Athens cracks crisis: Kypseli buildings damaged by metro tunnel excavation, TBM suspended, prosecutor investigates

Project and damage

The Line 4 metro tunnel between Kypseli Square and Evelpidon is being dug by TBM Niki. Excavation began earlier this year, but by March 2026 residents started noticing loud vibrations and cracks. In over 20 apartment buildings, deep fissures have appeared across walls, beams, doors, windows, and even floor tiles. Alexandros Koutroularis, a resident whose flat is roughly 100 metres from the square, said the damage was immediate.

It started right after the TBM passed. It must have been March or April. Right from the first week they appeared and, because we don't know if the subsidence is still active, new cracks keep appearing or existing ones keep expanding.

A residents' initiative estimates that up to 200 apartments have recorded damage from the square diagonally to Evoias Street. Some tenants fled as soon as the cracks emerged, while owners stay in homes they cannot sell. The recent collapse of a building in Petralona has turned anxiety into outright terror.

Company response

Elliniko Metro S.A. acknowledged the subsidence but insisted no structural integrity issues exist. In a statement, the company confirmed TBM work halted on 8 May 2026.

The works of the TBM have been suspended since 08/05/26 as unexpected and detectable conditions were found in the particularly weak geological background that had already been studied during the project's design phase.

The statement said monitoring systems show no further progression of the phenomenon, and the contractor has already started restoring cracks at its own expense after inspections. A technical investigation involving independent experts from Greece and abroad is underway before TBM operations can resume. The company also emphasised that the TBMs are latest-generation machines designed for urban tunnelling.

Official and political reaction

The Athens prosecutor's office ordered an urgent preliminary examination to determine if any crimes were committed or if the works pose a danger. At the City Council session on 15 July, representatives of the residents presented correspondence and demanded full structural and geotechnical reviews. All party leaders backed the municipal authority; former mayor Kostas Bakoyannis proposed a cross-party committee. Mayor Haris Doukas said the municipality would support residents legally and with all its services.

Many residents were forced to leave their homes. That's why I referred the matter to the competent prosecutor, who in turn ordered an urgent preliminary investigation to determine responsibility, and at the same time I have requested a meeting with the relevant Minister of Infrastructure and Transport and the management of Elliniko Metro about what exactly is happening there.

Doukas also announced a meeting with Elliniko Metro CEO Christos Fafoutis on 16 July. The mayor separately informed the council about the collapsed building in Petralona, noting the municipality would remove the debris for the first time.

Residents' demands and next steps

Residents are asking for a full structural audit by the Technical Chamber of Greece (TEE), a re-evaluation of geotechnical studies, and coverage of all expert fees. Many complain that Elliniko Metro has not shared inspection results, leaving them in fear for their homes and local schools. The subsidence has stopped after the shutdown, but whether the ground stabilised permanently remains unclear. With the criminal probe and technical review ongoing, the fate of over 200 households hangs on the findings of the investigation and the planned meeting at the mayor's office.