FRANKFURT -- Thirteen people were injured, four of them seriously, in an explosion on Monday at a German factory operated by ball-bearings maker Schaeffler, German police said.
An explosion at a cleaning facility for industrial salts at Schaeffler's plant in Eltmann, Bavaria, was reported to police at about 10:15 am local time.
More than 120 firefighters as well as police and a large contingent of rescue staff were on the scene but police said there appeared to be no danger for people living nearby as no hazardous or toxic substances were released.
The four people seriously injured were flown by helicopter to hospitals while workers at the factory were asked to briefly vacate their positions. The majority of the labor force have since returned to work, police said.
Criminal police and prosecutors have started investigating the incident.
Schaeffler said an initial assessment indicated there will be no interruptions in deliveries to customers.
The plant is located about 90 km (55 miles) north of Nuremberg and employs about 500 people. It is Schaeffler's lead plant for production of rolling bearing components for the company's FAG unit.
Schaeffler also makes components for transmissions and engines used by Volkswagen and Daimler.
Automobilwoche contributed to this report