PUBLIC SAFETY BRIEFING Chemical Hazard Zone Analysis & Multi-Facility Risk To: Surprise City Council & Local Emergency Managers Date: May 27, 2026 Subject: Rinchem RMP Alternative Release Impact on Proposed Detainee Facility & Local Schools Source: EPA Risk Management Plan (RMP) — Offsite Consequence Analysis (Reading Room, April 23, 2026) 1. Executive Summary: The Overlooked Hazard Profile This briefing addresses a critical, unmitigated public safety conflict within the industrial corridor of Surprise, Arizona. Current municipal planning discussions regarding the proposed Immigration and Customs Enforcement (ICE) processing and warehousing facility — designed to hold 542 detainees — have entirely omitted the official hazard footprint of the adjacent Rinchem Co. Surprise Facility. According to Rinchem's legally binding EPA Risk Management Plan (RMP), a localized mechanical failure at their site will yield an Alternative Release Scenario (ARS) that disperses a highly toxic, ground-hugging chemical plume to a 2.7-mile endpoint distance, encompassing a baseline residential population of 73,642 people, over a dozen active educational campuses, and the exact site of the proposed detention warehouse. CRITICAL REGULATORY DISTINCTION This data does not represent a hypothetical 'Worst-Case Scenario' under impossible weather conditions. An Alternative Release Scenario reflects a realistic, baseline mechanical failure (such as a manifold or seam fracture) modeled under typical, everyday local Surprise weather conditions. The facility has legally acknowledged that this event is a plausible operational risk. 2. Chemical Dynamics of the Threat Vector The specific chemical vector analyzed in the ARS is a release of 20,000 lbs of Anhydrous Hydrogen Chloride (HCl) from a failed manifold or structural seam. The physical and chemical behavior of this compound creates an immediate, highly specialized operational challenge for local emergency services: Flash Acidification: Anhydrous HCl is a pressurized liquefied gas. Upon structural containment failure, it undergoes instant flash vaporization. Because it is highly hygroscopic (water-seeking), it instantly reacts with atmospheric moisture, transforming from an invisible gas into a dense, opaque white mist of airborne hydrochloric acid aerosol. Ground-Hugging Plume Trajectory: Due to the extreme drop in temperature during depressurization and its reaction with atmospheric water, the resulting acid cloud is significantly heavier than air. It does not rise or dissipate harmlessly into the upper atmosphere; it hugs the topography, rolling at ground level directly across transportation lines and into adjacent structures. Toxic Endpoint Boundaries: The 2.7-mile endpoint distance is defined precisely as the distance at which atmospheric concentration decays to the federal toxic endpoint of 0.030 mg/L (approximately 20 ppm). Within this entire 2.7-mile endpoint distance, air concentrations are modeled as hazardous to human life under the ARS conditions. 3. Institutional Vulnerability & Mass Incapacitation Exposure The proposed placement of a locked, high-occupancy facility immediately adjacent to this chemical footprint introduces a profound logistical and human rights liability. Concurrently, the plume intersects critical public infrastructure, specifically local schools. The Proposed ICE Detention Facility (Immediate Impact Zone) Sited directly across the street from the Rinchem facility, the proposed warehouse is positioned inside the immediate high-concentration zone of the plume, where HCl concentrations would vastly exceed 20 ppm at close range. The Evacuation Impossibility: Standard industrial facilities rely on immediate evacuation or rapid shelter-in-place protocols. For a locked facility housing 542 detainees under armed guard, immediate evacuation is logistically impossible during an airborne toxic hazard event. The time required to secure, organize, transport, or safely relocate 542 non-free individuals under emergency conditions guarantees prolonged, high-concentration acute chemical exposure. Educational Institutions Within the 2.7-Mile Endpoint Distance Over a dozen educational facilities sit directly within the path of this acknowledged chemical hazard zone. Most notable is Dysart High School, alongside surrounding elementary and charter schools, placing thousands of minors within the toxic endpoint perimeter. Facility / Institution Vulnerability Profile Operational Impact Under ARS Event Proposed ICE Facility (Directly adjacent) 542 Detainees (Locked / Non-Free) Immediate exposure at maximum concentration. Total failure of traditional evacuation capabilities due to custodial security constraints. Severe legal and humanitarian liability. Dysart High School (Within endpoint perimeter) ~1,600+ Students & Staff (Minors/Adolescents) Rapid-onset respiratory distress. Acute hazard to outdoor athletic fields. High probability of HVAC-driven indoor contamination if not isolated promptly. Surrounding K-8 & Charter Campuses (12+ locations inside zone) Thousands of Young Children (Pediatric Physiology) Children possess higher baseline respiration rates, making them physiological multipliers for toxic inhalation hazards. Mass panic risks during localized lock-downs. 4. Actionable Directives for Municipal Leadership To ignore these overlapping vectors is to accept severe, quantifiable municipal liability. The City Council must shift its evaluation of the proposed warehouse from a simple zoning and land-use issue to a comprehensive, multi-agency safety evaluation. The following actions are requested: 1. Mandate a Joint Hazard Intersect Study: Require the Maricopa County Local Emergency Planning Committee (LEPC) and the Surprise Fire-Medical Department to formally review the Rinchem RMP alongside the specific security and operational blueprints of the proposed ICE facility. 2. Require an Incarceration Evacuation Matrix: Before any zoning permits are issued or finalized for the detention site, developers must submit a fully verifiable, zero-delay evacuation plan demonstrating how 542 locked occupants can be safely protected or moved out of an airborne hydrochloric acid plume. 3. Enforce Industrial-Grade HVAC Mitigation: If the project proceeds, mandate that the detention facility be engineered with advanced, automated chemical-sensing isolation dampers and positive-pressure clean air systems capable of completely sealing the building automatically upon gas detection. This document was prepared compiling publicly available regulatory disclosures submitted by industrial operators to the Environmental Protection Agency under Section 112(r) of the Clean Air Act. Offsite Consequence Analysis data was obtained via EPA reading room review (Sandra Day O'Connor Federal Courthouse, Phoenix, April 23, 2026) and is drawn from Rinchem's own submitted RMP (EPA Facility ID 100000253325).