Fire consumed the old two-story capitol building in 1852, which created a new urgency to complete the Statehouse project as government offices were forced to relocate to various buildings around Columbus. While some suspected arson, the exact cause of the fire remains a mystery to this day. With the Statehouse exterior nearing completion by 1854, Columbus architect Nathan Kelley was hired to supervise the design and construction of the building's interiors. One of his major tasks would be to provide a system for heating and ventilation in the building, which had not been considered previously. An innovative steam heating system was constructed, with warmed air moved through the building in what Kelley called "air sewers"—small passages made of bricks that linked the various floors of the building. With great fanfare, the new Statehouse opened to the public on January 7, 1857, and soon thereafter the Ohio General Assembly convened in their new chambers. Most of the building was completed, with the notable exception of the rotunda. Although actual work on the building was proceeding smoothly, government officials were deeply dissatisfied with Kelley, citing problems with his working methods and aesthetic choices.