At the state level, there have been several notable pieces of legislation passed in order to mitigate potentially dangerous externalities of hydraulic fracturing. In December 2010, outgoing New York Governor David Paterson signed an executive order instituting a seven month ban on gas drilling in the state. The move came on the heels of Governor Paterson's veto of a bill that would have suspended all new natural gas permits until May 2011 based on concerns of citizens and legislators in the state over potential groundwater pollution. In March 2013, the New York State Assembly passed a two-year moratorium on fracking in the state, effectively extending the ban already in place.
At least five states have considered or passed bills limiting or banning gas drilling in parts of those states out of concerns for public health. In May 2012, Vermont became the first state to completely outlaw fracking anywhere in the state. The ban came just four months after the legislature of New Jersey banned gas drilling for one year, which itself followed New Jersey Governor Chris Christie vetoing a bill that would have permanently banned fracking in the state. In July 2012, North Carolina Governor Beverly Perdue vetoed a bill that would have lifted North Carolina's statewide ban on fracking, citing the need for better safeguards before beginning drilling. In June 2013, Illinois enacted the most restrictive fracking regulations in the US into law.
Other state legislatures have chosen to pass legislation that encourages industry presence and limits the ability of local governments to restrict interference with gas industry development. Pennsylvania's House Bill 1950, otherwise known as Act 13, has been subject to extensive litigation as a result of what some see as a violation of the state's constitution. Act 13 requires all municipalities in the state to allow Marcellus Shale drilling operations in all zoning districts, including those classified as residential. The bill also allows doctors treating those who may be affected by drilling chemicals to access the list of chemicals; however, the doctors are barred from ever discussing the contents of that list. Many groups and municipalities protested the bill as unconstitutionally stripping zoning rights from municipalities, and a legal challenge resulted in injunctive relief until the Pennsylvania Commonwealth Court could decide whether the law should stand. The law was ruled unconstitutional by the Commonwealth Court, and the state Supreme Court has agreed to hear the case.
The most frequent state legislation concerning fractured gas wells has focused on regulating disclosure of fracking fluid's chemical composition to the public. In 2010, Wyoming became the first state to require drilling companies to fully disclose the contents of their fracking fluid. Since then, at least two states, Michigan and Texas, have followed suit with their own legislation requiring disclosure of the chemical constituents of fracturing fluid. Other state bills have sought to protect public water supplies, regulate well inspections and even stop drilling altogether.