DuPont closed a chapter on explosives manufacturing in the Chequamegon Bay area in the early 1970s when it shuttered Barksdale Works. But work there is far from over.
The DuPont facility began manufacturing explosives such as TNT, dynamite and nitroglycerine for the U.S. military, mining operations and agriculture at the beginning of the 20th century. During its nearly 70 years of operation, 36 men were killed at Barksdale Works — a 1928 explosion claimed two lives and another in 1952 killed eight.
After DuPont closed the 1,800-acre facility between Ashland and Washburn, it faced the daunting — and lengthy — task of cleaning up chemical contamination at the site. That effort launched in 1998, and to date, about 787 acres have been opened for recreational use and 702 acres for unrestricted use.
But much more work needs to be done, and Bradley S. Nave, project director for Chemours Corp. Remediation Group, explained the ongoing process to the community at Northern Great Lakes Visitor Center Thursday evening.
Working with the U.S. Army Corps of Engineers, the company has focused in recent years on locating and destroying TNT in a 329-acre former World War I production area, Nave said.
Nave has worked on the Barksdale remediation process for about 18 years, and he and his coworkers have been piloting a remediation technique that uses living creatures to do a lot of the cleanup work.
The company's biological remediation, otherwise known as bio-pilot cells, destroys the explosive DNT, project manager Cory Pooler said.
In areas containing predominately DNT, the ground is aerated, and when rain saturates the soil, indigenous microorganisms eat the DNT, converting it to carbon dioxide and water.
But the presence of TNT inhibits the growth of the microorganisms, so the company then adds hydrated lime to the soil to reduce the concentration of the explosive.
"We found it to be quite successful," Nave said.
But there was a caveat. The hydrated lime maneuver works well only when TNT is present in small pieces. Therefore, Chemours is experimenting with ways to reduce the size of TNT to manageable chunks with the help of the U.S. Army Corps of Engineers.
The company prefers to handle all remediation efforts on site, but if it finds workers and techniques can't handle the materials it hauls them away for destruction elsewhere.
About a dozen community members attended the annual update, and Nave said considering the continuing interest, Chemours probably will schedule another update next year.
Nathanael Bonnell, who rents a room in a house on Nolander Road in the town of Barksdale, attended the update over concerns about possible water contamination.
DNT is supposed to be a carcinogen, said the 30-year-old recent arrival to the Chequamegon Bay area, and he sought answers about groundwater contamination.
After listening to Nave's presentation, Bonnell said he felt about as good as he could about the cleanup, although he still wasn't thrilled a largescale explosives plant had operated in the area.
Remediation crews will continue to work at the site for about another month and return next year after the ground thaws. Nave said Chemours would return year after year until the site is clean of contaminants.