A 15-year-old girl was seized by police after she set off an anti-attack spray in a crowded museum on a school trip injuring nearly 60 people.
Officials say 27 museum-goers had to be taken to hospital after the spray went off in the lobby as visitors queued for the lifts.
A further 30 needed medical treatment on the spot after the building in Bremerhaven, northern Germany, was evacuated.
The teen is now under investigation for causing grievous bodily harm, according to police spokesman Jens Ammermann.
But she has refused to say if the discharge was deliberate or accidental.
She can also expect a hefty bill for the clean up operation and commercial losses at the Klimahaus – or Climate House – museum.
Local authorities did not reveal her name because of Germany’s strict privacy laws.
Around 500 people were in the museum at the time.
A spokesman for the Klimahaus said it had registered several school classes and groups of tourists from all over Germany and abroad.
A museum worker set off the fire alarm when visitors complained of burning eyes, blurred vision and breathing difficulties.
The Klimahaus remained closed for the rest of that day.
Bremerhaven administration official Volker Heigenmoser said that, if found guilty, the teenager would be ordered to pay the costs of the museum and the city’s emergency service response.
The Klimahaus has been praised for its innovative approach to topics such as pollution of the environment and the effects of climate change on the lives of people on all continents.
Located in the port district of Bremerhaven – a city of 113,000 residents near Bremen, northern Germany – the museum registers between 400,000 and 600,000 visitors each year.
Its 11,500-square-metre showrooms have been attended by Kenyan-British activist Auma Obama, German President Frank-Walter Steinmeier and former German Chancellor Angela Merkel and over the years.
Irish musician and activist Bob Geldof held the main speech at its opening ceremony in June 2009.