The mold is a result of water damage from a storm two years ago that caused roof and exterior damage to buildings at the museum.
Sandy Schmidt, president of the Franklin County Historical Society said additional funds will be needed to get the facility back to normal.
A mold inspection was conducted on the building which found a spore count that ranged from 325-7,500 on various display items in the museum as mold continues to grow. A 100 spore count is considered acceptable.
The Historical Society faces had estimated that 600-700 labor hours at a cost of $50,000 will be needed to complete the mold cleanup.