A 250-meter-long mass weighing 130 metric tons has blocked a Victorian-era sewer tunnel in the east side of London, the BBC reports.

To put the size and heft of the clog in perspective: it’s longer than two American football fields and as heavy as 11 double-decker buses. The mass is a concrete-hard amalgamation of flushed items, including condoms, diapers, and—most notably—wet wipes that have all been cemented together with oils and fats that were also washed down drains. For that reason, these types of clogs are sometimes called “fatbergs.”

Authorities expect it will take three weeks to remove.

While the size of this particular clog is extraordinary—possibly the largest ever reported—its existence is no surprise to those who manage wastewater systems. In fact, it highlights a growing problem in the world’s sewer systems: unflushable flushables.

The popularity of wet wipes and other pre-moistened disposable wipes in the last few decades has led to messy questions about what it means to be “flushable” and what those products are doing to our wastewater infrastructure. In 2015, personal wet wipe sales hit an estimated $2.2 billion, The Atlantic pointed out last year. And while manufacturers say their standards for “flushability” are sufficient, municipal utilities and consumers have been plagued by clogs and damages to wastewater equipment that they allege are from flushing the “flushable” items.

In 2013, English authorities found a 10-metric-ton “bus-sized” fatberg in another English sewer that cost £400,000 to remove. And according to a 2015 report by C&EN, New York City spent more than $18 million in recent years to remove wipes from its wastewater treatment facilities.

Numerous consumers have brought lawsuits against wipe makers over damaged plumbing. Likewise, the city of Wyoming, Minnesota, filed a federal class-action lawsuit in 2015 against six wipe makers over allegations that the flushed products damaged municipal infrastructure. The lawsuit cited many other cities and counties that had suffered wipe-damage, including Denver; Orange County, California; Raleigh, North Carolina, and San Antonio, Texas.

The problem is likely costing billions worldwide, according to Rob Villee, the executive director of the Plainfield Area Regional Sewerage Authority in New Jersey. “This is an international problem,” he told The Atlantic. “This isn’t the United States, this isn’t Canada. It’s England. It’s Spain. It’s Australia. It’s Israel, France.”

Wipe makers and nonwoven fabric industry representatives acknowledge that there are problems with some wipes on the market. But they argue that flushability testing standards the industry has laid out are working for manufacturers that follow them. The standards involve seven tests that assess disintegration and degradation, drain clearance, and fiber settling. The wipe industry also argues that most of the clogs, fatbergs, and infrastructure damage are caused by consumers flushing products that were never intended to be flushed or labeled as flushable, such as baby wipes.

“We agree that there are issues out there. We have great empathy for what the wastewater industry is facing,” David Rousse, president of the Association of the Nonwoven Fabrics Industry (INDA) told C&EN. “But, there are many, many kinds of wipes.”

Other experts disagree with the stance. “It’s an exaggeration to say that it’s not the flushable wipes causing the problems,” Cynthia A. Finley told C&EN. Finley is the director of regulatory affairs with the National Association of Clean Water Agencies, an advocacy group that represents publicly owned sewage treatment plants.

Wipes are clearly part of the new fatberg, according to Matt Rimmer. He’s the head of Thames Water utilities’ waste network, which is chipping away at the mammoth clog in London. Calling the latest fatberg a “total monster," he vented to the BBC about the larger issues: