The emergence of a natural salt dome in southeastern Veracruz triggered fears among residents that a volcano was forming, but state officials say their worries are unfounded.

However, the dome, which appeared in the municipality of Moloacán, does pose other possible risks, including contamination of water supplies, possible burns from contact with boiling saline-infused mud, and accidents due to possible soil erosion.

Officials said the saline was damaging flora and fauna exposed to the salt-infused mud near the dome and contaminating the water. The boiling hot mud is releasing vapors that had led to residents’ fears about a volcano.

Biologists with the Civil Protection agency said the phenomenon was caused by movements in the ground that are causing shifting and cracks that allow certain gases to escape.

State officials also warned area residents not to drink from local water supplies nor give animals water from nearby sources like streams. In addition, they warned residents not to turn the dome into a local attraction because of possible soil erosion around it.

Salt domes can occur in sedimentary basins where thick salt deposits dating back up millions of years have been buried by at least 500 feet of sediment. If the sediment layers exert enough pressure on the salt layer, it can cause some parts of the salt layer to push upward through sediment.

Salt domes have appeared in the area before. Three domes appeared in 2014 between Moloacán and the municipality of Las Choapas. The natural occurrence eventually disappears, they added, and predicted that new one would last anywhere from a few weeks to a few months.

Sources: Milenio (sp), Imagen de Veracruz (sp)