What Caused Catastrophic Pressure Vessel Failure at Loy Lange Box Company?

May 29, 2017

The U.S. Chemical Safety Board (CSB) released a Factual Investigative Update on the April 3, 2017, catastrophic rupture of a pressure vessel at the Loy Lange Box Company that killed four people and left another in critical condition.

The CSB’s ongoing examination of the incident has identified a history of leaks in the pressure vessel, which was part of a steam generation system. In 2012, the vessel was repaired when it was discovered that water was leaking from the bottom of its tank. In what was termed an “emergency repair,” a portion of the bottom of the tank was replaced with a custom made center section.

On Friday, March 31, 2017, employees again noticed a leak from the bottom of the vessel. Photos taken by the employees revealed leaks coming from at least two distinct sections of a 6-inch ring of original tank material that had been left surrounding the replacement center section of the vessel in 2012. Three days later, on April 3, Loy-Lange started up the steam generation system and the vessel ruptured in the area of that ring.

In examining the vessel post-incident, investigators found the metal in the rupture area extremely thinned from its original state. While the thickness of the metal should have been a quarter of an inch (0.25”) thick, this specific area had been worn down to eight hundredths of an inch (0.08”).

The immediate cause of this incident is the sudden mechanical integrity failure of the entire ring of the original bottom of the pressure vessel. This rupture separated the bottom of the tank from the rest of the pressure vessel. This created the unique conditions for a steam explosion, launching the vessel through the building about 520 feet before landing at the Fautless Healthcare Linen’s site. This was a massive explosion—releasing energy equivalent to about 350 lb of TNT.

The City of St. Louis is required to inspect the pressure vessel by its ordinance; however, the CSB has received no evidence of inspection.

The investigation will continue with mechanical analysis and additional document reviews, interviews, research, and analysis. A full factual investigative update can be found here.

The CSB is an independent, non-regulatory federal agency charged with investigating serious chemical incidents. The Board does not issue citations or fines but does make safety recommendations to plants, industry organizations, labor groups, and regulatory agencies such as OSHA and EPA. Visit our website at http://www.csb.gov/.

For more information, contact Communications Manager Hillary Cohen, cell 202-446-8094 or email public@csb.gov.

Study Looks at Possible Health Risks in Fire Stations

When firefighters respond to a fire, their gear and other personal protective equipment protect them from exposure to dangerous chemicals. What protects them between calls, however, when they simply are sleeping or eating in the fire station? On the surface, the fire station seems like a safe environment, but it may contain hidden risks, according to a new study funded by the National Institute for Occupational Safety and Health (NIOSH) at Harvard with the Dana-Farber Cancer Institute, the Boston Fire Department, and Boston Firefighters Union Local 718.

Employers Urged to Protect Workers During Sizzling Temperatures

As temperatures in Northern California reach triple digits, Cal/OSHA urges all employers to revisit their Injury and Illness Prevention Programs and their emergency response procedures to make sure they are thoroughly prepared for high heat.

“During heat waves and whenever temperatures reach or exceed 95 degrees, employers must take additional steps to monitor workers for signs and symptoms of heat illness,” said Cal/OSHA Chief Juliann Sum. “Water, rest and shade can protect workers from the heat.”

California’s outdoor workplace Heat Illness Prevention regulations require employers to take four steps to prevent heat illness:

Training – Train all employees and supervisors on heat illness prevention
Water – Provide enough fresh water so that each worker can drink at least 1 quart per hour, and encourage workers to do so
Shade – Provide shaded areas upon request or when temperatures exceed 80 degree, and encourage any worker to take a cool-down rest in the shade for at least 5 minutes to protect against overheating. Workers should not wait until they feel sick to cool down
Planning – Develop and implement effective written emergency response procedures for complying with Cal/OSHA’s Heat Illness Prevention Standard

Cal/OSHA will inspect outdoor worksites of industries such as agriculture, construction, and landscaping throughout the heat season. Cal/OSHA’s Heat Illness Prevention program, the first of its kind in the nation, includes enforcement of heat regulations as well as multilingual outreach and training for California’s employers and workers.

Information on heat illness prevention requirements and training materials is posted on Cal/OSHA’s Heat Illness Prevention web page and on the “Water. Rest. Shade. The work can’t get done without them” educational campaign website. A Heat Illness Prevention e-tool is also available on Cal/OSHA’s website.

NIOSH and Partner Laboratories Evaluate Fit-Test Systems

May is Better Hearing and Speech Month! It is also an opportunity to remember to choose earplugs that fit to protect your hearing at work. A good fit, however, depends upon more than just ear anatomy; it also depends upon the proper training in earplug use. Furthermore, the length and intensity of noise exposure also affects earplug selection. To help workers choose the best earplug fit for their workplaces, several hearing protector fit-test systems are available. These systems measure how well particular hearing protectors work for individuals.

NIOSH and three partner laboratories recently evaluated three systems to measure the accuracy of the fit tests. Investigators at NIOSH, Honeywell Safety Products in San Diego, California; Michael & Associates in State College, Pennsylvania; and U.S. Army Aeromedical Research Laboratory in Fort Rucker, Alabama, each recruited 20 local volunteers to test the systems, which included the NIOSH HPD Well-Fit, Michael & Associates FitCheck and Honeywell Safety Products VeriPRO. For comparison, the investigators used the standard laboratory-hearing protector testing protocol recommended by the American National Standards Institute (ANSI) as a control.

Study results, as reported in the Journal of Occupational and Environmental Hygiene, showed that two of the fit-test systems provided noise reduction levels that were comparable to the ANSI laboratory fit test and one system tended to underestimate the noise reduction measurements compared to the control. However, the results of the fit tests varied significantly between the four sites, with the greatest level of measured noise reduction and the smallest variation between tests noted at the Michael & Associates lab. In contrast, the fit tests at NIOSH found the lowest level of noise reduction and the largest variation between tests. These differences could stem from different levels of experience with earplug fitting among the testers and study participants. To address this issue, investigators noted that tailored training should occur before using a particular fit-test system. NIOSH plans to expand upon this research and, ultimately, develop guidelines for earplug fit testing.

During May—Better Hearing and Speech Month—think about earplug fit and check out other NIOSH resources such as the new NIOSH Sound Level Meter app. Workers can download the free app on their smartphones to measure noise levels in their own workplace and learn about noise-exposure limits and hearing-loss prevention. Knowledge of exposure levels and the noise reduction provided by properly fitting hearing protection devices can help to reduce the risk of noise-induced hearing loss.