State environmental investigators are looking into a possible leak at a phosphate gypsum stack in Polk County. The incident reported last week is the latest at a site with a troubled history.
Mosaic mining officials reported the tear beneath a gypsum stack in New Wales, near Mulberry. The massive retention stack contains toxic process water from the production of fertilizer.
The state Department of Environmental Protection said the potential tear could result in an unknown amount of process water being released into the environment.
Mosaic spokeswoman Jackie Barron told the Ledger newspaper the company has not confirmed a liner leak. Water levels have not dropped, she said, and no off-site impacts have been reported.
In 2016, one of the deepest sinkholes ever recorded in Florida opened beneath Mosaic's New Wales site. It took more than two years to seal the opening where more than 200 million gallons of polluted water spiraled into the Floridan aquifer, which is the main source of drinking water for the state.
Here's the notice sent by Mosaic officials to the state:
![Letter to the Florida Department of Environmental Protection](https://npr.brightspotcdn.com/dims4/default/84b3fa5/2147483647/strip/true/crop/648x1249+0+0/resize/880x1696!/quality/90/?url=http%3A%2F%2Fnpr-brightspot.s3.amazonaws.com%2F9e%2Fd0%2F035aacf94c0682da912d362c2a8c%2Ftear.jpg)