It was just after 8 a.m. on Jan. 30 when Elk County emergency crews were first summoned to the scene of a fatal industrial explosion at Mersen USA’s St. Marys plant. The blast, caused by incorrect placement of flammable materials in a curing oven, left one worker dead and another seriously injured. 

Now, nearly one-year later, newly released findings from an Occupation Safety and Health Administration (OSHA) investigation detail troubling evidence linking misguided management calls, unforgiving production demands and flawed safety training to the blast, as well as prior close calls. 

The resulting months-long OSHA probe — and heavily redacted case file recently obtained by The Era through a Freedom of Information Act request — include interviews with workers, and emergency first responders. They described a harrowing scene at the Trout Run Road plant in the minutes after the blast, as well as lingering conflict surrounding the actions that caused it. 

According to OSHA records, it was first shift workers acting under supervision, who loaded the fateful batch of carbon and graphite parts, coated in a highly flammable alcohol and iodine solution. 

The oven, unequipped to handle combustibles, exploded roughly 15 minutes later. OSHA said the force ripped the oven’s door from its hinges, causing the heavy metal object to strike a group of three workers on a tour of the facility, 15 to 20 feet away. The result is listed as “death and broken bones.”  

In statements to OSHA, workers describe the ensuing rush to tend to the injured, and dying, through a blinding debris cloud, momentary hearing loss, and a frantic scramble for outside medical assistance. 

In the aftermath, Dr. Arwed Ralf Uecker, a 52-year-old visiting engineer from Mersen’s Boonton, N.J., office, lay dead, the cause ruled blunt force trauma by Elk County coroner Michelle Muccio.

Another employee, then 58-year-old production supervisor Neil Carter of Ridgway was seriously injured. A third, unnamed worker was treated and released. 

The incident prompted a lengthy review by health and safety agencies — the second such probe at the factory since a worker bled to death after impaling himself on a forklift in 2012. 

The latest probe found workers claimed no knowledge of the difference in ovens used to cure the carbon and graphite parts produced at the plant. It also found the same flammable parts had been run through the oven on at least one prior occasion, without incident, in the days leading up to the explosion.  

“I don’t recall being told the event oven was different,” one writes in a statement. The “event” oven  – a Despatch-brand electric oven — had reportedly been purchased by the company to cure water-based calcium treatments roughly four years earlier. 

But workers say with all appropriate ovens either in-use or under repair at the time, and with batches of parts sitting in need of drying, supervisors motivated by production pressures and constraints told them to use the “event” oven.

“Thursday, regular oven still not fixed,” a worker writes. “(REDACTED) said it was okay to use the event oven … Regular oven couldn’t get up to (proper) temperature on the day of the explosion.” 

Employees claimed to have been unaware of the risks and point to a production supervisor’s authorization, despite a sticker advising against it. 

In explaining the decision, an unnamed supervisor said, “I probably told him it would be OK,” adding it was believed the oven’s lower curing temperature and ventilation system would mitigate the risks.  

“I just did what (REDACTED) told me to because he was training me,” writes the worker who loaded the oven that day.  

Employees were also critical of the extent of training required of oven-operators, with one writing, “Training could be better, on-the-job training for 3 to 4 days and then it’s yours.” 

OSHA agreed, ruling Mersen failed to properly train workers on the risks of using ovens not designed for processing flammable materials.  

The company was cited for failure to provide a safe work environment, failure to provide respirator training and assessed a $7,000 fine. 

A Department of Labor spokesperson said both issues have been corrected. 

In addition, employees interviewed weeks after the explosion said, “We are (now) labeling, clarifying all ovens for treatments and products allowed.” 

In a statement issued to The Era on Tuesday, Mersen USA-St. Marys general manager Noah Nichelson writes, “In cooperation with OSHA, Mersen USA-St. Marys has retrained all employees in the effected department to ensure compliance with all applicable OSHA regulations.” 

He adds, “The company also presented the agency with a certification that any hazards related to ovens in the workplace have been abated. Mersen remains, as always, committed to the safety and health of its valued employees.” 

When reached by phone at his Ridgway residence on Wednesday, Neil Carter declined to comment on safety procedures at the plant.