The blaze began in an electrical room and caused substantial damage, New York fire department assistant chief David Simms said. Firefighters struggled to knock down the flames due to catwalks and rigging but eventually brought it under control, multiple reports said. The cause remains under investigation, and it is unclear how long the theatre will be out of operation or whether Tuesday's performance will occur.
Damage was largely confined to the fourth-floor area and a backroom containing lighting equipment and chandeliers, with some water damage, Simms said. One firefighter suffered minor injuries; the full extent of damage and any other injuries are not yet known.
The Book of Mormon has more than 5,000 performances since opening at the Eugene O'Neill Theatre in 2011. The theatre, which opened in 1925, has previously hosted productions of Sweeney Todd, Cat on a Hot Tin Roof, and Spring Awakening.