Germany’s Hamburg Airport terminals 1 and 2 were temporarily closed Sunday, Feb. 12 after passengers and staff complained of nausea at the central security checkpoint.

According to an airport statement, “Around 130 emergency services personnel from the fire service and the German Red Cross provided assistance to some 68 people.”

The airport said police and fire service reports concluded an “irritant gas had been released into the air and this is assumed to have been the cause of breathing difficulties.” An initial investigation revealed pepper spray was the suspected cause, although the investigation is ongoing.

According to the airport, flight operations were suspended from 12:10 p.m. until 1:40 p.m. central European local time; 14 flights (six arrivals, eight departures) were canceled and several flights were diverted.

On Monday morning, Hamburg Airport announced 14 members of security personal again complained of nausea in the same area as the day before. However, the airport said “nothing unusual could be determined or identified and flight operations continued unimpaired.”