Wildfire planning often begins with vegetation, structures, evacuation routes, defensible space, and suppression resources. Those layers matter, but they do not fully describe the risk in wildland-urban interface areas where fire can reach garages, shops, warehouses, water-treatment facilities, agricultural sites, propane storage, fuel tanks, pool chemicals, batteries, pesticides, and other hazardous materials.

This presentation argues that wildfire planning needs a hazmat overlay. Tier II chemical inventory data, facility pre-plans, parcel and structure data, access routes, evacuation zones, water pathways, and responder staging areas should not live in separate planning silos. When a wildfire reaches the built environment, the question is no longer only “what will burn?” It becomes: what may explode, react, vaporize, contaminate runoff, threaten responders, or change evacuation and recovery decisions?

The talk will present a practical open-source geospatial workflow for integrating hazardous chemical planning into wildfire preparedness. The workflow begins with a decision question: which facilities or storage locations require pre-incident attention before a wildfire occurs? From there, the presentation will walk through a lightweight pipeline using open-source tools such as QGIS, PostGIS, DuckDB, Python, GeoPandas, GDAL, and simple web mapping libraries. The workflow will show how teams can ingest or reference Tier II-related facility data where authorized, combine it with wildfire hazard zones, WUI boundaries, evacuation routes, access constraints, drainage pathways, critical facilities, and jurisdictional boundaries, then produce a usable planning layer rather than another ornamental map.

The proposed workflow includes four outputs. First, a facility risk visibility layer that identifies chemical storage sites near wildfire hazard areas or evacuation corridors. Second, a responder pre-plan packet that summarizes facility contacts, access points, known hazards, and operational notes at the smallest useful scale. Third, a runoff and recovery concern layer that helps planners think about where contaminated ash, debris, or fire suppression runoff may require follow-up. Fourth, a governance checklist that clarifies who owns the data, who can see it, how often it is updated, and how it reaches incident command before the emergency.

The presentation will also address constraints. Tier II data may be sensitive, incomplete, threshold-based, or governed by state-specific access rules. Not every chemical risk is captured in Tier II reporting, and not every mapped facility should be exposed publicly. The goal is not to publish sensitive chemical inventories. The goal is to build a responsible planning workflow that helps emergency managers, GIS staff, fire departments, environmental health staff, and public works teams ask better questions before the fire starts.

This talk is designed for GIS analysts, emergency managers, public-sector data teams, environmental planners, and open-source geospatial practitioners interested in wildfire resilience, hazardous materials planning, and practical cross-silo workflows. It connects open geospatial tools to a real operational gap: wildfire maps often show where fire may go, but not enough about what the fire may encounter when it gets there.