Feb. 11 (UPI) -- Australia's Sydney Water confirmed there is a massive fatberg estimated to be "the size of four buses" in a difficult-to-reach position under a wastewater plant.
The supersized fatberg -- a collection of fats, oils and greases -- under the Malabar wastewater treatment plant is now believed to be the source of black balls that have periodically been washing up on Sydney-area beaches since 2024.
The balls were originally thought to be tar from a possible oil spill, but an analysis at the University of New South Wales discovered they contained human feces.
Sydney Water managing director Darren Cleary said officials are now aware of a giant-sized fatberg in the tunnels underneath the Malabar plant.
"We don't know exactly how big the fatberg is," Cleary told the Australian Broadcasting Corp. "The size of four buses, that would be the maximum potential extent of it. It may be that, it may be slightly smaller. We don't exactly know."
He said the blockage is located in an "inaccessible dead zone."
"There's a component of that tunnel which we can't safely access," Cleary said.
He said the balls that have been washing up on beaches are likely caused by water flows in the tunnels skimming across the surface of the fatberg and breaking off small pieces.
"I can't guarantee there won't be debris balls in the future. We are doing what we can to minimize the risk of that occurring," Cleary said. "We certainly do apologize for the inconvenience that it's caused."
Sydney Water announced a plan in January to overhaul the Malabar plant's system to stop the flow of the debris balls. The plan, with an estimated cost of over $2 billion, is expected to take about 10 years.
