Diesel overflow during bunkering at a typhoon shelter pier

Stop the source first

• Signal or shout to the supplier to stop the pump, then close the vessel's manifold valve and the tank inlet valve. Do not wait for the supplier to finish the delivery.
• Plug the missing scupper immediately with the available plug or rags, and place drip trays or buckets under the vent and hose connections.
• Do not wash the deck down with water or use a hose to disperse the diesel. That spreads the spill and may itself be an offence.
• Spread absorbent pads or granules on the deck and around the vessel's waterline. Use a boom if one is available. Recover used absorbent into a closed container for approved disposal.

Safety Stop all hot work and smoking nearby, and keep ignition sources away. Diesel on a hot surface or in a bilge is a fire risk. Check that no fuel has entered the bilge; if it has, do not run the bilge pump overboard.

Reasoning Every minute the pump runs adds 200 L to the spill. Stopping the transfer and plugging the scupper are the two actions that most reduce the damage. Cleaning up before reporting is not a substitute for reporting.

Notifications

• Inform the master and the vessel owner immediately.
• Report the spill to the Marine Department without delay. In a harbour or typhoon shelter, the Vessel Traffic Centre and the marine pollution response authority need to know the location, product, estimated quantity and whether the spill is continuing.
• Inform the pier operator and the fuel supplier so that their own response and records are activated.
• If the spill affects other vessels or the shoreline, the Marine Department will coordinate; do not arrange private clean-up contractors without informing the department.

Records Record the time the transfer started and stopped, the tank soundings before and after, the estimated quantity spilled, the weather and tide, the absorbents used, the disposal route and the names of witnesses. Keep the supplier's delivery note and the vessel's oil record book entries.

Legal point Causing or permitting oil to enter Hong Kong waters can lead to prosecution and cost recovery. The master and owner have duties under local pollution and port legislation. Prompt reporting and honest records are not an admission of guilt; they are required, and concealment makes the position worse.

Safe fill calculation A practical safe fill leaves at least 5-10% ullage for expansion, trim and heel. For a 3,000 L tank:

• 95% fill = 2,850 L
• 90% fill = 2,700 L

With 2,200 L already in the tank, a 90% safe fill allows only 500 L, not the 700 L intended. At 200 L/min that is 2.5 minutes of transfer, not 3.5 minutes. If the tank is tilted or the sounding pipe is inaccurate, the safe figure may be lower still.

Prevention

• Sound the tank directly and calculate the ullage; do not rely on the gauge or on an assumed starting volume.
• Agree the maximum quantity and transfer rate with the supplier in writing, and use the bunkering checklist.
• Never leave the transfer unattended. If the engineer must leave, the pump must be stopped first.
• Fit the scupper plug before the hose is connected and check the vent is clear.
• Use a drip tray, an overflow alarm if fitted, and agreed stop signals. The missing scupper plug and the unattended transfer were the direct causes; the calculation error made the overflow likely.