The explosion registered at seismic stations across Eurasia, and air waves from the blast were detected in Germany, Denmark, Croatia, and the United Kingdom – and as far away as Batavia, Dutch East Indies, and Washington, D.C.

Or what do you think, which part of the story is not true? The explosion happened that's sure, and the size should be at that range. In 1908 there were not much ways to make an explosion this big, we are well before nuclear bombs.

The largest ever artificial non-nuclear explosion was the Halifax explosion, with 2.9 kt energy. 2 huge ships collided, one full of explosives. Tunguska event had around 12 MEGAtons of energy, so around tenthousand times more. There is no way it was caused by humans. https://en.wikipedia.org/wiki/Largest_artificial_non-nuclear_explosions#Largest_accidental_artificial_non-nuclear_explosions_by_magnitude