Capt Mike Kaczmarek, Chairman, Clean Shipping Alliance, noted that the recent IMO Sub-Committee on Pollution Prevention and Response (PPR 13) in London concluded with continued debate around exhaust gas cleaning systems (EGCS), but one outcome was clear: proposals to alter established IMO procedures did not gain consensus.
Kaczmarek said: “At PPR 13, EGCS were again under scrutiny as NGOs renewed calls for restrictions or bans, while an EU proposal would have allowed coastal States in Particularly Sensitive Sea Areas (PSSAs) to unilaterally prohibit EGCS discharges through new Associated Protective Measures without prior IMO approval or scientific evaluation in the form of completed risk assessments under MEPC.1/Circ.899. This would have been a significant departure from the IMO’s science-based, evidence-led framework. Fortunately, the Sub-Committee did not support this approach. Instead, it reaffirmed that any EGCS-related measures must proceed through existing IMO processes, based on area-specific scientific justification.
“This debate extends beyond EGCS. Accepting regulatory shortcuts to established MARPOL procedures could set precedents for future decisions on black carbon, alternative fuels and other abatement technologies, including carbon capture, creating a fragmented and legally uncertain patchwork of rules that undermine confidence in IMO as the sole global regulatory authority for shipping.
“Concern for the marine environment is widely shared. The real question is whether proposed measures follow the scientific and procedural standards IMO has already agreed. Where a need for incremental improvement is credibly demonstrated, IMO’s goal-based Guidelines already support proportionate action.
“A central issue beyond PPR 13 is whether EGCS restrictions can be justified, or even considered legitimate, without sound scientific evidence, including site-specific risk assessments conducted in accordance with IMO standards. Simply identifying the presence of substances is not the same as demonstrating environmental risk. Concentrations, dilution, persistence, end states and measured impact must be assessed together using approved methodologies.
“Whole-effluent toxicity (WET) testing, the primary IMO-approved risk assessment method currently available, evaluates the combined impact of discharge on marine organisms under simulated post‑discharge conditions, using local ambient seawater as a control. Chemical analysis compares inlet seawater with EGCS discharge to calculate the system’s incremental contribution for each substance, which may then be compared against local, national and international water quality standards. Across hundreds of samples from ships operating worldwide, results have consistently fallen within major regulatory limits, with very low or negligible levels of metals and other substances – often already at or near background seawater concentrations.
“Despite this, there are no publicly available examples of existing EGCS discharge bans that have been preceded by completed risk assessments that comply with MEPC.1/Circ.899. Restrictions already in place in parts of Europe and elsewhere have been introduced on what is effectively a precautionary basis, contrary to IMO’s intent that precautionary measures are only temporary, pending the completion of scientific assessment. These restrictions continue to appear despite decades of global EGCS operation and multiple studies, including WET testing using IMO aligned methods, that have not produced any verified evidence of harm to the marine environment.
“Substantial empirical evidence is already before IMO, including most recently the largest qualified EGCS discharge dataset submitted to date, comprising more than 1,000 samples from around 80 ships analysed by ISO‑accredited laboratories. This work, which supports GESAMP’s ongoing assessment of emission factors, also shows incremental concentrations well below major water quality limits. Several delegations indicated a preference to await the GESAMP Task Team’s findings before advancing further measures, and MEPC 84 is now expected to extend the timeline for this output to 2027.
“Flag States and industry bodies have warned that bypassing agreed IMO procedures for EGCS would set a broader negative precedent. Regional measures outside IMO, including EGCS discharge restrictions in ports and inland waters recently pursued through OSPAR Contracting Parties, without evidence that completed risk assessments have been conducted per IMO Guidelines, risk regulatory fragmentation that weakens both legal certainty and industry confidence. For a global industry, predictable, evidence‑based rules are essential.
“PPR 13 showed that while views differ, there is still broad support for regulation that follows evidence rather than assumption. The priority now is to complete ongoing scientific work, apply IMO’s existing risk assessment framework wherever restrictions are being considered, and preserve confidence in a rules-based international system.”
Image: Capt Mike Kaczmarek (Clean Shipping Alliance)
