by Capt. Mike Kaczmarek
A committee meeting this week discusses regulation of discharge from exhaust gas cleaning systems.
The International Maritime Organization’s (IMO) Sub-Committee on Pollution Prevention and Response is meeting this week, and exhaust gas cleaning system (EGCS) discharges are on the agenda.
Today, approximately 4,000 ships globally (about 8% of the global merchant fleet) are fitted with EGCS, or scrubbers. They provide a practical, transitional solution while low- and zero-carbon alternative fuels are not yet market ready.
Environmental NGOs have renewed calls for restrictions or bans, alongside an EU proposal that would enable coastal states of particularly sensitive sea areas (PSSAs) to prohibit EGCS discharges through associated protective measures. This would enable the use of the PSSA framework to circumvent the requirement for risk and impact assessments under the IMO’s own guidelines, and prior approval by IMO, as required under established procedures.
In short, this proposal would bypass the IMO’s long-standing deliberative process for PSSAs.
Several submissions to this week’s meeting, including those from Liberia, the International Chamber of Shipping, the Baltic and International Maritime Council, Cruise Lines International Association, and the World Shipping Council, raise concerns about the new PSSA proposal and its impact on regulatory coherence.
At stake is whether decisions affecting global shipping regulation will continue to follow the science-based, risk assessment framework the organization has already agreed on. This matters not only for EGCS but for the credibility and durability of IMO decision-making in general.
IMO has already agreed on how to assess environmental questions relating to EGCS discharges. The 2022 guidelines for risk and impact assessments of EGCS discharge water establish two recognized methodologies: emission-factor-based assessment and whole effluent toxicity (WET) testing.
Although the IMO’s work on EGCS emission-factor development is ongoing with the GESAMP Task Team, which advises the UN on maritime environmental matters, the alternative assessment method recognized in IMO guidelines — WET testing, considered by many as the gold standard — remains available for conducting local risk assessments.
For locations where EGCS discharge restrictions are currently in place, there do not appear to be publicly available records of completed risk and impact assessments conducted in accordance with IMO guidelines. This matters because the IMO framework is designed to ensure regulatory decisions are informed by completed scientific evaluation using recognized methods, rather than precaution alone. Where precautionary measures are applied, they are intended to be temporary, pending the availability of sufficient evidence.
After decades of EGCS global operation and years of testing using IMO-approved methods, multiple studies based on large, qualified data sets and hundreds of samples from real-world operations demonstrate minimal environmental risk from EGCS discharge water.
This discussion has an impact on the global economy: For shipowners operating internationally, regulatory predictability and consistency are essential. Fragmentation of the implementation of MARPOL Annex VI, intended to prevent air pollution from ships, through unilateral or regional measures creates complexity and uncertainty while increasing compliance and safety risks, without any clear evidence of a corresponding environmental benefit.
Any new regulations related to these areas (or any area) must be grounded in robust, standard science, not assumption. Otherwise, the overall integrity of the IMO’s decisions is at risk.
Capt. Mike Kaczmarek is the chairman of the Clean Shipping Alliance.
Image Credit: IMO
Originally published at: https://oceaneconomy.news/2026/02/12/imo-debates-exhaust-scrubbers/