MOL Group closed construction on the atmospheric-vacuum distillation (AV-3) unit at its 163,000-b/cd Százhalombatta refinery on Sept. 22, ending a year-long, HUF 18 billion (US$57.1 million) rebuild triggered by an Oct. 20, 2025 fire. The Hungarian operator has set an October target for the first crude throughputs back into the unit, once construction equipment is removed and a defined pre-start checklist is cleared.

How badly did the fire damage the unit?

The blaze cut crude distillation capacity at the 8.1-million-tonnes/year refinery along the Danube River by roughly 50%, according to the operator's 2025 annual report to investors. The fire forced a temporary shutdown of the site, with units outside the fire envelope quickly restarted to keep gasoline, diesel and secondary product flows moving.

MOL backfilled Hungarian and regional supply gaps from inside its own downstream footprint:

• Slovnaft AS in Bratislava — a 6.1-million-tonnes/year (122,500-b/cd) integrated refining and petrochemical complex
• INA Industrija Nafte DD at Urinj, near Rijeka, Croatia — a 4.5-million-tonnes/year (90,000-b/cd) refinery operated under MOL's majority control
• Third-party product imports routed through the group's trading book

What did the rebuild cover?

MOL said the repair project finished on schedule. The mechanical scope ran beyond simple equipment replacement and included demolition and reconstruction of the unit's reinforced concrete structure, restoration of every piece of equipment impacted by the fire, and rebuild of the unit's control and electrical backbone.

Key hardware items installed during the campaign:

• 27 new high-capacity pumps
• 8 km of replacement piping
• 100 km of new electrical cabling

What does the restart sequence look like?

Construction crews have demobilized. Downstream staff will now work through a defined pre-start checklist before crude is reintroduced to AV-3:

• Flushing of unidentified unit systems
• Executing pressure tests
• Functional tests of process control and safety equipment
• Connection of all associated auxiliary power supplies
• Coordination of AV-3 operation with associated plants of the refinery

Phased production restart will follow once the complementary safety inspections and operational tests clear, MOL said.

What does AV-3's return mean for central European supply?

Krisztián Pulay, MOL's senior vice-president of downstream production and development, framed the restart as a regional capacity story, not a Hungarian one.

"The effects of the war in Iran and the global energy crisis have already spread to our region; everyone is competing for alternative sources, which increases the value of every reliable supply route and European refining capacity," Pulay said.

"Recent months have also shown that we can put our fuel supply on a solid footing through our own production, diversified procurement, and import options. With the return of AV-3, we are regaining an important capacity: the Danube refinery will become stronger and more flexible, giving MOL greater leeway in meeting domestic and regional demand," he said.

What to watch

MOL has set October as the restart window but has not pinned down a date for first crude feed or for full restoration of nameplate crude throughput. Watch items: confirmation of first oil into AV-3, the rate at which throughput ramps back toward 163,000 b/cd, and any disclosure on the underlying cause of the October 2025 fire.