Residents asked to OK monitoring

Photo provided by Louisiana State Police Air Support Unit -- Some Bayou Corne-area residents who evacuated because of the potential dangers caused when a salt cavern failed, creating a sinkhole, seen from above Wednesday, will ask for permission for contractors to install methane detection and ventilation systems in their homes.
Photo provided by Louisiana State Police Air Support Unit -- Some Bayou Corne-area residents who evacuated because of the potential dangers caused when a salt cavern failed, creating a sinkhole, seen from above Wednesday, will ask for permission for contractors to install methane detection and ventilation systems in their homes.

Bayou Corne-area residents will be given permission forms Thursday allowing Texas Brine Co. contractors to install equipment to mitigate the explosive risk of any methane trapped under the northern Assumption Parish community, company officials said.

The forms are to be distributed when residents pick up their weekly housing assistance checks, company officials said.

The state Office of Conservation on Monday directed Texas Brine to install methane monitors and ventilation systems to avoid an undetected accumulation of methane in enclosed spaces inside slab-foundation homes.

Methane is colorless and odorless and poses an explosive risk at high enough concentrations.

Sonny Cranch, spokesman for the Houston-based company, said Wednesday that the forms ask for contact information and for permission to let Texas Brine representatives do the work.

Cranch said the company is trying to find contractors and specialized methane detectors to comply with the state’s requirement. But he said Texas Brine wants to identify which structures in the evacuated area around Bayou Corne and Grand Bayou have slab foundations.

“We’re trying to get an accurate count and find the personnel that can do this,” Cranch said.

State officials have said homes on piers do not have the same risks for accumulation because the gap between the bottom of the home and the earth dissipates the methane.

The $875 weekly assistance checks are distributed from 9 a.m. to 6 p.m. on Thursdays at St. Joseph the Worker Catholic Church hall, 3304 La. 70, Pierre Part, to residents who have their primary residence in the evacuation zone.

Cranch said Texas Brine would be in contact with property owners whose primary residence is not in the area.

“We thought this (the check distribution) was a good opportunity to start gathering information, and that’s what we’re going to do, but we recognize we still have to get information from the other property owners,” Cranch said.

Office of Conservation and private industry scientists believe methane lurks at low pressures 20 to 40 feet underground inside a shallow clay layer. The gas is suspected as being one consequence of the failure of a Texas Brine salt cavern inside the Napoleonville Dome this summer.

The failure, a wall breach at several thousand feet underground along the salt dome’s western flank, followed months of gas bubbles in waterways and land-based water wells, as well as earth tremors.

Located south of La. 70 South between Grand Bayou and Bayou Corne, the sinkhole prompted an evacuation of 150 homes Aug. 3, the day a slurry hole was found in swampland.

Since then, the hole has widened to 8 acres at the surface but become shallower, at 111 feet deep.

The evacuation remains in effect.

The salt dome is a 1-mile-by-3-mile salt deposit that for years has been the focus of brine mining, hydrocarbon storage, and oil and gas exploration.

State officials have said in-home air monitoring a few months ago and during a resumed effort over the past week have not detected unsafe methane levels.

But Shaw Environmental and Infrastructure geologist Gary Hecox underscored at a Tuesday meeting in Pierre Part the importance of the equipment for residents to safely return home, saying it is virtually impossible to know where the gas might come up through dry land.