Highly polluting discharges have become less common but have taken place since 2000. In 2003, Gatwick Airport Ltd pleaded guilty to charges of allowing chemical pollution to enter the River Mole after a detergent, used to clean rubber and oil from the runway, was washed into Crawters Brook by airport workers. The Environment Agency estimated that up to 5200 fish of 14 different species were killed as the pollution drained downstream. The airport was fined £30,000 by Lewes Crown Court. In May 2003, sewage leaking from a pump operated by Thames Water leaked into the Stanford Brook, killing coarse fish in the Gatwick stream.