Swedish specialty steelmaker SSAB has announced that it has temporarily suspended all construction activities at its new steel mill site in Luleå after multiple subcontractor workers reported illness-like symptoms.
The first confirmed cases emerged on April 3, when four workers sought medical attention. In total, around 20 individuals have reported symptoms, with seven requiring treatment.
Investigation into potential gas exposure
As a precaution, all work at the site has been halted, following earlier partial stoppages after initial symptoms were identified.
Preliminary investigations have focused on potential gas exposure. Measurements conducted on April 2 showed that ambient air levels remained well below regulatory limits for gases such as hydrogen sulfide, carbon dioxide, nitrogen dioxide and sulfur dioxide.
Elevated levels detected in machinery cabin
However, elevated concentrations of nitrogen dioxide and sulfur dioxide were detected inside the cabin of a tracked excavator during operation, exceeding regulatory thresholds.
During these tests, operators were equipped with assisted breathing systems, while hydrogen sulfide and carbon dioxide levels remained within acceptable limits.
Expanded monitoring and testing
SSAB has expanded its monitoring activities to include additional air and soil sampling across the construction site. The company noted that earlier measurements conducted after previous incidents had not indicated elevated gas levels. Since 2022, more than 2,000 samples have been analyzed as part of environmental and safety assessments.
The root cause of the reported symptoms has not yet been determined, with some test results requiring further analysis. SSAB stated that construction will only resume once conditions are confirmed to be safe, emphasizing that workplace safety remains its top priority.