IMO's MARPOL cleaning criteria require that all horizontal and vertical tank surfaces are washed by direct impingement or by deflection or splashing of the impinging jet.

• A. True
• B. False
• C. False
• D. False

Answer: (A)

MARPOL cleaning criteria require that every tank surface, both horizontal and vertical, be washed by a jet that either hits directly (impingement) or is deflected or splashed so the jet’s energy reaches all areas. This approach ensures residues and contaminants are physically dislodged and flushed from every surface, including corners, seams, and the bottom, meeting the required cleanliness and environmental protection standards. That’s why the statement is true. The other options would suggest methods or requirements that don’t align with MARPOL’s demand for thorough jet-based cleaning to ensure complete surface contact.