Firehouse 51 rushes to the scene of a deadly chemical leak inside an industrial building in the next episode of "Chicago Fire."

According to the Spoilers Guide, It's all hands on deck when the situation at the industrial pack escalates in the next episode, titled "I Am the Apocalypse," airing next Tuesday on NBC.

"The situation takes a turn from bad to worse in the midst of the chaos when a 'patient' planted inside the hospital goes on a suicide mission armed with a grenade and claiming to be the carrier of a deadly airborne disease," according to the Spoilers Guide description.

"Trying to stop the madman from engaging the explosive device, a member of the firehouse team is severely wounded in the blast and left to face life-threatening injuries. With no other choice, Chicago Med is forced into lockdown until doctors and the Hazmat team can determine the severity of the airborne virus."

Many victims are rescued from the scene but have to be quickly transferred to Chicago Med because they have suffered from respiratory distress.

In the last episode, "Forgiving, Relentless, Unconditional," Herrmann saved a baby in a structural fire then went on a quest to solve the circumstances involving the event making a promise to the baby's father, according to Celebrity Dirty Laundry.

Maybe Herrmann got so involved because the fire was just two blocks away from where he grew up. When he saw that the father had to leave his child behind, he promised the man that he would get his son out alive.

Hermann went against the Chief's orders, risked his own life, and went inside the burning building just to keep his promise.

In the next episode, the men risk their lives to save others as well. A member of the team jumps on top of the man who tried to let off a grenade in the hospital and it is not clear if he will survive his life threatening injuries.

Tune into the next episode of "Chicago Fire" on NBC Tuesday, April 7.