In the German city of Leverkusen, a massive explosion shook a chemical complex, forming a large black cloud in the air, injuring and missing a number of people.

According to the German news agency, "the German Federal Office for Civil Protection and Disaster Relief classified the explosion as a (significant threat), and asked residents to stay at home and close windows and doors."

According to German media, the number of casualties caused by the explosion was 16.

The operators of the Kimbark site in Leverkusen, some 20 kilometres north of Cologne on the Rhine, said that the cause of the explosion was not yet clear.

According to their statement on Twitter, firefighters and pollution detection vehicles were deployed.

Police in the nearby town of Kowloon stated that they had no information on the cause or magnitude of the explosion and were not aware of any injuries at this stage, but had deployed a large number of soldiers and ambulances to the scene.

The police asked all residents to stay at home, warned residents outside Leverkusen to avoid the area, and closed several major highways nearby.

According to Köllner Diaspora, the explosion occurred in the Boyrig area near the waste burning plant. A cloud of smoke was moving in the northwest direction towards the towns of Borscheid Laichlingen.

It should be noted that Leverkusen is home to Bayer, one of the largest chemical companies in Germany.