Hundreds of residents near Tampa Bay are allowed to return home after being evacuated for fear of a toxic flash flood from a nearby sewage tank.
Emergency work has been completed on the containment wall surrounding the Florida facility.
Investigations by the US Army Corps of Engineers revealed a “reduced risk of catastrophic collapse” at the site of the former Piney Point phosphate plant.
The army corps and local public safety teams worked around the clock for days to pump hundreds of millions of gallons of water out of the tank to relieve pressure on its weakened containment wall.
The crisis began last Thursday when officials discovered leaks in the structure, lined with tall piles of waste phosphogypsum – an industrial by-product of fertilizer manufacturing.
The substance is known to emit radon, a carcinogenic radioactive gas.
State environmental officials said tests of water seeping from the reservoir showed it was not radioactive.
But local officials said they fear an uncontrolled breach in the wall could release a 20-foot torrent of untreated sewage into the surrounding area.
More than 300 homes were ordered to evacuate over the weekend as a precaution.
While the pumping operation has mitigated the threat to homes and businesses adjacent to the reservoir, the sewage drainage is routed to a nearby Gulf Coast seaport, posing environmental concerns.
Ed Sherwood, executive director of the Tampa Bay Estuary program, said pumping the nutrient-rich discharge into Port Manatee at the mouth of Tampa Bay could lead to algal blooms toxic to marine life in the estuary.
Today, Sky News is launching the first daily prime-time news program dedicated to climate change.
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