Under what condition are mercury barometers or thermometers permitted in carry-on bags?

• A. No
• B. Yes
• C. Yes if carried by a government weather bureau representative
• D. Yes in all cases

Answer: (C)

Mercury-containing measuring instruments pose a hazard because mercury is toxic and spills are difficult to manage on an airplane. For this reason, such devices are generally not allowed in carry-on baggage. The only exception is when the item is being transported by an official government weather service representative on duty. In that specific case, the device may be permitted in carry-on form under the custody of that authorized official, with the appropriate handling and packaging in line with regulations. This is why the correct condition is that mercury barometers or thermometers are allowed only if carried by a government weather bureau representative.