SAVANNAH, Ga. — Georgia authorities said Sunday they are investigating the “catastrophic failure” of a dock gangway that collapsed and killed seven on Sapelo Island, where crowds had gathered for a fall celebration by the island’s tiny Gullah-Geechee community of Black slave descendants. “It is a structural failure. There should be very, very little maintenance to an aluminum gangway like that, but we’ll see what the investigation unfolds,” Georgia Department of Natural Resources Commissioner Walter Rabon said at a news conference. [time-brightcove not-tgx=”true”] The gangway was installed in 2021, authorities said. Rabon said three people remained hospitalized in critical condition from Saturday’s collapse. Rabon said “upwards of 40 people” were on the gangway when the “catastrophic failure” occurred, and at least 20 people fell into the water.