BRISTOL, R.I. – A contractor repainting the Mount Hope Bridge will be fined “tens of thousands” of dollars after wooden planks fell twice from scaffolding in the last few weeks, officials said.

In the most recent incident last Thursday night, a plank used for scaffolding walkway fell 20 feet and cracked the windshield of a car that was crossing the bridge. The driver and her passenger were not injured.

The Rhode Island Bridge and Turnpike Authority, which owns and runs the bridge, imposed the fines against Maine-based Cianbro Corp. The exact amount has not been determined, but David Darlington, chairman of the authority, warned that it would be “significant.”

“We are exceptionally pleased with the cooperation and level of response provided by everyone involved, but must communicate in the strongest possible terms that such incidents are unacceptable,” Darlington said in a statement.

The authority also announced additional precautions and an independent inspector to review safety policies and procedures.

Cianbro is in a two-year, $10 million project to repaint the north tower of the bridge, which links Bristol to Portsmouth and serves as an important connector to Aquidneck Island.

The police closed the bridge through midnight Thursday.