Discover the swamp locations to trace the barrel’s origins in Arc Raiders’ A Toxic Trail quest.

In the quest “Completing A Toxic Trail” in Arc Raiders, you’ll find yourself back at a familiar spot from a previous mission, specifically where you had to track down a toxic barrel dumped in a drain during the Source of Contamination quest. This time around, you’re revisiting the same area and barrel, but there are a few extra steps that could catch you off guard.

Since the last thing you want is to be wandering through the swamp while other loot-hungry Raiders are lurking about, here’s the plan. It’s advisable to skip a free loadout for this mission, as a key you’ll need later drops at the end. As we learned from the Armored Transports quest, losing mission-critical keys can be a real hassle.

Your first task is straightforward: head back to the drain located just north of the Water Treatment Control building. Locate the barrel, which is marked on the map above, to complete this initial step.

While you visited this area before for the Source of Contamination quest, this time you won’t need to examine the barrel. Instead, you’ll be tasked with finding its source in the swamp.

Look for a partially submerged truck carrying a load of barrels just northwest along the river, also marked on the map above. Approach the vehicle, and you’ll receive the objective to “take a photo of the barrel truck.” You can do this by interacting with any of the yellow icons on its side.

After snapping the photo, your next objective is to “search the truck for clues about the saboteur’s identity.” Simply interact with the yellow icon near the driver’s door. This will yield a Spaceport Warehouse Key. Interestingly, you don’t need to pick up this key to finish the quest, but it’s likely you’ll need it later, so either stash it in your safe pocket or exfiltrate at the nearby Swamp elevator right away.