Neat little thing the TSA made here:
http://apps.tsa.dhs.gov/mytsa/cib_home.aspx
And from their
blog 4 years ago, "The
only kind of curling and straightening irons you have to be concerned with are the types that take a butane cartridge. These are only allowed in your checked baggage, as long as you only have one and a safety cover must be over the heating element. No spare cartridges are allowed. This type of iron is not permitted in your carry-on luggage.'