Mercury Thermometer
Mercury glass thermometers are restricted to one per passenger, in checked baggage only, in a protective case.
Carry-on
Not allowed
Checked
Allowed with conditions
Carry-on details
Not allowed. Old-style mercury glass thermometers aren't permitted in carry-on at all, because of the risk of a mercury spill if the glass breaks.
Checked-bag details
Allowed with conditions. Checked baggage allows one mercury thermometer per passenger, and it must be in its original manufacturer's packaging or another sealed, protective case to prevent breakage.
Quantity limit
1 count (per passenger)
Special instructions
A digital, forehead, or ear thermometer has none of these restrictions — see the digital thermometer entry if you don't specifically need a mercury one.
FAQ
- Can I bring more than one mercury thermometer?
- No — checked baggage allows exactly one mercury glass thermometer per passenger, and it must be in protective packaging.
- Is there an easier alternative to a mercury thermometer for travel?
- Yes — a digital, forehead, or ear thermometer has no restriction at all and is a simpler choice for travel.
Related items
Source: TSA — What Can I Bring? · Last verified: 2026-08-02
Final decision rests with the security officer at the checkpoint.