The U.S. Environmental Protection Agency (EPA) conducted a radiation survey of public and private buildings in the vicinity of mineral mining areas to establish the use, if any, of radioactive mineral waste materials in any phase of construction. The survey was conducted in two phases. The initial phase utilized a mobile van equipped with radiation detection instrumentation to survey radioactive levels in the vicinity of the structures of interest. Areas or structures which indicated higher than normal background levels of radiation were recorded for further investigation. The mobile survey van remained on public roads and thoroughfares during these surveys, except when a survey was specifically requested by an owner of remote private property. The radiation detection equipment was typically capable of detecting an anomaly as far away as approximately 150 feet. While the mobile survey system would detect an area of increased radioactivity, it could not identify the source of the radioactivity. The radiation source could have been a pile of radioactive rocks in a yard, a stone facing on a house, or a house foundation consisting of radioactive materials.