Hikers in Hidden Falls Regional Park dodge crews operating a sonic drill boring into the forest floor.
The well being installed is one of nine new groundwater monitoring wells going in along the Mississippi River as Ford Motor Co. and the state move closer to cleaning up one of the region's more colorful toxic waste dumps.
The large waste hill that abuts the St. Paul park is overgrown now, with a parking lot on top that's been used in the past as a State Fair park-and-ride. But from the mid-1940s to the mid-1960s Ford workers dumped paint sludge and solvents from Ford's painting operations there at the base of the river bluff, leaving a toxic legacy that includes lead, arsenic, mercury, cyanide and polychlorinated biphenyls, or PCBs.
Called Area C, the riverfront landfill sits on a 22-acre parcel Ford still owns. The dump has languished, while the main Ford site above was remediated and sold to developer Ryan Cos. for a green new urban village christened "Highland Bridge."
Down below, Area C's fate remains unknown.

Data from the nine new monitoring wells going in and around the site — adding to the 10 already there — are expected to help determine the scale of cleanup Area C requires.
"We'd like to see the entire waste pile removed," said Colleen O'Connor Toberman, director of the River Corridor Program at Friends of the Mississippi River. "We think that would be the right thing to do for the neighborhood and the river."
Area C isn't the worst threat facing the Mississippi River, she said, but it's a unique one in that "there's a very clear responsible party for the contamination, and that responsible party is still around."