The incident is already being investigated by the Georgia Department of Natural Resources and the Georgia Bureau of Investigation.

Before the gangway collapsed, officials said there were upwards of 40 people standing on it. But the Georgia Department of Natural Resources told Channel 2 Action News that its engineering firm calculated that it should have been able to support the weight of 320 people. Here is how the engineers reached the calculation.

Authorities are working to identify the cause of a partial ferry dock collapse on Georgia’s Sapelo Island that turned a day of celebration into tragedy, leaving at least seven dead and six critically injured as crowds gathered for a cultural festival.