Sulphuric acid leak in Kemi went undetected for days

A sulphuric acid leak at Nevel Oy’s heat production plant in Kemi’s Veitsiluoto went undetected for about a week before it was discovered on Friday, according to Olli-Pekka Vieltojärvi, senior inspector at the Finnish Permit and Supervision Agency.

The leak originated from a storage tank with a broken pipe. By the time the incident was detected, the tank was half-empty, with an estimated 10,000 litres of sulphuric acid having escaped.

Vieltojärvi said the environmental damage was contained in time, though acidic emissions at sea are particularly challenging. The entire marine ecosystem suffers when seawater pH levels drop, he noted. Unlike oil, which floats and is easier to clean, sulphuric acid dissolves efficiently into water, making mitigation difficult.

Monitoring of acidity levels in the sea has been intensive since Friday, Vieltojärvi added.

The acid first leaked into the plant’s drainage basins before flowing, diluted, into the sea. Authorities are now neutralising the basins with lime treatment to raise pH levels. Nevel Oy’s sustainability director, Hanna Viita, confirmed the measures and said the company has also built a containment barrier toward the sea to prevent further leaks and increased surveillance.

Viita declined to comment on the duration of the leak at this stage, stating that efforts are focused on controlling the situation. She said the leak was detected via a remote monitoring system and that an investigation will begin as soon as possible.

The cause and timeline of the leak remain unclear, and police have not yet opened an investigation.