MARPOL Regulations

IMO MARPOL Convention

The International Convention for the Prevention of Pollution from Ships (MARPOL) is the main set of international regulations safeguarding against pollution of the marine environment. It covers the different forms of marine pollution including oil, noxious liquid substances, harmful substances, wastewater, garbage and emissions of sulphur oxide (SOx) and nitrogen oxide (NOx) at sea.

Overview of MARPOL Annex VI framework

Global marine traffic for trade is expected to grow by approximately 3.8 % per annum in the next few years. This growth has made it even more imperative for strict emissions standards to be in place.

MARPOL Annex VI entered into force in 2005. As of 21 May 2019, 93 states are party to it. This constitutes approximately 96.68% of the gross tonnage of the world’s merchant fleet. Accordingly, the state parties have the obligation to control the discharge of pollutants into the atmosphere and can enforce the same as against other state parties’ ships operating in their territorial waters.

There are a total of five chapters (25 regulations) in MARPOL Annex VI. In particular, Chapter 3 covers the requirements for control of emissions, namely Regulation 13 for NOx and Regulation 14 for SOx respectively.

MARPOL Annex VI Regulation 13 Governs Vessels NOx Emission

This regulation applies to vessels with an engine exceeding 130kW power output installed on ships constructed on or after 1 Jan 2000. There are three tiers of emissions standards – Tier I, Tier II and Tier III – which are progressively stricter for vessels built on or after 1 Jan 2011 and 1 Jan 2016 respectively. Tier-II and Tier III stipulate a 20% reduction and 80% reduction in emissions as compared to Tier I. Tier III is currently applicable in the North American and US Caribbean Sea Area Emission Control Area (ECA). It will also be applicable in the Baltic and North Sea ECAs from 1 Jan 2021. The standards apply to both main propulsion and auxiliary engines.

MARPOL Annex VI Regulation 14 Governs Vessels SOx Emissions

This regulation regulates the sulphur content of fuel oil used on board ships, which correspondingly reduces SOx emissions. About ten years ago, the sulphur content for ships in non-ECAs could not exceed 4.5% m/m while for ECAs, the limit was 1.5% m/m. The standards have been progressively tightened.

For non-ECAs, from 1 Oct 2012, the threshold was reduced to 3.5% m/m and from 1 Jan 2020, it was further reduced to 0.50% m/m. For ECAs, the threshold was reduced to 1% m/m from 1 July 2010 and then to 0.10% from 1 Jan 2015. The ECA threshold applies in the four established ECAs: the Baltic Sea area; the North Sea area; the North American area (covering designated coastal areas off the U.S. and Canada); and the U.S. Caribbean Sea area (around Puerto Rico and the U.S. Virgin Islands).

SeaCrestor AUS40 Marine Urea Solution

SeaCrestor is a premium brand of AUS40 (Marine Urea Solution). AUS40 acts as a reduction agent in SCR (Selective Catalytic Reduction) converters for the control of NOx emissions in marine vessels. SCR converters are particularly effective in reducing NOx emissions of internal combustion engines.

Meets ISO 18611-1:2014 standards

SeaCrestor satisfies ISO 18611-1:2014 standards which specify the quality requirements and guidelines for AUS 40 in marine applications.

Meets ISO 18Penalties for non-compliance with MARPOL Annex VI framework

In the North American and U.S. Caribbean Sea ECAs
The US Environmental Protection Agency (EPA) has jointly worked with the US Coast Guard since 2011 to conduct inspections, investigations and enforcement actions if violations are detected. These would take place in the form of oversight of marine fuelling facilities, on board compliance inspections, and record reviews. The Coast Guard works on the frontline, with EPA’s assistance if required, and then refers cases to the EPA for further action.

In January 2015, EPA released a penalty policy for violations of the sulphur in fuel standard and related provisions for ships. This action reinforces the agency’s commitment to pursue violations of U.S. and international air pollution requirements by ships operating in the North American and U.S. Caribbean Sea ECAs. Accordingly, in calculating the penalty, the EPA may be guided by the provisions of the Act to Prevent Pollution from Ships (APPS), which implements MARPOL Annex VI. For example, pursuant to s. 1908(b) of APPS, the EPA may impose a civil penalty of US$25,000 per violation, per day. The actual penalty to be imposed would depend on the nature, circumstances, extent and gravity of the violation, the degree of culpability, history of offences and any other relevant factors. The penalty policy also seeks to deter and remove the economic benefit of non-compliance. Although primarily developed for violations of the sulphur cap, it can be adapted for other violations, for example, record keeping violations. For record keeping violations, the penalty could range from US$2500 to US$15,000 per violation, per day depending on the gravity of the violation. It is important to note that the EPA may, on a case-by-case basis, amend the penalty policy, or create a separate penalty policy. The US has historically played a key role in MARPOL enforcement and this has continued with the Annex VI regulations.

In the Baltic sea ECA, there appears to be similar success in enforcement. Between 2014 and 2016, SOx emissions had reportedly fallen by more than 80% according to the Finnish Meteorological Institute. Some observers have flagged uneven enforcement by different port states, meaning that unreported SOx emissions violations at sea could go undetected. That said, some states like Denmark have deployed advanced drone technology in their enforcement which has proven to be quite effective. As a result, in 2016 for example, 12 shipping lines were found to be using banned high SOx fuel.

Enforcement in developing countries

After initially considering an exemption for its domestic maritime sector to avoid pushing costs up, India did a U-turn. Its shipping ministry announced that its domestic sector would comply with the new non-ECA 0.50% m/m sulphur cap. Therefore, all its flag carriers would be required to comply with the MARPOL VI regulations. Similarly, in August 2019, Indonesia announced that it would fulfill its MARPOL Annex VI obligations to enforce the 0.50% (5,000 ppm) sulphur cap regulations. In general, it appears that after concerns were allayed over the supply of cleaner fuel in compliance with the new regulations, it was easier to get buy-in from countries.

It is important to note that the IMO has rejected a proposal by several flag states, and backed by the United States, to introduce an experience building, or “transition phase” for the sulphur cap.

Although the sulphur cap is the latest move in the tightening of the MARPOL Convention, compliance and enforcement is generally left to individual countries. However, while enforcement will vary across jurisdictions, all non-compliant vessels can expect civil, and possibly criminal sanctions. As MARPOL Convention Art 4(4) states, penalties should be “adequate in severity to discourage violations…irrespective of where the violations occur”.


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See for 2011 MOU between EPA and the US Coast Guard.

See for EPA’s memorandum on its penalty policy.

See report by Holman, Fenwick & Willan (HFW):

See S&P Global Platts’ report on India’s shipping ministry’s position:

See Singapore Business Times’ report on the Indonesian Transport Ministry’s statement: