BATON ROUGE, La. (AP) — Studies of the area where a sinkhole formed last summer in Assumption Parish indicate scientists suspected as early as 1991 that the Napoleonville Dome was not shaped as state regulators believed when they permitted industry to create caverns in the massive underground formation.

The shape of a salt dome is important because it dictates where to safely locate caverns created by pumping water underground to dissolve the salt, leaving empty space.