Obama administration tightens rules on chemical disclosure

Photo: Fracking operation near Mead (AP Photo)ASSOCIATED PRESS
In this March 25, 2014 photo, workers keep an eye on well heads during a hydraulic fracturing operation at an Encana Corp. oil well, near Mead, Colo. 

A final rule released Friday also updates requirements for well construction and disposal of water and other fluids used in fracking.