The 354 steps that spiral up to the Statue of Liberty's crown are the only escape route for visitors in case of an emergency.
When a smoke alarm tripped inside last month, hundreds of tourists were rushed down the equivalent of 15 flights of stairs.
Firefighters would need to trudge up the same stairwell to fight a blaze inside the 125-year-old New York landmark. National Park Service officials have closed the statue in recent years for a $20 million security upgrade, and kept the crown shut since the Sept. 11, 2001, terror attacks until last year to improve its fire safety.
Next year the statue will close again for more safety improvements, for nine months to a year, so workers can build a second stairwell at its pedestal.