CSB: Steam System Leaked In Days Before Fatal Blast

Employees at a St. Louis packaging company noticed a leak from a pressure vessel three days before it exploded and killed four people.

The U.S. Chemical Safety Board last week released an update of its ongoing investigation into the April 3 explosion at Loy Lange Box Company.

The pressure vessel was part of the facility's steam generation system and had a history of leaks, investigators said.

A portion of the bottom of the tank was replaced in 2012 after a leak, and on March 31, Loy Lange employees took photos showing two distinct leaks from an original section of the tank.

When the company started the steam system on the morning of April 3, a rupture occurred in the leaking section, which had been worn down from the original quarter of an inch thickness to just eight hundredths of an inch.

The rupture create a steam explosion that launched the vessel more than 500 feet. Loy Lange engineer Kenneth Trentham was killed at the facility, while three others — Christopher Watkins, Tonya Gonzalez-Suarez and Clifford Lee — were killed when the vessel crashed into an office at nearby Faultless Healthcare Linen. A fifth victim was injured in the incident.

CSB investigators also indicated that they agency had not received evidence of an inspection of the system by city officials as required each year.