Officials were left red-faced at a beer factory in Japan's Okinawa region on Tuesday, after a mishap turned a large body of water a sinister shade of scarlet.
A leak filled a port area in the city of Nago with the lurid-coloured water, which one Twitter user described as looking "venomous".
Orion Breweries said water used for cooling, which contains a liquid called propylene glycol -- dyed red with food colouring -- had leaked from a factory in the area.
In a statement, it apologised for "causing enormous trouble and worry".
"We believe the leaked cooling water seeped through rainwater gutters into a river, and consequently turned the ocean red," the company said.
Okinawa is a subtropical island chain famed for its crystal blue waters, and is popular with scuba divers.
"The red does look venomous, but it's a relief to learn it's just food colouring and not likely to cause major damage," wrote a Twitter user under the name Aresu.
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© Agence France-Presse
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