Urban myth - decomposing granite causes malarial fever
Though the medical men of the day pooh-poohed the idea, this urban myth was spread so far that it held up for at least 50 years.
1844 - Friend of China 30.3.44 edition
"M/s Milne and Vesey are contracted to government to fix the drains but week after week nothing is done and now the hot weather is almost upon us. They should not turn over the soil now and expose us to the noxious disease-causing fumes in the decomposing granite subsoil. We prefer instead to rely on the Police Superintendent sluicing the drains daily."