelter Saturday morning in Assumption Parish after officials called for an evacuation of the Bayou Corne/Grand Bayou areas. Volunteers will open the shelter at 8 a.m. at Belle Rose Middle School in the community of Belle Rose. Evacuated residents who are unable to stay with friends or relatives are welcome at the Red Cross shelter. Make sure to bring required medications and food for any special dietary needs. The Red Cross has been coordinating with parish officials throughout the day, as well as working with local partners.