Here is an interesting case of detection, mentioned in the Krakow Post

A recent seizure has put a new meaning behind the phrase “a killer pair of shoes.” On April 22nd, customs officials on the western border of Poland seized 32,000 pairs of flip-flops – plastic sandals with only a strap in the front – that were made of carcinogenic substances. The footwear had been imported from China for sale in the country.

Is it just me or is there more humor in the English versions of European news sources than in America? Killer fashion? Good one.

The carcinogenic material in the shoes was originally detected by the border guards due to a strong odor coming from container. Tests at the Wroc?aw Customs Laboratory confirmed the presence of carcinogenic substances, which become active when exposed to heat. The shoes were shipped back to China before a single pair made it to the Polish market.

Were these guards trained in smelly shoes? Haha. The odor must have been something unmistakable like burning plastic, or maybe the guards automatically suspect Chinese export controls are lax and opened the shipment for special attention.