At least 24 people were hurt in a four-alarm fire that ripped through a Manhattan building on Thursday. The fire broke out on the third floor of a 33-story apartment around 5 p.m., and quickly spread up the building. Heavy smoke on the upper floors made it difficult for firefighters to combat the blaze. Among the injured parties are four firefighters and 20 civilians, six of whom are listed as "seriously" hurt. Dense smoke on the 21st floor caused one seven-year-old to go into cardiac arrest, ABC reports. Firefighters were able to evacuate her to the street, where she was revived. The fire has been extinguished, but authorities were still searching the building as of Thursday night.