United States Customs and Border Protection officers say 99 per cent of travellers going into the country are legitimate. It’s their job to find the other one per cent.

“They don't have a certain look. They don't have a certain gender. They don't have a certain skin colour,” said Brian King, customs and border protection field operations officer.

And officers only have seconds to decide who to check a little closer. Following 911 systems changed to help with that decision, now everyone crossing the border goes through yellow radiation detectors.

“The fear is someone might smuggle some radioactive source into the United States to create a dirty bomb,” said Chief CBP Public Liaison Officer Chris Misson.

But getting flagged doesn't mean you can't cross. Radiation in substances such as propane, even medicines in your body, can set off detectors.

Handheld isotope scanners let officers verify what type of material set the detector off.

Another new feature is scanners. The Pembina port scans several hundred vehicles each day to help find illegal goods.

“We’ve found floors with drugs with it. Walls that have been packed with drugs,” said CBP Officer Kautz.

If they detect something strange in the scan, the next step is a search. Officers don’t just search the inside of your vehicle. They're also looking at any nook or cranny where something could be hidden.

Being thorough, quick and careful at once is easier than it looks and you never know what to expect.

“Open a suitcase and there's a 10-foot boa constrictor in there. That'll wake you up,” said King.

Sometimes they call in an expert. Grey the German Shepard can sniff out hidden people and drugs.

“We might sweep 500 cars a day just doing exteriors of the vehicles, “ said his handler, CBP Officer Matt Misson, Chris’ brother.

Officers say that when crossing the border having your ID ready and answering questions directly could save time, but no matter what you do, you may get searched.

“Could be officer intuition - sometimes the computer randomly tells us," said Chris Misson.

“We're looking for one per cent and we have to inspect a lot of vehicles to find that one per cent," said King.

Ten thousand vehicles pass through Pembina port each week and it’s their duty to make sure no threats slip through.