Hamburg airport was evacuated on Sunday after a discharge of a corrosive substance caused eye irritation and breathing difficulties among 50 people.
Mail Online reported that the incident was caused by pepper spray leaking into the air conditioning system near a security check area.
It said the canister, used by police, was set off in a bin after being discarded by a passenger.
The website put the number of those affected at 68 and said nine people were taken to hospital.
Reuters said the incident had affected 50 people and had led to hundreds of people being evacuated.
Firefighters and ambulances were rushed to the scene after the incident, which occurred in an area where passenger luggage is scanned by security staff.
Firefighters are trying to determine the source of the discharge and the nature of the corrosive substance, Reuters reported.
Lightly dressed passengers were rushed outside the terminal but were allowed back in shortly after, a police spokeswoman said.
A spokeswoman for the airport said flights had resumed as of 1.45pm (1245 GMT).
According to live flight tracking website flightradar24.com some flights were diverted to other airports after the incident.
David Morris said he was checking in for a flight to Edinburgh when he started coughing.
The 28-year-old told the Mail: “It was getting quite bad and we saw other people starting to cough at the same time.
“The people behind the desk were coughing the most and quite aggressively.
“Within two minutes, they shouted for everyone to get out.”