Officer has petrol and what it makes (10)

I believe the answer is:

supercargo

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'officer' is the definition.
(supercargo is a kind of officer)

I don't understand the rest of the clue.

(Other definitions for supercargo that I've seen before include "Owner's representative on merchant ship" , "Ship's officer" , "Merchant navy officer responsible for what a ship is carrying" .)

I've seen this clue in the Sydney Morning Herald.

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