Prior posts have noted that most adverse environmental impacts from fracking operations occur in surface or shallow aspects of operations (e.g., leaking waste storage ponds). However, be that as it may, a study by the Associated Press has found that, on average, the Federal Bureau of Land Management ("BLM") fails to inspect 4 out of every 10 new oil and gas wells near national forests and fragile watersheds or otherwise identified as higher pollution risk projects. As you might expect from the qualifier "on average", there is significant variation from State to State.
According to BLM records for fiscal years 2009 to 2012, roughly half-plus of wells on Federal and Indian land in Colorado, Utah, & Wyoming were not checked. BLM records showed that 1,400 high priority wells in 13 States were not Federally inspected. Wyoming had the most, 632 (45%); South Dakota had 1 out of 2 uninspected; and Pennsylvania had 1 out of 6. In contrast, all high risk wells were inspected in Alabama, Michigan, Mississippi, New York, Ohio, & Texas.
Just to put the well figures in perspective, there were nearly 500,000 producing gas wells in 2012, according to the Energy Information Administration. BLM field personnel note that chronic underfunding of their activities has been a problem for about a decade in some regional offices. BLM budget requests for executing required inspections have not successfully passed in Congress for the last several years.
BLM inspects wells on public lands. States have their own inspection programs, which were not addressed in the AP study. Information on State studies in 2011 can be found at http://www.blm.gov/wo/st/en/prog/energy/oil_and_gas/Energy_Facts_Enforcement.html. The AP study can be found at http://m.apnews.com/ap/db_289563/contentdetail.htm?contentguid=udIa3DsR.