The fat is the product of Londoners’ “sewer abuse” — using the water system as general garbage disposal. Particularly troublesome is Londoners’ habit of pouring used cooking oil down the sink. Once in the sewer, the oil cools, congeals and then traps other garbage. Getting at the goo was not easy. Teams of workers, replete with breathing apparatus to protect them from the rancid smell, had to attack the fat with shovels. They then used water cannons to break down the “fatbergs” inside the sewer.