To avoid excessive electrostatic generation in the washing
process due to the presence of water in the crude oil washing fluid,
the contents of any tank to be used as a source of crude oil washing
fluid must first be discharged by at least 1 metre before being so
used. Any tank used as a slop tank on the previous ballast voyage
shall be completely discharged and refilled with dry crude oil if
that tank is to be used as a source of washing fluid.