Historic floods have continued to devastate Colorado, sweeping through 15 counties, leaving more than 1,200 people unaccounted for, shattering rainfall records, cutting off entire communities, destroying or damaging roughly 19,000 homes and forcing thousands to evacuate. The National Guard has been deployed. Five people are confirmed dead, and a sixth — an elderly woman — is presumed dead after her home washed away. Many have raised concerns about toxic contamination from oil, gas and chemicals used in the gas-drilling process known as fracking, after at least one industry pipeline broke and began leaking.