Hundreds of fire and rescue workers scoured through tons of rubble on Thursday after a 12-story oceanfront residential building partially collapsed in southern Florida, with at least one person dead and 51 still unaccounted for, officials said.

Sally Heyman, a Miami-Dade County Commissioner, said officials have been unable to make contact with 51 people who “supposedly” live in the building, home to a mix of people including families and part-time “snow birds” who spend the winter months in Florida.

“We have 51 people that were assumed to have been there, but you don’t know between vacations or anything else, so we’re still waiting,” Heyman told CNN by phone. “The hope is still there, but it’s waning.”

A fire official said 35 people were rescued from the building in Surfside, a seaside enclave of 5,700 residents on a barrier island across Biscayne Bay from the city of Miami, including two who were pulled from the rubble as response teams used trained dogs and drones in a search for survivors.

After speaking with local officials, Florida governor Ron DeSantis said it was possible that more victims could be found in the rubble. He said he planned to go to scene.

“We’ll hope for the best in terms of additional recoveries, but we are bracing for some bad news, just given the destruction that we’re seeing,” DeSantis said at an event at a community college near Tampa.

Built in 1981, the Champlain Towers South had more than 130 units, about 80 of which were occupied.