Chart: States With Drilling Disclosure Rules

Five states have passed laws or administrative rules requiring drilling companies to reveal some of the chemicals they use when injecting fluids to free natural gas and oil from underground rock formations.

* Wyoming was the first state to require disclosure of fracking fluids.

** Pennsylvania officials did not return calls or emails seeking clarification.
*** The Texas legislature passed the law in May 2011, but state regulators have until 2013 to complete the actual rules.

<strong>Source:</strong> <em>Reporting by Nicholas Kusnetz/ProPublica</em>