Gasoline Tanker Rollover: Isolation, Foam Capability, and a Bystander With a Lighter
At 22:00 you arrive on a two-lane rural highway for a rolled tanker-trailer. The rig is on its side in a ditch; the tank is not breached, but a valve manifold is seeping gasoline onto the shoulder, and product is running toward a culvert that drains to a creek 300 feet away. The driver is out and walking, dazed. Wind is light from the north. You carry 1,000 gallons of water and 20 gallons of AFFF 3 percent concentrate; the nearest water supply is a dry hydrant 1.5 miles away. Traffic is still moving past the scene, and a bystander is approaching the spill with a lit cigarette lighter.
1. Set your initial actions and notifications in order. Where do you position apparatus and what do you tell dispatch?
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Position and approach first, notifications second, but both inside the first two minutes.
Positioning:
- Approach from the north, upwind and uphill, and stop well short of the spill - the vapor, not the flame, is the hazard.
- Establish initial isolation per the current ERG (Guide 128 for gasoline): a large spill calls for isolation and evacuation on the order of 800 feet in all directions; confirm against the edition in your apparatus.
- Do not drive or park over the runoff path or the culvert. Keep apparatus out of the drainage.
Notifications, in this order:
- Dispatch: confirmed gasoline release, size-up, isolation distance, and a request for hazmat, a second engine, EMS, and law enforcement for traffic control.
- Environmental/state spill response and the downstream water authority - the culvert drains to a creek 300 feet away, and containment at the culvert is time-critical.
- The pipeline/terminal or shipper identified from the placard and shipping papers.
Product ID: UN 1203, gasoline, from the placard and the shipping papers - do not rely on odor alone.
2. Calculate whether you can put a foam blanket on the pool. Show the arithmetic and state your recommendation.
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Arithmetic:
- 20 gallons of 3 percent concentrate makes 20 ÷ 0.03 ≈ 667 gallons of foam solution.
- Assume a pool of roughly 30 by 30 feet ≈ 900 square feet. At a typical hydrocarbon application rate of 0.10 gpm per square foot, that requires about 90 gpm of solution, or about 2.7 gpm of concentrate.
- 20 gallons ÷ 2.7 gpm ≈ 7 minutes of concentrate.
- Water: 90 gpm × 7 min ≈ 630 gallons - most of your 1,000-gallon tank, with a dry hydrant 1.5 miles away.
Recommendation: do not attempt a blanket.
- You can produce one application and nothing else. There is no water for exposure protection, no reserve for reapplication, and no resupply inside a useful timeframe.
- A foam blanket that is applied thin, breaks down, or is disturbed by wind and passing traffic creates a false sense of security over a pool that will re-release vapor.
Do instead: dike and contain with soil and absorbent, block or cover the culvert to stop the run to the creek, control all ignition sources, protect exposures, and hold foam and water for hazmat with a sustainable supply. Never apply water fog to a gasoline pool - it spreads the product and the vapor.
3. Traffic is still moving and a bystander with a lit cigarette is walking toward the spill. How do you handle both, and what is the reasoning?
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Stop the traffic, not just slow it.
- Gasoline vapor is heavier than air and travels along the ground and into the ditch and culvert - the ignition source does not have to be in the pool. A vehicle passing through the vapor area can ignite it from exhaust or catalytic converter heat.
- Block both directions beyond the isolation distance with apparatus and request law enforcement for hard closure. Kill engines inside the zone. No flares, ever, at a flammable liquid release.
The bystander: shout a clear, short command from a distance - do not walk into the vapor path to grab them. Direct them to extinguish the lighter and move upwind and uphill, then keep them there.
- Reasoning: a person with an open flame who is startled or physically grabbed may drop the lighter or panic and move unpredictably. Distance and a clear instruction are safer and faster than a physical intervention.
- Once clear, keep them out of the hot zone; a curious bystander will walk back in if nobody is assigned to hold the line.
Driver: move the dazed driver upwind and away from the vehicle, and have EMS evaluate - a disoriented driver may wander back toward the truck or be a head-injury patient.