The room kills more squads than the things in it. Hazards covers the rules for compartments that are actively trying to murder you; and what counts as adequate protection.

Environmental Damage

Hostile environments, ruptured coolant lines, irradiated decks, vacuum breaches, burning compartments, use the Suffering condition to represent ongoing harm.

An environmental hazard is expressed as a type and a number, e.g. Suffering(1-Thermal), Suffering(3-Chemical).

In combat: damage is applied at the start of each of your turns (existing rule).
While exploring: damage is applied at the start of each Sweep (same mechanic, different clock).
Suffering stacks by type; two sources of Chemical damage combine into a single, higher Suffering level.

Appropriate protection negates the damage entirely: vac suits block vacuum and radiation, chemical filtration stops corrosives, thermal gear handles fire and cryo. If your protection is rated for the hazard, you don't take the hit.

Worked Example; Ruptured Coolant Line

The squad enters a maintenance corridor where a cracked pipe is venting chemical coolant. The GM assigns Suffering(1-Chemical) to anyone in the corridor without sealed armor or filtration.

Sweep 1: Each unprotected character takes 1 Chemical damage before resolving their Check. Zoe patches the pipe (Engineering check). Joe searches the far end of the corridor. Zuckburger watches the door.

Sweep 2: Zoe succeeded; the leak is sealed and the Suffering ends. No further damage.

Had Zoe failed, the Suffering would continue each Sweep until the source is dealt with or the squad leaves the area.