Baltimore City

'Fatberg' of congealed fat, wet wipes and waste discovered under Baltimore's streets, causing sewer overflows

Turns out Baltimore has its own fatberg in its sewer systems – a congealed lump of fat, along with wet wipes and other items that do not break down in sewer systems. (Video courtesy of Baltimore City Department of Public Works)

A massive lump of congealed fat, wet wipes and other detritus — dubbed the "fatberg" — is growing underneath the streets of Baltimore.

The Baltimore Department of Public Works said Monday it discovered the fatberg earlier this month in a sewer main between Baltimore Penn Station and the 1700 block of Charles Street. So far the fatberg has been responsible for a dry weather sewer overflow on Sept. 21 that discharged around 1.2 million gallons of sewage into the Jones Falls, the department said.


A similar fatberg estimated to weigh more than 140 tons was also recently discovered in London's sewer system and is expected to take weeks to destroy. Baltimore's fatberg, however, has been mostly scraped off and sent to the landfill on Quarantine Road.

Congealed fats, oils and grease have blocked a sewer main between Baltimore Penn Station and the 1700 block of Charles Street.

When engineers decided to explore the sewer to determine the cause of multiple sewer overflows in the area, they discovered the fatberg, DPW said. The walls of a 100-year-old, 24-inch wide pipe were caked with congealed fats, oils and grease. Up to 85 percent of the pipe was clogged with the congealed fat, blocking the flow of sewage.Raymond said there were other, smaller fatbergs throughout the city's pipes, but none as large as the one under Penn Station.


Raymond said the city has a fats, oils and grease — known as FOG — prevention program targeting restaurants and other food service establishments. When the substances go down a pipe, they congeal, harden and often attach to other items that don't break down in the sewer, such as wet wipes.

Plus, Raymond added, FOG can block up a homeowner's pipes, causing an expensive call to a plumber.