Know your data sources.

Colorado CDPHE — Front-Range air quality, hazardous waste, voluntary cleanup, Superfund. - searchAirQualitySites ⭐ ~15.7K APCD facilities + ~359 CCND monitors merged - searchVoluntaryCleanup ⭐ ~1.7K VCUP + NAD applications. AppStatus: APPROVAL (1465) / WITHDRAWN / DENIAL / PENDING - searchHazardousWasteFacilities ~6.1K RCRA handlers (Generator_Status: VSG/SQG/N/LQG) - searchSuperfundSites ~31 NPL sites, getServiceInfo upstream quirks: Multi-server (AGOL + cohealthmaps.dphe.state.co.us). maps.dphe.state.co.us native UNREACHABLE externally. Air facility schema lean (5 fields, NO County). VCUP fields abbreviated (CityNam, RV_Nmbr). RCRA County UPPERCASE, maxRecordCount=1000.

Montana Department of Environmental Quality USTs + petroleum tank releases + MPDES water permits + air-quality monitoring + hazardous waste via gis.mtdeq.us/hosting. - searchUSTFacilities ⭐ 1.1K UST facility registry - searchTankReleases ⭐ 4.5K PTC cleanup events (Resolved/Open/Rescinded/Reopened) - searchWaterPermits ⭐ 2.7K MPDES discharge permits across 27 types - searchAirQualityMonitors ⭐ 21M hourly AQS readings (33 sites, PM25/O3/NO2/...) - searchHazardousWaste 3K RCRA generators §0: Native CRS 32100 (MT State Plane); outSR=4326. Host historically flaky — handler retries once. Most layers have NO county column (only Hazardous Waste does).

Oklahoma DEQ wellhead protection + remediation + monitoring. Native ArcGIS REST MapServers, no auth. - searchWellheadProtectionAreas ⭐ — drilling-restriction polygons (~5.9K) around PWS - searchRemediationSites ⭐ — Institutional Controls (~890) under formal cleanup programs - searchVoluntaryCleanupSites, searchAccreditedLabs (~151), searchAirQualitySites (28) - getServiceInfo quirks: WHPA has NO name / county / facility id — only ZONE (A/B/C) + SOURCE_IND. Filter zone or bbox. Remediation County values dirty (Garfeld vs Garfield, "Tulsa" vs "Tulsa County") — handler LIKE-matches + Title-Case strips trailing " County". LabAccred Lab_Type has typos. Base_Certification_Status always 'Accredited'. Air POLLUTANTS comma-joined; LIKE-matched.

Texas Commission on Environmental Quality contamination, water, and air datasets. Public ArcGIS REST MapServer, no auth. Layers: - lpst (~30k Leaking Petroleum Storage Tanks) - pst (~19k active Petroleum Storage Tanks) - superfund (~170 state Superfund sites) - vcp (~3k Voluntary Cleanup), brownfield (~210), ihwca (~5.7k Industrial Hazardous Waste) - pws (~19k Public Water System wells), ww_outfall (~4.6k wastewater outfalls) - aqs (~230 air-quality monitoring sites) Counties stored UPPERCASE upstream; returned Title Case. PWS and AQS layers have no county field — pass bbox or near. getGroundwaterOverlay combines Edwards Aquifer + PGMA + GCDs in one call.