One person died and 16 people were injured Tuesday following an explosion at a chemical park in Leverkusen, Germany, the site operator said as residents were urged to stay indoors because of black smoke rising from the area.
The blast happened at around 09:40 am (0740 GMT) “for still unknown reasons”, Chempark operator Currenta said.
At least two of the injured were in a serious condition, and four workers were missing, it added.
The explosion prompted Germany’s NINA warning app to send an “extreme danger” alert to residents, telling them to close their doors and windows and keep emergency numbers free as much as possible.
Currenta said the incident occurred at Chempark’s landfill and waste incineration area in Leverkusen’s Buerrig district.
The area is separate from the main industrial park that houses numerous chemical companies including Bayer, Lanxess and Evonik Industries.
“We are deeply saddened by this tragic accident and the death of an employee,” Currenta said in a statement, adding that “rescue efforts continue at full speed” to find the four missing employees.
The city of Leverkusen said on Facebook that the blast triggered a fire at a solvent storage tank that took several hours to put out, with firefighters from nearby Cologne called in to help with the efforts.
Large numbers of police, firefighters and rescue crews were deployed to the scene, as well as pollution detection experts amid concerns that the smoke coming from the site could pose a health risk.
Police in Cologne tweeted that they had closed several motorways in the area because of “major damage”.
They urged drivers to stay away and repeated the message that residents should move indoors “and close all windows and doors as a precaution”.
Locals shared images on social media of the black cloud rising into the air, with some saying their windows were rattled by the force of the explosion.
Leverkusen, on the eastern bank of the Rhine river, lies about 20 kilometres (12 miles) north of Cologne in the western state of North Rhine-Westphalia. It has a population of more than 160,000 people.
According to Currenta, the Chempark chemicals complex is one of the largest in Europe.
More than 70 companies are based at its three locations in Leverkusen, Dormagen and Krefeld-Uerdingen.