A radiological characterization was study conducted from March 1994 through September 1995 in Area IV of the Santa Susana Field Laboratory (SSFL). The purpose of the study was to locate and characterize any previously unknown areas of elevated radioactivity in Area IV. The study provided a comprehensive investigation of the radiological status of regions in Area IV which had not previously been characterized. It focused on those regions of Area IV which were thought to be free of radioactive contamination (i.e., had not been identified previously as locations of activities involving radioactive materials), and thus had not previously been surveyed.
The following are the major plans and procedures that were used to guide the survey.
The radiological status of Area IV was investigated by three complementary methods: ambient gamma survey, surface gamma scan survey, and soil sampling and analysis. The results of each of the methods showed that the radioactivity in Area IV is predominantly from naturally occurring radioisotopes and radioactive fallout from weapons testing performed by the US and USSR at other locations. Ambient radiation levels and soil concentrations of most radioisotopes were, in general, found to be statistically indistinguishable from local background levels, and the result of factors not related to radiological operations performed in Area IV. There was no evidence of significant, widespread contamination of Area IV as a result of radiological operations at the Santa Susana Field Laboratory.
The following are the four volumes of the Area IV Characterization Survey final report.
The following factsheets provided to the public summarized the survey plan and survey results.
EPA and the Committee to Bridge the Gap provided comments in April 1997 after reviewing the final report.
Boeing responded by letter to these comments in June 1997 and later in a briefing given to EPA in October 2002 and finally in the Area IV Environmental Assessment in March 2003