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Firestone (2014) asserted evidence for numerous (23) nearby (d<300 pc)supernovae within the Middle and Late Pleistocene. If true, this would havestrong implications for the irradiation of the Earth; at this rate, massextinction level events due to supernovae would be more frequent than 100 Myr.However, there are numerous errors in the application of past research. Thepaper overestimates likely nitrate and 14C production from moderately nearbysupernovae by about four orders of magnitude. Moreover, the results are basedon wrongly selected (obsolete) nitrate and 14C datasets. The use of correct andup-to-date datasets does not confirm the claimed results. The claims in thepaper are invalidated.

Has the Earth been exposed to numerous supernovae within the last 300 kyr?