Three people have died in an accident at a leather factory and fur tannery in Runkel, north-west of Frankfurt, German officials said on Thursday.
Two others were seriously injured and taken to hospital, the Interior Ministry of the state of Hesse said.
They are in critical condition, a spokesman for local hazard response told dpa.
Some 150 emergency forces were deployed to the scene, according to the spokesman.
The five affected were found in a septic tank at the tannery, he said, adding that it was still unclear which chemicals in the tank had caused the serious injuries.
According to the ministry, carbon dioxide (CO2) is currently being considered.
Because various chemicals are used at the affected facility, around 45 to 50 emergency personnel who had direct contact with the victims are being decontaminated and, as a precaution, being seen by a doctor.
According to hazard response, there is no danger to the public due to the incident.
Hesse’s Interior Minister Roman Poseck is expected at the accident scene on Thursday evening.
Emergency workers stand on the scene after an accident at a leather factory and fur tannery in Runkel. Several people have lost their lives and others were seriously injured and taken to hospitals. Sascha Ditscher/dpa