Around 53 people were treated for minor injuries after reporting nausea and sore eyes from noxious gases coming from the toilet at Berlin’s Tegel airport, according to thelocal.de.

Fire fighters arrived at the scene to investigate the toilet, but upon entering the room they too became ill.

“Since around 7 am police officers from the forensic department have been at Tegel testing the air quality,” police spokesman Martin Dams told Der Spiegel. “A high level of ammonia was measured early this morning,” he added.

Tegel's entire inner lobby was shut and terminal A was also closed, so that the source of the poisonous fumes could be tracked down. Officials re-opened it mid-morning and Dams confirmed that the building, and the toilet in question, had been given a thorough airing.