Some attending the conference blamed Nikola Tesla, the eccentric American scientist who said he had developed a death ray – a particle beam weapon capable of moving at the speed of light. They claimed he had been testing it.
Actually, a Russian scientist has already figured out that the Tunguska explosion was caused by a meteorite. Using matchsticks to replicate trees, he was able to show how fast it was moving, what angle it entered the atmosphere at, and what force it exploded with. Also, someone drained the swamp surrounding the area, dug into the crater and found pieces of the meteorite.
(But Mulder still got infected by the virus it was carrying, though, like the others who were infected, he didn't lose his arm.)