Assumption Parish officials on Thursday lifted the more than 2-year-old mandatory evacuation order in a part of the Grand Bayou area near the Bayou Corne sinkhole but left the order intact in the nearby, larger Bayou Corne community.

The Grand Bayou community, which lies east of Grand Bayou and was part of the original mandatory evacuation order, has been redesignated as a voluntary evacuation area, parish officials said Thursday.

The Grand Bayou community has just a handful of homes and is east of the Bayou Corne community, where more than 150 families once lived and the full mandatory evacuation order remains in place.

John Boudreaux, director of the parish Office of Homeland Security and Emergency Preparedness, said Texas Brine Co. has depleted natural gas pressures in the Grand Bayou area.

“All indications are that the gas is gone, but they (Texas Brine officials) are still going to have to come back” and do more testing to verify that, Boudreaux said.

Once that testing is completed, the evacuation order could be lifted entirely in that area. Boudreaux said he knew of only one person still living in Grand Bayou.

The sinkhole emerged in early August 2012 after a Texas Brine-operated salt dome cavern failed. The cavern’s sidewall collapsed and unleashed natural methane gas deposits that collected in shallow aquifers under Bayou Corne and the nearby Grand Bayou community.

Since then, Texas Brine has been under state orders to remove the gas. Boudreaux and other officials identified the lingering gas, which poses a risk of explosion to residents, as the major impediment to lifting the long-standing evacuation order.

The order was issued less than 24 hours after the sinkhole emerged in swampland between Bayou Corne and Grand Bayou sometime during the night between Aug. 2, 2012, and Aug. 3, 2012.

In all, about 37 million cubic feet of gas have been removed from under the Bayou Corne and Grand Bayou areas since the sinkhole appeared. Boudreaux said that while 15 vent wells, which burn off the methane, are still removing gas, only three are removing significant amounts.

Still, he said, several gas bubble sites in the Bayou Corne waterway and elsewhere continue to release gas.

He said he expected gas venting from wells in the section of the Bayou Corne community south of La. 70 to continue. The largest producing gas well is in the parking lot of the Bayou Corne boat launch.

“That area is going to be a while,” Boudreaux said.

He said none of the vent wells in Bayou Corne north of La. 70 are producing gas and he expects that area would be the next one to have the mandatory evacuation order shifted to a voluntary one.

He said about 13 families still live in Bayou Corne despite the evacuation orders. Many other families have moved out and taken buyouts from Texas Brine or pursued class-action litigation.

Follow David J. Mitchell on Twitter, @NewsieDave.