A Defective Cargo Tank Valve and a Gasoline Load near Lake Charles
You drive a 10,000-gallon, 4-compartment cargo tank (2,500 gallons per compartment) with current tests and a cargo tank endorsement. At a Lake Charles terminal, you are to load 9,000 gallons of UN1203, Gasoline, 3, PG II, for a customer 180 miles away. Before loading, the loader finds the gasket on compartment 2's manhole cracked and compartment 4's emergency shutoff valve will not fully close. The terminal proposes loading 7,450 gallons into the three remaining compartments-about 2,483 gallons each-so the load can still go out. It is 3:00 p.m., the forecast is 98°F, and the customer says the tank is needed by 6:00 a.m. The terminal says the valve 'has been like that for weeks' and the gasket can be 'watched.'
1. Is the terminal's plan to use the three remaining compartments acceptable? Analyze the valve, gasket, and outage.
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No. A cargo tank with an emergency shutoff that will not fully close and a cracked manhole gasket is not in proper condition; those are primary containment and emergency controls, and the tank as a whole must be roadworthy. The terminal cannot simply 'load around' a defective valve. Even if the defects were repaired, 7,450 gallons in 7,500 gallons of capacity leaves only 50 gallons, or about 0.67 percent outage. That is below the 1 percent minimum liquid outage required under 49 CFR 173.24b and far too tight for gasoline at 98°F. Expansion can fill the compartments, build pressure, and cause a release. The correct action is to repair the valve and gasket and load only within the required outage, or use another tank.
2. If the gasket and valve are repaired, what loading and documentation checks must be completed before you leave?
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Verify that the repairs are documented and that the tank's test and inspection dates are current. Check the shipping paper for 'UN1203, Gasoline, 3, PG II,' the total quantity, package type, and emergency response telephone number and information. Confirm that FLAMMABLE placards are displayed as required and that all manhole covers, gaskets, and valves are secure. Before transfer, set the brakes, chock the wheels, bond and ground the tank to the loading rack, eliminate ignition sources, and confirm the emergency shutoff works. Load at the approved rate, watch for leaks, and leave the correct outage. After loading, recheck for leaks, secure the tank, and confirm the vehicle is not overloaded.
3. During loading you see a gasoline sheen on the ground and smell strong vapor near compartment 1. What do you do?
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Stop loading immediately and shut off the pump or emergency shutoff if you can do so safely. Do not start the engine or use anything that can spark. Notify the terminal operator, move nonessential people away, and call 911 or the fire department if the pool or vapor cloud is significant. Keep product out of drains with absorbent or dikes; do not wash it away. Do not resume loading until the source is found and repaired, the area is cleared, and the terminal authorizes the restart. If the release meets reporting criteria, make the National Response Center notification and complete the written incident report.