  We compute the value of effective photon mass $m_\gamma$ at one-loop level in
QED in the background of small ($10^{10}\,\text{g} \lesssim M \ll
10^{16}\,\text{g}$) spherically symmetric black hole in asymptotically flat
spacetime. This effect is associated with the modification of electron/positron
propagator in presence of event horizon. Physical manifestations of black-hole
environment are compared with those of hot neutral plasma. We estimate the
distance to the nearest black hole from the upper bound on $m_\gamma$ obtained
in the Coulomb-law test. We also find that corrections to electron mass $m_e$
and fine structure constant $\alpha$ at one-loop level in QED are negligible in
the weak gravity regime.
