In this work, we evaluate current density and thermal criticality of an unsteady flow of incompressible reactive third-order material in a cylindrical channel with varied electrical conductivity. The electrically conducting fluid is assumed undergoing an exothermic reaction following Arrhenius kinetics, with no consideration given to material consumption. Numerical solution of the derived nonlinear time dependent differential equations of momentum and energy balance are provided via Pseudo-spectral approach. Important properties of the velocity distributions, temperature distributions, current density, skin friction, heat transfer rate and thermal criticality conditions are presented and discussed quantitatively. Our findings show that the terms that increase current density and exothermic reaction of the system need to be augmented to improve the usage of current carrying fluid in industries and complete combustion process in an engine.