We have measured step growth kinetics on barium sulfate (001) as a function of step length, supersaturation, and temperature. rising a one-dimensional nucleation model, we report kink detachment coefficients for [120] monolayer steps of w- = 114 (+/-14), 187 (+/-17), and 357 (+/-43) s(-1), at 90, 108, and 125 degrees C, respectively, giving an activation energy, E-a = 0.39 (+/- 0.05) eV. The kink formation energy, epsilon, was found to be 0.16 (+/-0.02) eV. The uncertainty in this energy is sufficient to envelop the experimentally determined kink densities, but the lack of increase in experimental kink density with increase in temperature points to kinetic limitations in the experiments. Due to the kinetic limitations of growth at kinks whether they are from diffusion or attachment, our results demonstrate that knowledge of the kink kinetics as a function of temperature is important in testing the applicability of the classical thermodynamic model to kinetic data.