DERR-2024-011828

669 West 200 South
Salt Lake City, UT 84101 October 24, 2024 Mr. Mark Crim, Esq. Division of Environmental Response and Remediation 195 North 1050 West Salt Lake City, Utah 84114 RE: Subsurface Investigation Report UTA Meadowbrook Division 3600 South 700 West South Salt Lake City, Utah FIN: 4001131, Release Site: OLL Dear Mr. Crim, A diesel spill was reported at Utah Transit Authority (UTA) Meadowbrook Division, located at 3600 South 700 West, South Salt Lake, Utah (Figure 1). At approximately 5:30 a.m. on August 23, 2024, Meadowbrook Division staff were fueling buses from two 20,000-gallon aboveground storage tanks (ASTs), T2 and T3 (Figure 2). During this process, staff noticed a high product level alarm and observed diesel fuel flowing from an overflow vent in tank T3, the diesel fuel was cascading down the side of the tank and onto the concrete secondary containment system. Fueling operations were immediately halted. Facility maintenance staff arrived at the spill site around 5:50 a.m. to assess the situation. They found approximately 6 inches of diesel fuel in a catchment basin situated between tanks T2 and T3, which is isolated from the down-gradient portion of the system by a closed gate valve (Figure 3). Inspection of the catch basin down-gradient of the closed valve revealed no evidence of the spill. Additionally, an oil-water separator located downstream of the closed valve showed no signs of diesel impacts (Figure 3). This spill was reported to Utah Department of Environmental Quality (UDEQ) on August 23, 2024, at approximately 1:50 p.m. The release from the overflow vent in tank T3 was caused by a failure of the check valve positioned between tanks T2 and T3. During the fueling operation, the check valve's failure resulted in backflow from tank T2 into tank T3, which was at peak capacity, leading to the overflow and triggering the overfill alarm. The check valve was replaced immediately after the cleanup of the spill and prior to resuming normal fueling operations. Approximately 70 gallons of fluid were pumped from the secondary containment system and the catch basin up-gradient of the closed valve. Following this, residual diesel fuel was removed using steam cleaning equipment, and all collected fluid was placed into a 200-gallon tote. After allowing the fluid in the tote to settle, approximately 30 gallons of diesel were observed floating on top of about 40 gallons of water. The diesel was transferred to a used oil underground storage tank
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(UST), identified as tank E11 (Figure 2). The contents of the used oil UST are disposed of on an as-needed basis by Tri State Oil Reclaimers. The water in the tote was directed into an oil-water separator adjacent to Building 3. The spilled diesel was contained within the secondary containment system and no diesel fuel came into contact with soil or groundwater. Photos Figure 1 – Meadowbrook Overview Map Figure 2 – Meadowbrook Petroleum Storage Tank Map Figure 3 – Meadowbrook Aboveground Storage Tank Map
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PHOTOS
Tanks T2, T3, and concrete secondary containment system (southwest). Note the arrows marking the locations of residual diesel fuel (photograph taken before steam cleaning).
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Catch basin between T2 and T3. Note residual diesel fuel on concrete (photograph taken before steam cleaning).
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Catch basin between T2 and T3 (photo taken before evacuation of the catch basin and steam cleaning).
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Gate valve and downgradient catch basin (that had no evidence of diesel impacts).
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Downgradient catch basin (no evidence of diesel impacts).
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Downgradient catch basin and oil/water separator (arrow).
Figure 1
Figure 2
T3T2
Figure 3
MEADOWBROOK ABOVEGROUND STORAGE TANK MAP