Some buildings at White Sands, such as the Public Affairs Office, contain granite rock taken from the Organ Mtns. which is radioactive. The rocks naturally contain measurable, but harmless, amounts of such radioactive elements as uranium and thorium.
Radiation comes from the nucleus of individual atoms.
Simple atoms like carbon and oxygen are very stable. The nucleus of an oxygen atom is made up of eight protons and eight neutrons. This organization holds together very well. The nucleus of a more complex atom like uranium is not as stable. Uranium has 92 protons and 146 neutrons in its core.