you have to read article... an extract...
....But criticism of sludge has come from quarters that no one could call over-emotive. Robert Swank, a senior Environmental Protection Agency official, testified to the US Senate in 2000 that US regulations "don't pass scientific muster". In 2002, a senior EPA microbiologist called Dr David Lewis led a University of Georgia study that analysed 53 incidents where health issues had been reported near sludge sites, and found a puzzlingly high incidence of staph infections. Lewis thought chemical irritants in sludge may be causing lesions that allowed staph easy access to the bloodstream. He told reporters: "In my opinion, the land-spreading of sludge is a serious problem. We have mixed together pathogens with a wide variety of chemicals that are known to enhance the infection process. It makes people more susceptible to infections." Taking excrement from hundreds of thousands of people, mixing it and spreading it on land is simply "not a good idea". Not long afterwards, he was fired....