FDA list of hazardous compounds in cigarette smoke and found not only polonium-210 but two well-known isotopes of uranium best associated with nuclear reactors (uranium-235 and uranium-238)

“When phosphate fertilizer is spread on the tobacco fields year after year, the concentration of lead-210 and polonoium-210 in the soil rises.” When the soil is stirred up – by planting, plowing, wind, whatever – radioactive particles drift into the air, attach to dust and other particulates there. As these settle back down to the ground, they are often trapped by the naturally sticky leaves of the tobacco plant.