Hydrochloric acid vapour leak has been detected in the German city of Frankfurt am Main, local firefighters reported.
"A leak of hydrochloric acid fumes from a container [occurred] in the Griesheim industrial zone," the fire department said.
Locals, living near the city's Griesheim industrial park, have been urged to keep doors and windows closed. As a precautionary warning, sirens were triggered in Griesheim and in neighbouring Nied district, a police spokesman said.
Early in the morning, a lorry loaded with a liquid chemical had toppled over. The fire brigade reported on its website that hydrochloric acid fumes had started leaking from a container.
While the authorities have been dealing with the leak, the two neighbouring districts have been closed to traffic.
Later in the day, the fire department gave the 'all clear': "The leak has been stopped, the situation is stable."
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According to the city's fire service, the situation in the area is currently being assessed as stable, with the latest air measurements recorded as normal.
Hydrochloric acid is of wide industrial use and must be handled with appropriate safety precautions because it is a highly corrosive liquid.