title: Characterization and geographic location of sources of radioactivity lost downhole in the course of oil and gas exploration and production activities in Texas, 1956 to 2001.
abstract: Case reports describing sources of radioactivity lost downhole in Texas from 1956 to 2001 were obtained from the Texas Department of Health Bureau of Radiation Control and entered into a computerized database. The events of the 45-y period of analysis were characterized, examining aspects such as source type, amount of activity, location of loss, depth, and date of occurrence. Results of the study found that 316 downhole source incidents were reported to the agency during this period of time, representing a total of 426 distinct sources of radioactivity lost downhole within the boundaries of the State of Texas. The sources lost were predominantly AmBe, accounting for 74 TBq of radioactivity at the time of loss, and Cs, accounting for 16.3 TBq of radioactivity. A longitudinal analysis of the data showed the average loss per active oil and gas rig in Texas (known as "rig count") at approximately 24 losses per 1,000 rigs. Specific geographic information was largely missing from many of the records, which prevented the geolocation of wells described to contain lost radioactive sources. As a result, most wells could only be located to the county level, and no comprehensive geographical information system (GIS) map could be accurately created from the data. However, when available, source location information was standardized to permit the characterization of the sources reported as lost. This effort produced the first dedicated compendium of lost downhole sources for the State of Texas and provides an important source of information for regulatory agencies. The ability to provide prompt information about the fate and location of sources of radioactivity is important to regulatory officials, given the recent concerns about radiation source inventory control in the post 9/11 world as it relates to the possible creation of radiological dispersal devices.
authors.affiliation: University of Texas Health Science Center at Houston, Environmental Health and Safety, 1851 Crosspoint Drive, OCB 1.330, Houston, TX 77054, USA. scott.j.patlovich@uth.tmc.edu
authors.forename: S
authors.initials: S
authors.lastname: Patlovich
authors.forename: R J
authors.initials: RJ
authors.lastname: Emery
authors.forename: L W
authors.initials: LW
authors.lastname: Whitehead
mesh_terms: D005648:Fuel Oils; D011835:Radiation Protection; D018788:Radioactive Hazard Release; D011848:Radioactive Pollutants / Q000032:analysis*; D013781:Texas; D013997:Time Factors
chemical_list: D005648:Fuel Oils; D011848:Radioactive Pollutants