1. In case of incidents or accidents that may result in leakage of the dangerous substances carried, the ‘Do not approach’ signal shall be given by vessels carrying the markings referred to in paragraphs 1, 2 or 3 of article 3.14, if the crew cannot avert the attendant danger to human life or navigation.
This provision does not apply to pushed barges and other non-self-propelled vessels. Nevertheless, if they are part of a convoy, the ‘Do not approach’ signal shall be given by the vessel with the convoy boatmaster on board.
2. The ‘Do not approach’ signal consists of a sound signal and a light signal. The sound signal is made up of one short and one long sound which are constantly repeated for no less than 15 consecutive minutes.
The light signal, referred to in article 4.01, paragraph 2, shall be given simultaneously with the sound signal.
After being activated, the ‘Do not approach’ signal shall be emitted automatically; the control device shall be set up in such a way as to make it impossible for the signal to be activated unintentionally.
3. Vessels detecting a ‘Do not approach’ signal shall take all possible measures to avert the threat to them. In particular, they shall:
(a) If moving towards the dangerous area, keep as far away from it as possible and, if need be, make a turn;
(b) If past the dangerous area, continue under way at the highest possible speed.
4. On board the vessels referred to in paragraph 3 above it shall be imperative immediately to:
(a) Close all windows and openings to the outside;
(b) Extinguish all unprotected fire and naked lights;
(c) Stop smoking;
(d) Stop all unessential auxiliary machinery;
(e) Avoid creating sparks.
If the vessel is stationary, all engines and auxiliary machinery shall be stopped or unplugged.
5. Paragraph 4 applies also to vessels berthed close to the dangerous area. Upon detecting a ‘Do not approach’ signal, the crew shall leave such vessels, if necessary.
6. When taking the action referred to in paragraphs 3 to 5, current and wind direction shall be taken into account.
7. The action prescribed in paragraphs 3 to 6 above shall also be taken by vessels if a “Do not approach” signal is emitted from the shore.
8. Boatmasters receiving a “Do not approach” signal shall do their utmost to report it without delay to the closest competent authority.