What shipowners need to know about SOx & NOx as Canadian Arctic joins the ECAs

With the Canadian Arctic and the Norwegian Sea designated as new ECAs under MARPOL Annex VI, shipowners face stricter sulphur and nitrogen oxide requirements across a broader portion of their trading routes.

These regions now join established ECAs such as the Baltic Sea, North Sea, North American coast, US Caribbean, and Mediterranean Sea, where vessels must comply with a 0.10 percent sulphur cap or use approved equivalent technologies. As enforcement extends into northern waters, compliance is becoming a continuous operational requirement rather than a regional exception.

What changes for your vessel operations

Inside SOx ECAs, vessels must either burn fuel with sulphur content not exceeding 0.10 percent or operate certified exhaust gas cleaning systems that achieve equivalent sulphur removal. In NOx ECAs, applicable engines must meet Tier III standards, typically achieved using selective catalytic reduction systems with 40 percent urea solution.

For fleets operating in Arctic waters, this means:

• Longer exposure to strict sulphur limits
• Greater dependence on scrubber reliability
• Consistent Tier III NOx performance
• Increased inspection and documentation scrutiny
• Additional cold weather handling considerations

Compliance must be stable, documented, and always maintained while inside the ECA.

Operational readiness is critical to remain compliant in ECAs

Regulations define the limits, but system performance ensures compliance. Technical teams must secure:

• Stable pH control and sulphur removal in scrubbers
  • Accurate urea dosing and catalyst protection in SCR systems
  • High purity emission control chemicals
  • Reliable product availability across ports
  • Clear documentation for Port State Control

In Arctic conditions, storage, pumping, and supply continuity become even more important. Any disruption can quickly translate into operational or compliance risk.

Strategy and supply chain alignment

Most fleets rely on a mix of low sulphur fuels, scrubber systems, and SCR installations. Regardless of the approach, chemical integrity is essential. Off specification urea can damage catalysts and reduce NOx efficiency, while inconsistent alkaline reagents can compromise scrubber performance.

Using marine specific, standardized products such as ISO 18611 compliant 40 percent urea solutions and controlled concentration Caustic soda supports predictable system performance and simplifies inspection processes.

Equally important is global supply capability. As ECAs expand, shipowners need consistent product specifications, flexible delivery formats, and reliable availability across multiple regions.

The importance of chemical integrity

In high compliance zones such as the Arctic, product quality directly affects operational stability.

Off specification urea AUS can cause:

• Catalyst fouling
• Reduced NOx conversion efficiency
• Increased ammonia slip
• Higher maintenance costs

Inconsistent alkaline reagents (Caustic soda) can lead to:

• Unstable scrubber pH
• Reduced sulphur removal efficiency
• Increased operational adjustments
• Potential compliance findings

Marine specific, standardized products help mitigate these risks. ISO 18611 compliant 40 percent urea solutions support predictable SCR performance across engine load ranges while protecting catalyst surfaces. Controlled concentration Caustic soda solutions enable stable alkalinity management in closed loop and hybrid scrubber systems.

Equally important is standardized documentation, which simplifies inspection processes and audit readiness

The designation of the Canadian Arctic as an ECA signals a clear direction for global maritime regulation. Environmentally sensitive regions will continue to fall under tighter emissions control.

For shipowners, the priority is preparation. Aligning fuel strategy, emission control systems, and chemical supply chains today ensures operational stability tomorrow. In an expanding ECA landscape, proactive planning is the difference between seamless compliance and costly disruption.