An 11-ton mass made up of congealed fat, wet wipes, and household waste broke a pipe in a west London sewer Tuesday.
The sheer weight of the glob, commonly called a "fatberg," broke the 1940s-era pipe, causing £400,000 (600,920 USD) worth of damage that will take around two months to repair, The Independent reported.
Fatbergs form when people dump fats or cooking oils down the drain or flush solid trash like wet wipes down the toilet. Fats that solidify at room temperature -- like bacon grease, for example -- block pipes once they cool down.
Municipal authorities say the problem is getting worse, in part because more people are using wet wipes as toilet paper. Unlike toilet paper, wipes do not break down easily after they get flushed.
"Wet wipes are particularly nasty when people flush them down the toilets," a spokesman for the utility company Thames Water told the Independent on Tuesday. "When all these things come together in our sewers, wet wipes stick to fat and anything that is flushed down toilets that shouldn't be, like nappies and sanitary items."
In the past five years, Thames Water has encountered 200,000 sewer blockages and 18,000 homes flooded with sewage, the company's repair and maintenance supervisor Stephen Hunt told The Guardian.
In 2013, Thames Water workers removed a 15-ton fatberg the size of a bus from the sewer. After that 'berg was discovered, officials in the United States warned that this kind of sewer blockage is not merely a London problem.
Sauk Centre, Minnesota, had a truckload of cloth material from wet wipes vacuumed out of a sewage lift station that same year, Marty Sunderman, the city's superintendent, told USA Today.
"Ideally, what we'd like to see flushed down the system is just toilet paper," Sunderman said. "When you put these type of rags down there, they don't come apart. They just stay with it all the way to the pumps."