While agreement on the IMO’s long-term Net Zero Framework (NZF) remains unresolved, the meeting advanced work on emissions regulation, exhaust gas cleaning systems, ballast water management, oily water handling, carbon capture technologies, and future environmental protection measures.
For vessel operators, MEPC 84 reinforces a broader industry trend:
Environmental compliance is becoming increasingly data-driven, operationally focused, and system-oriented.
This article summarises the key factual outcomes from MEPC 84 and highlights the areas expected to shape future maritime compliance requirements.
Net Zero Framework Discussions Continue
One of the most closely watched topics at MEPC 84 was the continued development of the IMO’s Net Zero Framework (NZF).
The meeting followed the Extraordinary MEPC Session (MEPC/ES.2) held in October 2025, where the proposed framework failed to secure sufficient MARPOL Annex VI support for adoption.
At MEPC 84, several alternative approaches were discussed, including:
- revisions to the original NZF proposal
- market-readiness approaches for alternative fuels
- technology-neutral pathways for greenhouse gas reduction
One joint proposal presented by Argentina, Panama and Liberia focused on:
- technology neutrality
- proportional incentives linked to well-to-wake emissions reduction
- support for emerging technologies such as onboard carbon capture systems (OCCS) and wind-assisted propulsion
- avoidance of direct IMO revenue collection mechanisms
As no final agreement was reached, MEPC 84 established further intersessional working groups to continue negotiations ahead of MEPC 85 later this year.
New IMO Greenhouse Gas Study Initiated
MEPC 84 also approved the terms of reference for the 5th IMO Greenhouse Gas (GHG) Study.
The study will support future decision-making around:
- fuel lifecycle assessment (LCA)
- greenhouse gas reduction strategies
- alternative fuel pathways
- methane slip and well-to-tank emissions calculations
An interim report is expected ahead of MEPC 86 in 2027, with the final report scheduled for review in 2028.
Further technical work will continue around:
- carbon capture and storage
- carbon capture and utilisation
- lifecycle emissions methodologies
- fuel emissions accounting
Progress on Onboard Carbon Capture Systems (OCCS)
MEPC 84 continued work on draft guidelines covering:
- testing
- approval
- survey
- certification
…for onboard carbon capture systems (OCCS).
The committee agreed to continue development using a technology-neutral approach, with additional work assigned to a correspondence group ahead of MEPC 86.
Interest in OCCS technologies continues to grow as shipowners explore alternative pathways for reducing greenhouse gas emissions while maintaining operational flexibility.
CII and EEDI Measures Remain Under Review
The meeting also reviewed ongoing concerns surrounding the Carbon Intensity Indicator (CII).
Discussions highlighted how geopolitical disruptions and vessel rerouting have impacted fuel consumption and operational efficiency, including increased voyage distances and reduced schedule predictability.
MEPC 84 acknowledged the need to continue reviewing:
- CII metrics
- operational correction factors
- efficiency measurement methodologies
Additional amendments were adopted relating to the Energy Efficiency Design Index (EEDI), particularly for vessels using:
- methanol
- ethanol
- ammonia
- hybrid propulsion arrangements
The changes aim to better reflect the growing diversity of alternative fuel technologies entering the market.
Amendments to MARPOL Annex I on Bilge Water Handling
One of the more significant operational developments from MEPC 84 was progress on amendments relating to oily bilge water handling under MARPOL Annex I.
MEPC 84 approved draft amendments introducing:
- a new Regulation 12B
- revisions relating to oily bilge water holding and service tanks
- updates to the IOPP Certificate supplement
The amendments are expected to be considered for adoption at MEPC 85 and could enter into force as early as 2028.
Integrated Bilge Water Treatment Systems (IBTS)
The committee also approved, in principle, the 2026 Guidelines for systems handling oily wastes in machinery spaces, including updated guidance for Integrated Bilge Water Treatment Systems (IBTS).
The revised guidance consolidates previous circulars and includes:
- updated IBTS definitions
- clarification of system connections and discharge arrangements
- guidance on forced evaporation arrangements
- revised flow diagrams
- additional provisions for oily residue handling systems
Importantly, the amendments formally recognise forced evaporation treatment methods for oily bilge water under defined operating conditions.
Exhaust Gas Cleaning System (EGCS) Discharge Discussions Continue
Discharge water from Exhaust Gas Cleaning Systems (EGCS), commonly referred to as scrubbers, remained an active discussion topic at MEPC 84.
The committee agreed that additional scientific assessment and harmonisation work is still required before further regulatory measures can be developed.
Work will continue through:
- GESAMP technical review groups
- future PPR committee discussions
- additional environmental impact assessment submissions
The target completion date for this work has been extended to 2027.
MEPC 84 also noted discussions around:
- discharge controls in Particularly Sensitive Sea Areas (PSSAs)
- technology-neutral approaches to EGCS regulation
- future MARPOL-based regulatory development
Ballast Water Management Updates
MEPC 84 approved draft amendments to the Ballast Water Management (BWM) Convention.
The amendments introduce additional requirements for Ballast Water Management Plans (BWMPs), including:
- type approval identification
- maintenance procedures
- ballast water exchange procedures
- contingency measures
- guidance for temporary storage arrangements where applicable
The committee also adopted the 2026 G4 Guidelines for Ballast Water Management Plans, intended to provide a more practical and standardised implementation approach.
If adopted at MEPC 85, the amendments could enter into force as early as 2028.
North-East Atlantic ECA Adopted
MEPC 84 adopted the new North-East Atlantic Emission Control Area (ECA).
The ECA will cover emissions relating to:
- NOx
- SOx
- particulate matter (PM)
The new area links several existing ECAs across the North Atlantic region and is expected to enter into force on 1 September 2027.
Additional Environmental Measures
Other outcomes from MEPC 84 included:
- continued development of a legally binding biofouling framework
- adoption of the 2026 Strategy and Action Plan on Marine Plastic Litter
- ongoing work on underwater radiated noise
- discussions on ozone-depleting substances
- preparatory work relating to Maritime Autonomous Surface Ships (MASS)
Looking Ahead
While MEPC 84 did not deliver final agreement on several major regulatory frameworks, it clearly demonstrated the continuing expansion of environmental regulation across the maritime sector.
The meeting highlighted ongoing industry focus on:
- emissions reduction
- fuel transition pathways
- integrated waste handling systems
- operational efficiency
- environmental monitoring and reporting
Further developments are expected at:
- intersessional working groups later this year
- MEPC 85
- future PPR committee meetings
As regulatory frameworks continue to evolve, vessel operators, ship managers and equipment manufacturers will be closely monitoring how these discussions translate into future operational and compliance requirements.