A sinkhole has opened up in Mulberry, Florida underneath a storage pond for wastewater from a fertilizer plant, draining an estimated 980 million liters (215 million gallons) of contaminated water into Florida’s main aquifer. Despite having actually occurred three weeks ago, the public has been told not to panic as the groundwater that has been tainted moves very slowly and has yet to reach public households, and the fertilizer company is apparently trying to pump out the contaminated water.

There are more sinkholes in Florida than in any other state, due to the geology of the region, which sits upon highly porous carbonate rock that is prone to forming vast voids underground that then collapse in on themselves due to the weight above. This latest event occurred underneath a large storage pond belonging to the biggest producer of phosphate fertilizer in the world, Mosaic. Known as “gypsum stack” the waste material contains sulfate, sodium, and gypsum, including the slightly radioactive phosphogypsum.

About 14 meters (45 feet) in diameter, the sinkhole was originally discovered on August 27, and is thought to drop all the way down to the massive aquifer below. Filled with groundwater, the aquifer is the main source of freshwater for most of the state, with many of the major cities, such as Tallahassee, Jacksonville, and Orlando, relying on the water found within it. When the hole was first detected, the fertilizer company began diverting the gypsum stack into other wastewater ponds, but not before roughly 980 million liters (215 million gallons) of the stuff had drained into the aquifer.

This isn’t the first time that a sinkhole has opened up underneath one of the company’s ponds, with another occurring in 1994. Ten years later, they were responsible for another environmental disaster – in 2004, during Hurricane Frances, around 300 million liters (65 million gallons) of contaminated water entered Tampa Bay, killing thousands of fish. Last year the company finally settled a massive federal environmental lawsuit, agreeing to $2 billion worth of upgrades and clean-up costs due to its hazardous waste pollution.

With this latest incident, the Florida Department of Environmental Protection is obviously aware of the situation, and has told residents that there is no risk to the public due to the slow speed at which the underground water moves. This still hasn’t stopped a backlash from local residents and environmental groups, angry not only that this has occurred, but that nothing was said for three weeks after the incident.