The New York Times' Ian Urbina reported over the weekend that, according to a report released by three House Democrats--Representatives Henry A. Waxman of California, Edward J. Markey of Massachusetts and Diana DeGette of Colorado--natural gas drillers injected hundreds of millions of gallons of 29 known carcinogens into the ground in 13 states while fracking for gas. Reports Urbina: Some of the ingredients mixed into the hydraulic fracturing fluids were common and generally harmless, like salt and citric acid. Others were unexpected, like instant coffee and walnut hulls, the report said. Many of the ingredients were "extremely toxic," including benzene, a known human carcinogen, and lead. Companies injected large amounts of other hazardous chemicals including 11.4 million gallons of fluids containing at least one of the toxic or carcinogenic B.T.E.X. chemicals — benzene, toluene, xylene and ethylbenzene. The companies used the highest volume of fluids containing one or more carcinogens in Colorado, Oklahoma and Texas. In February a congressional investigation found that natural gas drillers injected over 32 million gallons of diesel into the ground in some states during the fracking process.