On August 26, 2010, the NRC issued a Notice of Violation and Proposed Imposition of Civil Penalty in the amount of $24,700 to Basin Electric Power Cooperative. The violations involved: (1) Severity Level (SL) II violation of 10 CFR 20.1301(a)(1) for failure to limit radiation exposure to members of the public to less than 100 millirem in a year, resulting in six members of the public received doses in excess of 100 millirem; (2) SL III violation of 10 CFR 20.1902(e) for failure to conspicuously post caution signs with the words "CAUTION, RADIOACTIVE MATERIAL(S)" or "DANGER RADIOACTIVE MATERIAL(S)" in areas where nuclear gauges were used; (3) SL III violation of 10 CFR 30.50(b)(4) for failure to notify the NRC within 24 hours after the discovery of an unplanned fire on March 8, 2007, that damaged the integrity of a licensed device; and (4) SL III violation of License Condition 21 of Amendment 10 to NRC Materials License 33-18224-01 for failure to close and lock the nuclear gauge shutters after plant operations had stopped and prior to allowing welders to begin work, resulting in welders exposed to the direct radiation beam from these nuclear gauges.