Australia is a signatory to a number of international conventions, aimed at pollution prevention, which provide for the construction, operation and state monitoring of ships at sea.
The most important convention regulating and preventing marine pollution by ships is the International Maritime Organisation’s (IMO’s) International Convention for the Prevention of Pollution from Ships (MARPOL).
MARPOL was developed after a series of major catastrophes when tankers were grounded and spilt vast quantities of crude oil along populated sections of the coastline. MARPOL has 6 technical Annexes:
1) Annex I—Regulations for the Prevention of Pollution by Oil
2) Annex II—Regulations for the Control of Pollution by Noxious Liquid Substances in Bulk
3) Annex III—Prevention of Pollution by Harmful Substances Carried by Sea in Packaged Form
4) Annex IV—Prevention of Pollution by Sewage from Ships
5) Annex V—Prevention of Pollution by Garbage from Ships
6) Annex VI—Prevention of Air Pollution from Ships
It is never legal to dispose of plastic at sea!
MARPOL applies to all vessels which operate under the authority of a Flag State, which in Australia would include almost every vessel.
Marine Orders 91 to 97, under the Navigation Act 1912 (Cth), apply to all Foreign vessels in Australian waters and Australian, State or Territory vessels at all times. State and Territory vessels are exempt where that State or Territory has implemented the MARPOL provisions in their own laws.
As NSW has currently implemented Annex I and II of MARPOL in the Marine Pollution Act 1987 (NSW) (and Marine Orders Parts 91 and 93) all NSW vessels must comply.
NSW may implement the Annexes III to VI in due course however the Protection of the Environment Operations Act adequately covers the detail of the remaining Annexes.
Beyond Australian Territorial Limits (usually 12NM)
Foreign Vessels must obey their own State Authority rules which implement MARPOL
Australian vessels must obey Marine Orders Part 91 to 97
NSW vessels must obey Marine Orders Part 91 to 97
3NM – 12NM or Australian Territorial Limits
Foreign vessels, Australian vessels and State vessels on interstate voyages must obey Marine Orders Part 91 to 97
NSW vessels operating beyond 3NM from land must comply with the requirements of Marine Orders 91 – 97
All vessels operating within NSW waters (within 3NM) are subject to NSW law which currently has more stringent requirements and much harsher penalties than Marine Orders.
For further information see the Marpol section on the AMSA website