Circumstances that originated 70 years ago are adding a costly and unusual expense to one of the biggest road projects this season in Lake County.

The county's $12 million project to rebuild and widen about two miles of Quentin Road, from near Route 12 north to Route 22 in Kildeer and Lake Zurich, will include paying to relocate a natural gas line in what's termed a Nicor Gas Co. "superior" easement. Paying to relocate the line amounts to about half of the total project cost, officials said.

The road project is set to go out for construction bids in April.

"Nicor was there back in the 1940s. (At) some time, they put in a gas main and had an easement for it," explained Chuck Gleason, project manager for the Lake County Division of Transportation. The gas main must be relocated to accommodate the road widening.

"The Lake County state's attorney has reviewed this agreement, and while rare, Nicor has a superior easement which causes Lake County to be responsible for the cost" of relocating the line, according to information provided to the county board's public works and transportation committee.

The committee on Wednesday considered an agreement with Nicor and recommended appropriating nearly $7.1 million -- the $5.9 estimated cost and a 20 percent contingency -- for the gas main relocation. The full county board will vote Tuesday on the appropriation.

"It's so different," said county board member Ann Maine, who chairs the commission. "It was not a surprise. They (staff) had known about it for some time."

The county usually doesn't pay for utility relocations, Gleason said, but this is a special case.

The blow will be softened because a federal grant will reimburse 80 percent of the gas main relocation. Still, Lake County will be responsible for about $1.2 million, according to Gleason.

Quentin Road was the first asphalt paved road in the county system when it was built in 1947. Originally, the gas easement and the road right of way abutted. But over time, the road right of way was extended into Nicor territory, Gleason said.

"That's why they call it a superior easement," he said. "Wherever it is in conflict with our job, we have to pay for them to move it." The new line will be relocated from the west to the east side of Quentin Road.

The road project extends from White Pine Road north to Route 22. It calls for two lanes in each direction with a median and fifth turning lane at intersections and sound walls.

A bike path will be built on the east side of the road to connect with Route 22. A sidewalk will be installed on the west side from a rebuilt intersection at West Cuba Road north to Route 22.

About 22,000 vehicles per day travel that stretch of Quentin. The widening has been on the county's to do list for seven or eight years.

"It's a real big project," Gleason said. "We've been looking forward to this for a while."