German environmental authorities said on Wednesday they were working on the assumption that the smoke generated from the blast that hit a chemicals plant in Leverkusen could contain toxic compounds.
The environment agency in the state of North Rhine Westphalia, in which Leverkusen lies, referred to dioxin, PCB and furane compounds that could have been carried to surrounding areas following the explosion on Tuesday morning.
An agency spokesman said the tanks involved in the blast at the Chempark in Leverkusen contained chlorinated solvents.
“For this reason, we are assuming currently that dioxin, PCB and furane compounds were carried by the smoke plume to the surrounding residential areas,” he said.
The levels at which this occurred was currently under investigation, but the tests were complex, he said.
The blast destroyed a tank depot at a disposal centre.
At least two workers died in the blast, with others missing or injured.
Residents of the city, which lies on the Rhine to the south of Cologne, were advised not to consume any produce grown in their gardens. Playgrounds were also shut and advice issued for doors and windows to be kept closed.