Routine soil sampling near Concord's Powder Mill Woods trail turned up uranium at 20 times the cleanup threshold, town officials announced Wednesday, Oct. 7.

Tests at the 2229 Main Street Superfund site showed localized uranium concentrations as high as 55 milligrams per kilogram. The site cleanup level is 2.7 mg/kg. The town plans to temporarily close the trail while crews excavate contaminated soil and remove trees, The Concord Bridge first reported.

No closure date has been set. As of Wednesday afternoon, the trail remained open, with workers using orange mesh to cordon off an area just outside the metal fencing that rings the 46-acre property.

A project risk assessor said the levels do not pose an unacceptable health or safety risk to trail users or nearby residents, according to town officials. The town also said the detected concentrations fall within safety standards for recreational activities where contact with soil is negligible.

Town officials said the uranium found in the limited area is consistent with contamination from historical operations at the site. Workers at the former Nuclear Metals Inc. facility, later known as Starmet, spent years manufacturing depleted-uranium penetrators for the U.S. Department of Defense.

The property has been a federal Superfund site since the U.S. Environmental Protection Agency (EPA) placed it on the national priorities list in 2001. The state began scrutinizing the site in the 1980s. Crews have collected more than 35,000 soil and water samples since federal involvement began, according to an April Concord Bridge report that cited project manager Kara Nierenberg.

At an April 2, 2026, community meeting, project coordinator Bruce Thompson of de Maximus Inc. explained that uranium's danger as a heavy metal drives the cleanup more than its radioactivity. "The radioactivity is not really what's driving us," Thompson said at the meeting, as The Concord Bridge reported.

The overall cleanup timeline was pushed to 2031, officials said in April. Workers are cleaning the site to residential-reuse standards and hauling contaminated material to a Michigan landfill. A planned 90-foot slurry wall around a former holding basin could begin construction in 2027 to permanently contain toxic materials.

In 2015, Concord Town Meeting voted to authorize the Select Board to acquire the property once cleanup reaches a residential standard. Select Board member Paul Boehm, who chaired the town's 2229 Main Street Advisory Task Force, told The Concord Bridge in April that he expects the town will eventually get the land.

The town has not announced a public meeting or community forum on the new uranium findings.