Murkoff has flooded the Sinyala Facility with toxic gas for the Chemical Leak Limited-Time Event in The Outlast Trials, part of the Season 7.1 update. The event tasks Reagents with locating and shutting off valves to clear the fumes, while earning Event Tokens that buy exclusive rewards from a matching Chemical Leak Catalog.
Quick answer: Play any MK-Challenge or Trial to earn Event Tokens, then spend them in the Chemical Leak Catalog before the event ends on Tuesday, October 6 at 10 AM ET. Any tokens left unspent at that time are lost permanently.
Chemical Leak event dates and how long it runs
The event is live now and runs through Tuesday, October 6 at 10 AM ET. When it closes, the Chemical Leak Catalog is removed and any Event Tokens you have not spent are forfeited. Unfinished Catalog items move into the regular Store afterward, so there is a hard cutoff for cashing out your tokens.
How to earn Chemical Leak Event Tokens
You collect Event Tokens by completing any MK-Challenge or Trial, whether or not it sits inside the “Special Therapy: Chemical Leak” tab. The payout scales with the difficulty you clear, and full Trials always reward more than MK-Challenges at the same level.
| Difficulty | MK-Challenge tokens | Trial tokens |
|---|---|---|
| Introductory | +3 | +6 |
| Standard | +3 | +6 |
| Intensive | +6 | +9 |
| Psychosurgery | +9 | +12 |
For fast farming, the “Eliminate the Past” MK-Challenge is the quickest route. It can be finished in under 10 minutes, while a standard Trial averages around 30 minutes. Repeating short MK-Challenges nets more tokens per hour than grinding long Trials, even though Trials pay more per completion.
Special Therapy: Chemical Leak tab and weekly rotation
On the Terminal you will find a “Special Therapy: Chemical Leak” section holding nine entries in total, split into 3 Trials and 6 MK-Challenges. These are the only activities that complete the Chemical Leak Tasks, which grant extra Event Tokens and additional rewards on top of the standard payouts.
The nine entries are swapped for a new set every Tuesday at 10 AM ET. If you are chasing the Task rewards specifically, check the tab each week, since last week’s lineup will no longer be available.
The two variators: toxic gas and valves
Every Special Therapy Trial applies two event variators that change how you move through the map.
| Variator | Effect |
|---|---|
| Chemical Leak | A leak fills the Trial with toxic gas. Find the valves to clear the gas from each area. |
| Shut off the Valves | Turn off the valves in the Trial to stop the chemical leaks. |
Some rooms are filled with a visible toxic gas. Standing in one builds your “Chemical” meter, and once that meter is full you start taking increasing damage. That damage continues until you either leave the room or die, so you cannot simply push through a gassed area on foot.
How to clear the gas with a valve
You will know it worked when the gas clears from that room and your Chemical meter stops climbing there. Each valve only affects its own area, so a large map may require shutting off several.
Spending Event Tokens in the Chemical Leak Catalog
Event Tokens are only good inside the Chemical Leak Catalog, which is available for the full run of the event. Spend them on the exclusive rewards before Tuesday, October 6 at 10 AM ET. Once the timer runs out, the Catalog disappears, and every remaining token is deleted, so there is no reason to hoard them.
The same Season 7.1 update that launched this event also adds two new MK-Challenges, “Change the Program” and “Fund the Campaign,” along with Invasion and Escalation balancing and new settings options. For the event itself, though, the loop is simple: run Trials and MK-Challenges, shut off valves to survive the gas, and cash in your tokens before the air clears.
