Thick clouds of orange smoke could be seen stretching out of the train station, The Moscow Times reported.
The 10.5 to 13.2 gallons of bromine spilled out of glass jars that were broken when the rail car carrying them was rolled down a rail hump.
An urban legend surrounding the potentially lethal chemical claims that bromine is used by the military to suppress sexual desire in soldiers. One Twitter user, Simwhite, commented that people in Chelyabinsk will face "a year without sex," the Times said.
Russia's chief sanitary doctor, Gennady Onishchenko, said that 36 people suffered bromine poisoning; however the Prosecutor General's Office later said that up to 103 people sought medical attention for potential bromine poisoning, 42 of whom were hospitalized.
City officials said the spill would not cause serious harm, but have several cars with loudspeakers in the streets alerting residents to the spill and urging them to stay inside, RIA Novosti reported. Schools were closed Thursday as a precaution.
"Bromine is a strong poison, not just an irritant. It really is dangerous," Moscow-based chemist Alexei Korunov