Hazardous cargo

Dangerous goods carried by a vessel are declared against its port call: the class, the UN number, the quantity, and where on the vessel it sits.

A call carrying declared hazardous cargo is marked as such wherever it appears, so a duty officer does not have to open a call to discover that it matters. The flag follows the declarations — it is set because a declaration exists, not because somebody remembered to tick a box.

The hazardous cargo report lists declarations across calls for a period, which is the form a port authority or an inspector normally asks for.