Work to uncover buried debris at Site 426 begins soon

A temporary containment structure will be used when excavation of four trenches, suspected of containing chemical warfare materiel, begins in May. The 80-foot long by 50-foot wide by 27-foot tall temporary structure will be placed on moveable rails to travel along the path of work taking place in the trenches. Using near-real-time monitoring and a multistage air filtering unit, the structure is designed to prevent any chemicals uncovered in the trenches from escaping into the surrounding atmosphere. The structure will have to be moved about 11 times to complete the excavation.

Signs of construction activity near the airmen’s dormitories on Main Base at Edwards will begin to be evident in March. The activity is in preparation for the May 2002 excavation of four trenches suspected of containing chemical warfare materiel (CWM), including mustard, lewisite and other military chemicals.

Located just 25 feet away from the dorms, the cleanup site contains four debris-filled trenches estimated to be 150 to 160 feet long by 15 feet wide by 10 feet deep.

Containment

Excavation of the site will be conducted under a temporary containment structure, which will be erected over the area where work is taking place. The structure will move on a rail system to keep all excavations fully enclosed.

"Due to the proximity of the cleanup work to the dorms, extra efforts are being made both to perform the work safely and to inform those who work or live in the area of what is going on," said Rebecca Hobbs, project manager for Site 426.

Monitored environment

The excavations will all take place in a monitored environment where filtration systems will prevent anything uncovered in the trenches from escaping the containment structure.

"The project area will be fenced and the containment structure will be fitted with an exhaust/ filtration unit that will keep it under negative pressure to prevent a release of CWM to the surrounding area," Hobbs said.

Continuous monitoring for chemical warfare agent (CWA) will be performed at the trench locations and at the air filtration unit.

Information

Safety, however, is not the only concern. In the months ahead, Hobbs and others connected with the project will be involved in activities intended to inform those who work on base or live at the dorms about the work going on at the site.

As excavation activity gets underway, a mobile office trailer, located at Site 426, will serve as an information center for base workers and others who want to ask questions about the project or who wish to observe the excavation in progress via real-time video. The information center will be open intermittently starting in May. In late June it will be open Monday through Friday during normal business hours.

Those who live at the dorms will be able to learn more about what’s going on during the construction phase through announcements by their leadership and briefings by Hobbs and others. A sign describing the activities at the cleanup site and listing working hours and a telephone number to call for information will be posted at the site.

Construction at Site 426 is expected to continue through May and will include installation of a fence around the site perimeter, a temporary gravel roadway and a parking lot off Mojave Drive, support lighting and erection of the containment structure.

What’s buried?

The main question: What’s really buried in the trenches? has remained unanswered since the site was first discovered based on archival records, historic aerial photos and geophysical investigations. The answer awaits excavation of the former World War II chemical warfare materiel storage yard.

"It’s possible that no CWA will be found there," said Hobbs. "We simply won’t know until we dig."

Whether CWA is found or not found at Site 426, the excavation will be worth it, Hobbs said.

"If nothing is there, it will be good that we verified that," she said. "If something is there, we will be able to take care of it appropriately. Not knowing isn't’t an acceptable answer."

If intact CWA-filled containers or munitions are uncovered, they would be packaged and transported by, or under the direction of, the U.S. Army Technical Escort Unit to a secure interim holding facility. CWA-contaminated soils and debris would be handled as hazardous waste with their disposition determined once the nature and extent of the materials is evaluated.

Site 443

Related to the interim removal action at Site 426, is a plan to use a known Explosive Ordnance Division burial location at Edwards as a disposal site for Site 426 waste. The materials would include hazardous and non-hazardous wastes other than intact containers of CWA that require disposal.

An opportunity for the public to comment on this potential action will be offered during March and April when an Engineering Evaluation/Cost Analysis, or EE/CA, will be issued proposing the construction of an engineered waste consolidation unit at the former burial location, or Site 443. A public availability session to provide information regarding this proposed action will be held at Rosamond’s Wanda Kirk Branch Library after the EE/CA is available for public review.