After a cargo ship caused a major bridge to collapse in Baltimore, leaving six construction workers presumed dead, investigators are working to determine how the collapse took place. | Subscribe and 🔔: http://9Soci.al/KM6e50GjSK9 | Get more breaking news at 9News.com.au: http://9Soci.al/iyCO50GjSK6 FOLLOW 9News Australia ► Facebook: https://www.facebook.com/9News/ ► Twitter: https://twitter.com/9NewsAUS ► Instagram: https://www.instagram.com/9news/ Join 9News for the latest in news and events that affect you in your local city, as well as news from across Australia and the world. #9News #BreakingNews #NineNewsAustralia #9NewsAUS