Hamburg airport was evacuated and all flights suspended for around a hour after dozens of passengers became ill from what appeared to be a discharge of a corrosive substance.

Firefighters said 68 people suffered problems including eye irritation and breathing difficulties. Nine had to be taken to hospital though none were seriously affected by the incident which occurred in an area where passenger luggage is scanned by security staff.

The fire service said what appeared to be a pepper-spray canister had been recovered. One report said the pepper spray had been dumped in a bin by a passenger.

#Hamburg airport was completely evacuated due to an unknown substance believed to have spread via air conditioning system. pic.twitter.com/m3mmEKDwQj — Aüd™ (@CodeAud) February 12, 2017

Passengers who had been evacuated were quickly allowed to return to the terminals because of the freezing temperatures outside.

Air traffic had to be paused because all the on-site emergency services were occupied dealing with the situation. However as more personnel were brought in from the city, flights were able to resume.

According to live flight tracking website flightradar24.com 13 flights were diverted to other airports after the incident, others had to circle the airport until it reopened.

Hamburg is Germany’s fifth biggest airport, handling 16 million passengers a year and serving 60 airlines, including Eurowings/Germanwings, Lufthansa, Air Berlin, Easyjet and Ryanair.