Toledo, Ohio, Aug. 18 (SANA)Two workers were killed and several others sustained minor injuries after explosions and a major fire struck an industrial recycling facility in Toledo early Tuesday, officials said.

Two explosions occurred shortly before 5 a.m. during a shift change at Brent Industries, Toledo Fire Chief Allison Armstrong said. Firefighters later recovered the bodies of a male and a female employee from the building.

Two or three other workers suffered minor injuries. Emergency crews faced hazardous materials, contaminated runoff and the risk of further explosions while searching the facility and accounting for employees.

Environmental monitoring detected no hazardous threat in the surrounding air, officials said. Residents who could see or smell smoke were nevertheless advised to close their windows and doors and avoid the area.

The fire continued burning into Tuesday afternoon, and the cause of the explosions remained unknown. Images from the scene showed extensive damage, including collapsed roofing and blown-out walls.

The US Occupational Safety and Health Administration has opened an investigation.

Brent Industries provides textile reconditioning and industrial recycling services at facilities in Ohio and Alabama. An explosion and fire at its Alabama location killed one person in 2015.