EPA announced Dec. 6, 2010, that extensive information about its enforcement actions during FY 2010 is now available online. For the second year in a row, the data has been mapped, and is searchable by criteria such as state, city, zip code, and type of media affected (air, water, etc.).
- Compliance and Enforcement, Annual Results FY 2010;  press release  (includes links to reports and data for 1999-2009).
In general, the Obama administration says that enforcement actions are up sharply compared to what occurred during the Bush administration. But it will take careful analysis of the data to determine whether that is accurate, if there are particular types of actions for which that is most applicable, and what the future holds. For instance, the Obama administration's actions in FY 2010 are substantially reduced in number from the previous year, with 41 fewer cases initiated -- an 11% drop but you'll need to compare the magnitude of the cases each year to know if this is meaningful.
Other issues to address include EPA staffing levels; variations in enforcement from region to region; the nature of ongoing cases; impacts of unfilled administration leadership posts and judge positions as Congress continues to delay appointments; the effectiveness of the voluntary disclosure program; and the net benefits, in health and dollars, to the public from enforcement actions taken so far.
When looking at the reductions in pollutants that EPA is citing, it will help to review the overall picture for pounds of pollutants released as tracked in categories such as criteria air pollutants and toxic releases.
Also of importance is what enforcement actions are justified, but aren't being taken, whether due to the inability of EPA and state officials to identify problems; funding or staff limitations necessitating inaction on known problems; political influences driving reduced enforcement; or negotiations that have resulted in non-enforcement solutions.
For a little perspective on the scope of enforcement versus the scope of potential pollution law violators, there are millions of properties in the country, and some experts estimate that about 20% of all real estate historically has been contaminated (though it's unknown if that same percentage applies to properties operating under today's regulatory environment).
In contrast, the enforcement actions that concluded in FY 2010 affected about 4,500 facilities. That's about 1% of the country's 350,000 or so manufacturing facilities; commercial, military, transportation, institutional, and residential sources add substantially to the number of total potential violators. To get data for each of these facilities, see the latest statistics from the US Census Bureau. In some cases, the data from the 2007 census is available; if it's not, see the 2002 census. This data is updated every 5 years, but it takes several years for all the data to trickle out.