Residents and tourists alike woke up to a surprise in Venice, Italy, on Sunday: The water in the city’s famed Grand Canal was a bright, fluorescent green.
The green patch was first spotted near the Rialto Bridge. It then grew larger and continued to spread throughout the day.
Residents, of course, reported the incident to authorities.
By Monday, Luca Zaia, president of the region of Venice, took to social media to reassure nervous residents.
There is “no danger of pollution from the fluorescent green patch that appeared yesterday morning in the waters of Venice, but the risk of emulation is worrying,” Zaia wrote on Twitter.
Why The Water Is Green
The good news is that the chemical used to dye the water is harmless, the Regional Agency for the Environment in Venice (ARPAV) announced after an investigation and analysis, according to CNN.
The non-toxic chemical used to dye the water has been identified as fluorescein. It is generally used in underwater construction or by municipalities to identify leaks in wastewater networks, according to The Guardian.
Considering the volume of dye released into the canal, however, the incident was not an accident, ARPAV said.
The local police and other authorities are investigating the incident. No group has claimed responsibility for it yet, but since it seems to be an act of so-called eco-vandalism, authorities are investigating groups known to be climate change activists.
Members of one such group, the Ultima Generazione, or “Last Generation,” recently climbed into the Trevi Fountain and poured black vegetable charcoal into the water. They then held up banners saying “We won’t pay for fossil [fuels] in Rome,” according to USA Today.
The group has also asked “for an immediate stop to public subsidies to all fossil fuels,” USA Today continues.
Nevertheless, when asked by CNN about the incident in the Grand Canal, a group spokesperson denied involvement.
A Previous Dye Job
Interestingly enough, this isn’t the first time the Grand Canal’s water has been dyed green with fluorescein.
On June 19, 1968, Argentine artist Nicolás García Uriburu dyed the waters green with fluorescein during the annual Venice Biennale.
That action, which was not part of the official program, “aimed to bring attention to the relationship between nature and civilization and to promote ecological consciousness as a critical part of culture,” according to the Metropolitan Museum of Art.
The green dye eventually disappeared after a low tide.