On November 20, 1980, a Texaco oil rig accidentally drilled into the Diamond Crystal Salt Company salt mine under the lake. Due to a miscalculation, the 14-inch (36 cm) drill bit entered the mine, starting a chain of events which turned the lake from freshwater to salt water, with a deep hole.
It is difficult to determine what occurred, as all evidence was destroyed or washed away in the ensuing maelstrom. One explanation is that a miscalculation by Texaco about their location resulted in the drill puncturing the roof of the third level of the mine. This created an opening in the bottom of the lake. The lake then drained into the hole, expanding the size of that hole as the soil and salt were washed into the mine by the rushing water, filling the enormous caverns left by the removal of salt over the years. The resultant whirlpool sucked in the drilling platform, eleven barges, many trees and 65 acres (260,000 m2) ofthe surrounding terrain.
So much water drained into those caverns that the flow of the Delcambre Canal that usually empties the lake into Vermilion Bay was reversed, making the canal a temporary inlet. This backflow created, for a few days, the tallest waterfall ever in the state of Louisiana, at 164 feet (50 m), as the lake refilled with salt water from the Delcambre Canal and Vermilion Bay. The water downflowing into the mine caverns displaced air which erupted as compressed air and then later as 400-foot (120 m) geysers up through the mineshafts.
There were no injuries and no human lives lost. All 55 employees in the mine at the time of the accident were able to escape thanks to well-planned and rehearsed evacuation drills, while the staff of the drilling rig fled the platform before it was sucked down into the new
depths of the lake, and Leonce Viator, Jr. (a local fisherman) was able to drive his small boat to the shore and get out. Three dogs were reported killed, however. Days after the disaster, once the water pressure equalized, nine of the eleven sunken barges popped out of the whirlpool and refloated on the lake’s surface.