2019-12-05_HYDROLOGY - M1999058 (4)

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On November 11, 2019 authorization was granted from the South Canyon Landfill to accept contaminated soil from CSQ. Removal and transport of contaminated soils promptly began once authorization was relayed to HRL. Factors Contributing to the Spill Like most incidents, the nature of this spill is complex and includes more than one factor contributing to the event. Initial focus of an investigation explores the physical factors of the incident. Two physical factors evident from this investigation are: - The switch from 480V to 240V power on the overnight generator - Missed assembly of the day tank vent following generator relocation The switch from 480V to 240V caused a condition where the float control, valves, and pump malfunctioned. The malfunction allowed the day tank to overfill and continue overfilling. As required by a root-cause analysis, a number of questions are raised by this failure point: • Why is there a switch? • Who flipped the switch? • Why is the switch accessible? • Why is the pump enabled when the prime power genset is not operating? The overnight generator is equipped to deliver various combinations of single-phase and multi-phase power in 1 1 OV, 240V, and 480V configurations. Depending on the usage case, generator settings will be selected to deliver the proper required power. The overnight generator was setup by Rapid Energy to provide power to the prime power generator as required by the specifications of the prime power generator. The switch is located on the back of the generator inside a lockable enclosure; however, this enclosure was not locked (Figure 3). The overnight generator was installed on September 25, 2019, was tested, and ran for approximately two weeks without issue. As previously noted, access to the switch was not restricted. Additional protection could be provided by limiting access to the 240V to 480V switch panel (Figure 3). On cursory inspection, the panel did not provide access to typical maintenance points of the machinery. Upon restart of the primary power generation, consideration should be given to locking the voltage panel. The second physical factor contributing to the spill was that the vent pipe was not reinstalled on the day tank following the relocation of the generators on July 171h, 2019 (Figure 3). Instead, a vent pressure cap was installed directly on top of the day tank in the previous location for the vent pipe. The fuel system was then operated in a test mode to trouble shoot and solve any fuel transfer issues. As a result, the vent cap was more than 10 feet lower than what was required to mitigate an overfill condition event (Figure 1). The vent pipe was reinstalled and extended to provide spill protection on October 161h 33