(Washington, DC) -- Natural gas companies should come clean about what toxic chemicals they use in their drilling. That's the warning from a top environmental aide to President Obama. Joseph Aldy said people living near shale gas reserves are fretting about their water getting contaminated by drilling chemicals. If the gas companies don't publish a list of those chemicals, states may step in and demand the information. And that could slow additional investment. The energy companies often refuse to publicize what chemicals they use in a technique called hydraulic fracturing. Shortened as "fracking," it involves cracking open shale beds to extract natural gas trapped beneath. Aldy said it's still unclear that fracking pollutes groundwater.
