Two workers are dead after a pair of explosions tore through an industrial recycling plant in south Toledo before dawn Tuesday, touching off a three-alarm blaze with flames shooting more than 100 feet into the sky and a partial collapse of the building.

Toledo Fire & Rescue crews were dispatched just before 5 a.m. to Brent Industries, an industrial textile-cleaning and rag-reconditioning facility in the 2900 block of South Avenue, near State Route 2. Roughly a dozen employees were inside during the shift change when the blasts hit, according to local fire officials. Most escaped with only minor injuries, but two did not make it out.

Family members identified one of the victims as Mary Allen, 64, a longtime employee remembered as a devoted mother and grandmother who was famously always first through the door for her shift, according to relatives who spoke to local reporters. Fire officials have not yet released the name of the second victim, a man.

Chemical tanks fueled the inferno

The facility stored multiple tanks of mineral spirits used in its cleaning operations, a hazard that firefighters said complicated their response and helped drive the fire's ferocity. Toledo Fire Chief Allison Armstrong described arriving to "heavy fire in the building" with part of the structure already caved in, forcing crews to fight the blaze defensively rather than push inside. Flames were largely knocked down by around 6:15 a.m., though smoke continued billowing from the wreckage for hours, per ABC News' report on the blast.

THIS IS, OBVIOUSLY, AN UNUSUAL EVENT; IT IS A TRAGIC EVENT.

Investigators with the fire department and outside agencies are now working to determine what triggered the initial explosions and how the mineral-spirits tanks factored into the collapse, a process fire officials say could take days given the scale of the damage. The Toledo Blade's coverage of the scene noted crews remained on site well into the afternoon accounting for personnel and stabilizing what was left of the building.

Neighbors near South Avenue described being jolted awake by the force of the blasts, with some reporting rattled windows blocks away. City officials said counselors and support resources were being made available to Brent Industries employees and their families in the aftermath.

Toledo Fire & Rescue says the site will remain an active investigation scene for the foreseeable future, with the Ohio State Fire Marshal's office expected to assist in determining a cause. No timeline has been given for when the business might reopen or when the second victim's identity will be released.