epaEPA environmental compliance and regulatory data combining three APIs: - ECHO: Enforcement & Compliance History Online - facility search, compliance tracking - Envirofacts: TRI toxic releases, SDWIS drinking water - UIC aquifer exemptions: injection wells injecting into EPA-exempted USDWs (GeoJSON) CRITICAL USAGE RULES: 1. ECHO and Envirofacts are free, no auth required 2. Use searchEchoFacilities() to find regulated facilities 3. Use getAquiferExemptions() for UIC injection wells + exempted-aquifer polygons (by state/wellClass), e.g. Class I/III/V where an aquifer exemption exists 4. AQS methods are now available in the dedicated authenticated connector "epa-aqs" 5. Per-program searches: CWA dischargers, CAA emitters (county→countyFips), RCRA handlers