The crew of the International Space Station evacuated its U.S. section on Wednesday morning after an alarm sounded, indicating a possible ammonia leak.. (Reuters)

Update:NASA has now confirmed that the leak was a false alarm, and U.S. astronauts will return to their segment of the space station. They'll wear oxygen masks while conducting tests for ammonia, and remove them once they confirm that the air is clear.

A portion of the International Space Station was evacuated followingcoolant loop pressure increases that possibly indicated a toxic leak of ammonia at 4 a.m. Eastern time Wednesday.All six members of the space station's crew are safe. An afternoon update from NASA confirmed that the problem was not an actual gas leak but a computer error that caused an alarm to sound unnecessarily.

The U.S. side of the space station was sealed off,the Russian Federal Space Agency said on itsWeb site. The statement characterized the situation as a leak of "harmful substances."

"The safety of the team was preserved thanks to swift actions of the cosmonauts and astronauts themselves and the team on the ground in Moscow and Houston," Maksim Matyushin, head of Russian Mission Control, said in the statement, as translatedby NBC News.

The currentExpedition 42 crew of the ISSincludes three Russians, an Italian and two Americans.

"The crew is safe, they're in the Russian segment, and we're working on understanding exactly what went on, NASA spokesperson Kelly Humphries told The Post on Wednesday morning. Humphries explained that we saw an increase in water loop pressure, on the crew cabin pressure, that could be indicative of an ammonia leak in a worst-case scenario.

Although some reports, citing NASA officials, characterized the issue as an ammonia leak, NASA tweeted Wednesday morning that there is "no ammonia leak confirmed."

This was repeatedduring an emergency newsconference at 7:55 a.m.,when NASA representatives said they wished to emphasize that there was "no hard evidence" of a real ammonia leak on the space station. The U.S. crew did indeed don oxygen masks and move into the Russian segment of ISS, shutting down non-essential equipment and shutting the hatch behind them.

But as of that newsconference, equipment in the U.S. segment was already being turned back on. Flight control teams on the ground will continue to monitor the data from ISS, which they believe is indicative of a perfect storm of sensor errors not an actual leak of toxic fluid.

Link:

A false alarm for crew on the International Space Station