Visitors to a pretty seaside resort in Japan got the shock of their holidays when they saw the beautiful, normally crystal clear, water had turned red.
In footage and videos of the peculiar incident, the water flowing through rivers and port areas of Nago city on the island of Okinawa appears to be an ominous deep red.
As the mystery went viral, a local brewery said they were to blame for the troubling sight.
They said there had been a leak at one of its plants and that the subsequent red water posed no threat either to humans or to animal life.
In a statement, Orion Breweries said: “We believe it was caused by the leakage of propylene glycol – a food additive listed in enforcement regulations of the Food Sanitation Act – contained in cooling water used to cool our factory facilities.
“We believe the leaked cooling water flowed into a river through a rain gutter, causing the sea to turn red.”
Later on, the brewery said the leak had been “plugged” by 9.30am on Tuesday, but a spokesperson for the Japanese Coastguard told CNN the seawater was still red on Wednesday morning.
While the discolouration caused several people to fear for the water’s cleanliness, experts have said the product which caused the colour change is not necessarily to be feared.
The chemical, propylene glycol, is commonly used in the food, cosmetics, and pharmaceutical industries.
The USA’s Food and Drug Administration has classified it as “generally recognised as safe” for use in food.
Meanwhile, Orion Breweries continued to apologise for the accident and said sorry for causing “inconvenience and enormous trouble and worry”.
They added that they were working with authorities to take “countermeasures”.
Despite the apologies of the brewery, the sea turning red still amused locals and people on social media.
One Twitter user said: “What is this? Is our ocean ok? The seawater is so red.”
This isn’t the first time the sea has changed to an unusual colour. Last month, people in Dunraven Bay in Bridgend were surprised when parts of the ocean turned a neon blue in the middle of the night.
The phenomenon was not caused by a chemical being dropped into the ocean but by nature itself.
It was caused by bioluminescence which occurs when chemical reactions within a living organism produce light.
In this case, the organism causing the light was a large group of plankton.