Millions of Americans have nicotine in their body and don't know it

Millions of Americans are being exposed to toxic secondhand smoke and have a byproduct of nicotine in their blood without even knowing it. That’s according to a new study published by University of Florida health researchers in the Nicotine and Tobacco Research journal. The findings suggest 56 million Americans are unknowingly and routinely exposed to toxic secondhand smoke. The researchers analyzed a survey of more than 13,000 adults and detected cotinine in the blood of 51% of people. Cotinine is an indicator that someone has been exposed to nicotine within a few days, primarily tobacco products.