The Threat Radius is the area within ½ mile of active oil and gas wells, compressors and processors.
It indicates that those within it have cause for concern about potential health impacts from oil and gas pollution. It is not a declaration that those within it will have negative health impacts. It does not quantify the threat posed by this pollution.
Using Census Bureau, Department of Education, and other publicly available data, the Oil & Gas Threat Map calculates the number of people, schools and medical facilities within the Threat Radius. It also allows anyone to search on a street address to determine if it lies within it.
Why ½ Mile?
Peer-reviewed studies in Colorado, Pennsylvania, and Utah have documented elevated levels of harmful air pollutants in and around numerous areas with oil and gas production activity, and have shown that oil and gas facilities are the source of the excess pollution. Research that specifically deals with health indicate correlations between risks and/or prevalence of disease and proximity to facilities.
We use a ½ mile radius because it is a very conservative estimate of the area within which elevated levels of toxic pollution are seen, and the distance within which health impacts have most clearly been correlated with the presence of oil and gas facilities. Also, independent research and analysis by EPA both indicate oil and gas operations have been linked to air pollution at distances much greater than ½ mile:
- EPA’s National Air Toxics Assessment calculates the risk of developing cancer from toxic air pollutants released from oil and gas sites. The results show that in some census tracts with no oil and gas sites within a half-mile of the census tract, pollution from oil and gas still causes a risk of cancer above EPA’s Level of Concern (see at above-right Denver region snapshot of the Threat Map).
- A recent study attributed a spike in local methane and ethane concentrations to a natural gas production field over 150 miles away.