It acknowledged that Navy training has elevated the levels of some metals in the soil of the former Live Impact Area, but holds that the levels are too low to harm humans. It concluded that "the public had not been exposed to depleted uranium contamination above normal background (naturally occurring) levels". It found that the air does not contain dangerous levels of chemicals. It claimed that at eight miles, the Live Impact Area is too far from residential areas for airborne dust and contaminants from training activities to be concentrated enough to cause harm when coming in contact with civilians. It determined that Naval training and testing has in no way affected the drinking water on Vieques. Usually most of the island's drinking water comes through an underwater pipeline from mainland Puerto Rico. The ATSDR report concluded that groundwater from the former Live Impact Area cannot contaminate the wells due to geological barriers, and although there were high levels of nitrates in some wells, this was due to local, most likely agricultural, sources. It cautioned that it is not safe for children and pregnant women to drink water from the contaminated wells.