Emergency workers evacuated dozens of residents of a rural Ukrainian region after a train carrying ammonia derailed near a village, reported the dpa with link the Interfax news agency.
The accident which took place in the eastern region of Poltova left one tanker car overturned and emptied of some 60 tons of ammonia, and a second tanker car badly leaking, officials at Ukraine's Ministry of Emergency Situations said.
A poison gas cloud forced the evacuation of 25 rural residents. No injuries were reported.
Clean-up crews had isolated the spill and returned rail traffic to its normal schedule by late afternoon, said Ihor Krol, a government spokesman.
There was no major danger to the environment from the spill, he added.
Industrial accidents involving toxic chemicals moving by rail are a frequent occurrence in Ukraine.
A poison cloud created after an accident involving a train carrying tons of phosphorus forced the hospitalization of more than 100 persons and the evacuation of some 3,000.
Ukrainian President Viktor Yushchenko ordered reforms of national transportation safety codes in the wake of the mishap, with little effect.