"At 11:44 a.m. [08:44 GMT], a caustic element from an air conditioning unit in the American segment of the International Space Station was discharged into the station's atmosphere. The American segment on the ISS is currently isolated, the crew is safe and located in the Russian segment," Roscosmos said in a statement.
The current ISS crew comprises specialists from the United States, Russia and the European Union. Expedition 42 includes NASA's Barry Wilmore and Terry Virts, Russia's Elena Serova, Alexander Samoukutyaev and Anton Shkaplerov, and the European Space Agency's Samantha Cristoforetti.
Expedition 43 is expected to begin in March 2015, with the crew welcoming three additional members, namely Scott Kelly from the United States, and Mikhail Kornienko and Gennady Padalka from Russia.