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Deadly Chocolate Factory Explosion Highlights Combustion Hazards


Last week’s deadly explosion at a Pennsylvania chocolate factory highlighted the combustibility of food factories in general and chocolate manufacturing in particular.

Powerful blast at 75-year-old RM Palmer Co. – which makes chocolate eggs, bunnies, bars, coins and other treats – killed seven people, sent 10 to hospital and damaged several other buildings in West Reading, a small town 60 miles away. (96 kilometers) northwest of Philadelphia, where it has long had a factory.

Local, state and federal investigations are ongoing. Pennsylvania State Police say “everything is on the table” as firefighters try to identify the origin and cause. Some workers told relatives they had smelled natural gas before the explosion, although gas utility UGI said it had not received any reports of gas leaks.

A look at some of the dangers of food manufacturing and what may have been behind this fatal explosion:


In general, commercial ovens and furnaces, commercial refrigerants using ammonia, and combustible dust produced by ingredients like cocoa powder and corn starch are the main explosion hazards in food factories, according to Holly Burgess, technical manager for industrial and chemical safety at the National Fire Protection Association. , a nonprofit group that produces hundreds of codes and standards.

“Most people, if you’ve never worked in food manufacturing, you don’t understand what your risks are and what you’re looking at,” Burgess said.

Chocolate manufacturers and other food manufacturers must take steps to mitigate dust-related fire and explosion hazards. Smaller particles that stay in the air pose a greater hazard than larger particles that quickly fall to the ground.

“It’s a common concern in many food production facilities handling fine combustible particles,” said Bob Zalosh, a retired Worcester Polytechnic Institute professor and fire hazard investigation and mitigation consultant. and industrial explosions.

Food manufacturers are expected to determine the combustibility of dust, perform a hazard analysis, and then take steps to manage it, adhering to the Fire Protection Association’s standard for preventing dust explosions in food processing plants.

Common dust control methods include dust collectors and industrial vacuum cleaners.


One possible explanation for the explosion is an explosion of highly flammable powdered starch, which confectionery companies often use to mold chocolate into shapes such as Easter eggs, said Terry Wakefield, a business consultant and scientist in food who ran a manufacturing plant that supplied chocolate. to R. M. Palmer.

The shock wave from an initial explosion could have shaken off dust that had accumulated on ceilings and other surfaces, he said. “And now you end up with a huge amount of starch, which is burning, and these explosion clouds are moving faster than sound and they have incredible force,” said Wakefield, who made his assessment after watching video of the explosion which was captured by a television. station weather camera.

“A lot of people don’t realize that starch can do this stuff,” he said.

Based on the types of candy made by Palmer, the company likely used the starch molding method, according to Wakefield.

Family business officials did not respond to questions from The Associated Press.

Dust explosions have long been a problem in manufacturing. Between 1980 and 2017, nearly 400 combustible dust fires and explosions killed 185 people and injured more than 1,000 across multiple industries, including food, chemicals, paper, pharmaceuticals and metal processing, according to the US Chemical Safety Board.

In 2008, a buildup of sugar dust ignited and blew up the Imperial Sugar plant in Port Wentworth, Georgia, killing 14 people.


At least two workplace accidents have occurred at Palmer since 2018, according to federal records.

The US Occupational Safety and Health Administration, which regulates workplace safety, visited the Palmer plant in West Reading in 2018, when an employee lost the tip of a finger while cleaning a valve under pressure. The company agreed to pay a fine of $13,000.

In 2019, OSHA investigated an accident at the Palmer plant in nearby Wyomissing, Pennsylvania, when a treadmill was turned on while a worker was cleaning a roller, according to federal records. The employee’s arm was broken in several places. The company settled with OSHA for $26,000.

And in January, records show, OSHA fined more than $12,000 after an inspection at the Wyomissing plant. Details of this case were not available.

The online records said nothing about combustible dust or any other explosion hazard at Palmer.


A woman who lived next door to the plant filed a lawsuit on Tuesday, alleging Palmer was negligent in failing to maintain her equipment and prevent the explosion. Betty Wright was “lifted off her feet and blown across the room”, suffering neck, back, hip and leg injuries, the suit said. She also lost property.

A statement from Wright’s attorneys at Morgan & Morgan said the company had assembled a “team of experts so that we can understand what caused this catastrophic explosion”.

Further trials are expected.

Joanna Swanson

Joanna Swanson is Europe correspondent at the Thomson Reuters Foundation based in Brussels covering politics, culture, business, climate change, society, economies and inclusive tech. With specific focus in breaking news, she has covered some of the world's most significant stories.