On July 29, 2026, U.S. Customs and Border Protection (USCBP) suspended operations at Montréal-Trudeau International Airport (YUL) after detecting a strong odour in the customs area.
Approximately 20 flights bound for the United States were cancelled following the suspension of U.S. preclearance operations, disrupting outbound traffic at the Montreal, Quebec airport.
The odour was traced to varnish fumes emanating from construction materials used in painting work nearby. This work is part of an extensive redevelopment effort at Montréal-Trudeau Airport.
Travelers heading to U.S. destinations were advised that delays and cancellations remained possible. The Montreal Fire Department inspected the affected customs
zone and confirmed there was no health risk associated with the odour. Increased ventilation measures were implemented in response.
Airport officials stated that USCBP operations were gradually resuming but warned that passengers should expect delays. The temporary halt was directly caused by the varnish-related odour. Authorities thanked passengers for their patience and asked those with questions about U.S. preclearance to contact USCBP directly.
Montréal-Trudeau International Airport is currently undergoing a $10-billion redevelopment project, one of the largest infrastructure transformations in its history. Construction work involving painting and other processes is expected to continue over the next decade.
