It appears the institute wasn't keep on following safety regulations when handling their chemicals, which resulted in nasty spill poisoning the area around the science wing.
When the Institute was shut down nobody really bothered to properly dispose of the leftover refuse , instead dumping most of it into the river. We'll need to locate and retrieve what is left of it for further disposal.
We have to make sure we Didn't miss anything, and that the soil wasn't too damaged by the chemicals. To that end, you will need to analyze the most pollued areas. Let's get this done.
While we got rid of the sources of pollution, we still need to treat the nearby area with a neutralizing agent. All you need is to deliver it, and be careful - the neutralizer can still be dangerous in its own right.