Documents outline tank removal at GPAC site
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It’s hard enough to build a $60 million performing arts center in the middle of Greensboro, but once you throw in the discovery of abandoned and leaking underground fuel storage tanks things get a bit more complicated.
That’s what happened in February when crews demolished the building at 125 Summit Ave. to make way for the future VIP parking spaces that will finance part of the Tanger Performing Art Center project’s debt service.
The building at 125 Summit Ave. was most recently home to Boston’s House of Jazz. Lease agreements between Boston’s and the building owner were a slight headache to the TPAC planning process in early 2014 when project boosters were forced to buy out the lease in order to include the property in the site plans.
Almost a year later as crews tore down the building, four underground storage tanks were uncovered.
As crews tore out the foundation and footings for the building on Feb. 4 they uncovered three gasoline and one used oil tanks beneath the site.
Greensboro-based Engineering Consulting Services prepared a Phase I environmental report in 2012 as part of the planning for the TPAC project. The report examined the existing 9,144 square foot Boston’s building, but also looked at historical records to determine that both an auto body paint shop and a former gasoline service station occupied the site going back to the 1950s.
Because no records existed of how the paint was handled or disposed of in the auto body operation the site was considered a recognized environmental condition. ECS was unable to pin down records for the gasoline station but observed monitoring wells that had been previously installed on the site.
ECS was called back in when the demolition crews discovered the underground storage tanks. Each tank had a 1,000-gallon capacity. Three gasoline tanks were unearthed near the edge of Summit Avenue, while the used oil tank was further into the site near the building’s northwest footing. Once ECS arrived on site, removal began with crews exposing the top of the tanks. Shamrock Environmental removed about 3,808 gallons of non-hazardous liquid and sludge from the tanks.
Because Summers Grading was responsible for the demolition work, Clarence Summers signed the Shamrock receipts, which originally list “gasoline mixture” as the waste removed. That was later marked through and replaced with “mud and water” on two of three receipts.
Crews removed the four tanks and Summers hauled them to DH Griffin on Feb. 10. The DH Griffin receipt lists “old oil drums” as the material disposed. The receipt lists 2,740 pounds as the net weight received but price per unit and total amount paid are marked out.
Back on site, ECS was responsible to analyze the soil surrounding the tanks to determine what level of pollution remained. The three gasoline tanks had not left pollutants in excess of reportable limits. However, a reportable release of used oil had occurred. ECS, in its written report to the engineering firm responsible for site preparation, stated that they “completed and submitted a 24 Hour Release and UST Leak Reporting form.” A copy of the form is included in the ECS report, however calls to both the state Department of Environmental and Natural Resources and Guilford County Department of Public Health, which manages underground storage tank matters for the state, failed to turn up any records of the situation.
Once the tanks were removed, soil remediation became the next challenge. The City of Greensboro contracted with Summers to remove the soil for off-site disposal. Some 725 tons of soil were removed from the site and shipped to Earth Tec of North Carolina, located in Sanford, for treatment. This left a giant hole in the ground where the VIP parking is slated to go, meaning the next step for crews was to fill in and stabilize the soil.
The ECS report states that delays caused by the weather meant that excavation did not begin until March 17. Receipts from Earth Tec, however, show six truckloads taken to Sanford on March 9. Some 40 additional loads were hauled on March 17 and 18.
The March 9 loads appear to be from an undercut of unstable material as ECS attempted to determine if the soil could be used as fill material. Engineers determined it could not be used “due to presence of organic matter and old construction debris (bricks, wood, etc.).” This left a 60×46-foot area to be backfilled in order for a stable parking lot to be built.
ECS field reports documented the procedure. A March 19 report states that “due to budgetary constraints” they decided to take a four-foot thick strip of unsuitable soil and place it at the bottom of the 10-foot-deep tank excavation. Imported fill was used to fill in the remaining seven feet “and compacted to project specifications.” Another stockpile of soil was spread to the south and west of the site.
“Based on observations, the areas where the unsuitable soils are being spread will require remediation during construction due to their instability prior to spreading the unsuitable soils,” wrote Sun Breza, ECS’s transportation services director in a report dated March 24.
Total costs for the tank removal and soil remediation remain unclear. Summers Grading had their contract increased by about $69,000 at the May 5 city council meeting. A change order for the site engineer, John Davenport Engineering, is being prepared for council approval. !