Asphalt leaching harmful chemicals into the ground and water. Fast bikers posing safety hazards. Loss of quiet and solitude.

Regular users of Lebanon Hills Regional Park, most of them Eagan residents who live nearby, cited those and other potential pitfalls last week as they continued objecting to a proposal to build a 6.5-mile paved trail through what they described as the heart of the park.

The trail is a key feature of a proposed master plan that would guide the development and preservation of the 2,000-acre park.

Dakota County commissioners last week voted to proceed with the park planning process by formally opening a 60-day public comment period.

Opponents of the trail have been tracking the master plan development and opposing it at every juncture.

"We don't usually get 55 pages of comments before we have released a document" for public comment, said Commissioner Nancy Schouweiler.

About 20 people spoke in opposition to the trail at the board meeting, and some asked the board to hold up the master plan and revise it, moving the trail to the perimeter of the park. That would follow a path outlined in a 2001 master plan for the park.

Commissioners declined to do that.

Schouweiler said the proposed plan is more detailed than the 2001 plan. Final adoption of the plan is still months away, scheduled now for February with time allowed in January for refinements reflecting public comment.

The park had 544,000 visits in 2012, but park planners noted that 70 percent of regional park visits by Dakota County residents are to regional parks outside Dakota County, including parks in St. Paul, Minneapolis and Scott County.

Currently the park has miles of dirt trails but no paved trails, a feature that draws many people to parks to walk, run or bike, planners say.

Several people, including representatives of organizations for the disabled, spoke in favor of the paved trail and the access it would provide people with limited mobility.

"I cannot walk on unimproved paths," said Jeff Spartz of Eagan, who is a former Hennepin County commissioner. "There are a whole lot of people like me." Preservation of the park must be balanced with some degree of access for all, Spartz said.

The route of the paved trail was chosen to lessen the impact on natural areas and take advantage of flat areas that were once used for farm fields and pastures, said Kurt Chatfield, planning supervisor for the county. Two paved loops also would be added around Holland Lake and McDonough Lake.

Opponents of the paved trail said it would detract from the uniqueness of the park.

"We have a rare park. We don't need to put an asphalt trail through the heart of it," said Laura Hedlund of Eagan.

It would be unwise "ecologically, spiritually and economically" to introduce the asphalt, Hedlund said.

"The asphalt is a knife in my view through that park," said Mike Stinson of Apple Valley. He suggested the park staff cut down rapidly spreading buckthorn, which is snuffing out the reseeding of new oak trees.

Other people predicted high-speed collisions with bikers using a paved trail. "We call this a trail, but a 10-foot trail is a road," said one Eagan resident.

Maryann Passe of Eagan said Lebanon Hills now offers a Boundary-Waters-type experience 10 minutes from the Mall of America. The proposed master plan is "a strip mall of a plan," she said. "Approving the plan is a turning point for the park." She asked the board to respect the comments people have offered and reject the proposed master plan.

An evening open house on the master plan will be scheduled at a time yet to be announced in December.