Can be found in the abandoned excavation camp just outside the Mariposa Military Base in the footlocker in the westernmost tent.
Our team of scientists has finished testing the sample obtained from the base. It has been confirmed as 99% pure. You can expect the sample to arrive shortly. As expected the worker population has mutated rapidly once exposed to the pure source. Heavy, but acceptable losses are reported. I've ordered the evacuation of the base. As soon as the last person is out, we'll blow the entrance to the base and seal the bastards in.
The footlocker also contains the survey map.