United States Armed Forces veterans who served at the base while it was used by the U.S. military described "black goo" oozing out of the soil, appearing to be a mixture of solvents, oils and other chemicals. Noxious vapors were also reported, along with radiation warning signs and a nearby pond that glowed green. Rainwater would reportedly flood tents and appeared contaminated with various chemicals. According to a 2015 Army study, 61 of the K2 veterans had been diagnosed with cancer or died of the disease, not counting the special operations forces.