GREEN BAY, Wis. (From news reports) - Crews responded to a fire at Procter & Gamble in Green Bay early Thursday morning, Aug. 1.

The fire started in the air handling system for two paper machines. "Fire crews were chasing fire through the duct system... when a large fireball erupted from the vent on the roof of the building," the Green Bay Metro Fire Department reported. Firefighters had to cut through the roof, which was labor-intensive.

While firefighters were trying to extinguish hot spots throughout the ventilation system, another fire was reported in the wall above the electrical room. Power had to be isolated to crews could safely breach the walls to reach that fire.

There was more activity after 6 a.m., including more fire trucks and ambulances arriving. The fire department says the heat in the building and the humidity on the warm night were taking a toll on firefighters, so they were rotated to keep them cool and hydrated.

A few firefighters got overheated from wearing their heavy gear in the warm temperatures and high humidity, but they're OK.

No firefighters were hurt from the fire attack, and no one working inside the building was hurt.

The fire is in the back of the plant on Quincy St. Some fire trucks staged at Green Bay Packaging nearby. No roads were closed.

The Green Bay Metro Fire Department received assistance from fire departments as far away as Manitowoc. They were also assisted by Procter & Gamble's response team.

At this time there's no dollar amount on the damage to the plant.

Exactly what caused the fire is under investigation, but at previous fires, the department has told us paper dust is prone to spontaneous combustion in paper mills' air handling systems.