BATON ROUGE, La. (AP) - As state scientists monitored the toxicity of naturally occurring radiation at a slurry hole in Assumption Parish, residents said Thursday they were furious with their public state officials because they think they have been withholding information.
The Louisiana Department of Environmental Quality said the slurry hole near Bayou Corne is near areas that have been used for oil and gas exploration. Low levels of radioactivity may be remaining from the work, though not at harmful levels, officials say.
"Out of abundance of caution and because of the ongoing incident, I have decided to further enhance our monitoring efforts," DEQ Secretary Peggy Hatch said in a statement.
Officials said the first set of 15 samples from the area show that there are no detectable levels of naturally occurring radioactive material on the surface of the sinkhole and Hatch says they're confident residents aren't at risk for exposure.
Department spokesman Rodney Mallett said such material tends to accumulate in low levels on equipment used to drill for oil and gas.
Gas bubbles have been erupting in the area for weeks. Residents have been especially alarmed at the possibility of a natural gas explosion after 28 residents in Grand Bayou had to evacuate their homes on Christmas 2003 because natural gas was seeping from a salt dome storage cavern and bubbling up into water wells.
Residents have also been reporting earthquakes but despite a battery of tests conducted by federal, parish and local officials, no one has been able to figure out the source of the tremors.
Randy Rousseau, who lives in Grand Bayou and owns a body shop in Belle Rose, said he's noticed tremors for years. He eventually moved out of his house because he didn't feel safe and has been unable to sell it because the property value plummeted after several small sinkholes opened up in his yard.
Scientists said at a community meeting Tuesday the sinkhole might be related to a brine cavern owned by Houston-based Texas Brine Co. contained within an underground salt dome.
The Advocate reported Thursday that officials at Texas Brine have known since at least January 2011 that there have been problems with the structural integrity of a brine cavern that was plugged in June 2010. Officials did not mention those issues at the meeting.
"It's what I've been saying all along, that they've been hiding things," Rousseau said. "I think our local officials are trying to do the best they can, but I think they're being hindered by the higher-ups hiding things."
Rousseau said he was especially worried after a parish official had him fill out a form asking him to list his next of kin Thursday morning.
"That's a little disturbing to me. They said it's in case they can't reach us to evacuate. But I mean, come on. They can reach everyone," he said.
Rep. Joe Harrison, R-Napoleonville, said he wants more transparency and answers from the Office of Conservation. He said he had no idea about structural issues within the brine cavern until he read about them in the paper.
"There is a serious lack of competence now in the state, and we knew nothing. Nothing. Why did they close the mine? We didn't get any answers. It's a real lack of competence now," Harrison said.
Sonny Cranch, spokesman for Texas Brine, said they're continuing to monitor the area for any changes.
"We've installed booms around the perimeter of the sinkhole to contain any floating contaminants, the diesel, anything else," Cranch said.
Dr. Madhurendu Kumar, director of the state Department of Natural Resources' oil and gas division, said the sinkhole could have been caused by structural problems within the salt dome that sits underneath it. The wall of salt between the brine cavern and the salt dome might be thinner than experts were led to believe, he said.
He said this sinkhole was unusual because it sits on the edge of the dome, when sinkholes normally sit right on top.
Officials said the sinkhole, which has swallowed up and liquefied a 372-foot wide circle of swampland, has not grown in size since Saturday. The owners of four natural gas pipelines nearby were asked to depressurize and vent off their pipelines as a precaution after the slurry area bent a 400-foot-long section of pipeline.
Gov. Bobby Jindal declared a state of emergency Friday in Assumption Parish and ordered an immediate evacuation of 150 homes and several businesses. The evacuation remains in effect.