If you are arrested for drunk driving, you will probably be transported to a police station and taken to a room where there is a breath machine sitting on a table. There may already be another arrestee sitting at the table, blowing into the machine. When he is finished, the officer will (hopefully) replace the mouthpiece on the tube connected to the machine, hand it to you and say "Blow in here, and keep blowing until I tell you to stop, then wait and do it again". Afterwards, you may find yourself thinking, "I wonder how many people have used that machine today?" And the uncomfortable thought may follow, "I wonder if any of them had tuberculosis?…or AIDS?" If you are in a metropolitan area, maybe a dozen or more suspects breathed into that machine before you; in the previous month, hundreds. And none of them were screened for communicable disease.
ITEM….From the Minnesota Department of Health's Facts on AIDS: A Law Enforcement Guide: "Use disposable breathalyzer masks on drunk driving suspects (HIV has been found in the saliva of some HIV-infected patients)…These precautions are also intended to reduce one's risk of becoming exposed to other infectious agents including hepatitis."
Assuming that the police do replace the mask/mouthpiece before each test, what about the breath tube? The mouthpiece is connected to a heated tube which carries the breath sample from the mouthpiece into the machine's sample chamber. If microbes can reside in a mouthpiece, they can certainly reside in the connecting tube. And the tube cannot be changed.
ITEM….From the manufacturer of BreathScan, a portable and disposable breath testing device: "The BreathScan tester can be used once and then disposed of, minimizing contamination associated with repeated use of non-disposable units (no AIDS cross-transmission)…." (emphasis added)
Now ask yourself: If arrested, would you blow into the Breathalyzer? p.s. And while you're sitting there at the table, where do you think all of those tuberculosis germs went when the other guy's breath sample was flushed from the breathalyzer out into the room?