Thirty-seven people were sent to hospital in Miramichi, N.B., Wednesday morning to be treated for exposure to carbon monoxide.

The patients all worked at an industrial manufacturing complex in the city.

By late afternoon, all but one of the patients had been treated and released, Miramichi Regional Hospital spokesperson Lisa Caissie told

Caissie provided no information on the condition of the remaining patient.

Police were first called to the Sunny Corner Enterprises complex on Wednesday morning after a man passed out in the building.

By the time officers arrived, the man had regained consciousness and was sitting outside with other employees. Officers noticed a strange smell, however, and ordered the building evacuated, Const. Todd Chadwick told The Canadian Press.

Some of the workers were complaining of headache, nausea and difficulty breathing.

It isn't clear what caused the potential carbon monoxide leak.

Police and fire crews were unable to determine the source, and an investigation determined the site did not represent a danger to the public.

WorkSafeNB continues to investigate the incident.