Oxygen generation system failures happen on the ISS, but the station has oxygen reserves.
A Russian cosmonaut told a specialist from the Mission Control Centre in the Moscow Region that the Electron-VM OGS installed in the Russian Zvezda module had failed.
The American segment of the space station has its own oxygen generation system.
Russian cosmonauts Anatoly Ivanishin, Ivan Vagner, Sergey Ryzhikov and Sergey Kud-Sverchkov, as well as NASA astronauts Christopher Cassidy and Kathleen Rubins, are currently working on the ISS.