ST. LOUIS — The Latest on the federal investigation into a deadly steam tank explosion in St. Louis (all times local):

11 a.m.

A St. Louis official is defending the city’s method of inspecting industrial-sized water tanks following a federal agency’s report on a tank explosion that killed four people.

The giant steam-filled tank exploded April 3 at Loy-Lange Box Co., flew into the air and smashed into a neighboring building. The U.S. Chemical Safety and Hazard Investigation Board said Thursday that the tank was restarted that morning even though it needed emergency repairs.

The agency also found no evidence of a city inspection. Unlike other places in Missouri, which are subject to annual state inspections, St. Louis requires on-site engineers to monitor tanks.

St. Louis Building Commissioner Frank Oswald says one of those engineers discovered the leak three days before the explosion, and the tank was shut down. It isn’t clear why it was restarted before repairs could be made.

9:30 a.m.

A federal report says a St. Louis company’s steam condensation tank exploded, shooting into the air and through the roof of a neighboring business, after the tank was restarted despite needing emergency repairs.

The U.S. Chemical Safety and Hazard Investigation Board released findings Thursday of its investigation into the April 3 explosion at Loy-Lange Box Co. Four people were killed.

The van-sized tank first sprung a leak in November 2012. The federal report says a contractor made emergency repairs but Loy-Lange ignored a recommendation to replace part of the tank.

Engineers again noticed a leak on March 31. The system was shut down and a technician was scheduled to arrive April 3. But investigators say the system was restarted that morning, before the technician arrived, and apparently exploded on startup.

6:30 a.m.

The federal agency investigating an April 3 steam tank explosion that killed four people in south St. Louis is preparing to release its findings.

The blast at Loy-Lange Box Co. propelled a van-sized steam condensation tank into the air and through the roof of a neighboring business. One Loy-Lange worker died and three people died at Faultless Healthcare Linen after the tank landed in that company’s office.

The U.S. Chemical Safety and Hazard Investigation Board will release its report Thursday.