The main objective of this work is to study the possibility of using the radiation sensitive carrageenan substance for routine process control in irradiation processing applications. The free radicals generated in the prepared carrageenan rods were investigated using the Electron Spin Resonance Spectrometer. The effect of relative humidity during irradiation on the response curve as well as short term and long term stability were investigated. The obtained data suggested the possibility of using the carrageenan substance in dose monitoring ranging from 0.5 to 50 kGy.