Unpacking health hazards in fracking's chemical cocktail


Meet the Master Well Formula -- the chemical cocktail that Encana Corp. will use to hydraulically fracture every natural gas well it drills in Wyoming's Jonah Field. Drillers mix 11,800 gallons of this solution with over a million gallons of water and a heavy dose of sand, inject it underground to release gas deposits, and collect the fuel as it spouts to the surface. Thirty to 70 percent of the solution re-emerges with "produced" water and is trucked off to evaporation pits. The rest lingers underground.

Chemical lists like this one weren't publicly available until September 2010, when Wyoming adopted an unprecedented rule requiring companies to publicly disclose them amid rising concern about fracking's potential health effects. But a loophole in the law still allows companies to hide recipes by applying for "trade secret status" -- something the Wyoming Oil and Gas Conservation Commission has granted for about 70 fracking products. The public may know more than before, but not quite enough to understand the full range of hazards.