MARPOL stands for the International Convention for the Prevention of Pollution from Ships. It is the main international treaty aimed at reducing marine pollution from ships.
It was adopted in 1973 by the International Maritime Organization (IMO) and strengthened by a Protocol in 1978 in response to tanker accidents. The combined instrument entered into force on 2 October 1983. It is administered by the International Maritime Organization (IMO), the UN agency responsible for shipping safety and pollution prevention.
MARPOL sets a simple global rule: operational or accidental pollution from ships must be prevented, not just cleaned up afterwards.
The Goal of MARPOL: Why It Was Created
MARPOL was introduced to address water pollution, air pollution, and the growing issue of plastic pollution from maritime activities. Real-world incidents – tanker disasters in the 1970s and chronic operational discharges – led to stricter regulations.
Key goals are:
- Minimize pollution of the oceans and seas, including dumping, oil, and air pollution from ships
- Set regulations that shipping vessels must follow to reduce environmental harm
- Establish certification and inspection regimes so compliance can be verified at ports
Data shows why this is critical: While big spills make headlines, oil spills account for just 12% of oil entering the oceans. Two to three times more oil reaches the sea through runoff, bilge water and small operational discharges. And pollution isn’t only oil – over 70% of the world’s marine protected areas are polluted by sewage.
The 6 Annexes of MARPOL Explained
MARPOL regulates six categories of marine pollution through six technical Annexes. Annexes I and II are mandatory for all parties.
|
Annex
|
Pollution Type
|
What It Covers
|
In Force
|
|---|---|---|---|
|
Annex I |
Oil
|
Prevention of pollution by oil, bilge water limits
|
Oct 1983
|
|
Annex II |
Noxious Liquid Substances
|
Control of chemicals carried in bulk
|
April 1987
|
|
Annex III |
Harmful Packaged Goods
|
Prevention of pollution by harmful substances in packaged form
|
July 1992
|
|
Annex IV |
Sewage
|
Prevention of pollution by sewage from ships
|
Sep 2003
|
|
Annex V |
Garbage
|
Prevention of pollution by garbage, total ban on plastic dumping
|
Dec 1998
|
|
Annex VI |
Air Pollution
|
Sulphur, nitrogen oxides, GHG, 0.50% global sulphur cap
|
2005
|
Annex I in detail: It has banned the discharge of oily bilge water with more than 15 parts per million of oil content since 1983. This is why ships must use Oily Water Separators (OWS) and Oil Content Meters (OCM) that stop discharge if levels exceed the threshold.
Annex V in detail: Critical for Nigeria. It bans plastic disposal at sea completely – a major driver of the waste NIMEPA removes during beach clean-ups.
Annex VI in detail: Governs air pollution, addressing sulphur oxides and nitrogen oxides, and features mandatory energy efficiency measures.
Water Pollution and Environmental Issues in the Nigerian Context
Nigeria’s marine threats, as documented by NIMEPA, are textbook examples of MARPOL violations:
1. Oil and Gas Discharges: Decades of spills, illegal bunkering and produced water in the Niger Delta have wiped out mangroves and breeding grounds.
2. Plastic and Hazardous Waste: Systemic dumping, including lead batteries found at Lagos beaches, points to non-compliance with Annex V.
3. Sewage and Invasive Species: Lack of sewage treatment and ballast water management allows pathogens and invasive species to spread – directly addressed by 7 Essential Marine Environment Protection Systems Used on Ships for Ocean Safety.
At The Nigerian Marine Environment Protection Association (NIMEPA), we work to raise awareness and promote sustainable solutions to protect these fragile ecosystems. We combat marine pollution through beach clean-ups, advocacy and research.
Certification, Inspection and The 7 Systems That Make MARPOL Work
A ship cannot just claim compliance. It needs:
- International Oil Pollution Prevention (IOPP) Certificate
- Oil Record Book
- Garbage Management Plan
NIMEPA trains ship operators on the seven MARPOL systems: oily water separators, oil discharge monitoring, scrubbers, sewage treatment, ballast water treatment, waste management and oil content meters.
These systems are not optional tech – they are legal requirements. For example, NIMEPA’s Pollution Reduction Programmes focus on practical solutions like plastic waste reduction, water quality monitoring, and oil spill awareness.
How NIMEPA Is Turning Policy Into Practice
As highlighted in our World Maritime Day 2026 statement, Nigeria must move from policy to practice by implementing MARPOL-compliant waste reception and low-carbon operations.
What NIMEPA does:
- Prevention at source: Advocacy for stronger enforcement at ports and training on MARPOL systems
- Community Engagement: Volunteer clean-ups, fisher cooperatives, and data collection on waste hotspots
- Blue Economy Integration: We were established to promote responsible marine environmental protection and sustainable maritime operations in alignment with Nigeria’s Blue Economy agenda
Understanding MARPOL is the first step. Compliance is what saves our oceans.
Join NIMEPA’s next clean-up or become a member to support enforcement of MARPOL in Nigerian waters.
