Marathon: How to Clear Tox Clear Rooms – Safe Looting Guide

The Short Answer

There are two ways to loot a Tox Clear room. The clean one: find the bright red laptop just outside the gas room — its screen shows a symbol matching the extraction devices inside — and spend a Hazard Override Card on it. That vents the gas for a short window, widely reported at around 30 seconds, then it refills. The dirty one: pop a Mechanic’s Kit for its brief toxin immunity, run the room hot, and heal through the damage-over-time, ideally with a Triage Med-Drone covering the doorway. Either way, sort your bag before you go in, take the deepest trunk first, and leave earlier than feels necessary — Toxin keeps ticking after you exit and makes your heals less effective while it does.

Current State (Verified July 2026)

Marathon is on Season 2: Nightfall, live since 2 June 2026 and running to 22 September 2026, 17:00 UTC. The current build is Update 1.1.5, released 21 July 2026 alongside the limited-time Vault Breaker PvE mode in Cryo Archive (21 July – 4 August).

On Tox Clear specifically: no Season 2 patch note we could find changes Toxin damage-over-time values, the vent window length, or Hazard Override Card behaviour. The mechanics below are the current understood behaviour, but be aware that the exact 30-second figure comes from community testing and third-party guides rather than official Bungie documentation — Bungie has never published a number for it. Treat it as a working estimate and give yourself margin.

Two Season 2 changes are still worth knowing before you commit to a room:

• Night Marsh. Nightfall added a nighttime variant of Dire Marsh built around heavily reduced visibility, alternating with the day version every 90 minutes after the season’s first week. Running a Tox Clear at night means the vent noise draws players you genuinely cannot see coming.
• The Cradle. Season 2’s shell-stat system converts loot into Energy for skill points. That quietly raises the value of a Tox Clear haul even when the trunks give you nothing you would equip — marginal loot now has a sink beyond selling it.

What a Tox Clear Room Actually Is

A small sealed area flooded with toxic gas, marked by warning signage and hissing vents, usually with multiple trunks visible through the doorway or window. When it is active, the whole room is Toxin. Walking in unprepared:

• Applies a heavy damage-over-time effect.
• Applies debuffs, including reduced healing efficiency.
• Can kill you after you have left, if you do not start healing early.

These are optional. No contract fails because you ignored one. That framing matters: you should only commit when you have a card, or when you are deliberately kitted to tank Toxin. Everything else is a greedy death waiting to happen.

The Hazard Override Card

An Enhanced-rarity key item, visually similar to a Lockbox Key, used exclusively for Tox Clear events. It does not permanently unlock the room — it buys you a short, timed window with no gas.

Where they come from:

• Randomly in containers, shelves, storage areas and side rooms.
• Off dead players.
• As a loose world drop — they do not only spawn inside containers.

They can be vaulted between runs, which is the right call: extract with one, store it, and only bring it into a raid where you are willing to build the run around hitting a Tox Clear.

Method 1: Vent It With the Card

1. Clear the outside first. The vent is audible. Other runners will hear it and push you while you are stuck opening trunks.
2. Sort your bag now. Not inside. Inventory Tetris during a 30-second window is how people walk out with two commons.
3. Find the red laptop. It sits just outside the room; the symbol on its screen matches the gas extraction devices inside.
4. Interact and confirm spending the card. Some guides note a short activation phase of roughly 15 seconds before the room actually clears — do not panic if the gas does not vanish instantly.
5. Take the deepest trunk first, then work back toward the door. That way, when the clock runs out you are already near the exit.
6. Leave at roughly the 25-second mark. Community reports on the window vary — most cluster around 30 seconds, some describe longer gaps before the gas returns. Build your plan around the shorter figure and you never get caught mid-animation.

Card-method mistakes

• Venting before clearing enemies. The noise is a dinner bell.
• Managing inventory inside the room. Do it at the laptop.
• “One more trunk” at 25 seconds. Ignore it and live.

Method 2: Run It Hot

Viable, but only if you respect how nasty Toxin is. The DoT stacks, keeps ticking after you exit, and the healing debuff means your meds do less than you expect exactly when you need them most.

What makes it survivable

• Mechanic’s Kit. Clears the Toxin status and grants temporary immunity, commonly cited at around 30 seconds. Pop it immediately before opening the door so the immunity overlaps your first trunks.
• Triage Med-Drone. If you or a squadmate runs the Triage shell, deploy the drone where it covers you in the doorway or inside. Continuous healing offsets enough of the DoT to buy real looting time.
• Surplus heals. Assume back-to-back healing after you exit, at reduced effectiveness.

The sequence

1. Clear the outside area — you will be weak when you come out.
2. Deploy the Med-Drone with line of sight into the room.
3. Pop the Mechanic’s Kit right before opening the door.
4. Sprint to the farthest trunk, work back toward the exit.
5. Watch your health bar constantly. The moment immunity drops and HP starts melting, finish the current interaction and go.
6. Exit earlier than you think. The DoT follows you out.
7. Chain heals immediately in clean air. Do not save meds “for later” — the debuff punishes every second you delay.

In squads, rotate one player in at a time while the others watch angles and call out HP.

When it is worth it

I only run hot when all of these are true: no card on me, at least one Mechanic’s Kit plus real healing, the room is visibly stacked with large trunks, and I am not already carrying loot I would be sick to lose. Late in a raid with a good bag, walking away is almost always the higher-EV play.

Getting Out Alive

• Reposition before sorting. Do not stand outside the door doing inventory management with a fresh vent still ringing across the zone.
• Know your extraction before you start. You do not want to be picking a route while debuffed and low.
• Assume you are weakened. After a hot run especially, avoid fights for a couple of minutes.

Bag space is the quiet failure point here: a full backpack turns a 30-second window into a 30-second sorting exercise. If you keep hitting that wall, our inventory space guide covers how Vault Expansion and Armory backpacks actually work in Season 2. For staying alive between events, six survival tips for longer raids is the companion read, and the Marathon hub collects our patch and map coverage.

TL;DR

• With a card: secure the area → sort your bag → red laptop with the matching symbol → vent → deepest trunk first → out at ~25 seconds.
• Without a card: only with a Mechanic’s Kit, strong healing and ideally a Triage Med-Drone. Kit first, far chest first, leave early, heal hard outside.
• Always: never Tetris inside the room, never treat Tox Clear as mandatory, and expect Bungie to eventually tune the timings.

FAQ

How long does the Hazard Override Card vent the gas for?

Community testing and third-party guides cluster around 30 seconds, with some reports of a longer gap before the gas returns. Bungie has not published an official figure, so plan for the shorter number.

Where do Hazard Override Cards drop?

Randomly from containers, shelves, storage areas and side rooms, off dead players, and as loose world drops. They are Enhanced rarity and can be stored in your Vault between runs.

Can I loot a Tox Clear room without a card?

Yes, but you want a Mechanic’s Kit for its toxin cleanse and brief immunity, plenty of healing, and ideally a Triage Med-Drone covering the doorway. Expect to keep taking damage after you leave.

Did Season 2 change Toxin damage or the vent window?

No Season 2 or Update 1.1.5 patch note we could find adjusts Toxin DoT values, the vent duration, or Hazard Override Card behaviour. An earlier April update made Tox Warden encounters and Tox plants more reactive, but that is a separate encounter, not Tox Clear rooms.