On April 3, 2017, an explosion occurred on the premises of Loy-Lange Box Co., a cardboard box plant in St. Louis, MO. The blast launched a 2,000-pound steam storage tank more than four-hundred feet in the air until it crashed into the roof of a nearby linen factory seconds later. Four people died as a result of the incident.

The U.S. Chemical Safety and Hazard Investigation Board conducted an investigation and reported their findings. Officials determined that the blast was caused because the tank was in use despite the fact that corroded portions of the unit were leaking and in urgent need of replacement.

Federal officials discovered that back in November 2012, a technician made emergency repairs to an earlier leak in the tank and suggested that the company replace sections around its base.

The company did not replace the parts, and investigators were unable to find safety inspection reports from the city.

Loy-Lange employees detected another leak on March 31, 2017. The company made an appointment with a repairperson for Monday, April 3rd. Yet, on Monday morning, the company restarted the system before the repairs could be completed.

The disaster was caused when a corroded, six-inch ring on the tank abruptly broke during the start-up process.

The resulting blast was “equivalent to about 350 pounds of TNT,” which “launched the storage tank like a rocket through the roof,” according to the official report.