The large tan tent at 4825 Glenbrook Road in the Spring Valley neighborhood of Washington D.C. will be coming down about six months ahead of schedule, signifying the end of high probability operations at the U.S. Army Corps of Engineers’ cleanup site at this prestige property.
The, The large tan tent is an Engineering Control Structure and has become a regular site in the neighborhood over the past three years. It is part of a multi-layered approach to public safety in place during high probability operations which involved expert teams digging up and removing items associated with the former American University Experiment Station (AUES) where the Army researched and tested chemical weapons during World War I.
The disassembling of the tent for the third and final time at the site since it was first erected in early 2013 will be the most noticeable symbol of the beginning of the end to what has been a complex effort to remediate contamination associated with a burial pit from roughly 100 years ago.
“We were very excited to be able to tell the surrounding neighbors that the high probability operations at the site were ahead of schedule. The early completion of our high probability operations that required the multiple layers of safety controls, including the tent, can now be removed from the site earlier than originally anticipated,” said Project Manager Brenda Barber, from the U.S. Army Corps of Engineers Baltimore District.
The property at 4825 Glenbrook Road was the site of a former burial pit for both munitions-related items and laboratory-related items, and crews have removed more than 600 pounds of glass, 39 intact glass containers, 151 pounds of metal debris, 10 75mm munitions debris items and various other munitions-related items during high probability operations. In addition to the AUES-related items recovered from the site, nearly 2,000 total cubic yards of soil was also dug up and removed from the site as well during high probability operations.
“Safety was always our top priority on this project,” Barber said. “We employed a multi-layered approach to public safety and worked to keep the community constantly informed of our activities and all relevant safety protocols.”
All high probability excavations took place within the tent operating under negative pressure with three Chemical Agent Filtration Systems to reduce the risk of any chemicals escaping the tent and reaching the neighboring properties. A Shelter-in-Place system was also in place as an additional safety precaution. Shelter in Place was designed in case a chemical release occurred at the same time the engineering controls failed. As part of the Shelter in Place program, nearby residents were trained to stay in their homes in the case of an emergency until the US Army Corps of Engineers team provided an all clear. Notifications were provided to the residents through various communication forms, including text messages, emails, phone calls, etc. The system was tested monthly but there was never a need to activate the system as all of the engineering controls at the site operated as planned.
Crews first tore down the house that stood at 4825 Glenbrook Road in November 2012 and the ECS structure was first erected in early 2013. Since then, it was disassembled and reassembled twice, covering three different footprints on the lot where high probability operations took place.
When high probability work began at the third and final tent location in February 2016, the Corps estimated it would continue through the following winter. As crews excavated under the third tent location though, they did not encounter nearly as much AUES-related material as under previous tents. While they removed concrete from the former structure’s basement floor and house footings and more than 300 additional cubic yards of soil, only 9 pounds of glass debris was removed and no munitions-related debris or metal scrap related to AUES was encountered.
With the lack of AUES-related material under the third tent location, crews progressed quickly and finished high probability operations at the end of May.
The next stages of the project are the careful decontamination and disassembly of the engineering controls and equipment used during high probability operations. Then the site will be readied for the completion of low probability soil removal in the backyard area and in the footprint of the former driveway area of the residence.
The Corps estimates the entire 4825 Glenbrook Road Project will be completed in summer 2017. At completion, the lot will meet residential cleanup standards and be returned to the property owner.