PHILADELPHIA (CBS)–British engineers say they have launched a “sewer war” against a giant fat blob clogging London’s sewers.

Thames Water officials said on Tuesday it is likely to take three weeks to dissolve the outsized ‘fatberg’.

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They caution against expecting quick results as the fatberg is 250 yards long and weighs as much as 11 double-decker buses.

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The unsavory mass consists of congealed wet wipes, diapers, fat and oil.

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Eight workers are using high powered jet hoses to break up the fatberg before sucking it out into tankers for disposal at a recycling site.