The EPA is the primary Federal agency regulating pollution in the United States of America. The EPA Web site provides a great deal of information about the agency and its various programs. The EPA has a very helpful library in New York City (212-637-3185).
Decisions: Lexis has databases for: EPA Administrative Law Judge decisions (ENVIRN;EPALD); EPA Regional Judicial Officer Decisions (ENVIRN;EPARJO); and most EPA documents made available to the public, via the Environmental Law Institute's Guidance & Policy Document Reporter (ENVIRN;GUIDOC).
To see how EPA decisions have been handled by later decisions and the courts, run the citation through KeyCite on Westlaw.
Enforcement Actions: The EPA's "DOCKET" database is "the official EPA database for tracking and reporting information on civil judicial and administrative enforcement cases under all environmental statutes (http://es.epa.gov/oeca/datasys/dcksys.html).
Supplemental Environmental Projects: A party caught in an EPA enforcement action can volunteer to clean up the polluted site as a way of reducing the ultimate penalty. The clean-up is called a "Supplemental Environmental Project" or "SEP." Information about SEPs is posted posted on the Supplemental Environmental Projects page of the EPA Web site.