Tanker Rollover with Flammable Liquid
A tanker truck has rolled over on a highway off-ramp. The tank is placarded FLAMMABLE and UN 1203 (gasoline). The tank is partially breached; a pool of liquid is spreading toward a storm drain. There is a slight uphill slope. The driver is trapped in the cab, conscious but with a leg injury. The weather is 85°F, sunny, with a light breeze from the west. The highway is busy with traffic. Your hazmat team arrives with a pumper, a heavy rescue, and a foam trailer. You have four technicians in Level B suits. The nearest hospital is 20 minutes away. A local fire department is providing traffic control.
1. What are the key hazards and how do you assess the risk to responders and the public?
Read the worked answer
Hazards: Flammable liquid (gasoline) with low flash point (-43°F) and explosive range (1.4-7.6%). Vapors can travel and ignite. Pool fire risk. Environmental hazard to storm drain and waterways. Risk assessment: Use ERG guide 128 (flammable liquids). Establish hot zone based on isolation distances (at least 50 meters in all directions). Consider vapor dispersion with breeze from west; downwind areas at risk. Exposure: Driver trapped in cab with potential exposure to vapors and fuel; risk of fire if ignition source. Responder safety: Level B PPE with SCBA; avoid standing in pools; use grounding and bonding. Public: Evacuate downwind areas; close highway; protect storm drains. Monitoring: Use combustible gas meter to monitor LEL; if >10% LEL, withdraw. Risk vs benefit: Rescue of driver is high priority but must be done safely; consider whether to rescue before or after controlling leak.
2. What containment and control tactics would you employ, and what are the response objectives?
Read the worked answer
Response objectives: Rescue the driver, contain the spill, prevent ignition, protect the environment, and stabilize the incident. Containment: Stop the leak if possible (plug, patch, or upright the tanker). Dike the pool with soil or absorbent to prevent spread. Cover storm drain with a temporary seal (e.g., drain cover) to prevent product from entering. Use foam to suppress vapors and prevent ignition. Control: Use non-sparking tools; ground and bond equipment. Do not attempt to upright tanker without heavy lift and safety officer. Rescue: Coordinate with rescue team to extricate driver using hydraulic tools while a foam line protects. Notification: Call for environmental cleanup and notify downstream water authorities. Decontamination: Set up decon for responders and driver. Safety: Establish a safety officer and continuous monitoring.