A 58-year-old American man has been charged with mischief after U.S. Customs and Border Protections discovered a “mock improvised explosive device” during an inspection of a traveler’s suitcase at Pearson International Airport on Thursday morning.

The discovery prompted U.S. Customs and Border Protection to investigate the Chicago-bound United Airlines flight 547.

The flight, which was scheduled to take off at 7 a.m., was held on the tarmac for several hours.

In a statement, U.S. Customs and Border protection says that the device was found inside a suitcase at the airport’s “Toronto Preclearance Facility.”

Officials say the device was tested for explosives and determined to be negative.

After declaring “no threat” to the aircraft, all operations at Pearson returned to normal.

Peel Regional Police confirmed to CTV News Toronto that the suspect accused in the case will be held for a bail hearing.

Earlier, officials described the investigation as a “major security breach.”

In video provided to CTV News Toronto by a passenger on board the plane, a United Airlines representative can be heard telling passengers that they're stuck on the aircraft because U.S. Customs had revoked their “preclearance privileges” to enter the U.S.

The representative went on to tell passengers that they would be reunited with their luggage before being re-searched and re-screened at an “isolation area.”

From there, the passengers were led back to the main building with their luggage where they had to clear Canadian customs and go through U.S. customs again.

A CTV News Kitchener employee on board the plane says he and the other passengers were on the tarmac for more than three hours before being escorted off the plane.

Tory Galick told CP24 via phone that they were initially told that the plane was delayed due to weather in Chicago.

“Shortly later, they announced that there was a security issue and then it turned into a serious security issue. They were going to deboard the plane and keep us in the jet way and then that plan changed into towing the plane into a quarantine area,” he said.

The exact nature of the investigation remained muddled for most of the morning.

“It’s a little nerve-racking because the plane has changed several times,” Galick said earlier this morning, while awaiting further instructions onboard the plane.

“Originally, we got on the plane at 6:30 a.m. and we were told it was about an hour delay. Then, we got an announcement that there was a security issue they were looking into. Then, there was another announcement 15 or 20 minutes after that saying that we would be towed to a quarantine area and an hour after that, there was another announcement saying that they were waiting for police to show up with a K-9 to search the plane.”

However, the representative then said that the search dogs would not board the plane.

Galick told CP24 he has tickets to see a Blue Jays game tonight in Tampa Bay but will likely miss it. The United flight was a connecting flight to Tampa Bay from Chicago.

United Airlines spokesperson Maddie King confirmed to CTV News Toronto that officials did meet Flight 547 this morning, though provided no further details.

Joseph Galaska has been charged with mischief in relation to the incident. He is scheduled to appear for a bail hearing in court on Thursday evening in Brampton.

Peel Regional police remained on standby if for any reason U.S. Customs and Border Protection required assistance.

By 2:30 p.m., many passengers had made it through Canadian customs but were still awaiting a new flight.