The floodwaters contain a number of hazards to the environment and human health. The Houston Health Department stated that "millions of contaminants" were present in floodwaters.Hiroko Tabuchi & Shelia Kaplan, A Sea of Health and Environmental Hazards in Houston's Floodwaters , New York Times (August 31, 2017). These include E. coli and coliform bacteria; measurements of colony-forming units showed the concentrations were so high that there were risks of contracting flesh-eating disease from the water.
