Kibera residents have been advised to avoid consuming rain water harvested from the rusted iron sheets lest they risk getting cancer.
Health experts have warned that the rust on the metals is dangerous if allowed into the body. and can cause several types of cancer.
Doctor Mable Anyango of Medicine San Frontiers in Kibera has instead advised the slum dwellers to use such water for other purposes and not for drinking or cooking.
"According to scientists, anything metallic that has rust or whose filings are loose, can cause cancer. It is therefore not advisable for people to use water that run on such metals because they risk getting cancer and cancer cells are very difficult to die," said Dr Anyango on Thursday during a phone interview with this reporter.
"They should not trap rain water from rusted iron sheets because it is very dangerous for their health. Unless the iron sheets have no rust, the water trapped from them should be used for other purposes and not for consumption," she added.