  Tiwari {\it et al.}\ have identified an annual modulation of the $\gamma$-ray
flux at the Soudan Underground Laboratory which is strongly correlated to the
radon concentration. The $\gamma$-ray flux results from ($\alpha$,$\gamma$)
reactions which are induced by the $\alpha$ activity of radon and its
daughters. Unfortunately, the quantitative analysis of the $\gamma$-ray flux is
based on unrealistic ($\alpha$,$\gamma$) cross sections, and thus the
calculated $\gamma$-ray fluxes are not reliable.
