Different methods = different conclusions: why standard methods matter in EGCS assessments in International Shipping News 28/04/2026 Claims about the potential environmental impact of exhaust gas cleaning systems (scrubbers) have become increasingly detached from the realities of how environmental risk is actually determined. That matters, because the methods used to assess evidence are as consequential as the evidence itself. Across many of the arguments made against EGCS, a similar pattern emerges: assumptions of harm are drawn from the presence alone of certain substances in discharge water, from desk-top calculations, or from worst-case modelling, without full consideration of how environmental risk is assessed in real-world conditions. Understanding that distinction matters in regulation as much as it does in science. Andreas Chrysostomou Standard methods = consistent findings The presence of metals and PAHs in discharge water does not in itself establish environmental harm. Many of these substances are already naturally present in seawater, so environmental risk is best evaluated by whether concentrations in receiving waters exceed established effect thresholds once dilution, dispersion, background levels and ecological response are taken into account. Standard environmental risk assessments consider these variables, and this is also reflected in the IMO framework through MEPC.1/Circ.899. Peer-reviewed studies in the U.S. (Puget Sound), Korea, Japan and Denmark, using real discharge water samples collected onboard ships under real operating conditions, together with standard laboratory chemical analyses, PEC/PNEC risk characterisation and whole effluent toxicity testing, have consistently shown that environmental risks from EGCS discharges remain negligible or very low, and well within accepted thresholds – even in sensitive port environments and enclosed waters. Long-term empirical monitoring reinforces this. At Mongstad in Norway, where EGCS discharges to sea have been monitored since 1991, decades of annual benthic surveys around the same fixed discharge point have found no accumulation of discharge parameters and no ecological degradation attributable to scrubber discharge. Natural processes, including the rapid biodegradation of PAHs, along with dilution and tidal dispersion, continuously reduce concentrations in the receiving environment. This means that when evaluated using established IMO-aligned and internationally accepted methodologies, the environmental performance of EGCS is consistent with MARPOL principles, as well as major national and international discharge water standards, and the case for blanket restrictions has not been established. Mike Kaczmarek Comparing fuels It should also be recognised that low-sulphur fuels such as MGO and VLSFO contain many of the same metals and PAH parameters as higher sulphur fuels, often at similar and sometimes greater concentrations. These are released through air emissions, with deposition to sea – or, while in port, onto land – with dispersion patterns that can be comparable to EGCS discharges. Their overall environmental loading may therefore be considered basically equivalent. The same methodology issue applies to fuel comparisons. It has recently been suggested that EGCS should be assessed against the broader environmental profile of compliant fuels. However, this approach is one-dimensional. When lifecycle impacts are included, the comparison changes materially. In assessm