Operational Intervention Levels (OILs) are action levels used to determine appropriate protective actions based on environmental measurements during an emergency without further assessment. OILs provide a practical tool for prompt decisions based on available data, as generic criteria are not directly measurable and cannot be used for immediate decisions. The OIL for evacuation is calculated based on generic criteria of 100 mSv dose in the first 7 days, assuming the most sensitive groups such as infants and pregnant women live normally in a contaminated area for 7 days, receiving exposure from ground deposition, inhalation of re-suspended material, and inadvertent ingestion. The calculation is done under conditions of a fission product release from a reactor with normal activities and no protection for

1. Operational Intervention Levels: background information and example April 1, 2011