Know your data sources.

California EPA — DTSC Envirostor cleanup database + OEHHA CalEnviroScreen + DTSC HWTS. - searchEnvirostorSites ⭐ ~13.7K cleanup sites. 13 site_types. county UPPERCASE - searchCalEnviroScreen ⭐ ~8K census tracts. PiP via {lat, lon}. Filter minCIscoreP/minCIdecile - searchHazardousWasteFacilities ~107K HWTS RCRA handlers (G/T/TSDF). NO county - searchBrownfields = Envirostor scoped to Voluntary Cleanup + Calmortgage + School Cleanup - getServiceInfo upstream quirks: Authoritative owners only — DTSC_Admin (Envirostor + HWTS) on services3.arcgis.com/Oy2JTCD10wkoelxS, Kelsey.Ranjbar_OEHHA (CalEnviroScreen 4.0) on services1.arcgis.com/PCHfdHz4GlDNAhBb. No standalone Brownfields Feature Service exists; modeled via Envirostor site_type filter.

Utah DEQ — Voluntary Cleanup Program, Brownfields, CERCLIS hazardous-waste sites. - searchVoluntaryCleanup ⭐ ~142 VCP sites (mostly Salt Lake County) - searchBrownfields ~29 sites (Targeted 18 + Other 11 combined) - searchHazardousWasteSites ~145 active CERCLIS sites (~469 incl. archived) - getServiceInfo upstream quirks: AGOL services1.arcgis.com/99lidPhWCzftIe9K owned by UtahAGRC. All 4 layers use SITECNTY (NOT COUNTY) UPPERCASE. Date columns are MM/DD/YYYY strings (NOT epoch). VCP STATE = 'UT' only and POSTTONET = 'Yes' only — degenerate. SITEREM has ARCHIVED Err/No/Yes; default activeOnly filters to "No" (~145 vs raw 469). No UT-published RCRA hazardous-waste-handler service exists — for RCRA G/T/TSDF use EPA Envirofacts (already exposed).