Prior to handling Class 1 explosive materials, which signal(s) is/are required to be displayed by the vessel?

Correct Answer: Option B — the Bravo flag and signs posted prohibiting smoking

Vessels handling Class 1 explosive materials must display the international Code Flag 'Bravo' by day (or a red all-round light by night) and post prominent no-smoking signs in accordance with hazardous material transfer safety requirements under 33 CFR.