Hello. Good that you are here. I have a job just for you since you are already familiar with it. Our engineers have successfully neutralized chemical leak from the factory, but the water is still not fully rectified. Although only remaining pollutants are specific to petroleum products. We assume that this is connected to the TPP fuel oil storage next to the factory. Know these? It’s hard to miss, there's a big stack. Technical rooms of fuel oil storage and furnace facility must be nominally equipped with the same radio- and gas analyzers you found in the factory, if, of course, they weren’t stolen yet. Locate and bring them in and we will solve the water problem in the region, at least for a while.
Unlocks the door to the pumping room, which contains loose loot scattered around the floor and table. The Gas analyzer can spawn here.
While Gas analyzers do spawn on Factory as suggested by the optional part of the quest, they are much more common to find on the map Interchange. By searching the shelving of all the electronics stores, multiple gas analyzers can easily be found in a single raid.
Trivia
The Door key can be found on a bench in the locker room on Factory