Unattended Gasoline Delivery Into a Taped-Over Tank
It is 22:40 and you are delivering 4,000 gallons of gasoline to a card-lock station in Peoria. The station is unattended. You park, set the parking brake, leave the engine idling to run the truck-mounted pump, and walk 30 ft to the underground tank. The tank is a 6,000-gallon regular tank that reads about 60% full on the station gauge, and its vent pipe is covered with a plastic bag taped in place. You drag out the 4-inch hose, connect it to the fill pipe first, then clip the ground cable to a painted section of the station's loading rack, then start pumping. Two minutes later you remember the truck's parking brake is set but the wheels are not chocked, you need to walk into the station office to reset the card reader, and your phone shows two missed calls from dispatch.
1. Identify the unsafe acts and lay out the correct sequence for this transfer from parking to disconnect.
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Unsafe acts in the order they occurred:
- Grounding after connecting the hose. Grounding and bonding must be established before any hose is connected or any valve is opened, so the truck and the storage tank are at the same potential before flammable vapor can be released.
- Grounding to a painted surface. Paint is an insulator. The clamp needs clean bare metal.
- No bonding connection between the truck and the receiving tank.
- No wheel chocks, which matters when a driver is away from the brake valve.
- The taped-over vent, which is a pressure and vapor problem, not a housekeeping detail.
- The plan to leave the transfer.
Correct sequence: park clear of traffic; set the parking brake and chock the wheels; engine off except where it must run to drive the pump, and never with the driver away from the controls; no smoking and no ignition sources; check the receiving tank's gauge and available outage; ground the truck to bare metal; bond the truck to the storage tank; connect the hose; open valves slowly and watch for leaks; stay with the transfer the whole time; close valves; disconnect the hose; break the bond; remove the ground last; replace caps and check for drips before moving.
2. Do the volume math for this delivery. What happens if you drop all 4,000 gallons, and what do you do before opening the valve?
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The tank holds 6,000 gallons and is 60% full, so it contains about 3,600 gallons. The space left is 6,000 - 3,600 = 2,400 gallons. The order is 4,000 gallons. Dropping the full load overfills the tank by about 1,600 gallons.
Overfill does not disappear. It goes out the vent, out the fill connection, or into the soil and storm drain, and with gasoline that is a flammable liquid release next to a card-lock station at night. The taped vent makes it worse: the tank cannot breathe out as product goes in, so pressure builds and product can blow back at the driver when the hose is disconnected.
Before opening the valve:
- Stop and do not start the transfer.
- Check the gauge yourself rather than trusting the order.
- Have the taped vent removed by the station, or refuse the delivery until it is clear.
- Notify dispatch and the station owner that only about 2,400 gallons fit, and that the tank must be filled only to its safe outage, not to the fill cap. The rule of thumb for outage is at least 1% of capacity for water and more for petroleum products, and the tank's marked outage and the station's fill limit govern.
- Deliver the reduced quantity or return the remainder; do not 'top off' to use up the load.
3. Can you leave the transfer to reset the card reader or take dispatch's call? Explain the rule and the failure it prevents.
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No. A bulk transfer of gasoline must be attended by the driver from the moment the hose is connected until it is disconnected. Attended means you are at the controls, watching the valves, the hose, the gauge, and the fill point, and able to shut the product off immediately. Walking into the office is not attendance.
The failures this prevents are specific:
- A hose or fitting lets go and product runs while no one is watching.
- A tank overfills because the gauge or the vent whistle was ignored.
- A customer drives over the hose or pulls the fill cap off.
- A spill finds an ignition source while the driver is inside a building.
Practical handling: reset the card reader before you start pumping, or have the station owner or a second person handle it, or ask dispatch to call back. If the pump must be shut down while you deal with the reader, shut the valve, stop the pump, disconnect the hose, break the bond, and remove the ground before you walk away, then start over correctly. The missed dispatch calls wait. Product in an unattended hose does not.