Two workers were killed and several others injured following two explosions that ripped through an industrial recycling facility in Toledo, Ohio, early Tuesday. The blasts at Brent Industries occurred shortly before 5 a.m. during a shift change, according to Toledo Fire Chief Allison Armstrong.

Firefighters discovered the bodies of a male and female employee inside the heavily damaged building. Two to three other workers sustained minor injuries. The explosions sparked a massive fire, sending thick black smoke over the area. Fire crews encountered hazardous materials, runoff, and the potential for further explosions as they searched for victims and accounted for all employees. Aerial images showed extensive destruction to the facility, with the roof largely gone and several walls blown out.

Environmental officials reported that air monitoring detected no hazardous threats. Demetrius Langston, who was approximately half a mile away, described feeling the force of the blasts and hearing them repeat.

The fire continued to burn into Tuesday afternoon. Authorities have not released preliminary indications regarding the cause of the explosions. Residents who could see or smell smoke were advised to stay away from the area and keep windows and doors closed.

Brent Industries, which is based in Alabama, offers textile reconditioning and industrial recycling services and uses mineral spirits in its cleaning processes. The Toledo facility reportedly contained tanks of this petroleum-based solvent, though its role in the explosions is currently unknown.

The company has a history of accidents and safety violations. In 2015, an explosion at its Alabama plant resulted in one worker's death after mineral spirit vapors ignited. The Occupational Safety and Health Administration (OSHA) subsequently cited Brent Industries for six violations, issuing a $27,000 fine. Brent Industries could not be immediately reached for comment.