NORTH HERO, Vt. — It will take more than an extra year before traffic will be traveling on a new drawbridge that links the Lake Champlain islands of South Hero and North Hero, the Vermont Agency of Transportation said Wednesday.

Cianbro Corp. of Pittsfield, Maine, is the contractor on the project.

A temporary bridge is now in place. The state said it had been hoped the new bridge could be open to traffic by May 2021 but said Wednesday it would now be open in the summer of 2022. Removing the temporary drawbridge will take another year.

Extra time is needed to address unanticipated soil contamination found at the construction site, the state said. Tests detected lead, which was expected, but they also found PCBs and a chromium compound.

“We are working collaboratively with our bridge contractor, Cianbro, to ensure that the project proceeds in a safe and environmentally responsible manner,” Chief Engineer Wayne Symonds said in a statement. “At the same time, our goal, as always, is to build a quality bridge that will last for next 100 years.”

The old drawbridge was built in 1953 and it had become increasingly unreliable. The $61 million replacement bridge will be among the most expensive ever built in Vermont.