You are planning to use the crude oil washing system on your tankship. What is required to prevent electrostatic buildup in the tanks?

Correct Answer: Option B — The source tank for the tank cleaning machines must have least one meter decanted from it.

Per 33 CFR 157.138, at least one meter of oil must be decanted from the wash source tank prior to washing. Decanting removes bottom water, preventing the washing system from spraying water-in-oil mixtures, which generate dangerous electrostatic charges when sprayed at high pressures through COW nozzles.