Bayou Corne Sinkhole: Cause, Settlements, and Mining Reform

The Bayou Corne sinkhole opened on August 3, 2012, in Assumption Parish, Louisiana, when an underground salt cavern operated by Texas Brine Company inside the Napoleonville salt dome collapsed. The failure swallowed trees and land, released methane into the shallow aquifer beneath homes, forced the evacuation of roughly 350 residents for more than four years, and produced tens of millions of dollars in settlements, state fines, and a package of new Louisiana laws governing salt dome mining.¹²

What Caused the Collapse

Texas Brine’s well, known as Oxy Geismar Well No. 3 or “Oxy 3,” had been used for solution mining: water is injected to dissolve salt, leaving a large underground cavity. The Oxy 3 cavern reached roughly 6,000 feet in depth.¹

State officials later determined the cavern had been mined to within about 150 feet of the salt dome’s outer wall. An earlier survey put the well less than 100 feet from the wall.³ In 2010, Texas Brine applied to expand the cavern and failed a state-mandated integrity test; the well would not hold pressure, and a company executive noted that a “breach appeared possible.” Texas Brine plugged and abandoned the well in 2011, the year before the collapse.⁴

In the weeks before the surface failed, residents reported bubbling in the bayou, diesel odors, and small earthquakes. Scientists later counted hundreds of seismic events preceding the collapse.¹⁵ When the ground gave way on August 3, the northwestern outer wall of the salt dome had failed, letting sediment flow into the void and dragging the surface down with it. The collapse also released a burst of diesel oil that had been used as a protective layer inside the cavern during mining.⁴

How Big It Got

The sinkhole covered about two acres at first. Within a year it had grown to 25 acres. By March 2014 it measured at least 750 feet deep and was still expanding, eventually reaching close to 37 acres, with some accounts putting it near 40.⁶⁴¹ The U.S. Geological Survey classified the event as human-produced, noting that Bayou Corne was not otherwise prone to natural sinkhole formation.

Methane, Water Contamination, and Health

The most immediate danger was natural gas. Methane released from the failed cavern infiltrated the shallow aquifer and bubbled up through yards, puddles, and the bayou. In some homes, concentrations were high enough that residents used monitors to check rooms before entering. Methane was still bubbling up from the ground after rainfall as of mid-2024.⁴

Water testing at the site turned up diesel fuel, benzene, toluene, xylene, ethylbenzene, and polycyclic aromatic hydrocarbons including naphthalene and pyrene. Naturally occurring radioactive material stored in the caverns also showed up: at 80 feet of depth, Radium-226 measured 63.6 pCi/L, more than twelve times the EPA’s drinking water limit of 5 pCi/L.⁷ Residents reported headaches and vomiting, which environmental scientist Wilma Subra correlated with spikes in seismic activity and chemical releases.⁴ An earthen berm was built to shield the bayou, and the sinkhole did not breach the freshwater waterway, though the surrounding area was left as an oily expanse of dead trees and contaminated water.¹

Evacuation, Buyouts, and the End of a Community

Local officials ordered an evacuation within hours of the collapse, and Governor Bobby Jindal declared a state of emergency. The orders stayed in place until October 7, 2016, more than four years later.¹⁸

During the evacuation, Texas Brine paid displaced households $875 per week, a program that totaled nearly $11.8 million.⁹ Most residents never returned. By early 2015, Texas Brine had completed 104 buyouts through a mix of direct purchases and the class-action settlement, shrinking the community from roughly 150 families to about a dozen. A Texas Brine subsidiary, Bayou Corne Holdings, acquired the properties and discussed converting the land into green space.¹⁰

For the 34 properties closed under the class-action settlement whose prices were made public, the average payout was $237,260, with amounts ranging from roughly $40,500 to nearly $779,000. Purchased homes had their utilities cut off, appliances removed, and structures cleaned out.⁹¹⁰

The Settlements

The main resident class action, LeBlanc v. Texas Brine Co., was filed in the U.S. District Court for the Eastern District of Louisiana and assigned to Judge Jay C. Zainey. The class was certified in May 2013. On August 13, 2014, Judge Zainey granted final approval of a $48.1 million settlement covering 269 residents representing roughly 88 families. Claimants received replacement costs for property sold to Texas Brine plus additional damages set by a court-appointed special master. The court awarded 25 percent of the fund to plaintiffs’ attorneys. That settlement was separate from 66 earlier direct buyouts Texas Brine had completed outside court by March 2014.¹¹¹²

A second class action, the Sanchez class, covered owners of uninhabited or undeveloped land within two miles of the sinkhole. Those plaintiffs reached a $1 million settlement with Texas Brine’s pre-2012 insurers (Zurich and AIG entities), dismissing claims against the insurers and all pre-sinkhole subsidence claims against Texas Brine. The district court approved it on February 19, 2020. Texas Brine appealed, but the Fifth Circuit dismissed the appeal in March 2021, holding that the company lacked standing because it could not show legal prejudice.¹² A bellwether damages trial for Sanchez class member Peggy Saizon produced a $30,000 award for diminished land value and lost use.¹³

Who Was Found at Fault

In Louisiana state court, pipeline companies including Florida Gas sued over damage to their infrastructure. After a December 2017 bench trial, Judge Thomas Kliebert Jr. of the 23rd Judicial District Court allocated fault at 50 percent to Occidental Chemical Corporation, 35 percent to Texas Brine, and 15 percent to Vulcan Materials. The judge found that all three had ignored warnings dating back to 1976 and had prioritized financial interests over environmental and safety concerns. An old, non-productive oil and gas well in the area was also found to have contributed to weakening the salt dome wall. Occidental Chemical filed motions for a new trial and said it would appeal.¹⁴

Texas Brine’s own countersuit against Occidental Chemical and Vulcan, seeking roughly $120 million in unreimbursed sinkhole costs, remained unresolved in the most recent available reporting.¹⁴ The state of Louisiana also sued Texas Brine and Occidental Chemical for state response costs, civil penalties, and wetland mitigation funds.¹⁵

State Fines on Texas Brine

The Louisiana Office of Conservation under Commissioner James Welsh moved early. On December 1, 2012, it fined Texas Brine $100,000 for delays in installing a containment system around the sinkhole, in-home gas monitors, and additional observation wells.¹⁶ On December 17, a second penalty of $160,000 followed for continued noncompliance, bringing the total to $260,000.¹⁷ Texas Brine paid the first fine and challenged the second, arguing that permitting and property-access issues had slowed its work. Louisiana Attorney General Buddy Caldwell separately issued a November 2012 demand letter for nearly $3.5 million in state agency expenses.¹⁸

By January 2014, Texas Brine said it had spent $55 million on the state-mandated response.¹⁹ Louisiana spent at least $12 million of its own money on response efforts through August 2013.¹⁵

How Louisiana Changed Its Salt Mining Rules

Before the sinkhole, state rules did not prohibit drilling as close to the outer wall of a salt dome as Oxy 3 had been.⁴ In the 2013 session, the legislature passed three bills that took effect June 12, 2013:

HB 493 required the Commissioner of Conservation to adopt new regulations for solution mining injection wells and caverns, including mandatory reporting of cavern locations, setback requirements, enhanced monitoring, and stability assessments.
HB 494 required sellers to disclose salt dome cavities within a half-mile radius and required operators to file survey plats of cavern well locations in public records.
SB 139 authorized penalties of up to $32,500 per day per violation of conservation regulations, with an additional $1 million for intentional violations causing severe environmental damage or endangering human life, and $50,000 per day for continued defiance of a cease-and-desist order.

The Office of Conservation then issued Statewide Orders 29-M and 29-M-3, effective February 2014. The new rules required a minimum 300-foot separation between new caverns and the edge of a salt formation, mandated the immediate permanent closure of any cavern with walls within 100 feet of the dome’s periphery, and required operators to help residents in potential evacuation zones and reimburse state response costs tied to rule violations. The Commissioner must review each permit at least every five years. The Office of Conservation also halted all new salt mining in the Napoleonville salt dome.²⁰

In June 2018, the Office of Conservation approved a permit for Boardwalk Louisiana Midstream to drill two new caverns elsewhere in the Napoleonville dome, finding the proposed sites far enough from the sinkhole and compliant with the new distance rules.²⁰

Where the Site Stands

Texas Brine still monitors the sinkhole and the surrounding ground. The site continues to pose environmental risks from subsurface instability and residual methane, and gas was still surfacing after rainfall more than a decade after the collapse.²⁰⁴ The community that was there in August 2012 is largely gone.

1
Places Journal. When the Ground Gives Way: Bayou Corne Sinkhole
2
Houma Today. Documentary Looks at Community Impact of Bayou Corne Sinkhole
3
The Advocate. State: Proposed Salt Dome Caverns Exceed Safety Standards, Too Far From Bayou Corne Sinkhole to Pose Risk
4
64 Parishes. An Ominous Effervescence
5
Seismological Research Letters. Pre-Sinkhole Seismicity at the Napoleonville Salt Dome
6
NASA Jet Propulsion Laboratory. That Sinking Feeling
7
Facing South. Environmental Health Risks Detailed at Louisiana Sinkhole
8
NOLA.com. Four Years Later, Last Evacuation Orders Lifted at Bayou Corne Sinkhole
9
The News Star. Bayou Corne Residents Move on After Sinkhole Settlement
10
NOLA.com. Residents Reluctantly Let Go of Cherished Way of Life on Bayou Corne
11
Claims Journal. Judge Approves Bayou Corne Sinkhole Settlement
12
FindLaw. Texas Brine Co. v. Sanchez Class, No. 20-30208
13
GovInfo. LeBlanc v. Texas Brine Co., Sanchez-Saizon Trial
14
NOLA.com. Judge: Fault for Bayou Corne Sinkhole Lies With Texas Brine, OxyChem, Vulcan
15
Fox 8 Live. State Suing Texas Brine Over Bayou Corne Sinkhole
16
Louisiana Department of Conservation and Energy. Office of Conservation Fines Texas Brine $100,000 for Failure to Comply With Directives
17
Louisiana Department of Conservation and Energy. Office of Conservation Fines Texas Brine Additional $160,000
18
NOLA.com. Texas Brine Fights Fines
19
WDSU. Texas Brine Wants Insurance Company to Pay Claims
20
The Advocate. State: Proposed Salt Dome Caverns Exceed Safety Standards