said by Mike_C:Last time I accompanied a friend who uses a wheelchair through an American Airport and the TSA checkpoint, we had a very informative TSA person (Las Vegas TSA are great I find). He mentioned that some hand lotions can contain a certain chemical that can trigger a false positive reading when they do their tests. The TSA agent we dealt with tested my friend's wheelchair first and then my friend's hands. Normally if they get a positive result on a test, they should be testing the rest of the chair and user just to make sure it's not a false positive.
The logical thing then would be for TSA to place a notice on their website warning about use of these particular hand lotions when flying. But I guess that would anger the manufacturers?