American Spirit Natural cigarettes are no different when it comes to radiation in the tobacco, then other brands like Marlboro. Polonium is in fertilizer to grow conventional cigarettes, maybe it is also used to grow Natural American Spirit as well. Maybe it's from fall-out from Japan or maybe the cesium and other isotopes that have been falling on the ground since March 11, 2011, may be taken up in the roots. Only a gamma spectrometer will be able to identify the isotopes in the tobacco.