The Chemical Leak is the limited-time event of Season 7.1 of The Outlast Trials (version 1.64). It ran from 8 September to 6 October 2026, ending at 10 AM Eastern, and it floods the trial environments with toxic gas that Reagents have to shut off at the valves.
How the Outlast Trials Chemical Leak event works
Poison gas floods the trials through Chemical Valves, and unwinding the valves is the program's secondary objective. Staying in a Chemical Area drains your health. Going into a hiding spot or leaving the area resets the Chemical Meter.
Weekly parts
Trials and MK-Challenges rotate each week while the variators stay the same at every difficulty. The MK-Challenges Change the Program and Fund the Campaign were part of the update.
| Part | Dates (2026) |
|---|---|
| I | 8 to 15 September |
| II | 15 to 22 September |
| III | 22 to 29 September |
| IV | 29 September to 6 October |
Variators and catalog
The event ran with the Chemical Leak and Shut Off the Valves variators on Introductory, Standard and Intensive, plus Increased Threat and Limited Hidespots on Intensive. See the variators guide for how they sit with the others.
Other changes in the update
The update came with a limited event catalog bought with event tokens. It also tweaked Invasion and Escalation, and it added FOV and HUD settings after mod support ended. The next event is Program Geister, which returns on 21 October 2026.
Outlast Trials Chemical Leak FAQ
When does Outlast Trials Chemical Leak end?
It ended on 6 October 2026 at 10 AM Eastern, per Fandom's event page.
Which amp helps with the gas?
Hiding spots reset the Chemical Meter, so hide when it fills. The loadout builder lets you plan a set for it.
What comes after Chemical Leak?
Program Geister returns on 21 October 2026, and Season 8 brings a new Prime Asset and trial environment.