The U.S. Chemical Safety Board(CSB) updated their report on the boiler explosion that killed four people near Soulard earlier this month.

According to the report from the CSB, the bottom pressure boundary of a semi-closed receiver failed, launching the 3,000 pound device 120 mph. The device flew 425 feet into the air and ended up 515 feet from its starting point.

The CSB used 3-D photo documentation to assess the scene, and they are still assessing both the Loy-Lange and Faultless Linen buildings for structural integrity. They are also working to find ways to reinforce the buildings and locate more potential evidence.