To date, at least 36 states impose various types of severance taxes on natural gas development, while 31 states specifically tax on the extraction of oil and gas. Here in Pennsylvania, operators pay a per-well impact fee, which generated more than $400 million in new revenue over the last two years. This impact fee is in addition to the more than $1.6 billion in taxes and more than $500 million road improvement investments Marcellus Shale operators have made over the past few years.