DP World says four workers were taken to hospital after an incident at the Fairview Container Terminal in Prince Rupert Wednesday.
A company official says all four were working in a specific area of the terminal when they suffered respiratory irritation around 11:30 a.m.
They were treated in hospital, but no other details about their condition have been released.
DP World, in a news release, says it suspended operations at the terminal and evacuated the container yard as a precaution.
The company says its incident command management team is working with emergency responders to investigate the source of the incident.