An Ammonia Leak at the Leixões Docks Empties a 1,000-Strong Fishing Festival
A refrigeration-unit explosion at Docapesca's ice factory vented ammonia during the opening of the São Sebastião fishing festival at the Port of Leixões late Friday, forcing about 1,000 people out and drawing 54 emergency operatives before the leak was controlled overnight.
An ammonia leak at the Port of Leixões forced the evacuation of a fishing festival attended by around a thousand people late on Friday, sending emergency crews into a night-long operation in Matosinhos, according to reporting by RTP and Observador.
The alert was raised at 22:55 on 17 July, at the ice factory run by Docapesca — the state company that manages Portugal's fishing ports and auction markets — inside the Leixões harbour complex. The Porto branch of the Public Security Police (Polícia de Segurança Pública, or PSP) said the leak followed an explosion in a refrigeration unit, releasing ammonia into an area that was, at that moment, packed with festival-goers.
A festival cut short
The timing could hardly have been worse. The docks were hosting the opening of the Grandiosas Festas do Mártir São Sebastião (Grand Festivities of the Martyr Saint Sebastian), the traditional celebrations honouring the patron saint of fishermen, with roughly 1,000 people gathered nearby. Authorities moved to clear the area as the gas spread, and at least one person suffered a minor injury and was taken to hospital for treatment.
Ammonia is widely used as a refrigerant in fish-processing and ice-making plants because it is cheap and efficient, but a leak in a crowded setting is hazardous: the gas is sharply irritating to the eyes, skin and airways, and can be dangerous at high concentrations. That combination — an industrial coolant venting beside a public event — is what turned a plant fault into a mass evacuation.
The response
The scale of the callout reflected the risk. According to the National Emergency and Civil Protection Authority (Autoridade Nacional de Emergência e Proteção Civil, or ANEPC), 54 operatives backed by 23 vehicles were deployed to the docks by around 00:40. Crews worked through the early hours to contain the escaping gas and secure the perimeter around the ice factory.
By the small hours, officials described the leak as controlled but not fully resolved, with teams remaining on site to monitor the refrigeration unit and ventilate the affected buildings. The priority overnight was to prevent any further release and to confirm that the surrounding festival ground and port facilities were safe to reopen.
A working port beside a public event
Leixões, in Matosinhos just north of Porto, is one of Portugal's busiest ports, handling cargo, cruise passengers and a large fishing fleet. The Docapesca facilities sit at the heart of that fishing activity, and the São Sebastião festivities are a fixture of the local calendar — a reminder of how closely the industrial and community life of the waterfront are intertwined.
No cause beyond the reported refrigeration-unit explosion had been confirmed as crews wrapped up the overnight operation, and it was not immediately clear whether the festival programme would resume or what checks the ice factory would need before returning to service. For a night meant to celebrate the fishermen's patron saint, the abrupt evacuation was a jarring turn — though one that, with a single light injury reported, could have ended far worse.
