Gov. Ron DeSantis said a controlled easing is already working to stop a “catastrophic flood” at a defunct Florida phosphate plant reservoir but that the site is “not out of the critical area yet.” Concern grew when the reservoir’s walls started to bulge, causing a danger of breaching that could create a 20-foot-high wall of polluted water, the Associated Press reports. Some 316 Tampa Bay-area homes were evacuated Sunday as work crews struggled to prevent disaster, according to the AP. The directive came after part of the 77-acre Piney Point reservoir’s containment wall shifted, leading officials to believe a collapse could be imminent.

Manatee County Jail Public Information Officer Randy Warren said 345 inmates were moved to “an undisclosed secure location in order to free up bed space for the remaining 721 inmates on the upper level of the Manatee Jail,” which would be in the path of a dam break. The collapsing reservoir is loaded with solid phosphogypsum, a radioactive byproduct from fertilizer manufacturing. However, state authorities insist the water within is not radioactive.