Rail Yard Ammonia Release: Command Structure at a Jurisdictional Boundary

Yes. Unified Command is appropriate when multiple agencies have jurisdictional or functional responsibility for the incident and share the same objectives. Here, the leak affects both city and county residents, the rail company controls the tank car and track, and evacuation crosses jurisdictions. A single city IC would not reflect county authority or rail-company responsibility.

I would recommend Unified Command with the city fire battalion chief, a county sheriff representative, and a qualified rail-company representative. Public works and public health should be Liaison Officer contacts or Technical Specialists rather than UC members unless they hold direct jurisdictional responsibility for a major objective. The UC should agree on one set of incident objectives, one Incident Action Plan, and one Operations Section. Each UC member retains authority over their own agency’s personnel and equipment, but no agency gives tactical orders outside the UC-approved plan. This preserves unity of command while avoiding duplicated evacuation orders.

If the rail representative cannot commit resources or make decisions, the UC should still include city and county, with rail as a technical specialist. The key test is not the number of agencies present, but whether separate jurisdictions or functions must jointly set objectives.

The Operations Section Chief should organize by geographic division and by function where needed. A workable first-period structure is:

• Division A - residential evacuation west of the yard: 1 engine, 2 sheriff patrol units, evacuation bus, and a volunteer engine once checked in.
• Division B - hot zone/leak control at the rail yard: city hazmat team, rail contractor hazmat team, 1 engine for water/backup, and public works supervisor for access control.
• Medical Group - 2 medic units and ambulance resources, with a treatment area outside the evacuation zone.
• Traffic/Perimeter Group - remaining law enforcement and public works for road closures.

This keeps each supervisor at roughly three to five subordinate resources, within the manageable span of control of three to seven. The Operations Chief should not personally direct all 14-plus resources. Divisions handle geographic areas; groups handle functional tasks. The hazmat team should not be split across divisions because it is a specialized resource with its own supervisor. As self-dispatched units arrive, they must check in at staging before assignment; unneeded units should be demobilized rather than folded into divisions without accountability.

The controlling principles are dispatch/deployment, accountability, and unity of command. Resources must be requested, dispatched, checked in, and assigned through the ICS organization. Self-dispatched units that go directly to work create freelancing: command does not know their location, capabilities, or safety status, and they may receive conflicting orders from their own officers and from the IC.

The immediate action is to establish a staging area and a check-in function, usually under the Planning Section’s Resource Unit Leader or Logistics. Arriving volunteer units should be directed to staging, logged by name, agency, qualifications, and equipment, and held until Operations requests them. The IC should issue a clear order that no unit is assigned without check-in and a briefing. Units not needed should be demobilized promptly. If a volunteer unit is already working in an area, command should either formally assign it under a division/group supervisor or withdraw it after a safe handoff. This preserves accountability and prevents an unaccounted-for resource from becoming a safety or liability problem.