This could damage President Obama’s push for greater use of natural gas as an alternative to oil: A report issued late Saturday by Congressional Democrats has found that the process of tapping into large reserves of natural gas—known has hydraulic fracturing or “fracking”—involves injecting hazardous chemicals into wells. Democrats on the House Energy and Commerce committee said their report was the first comprehensive national inventory of chemicals used by companies that engage in the practice. The report says that between 2005 and 2009, more than a dozen leading energy companies have injected hundreds of millions of gallons of drilling fluids containing possibly carcinogenic compounds, including methanol, benzene, sulfuric acid, and lead. Some 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 added. But many ingredients were "extremely toxic."