A faulty battery was the cause of a small fire at John C. Munro Hamilton International Airport on Tuesday morning, according to the Canada Border Services Agency.
Around 7 a.m., a package received by UPS ignited while CBSA staff were examining it.
The package was extinguished and no one was injured, police said.
Paramedics assessed one person for shortness of breath, but did not take the individual to hospital.
Hamilton Police Services called in the Halton Regional Police's Emergency Disposal Unit to assist with the investigation, but the package was later deemed not to have been suspicious.