Deadly chocolate factory blast highlights combustion risks

Mar 28, 2023, 1:42 PM

Emergency responders and heavy equipment are seen at the site of a deadly explosion at a chocolate ...

Emergency responders and heavy equipment are seen at the site of a deadly explosion at a chocolate factory in West Reading, Pennsylvania, Saturday, March 25. (AP Photo/Michael Rubinkam)

(AP Photo/Michael Rubinkam)

Last week’s fatal blast at a Pennsylvania chocolate factory highlighted the combustibility of food plants in general and chocolate making in particular.

The powerful explosion at 75-year-old R.M. Palmer Co. — which makes chocolate eggs, bunnies, bars, coins and other treats — killed seven, sent 10 to the hospital and damaged several other buildings in West Reading, a small town 60 miles (96 kilometers) northwest of Philadelphia, where it has long had a factory.

Local, state and federal investigations are ongoing. Pennsylvania State Police said “everything’s on the table,” as smelled natural gas before the blast, although the gas utility UGI said it received no reports of a gas leak.

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


In general, commercial ovens and furnaces, commercial refrigerant using ammonia and combustible dust produced by ingredients like cocoa powder and corn starch are primary explosive hazards at food plants, according to Holly Burgess, technical lead 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 not been in any sort of food manufacturing, you don’t understand what your hazards are and what you’re looking at,” Burgess said.

Chocolate companies and other food manufacturers must take steps to mitigate the risk of fire and explosion from dust. Smaller particles that stay aloft pose a greater danger than bigger particles that quickly fall to the floor.

“It is a common concern at many food production facilities handling fine combustible particulates,” said Bob Zalosh, a retired professor at Worcester Polytechnic Institute and a consultant on industrial fire and explosion hazard mitigation and investigations.

Food manufacturers are supposed to determine the combustibility of the 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 methods for controlling dust include dust collectors and industrial vacuum cleaners.


One possible explanation for the blast is an explosion of highly flammable powdered starch, which candy companies often use to cast chocolate into shapes such as Easter eggs, said Terry Wakefield, a business consultant and food scientist who used to run a manufacturing facility that supplied chocolate to R.M. Palmer.

The shock wave from an initial explosion could have jarred any dust accumulated on ceilings and other surfaces, he said. “And now you end up with a massive amount of starch, which combusts, and those explosion clouds move faster than sound and they have unbelievable force,” said Wakefield, who made his assessment after watching video of the explosion that was captured by a TV station’s weather camera.

“A lot of people don’t realize that starch could do that sort of thing,” he said.

Based on the kinds of candy Palmer makes, the company likely used the starch-casting method, according to Wakefield.

Officials at the family-owned company have not responded 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, chemical, paper, pharmaceutical and metal processing, according to the U.S. Chemical Safety Board.

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


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

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

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

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

The online records did not say anything about combustible dust, or any other explosive hazard at Palmer.


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

A statement from Wright’s lawyers at Morgan & Morgan said the firm has put together a “team of experts so we can understand what caused this catastrophic explosion.”

Additional lawsuits are expected.

National News

In this photo provided by Vernon Tyau, Jarek Agcaoili, left, with his mother Danielle, sister Jessi...

Associated Press

3 dead, 2 missing after family fishing trip in Alaska becomes a nightmare

JUNEAU, Alaska (AP) — An Alaska fishing adventure became a nightmare for a family of eight when disaster struck one of the two boats they chartered over the Memorial Day weekend, leaving three people dead and two more missing despite a desperate search over hundreds of square miles of ocean. The tragedy tore the Tyau […]

23 hours ago

FILE - The sign for Fort Bragg, N.C., is displayed, Jan. 4, 2020. Fort Bragg will shed its Confeder...

Associated Press

Fort Bragg to drop Confederate namesake for Fort Liberty, part of US Army base rebranding

RALEIGH, N.C. (AP) — Fort Bragg will shed its Confederate namesake to become Fort Liberty in a Friday ceremony that some veterans view as a small but important step in making the U.S. Army more welcoming to current and prospective Black service members. The change is part of a broad Department of Defense 2020 George […]

23 hours ago

FILE - Tennessee Gov. Bill Lee responds to questions during a news conference, April 11, 2023, in N...

Associated Press

In gun law push, Tennessee governor’s office memo says NRA prefers to ’round up mentally ill people’

NASHVILLE, Tenn. (AP) — Tennessee Gov. Bill Lee’s administration accused the National Rifle Association of wanting to use involuntary commitment laws “to round up mentally ill people and deprive them of other liberties,” according to documents drafted by the Republican’s staffers as part of their initial attempt to pass a gun control proposal earlier this […]

23 hours ago

Chips sit on a roulette table at the Hard Rock casino in Atlantic City N.J., on May 17, 2023. With ...

Associated Press

As legal gambling surges, should schools teach teens about risk?

ATLANTIC CITY, N.J. (AP) — As a high school senior, Nick was blessed with a deadly accurate jump shot from the three-point range — something he was quick to monetize. He and his gym classmates not far from the Jersey Shore would compete to see who could make the most baskets, at $5 or $10 […]

23 hours ago

Sage Chelf poses for a photo at her home in Orlando, Fla., May 27, 2023. Recent Florida legislation...

Associated Press

Some trans people turn to crowdfunding to leave Florida after anti-LGBTQ+ laws

ORLANDO, Fla. (AP) — Dozens of transgender people in Florida have turned to crowdfunding appeals to help them leave the state after the passage of new legislation that targets the LGBTQ+ community, including a law that curtails access to gender-affirming care for adults and bans it for minors. For Sage Chelf, the decision to leave […]

23 hours ago

Associated Press

US, Taiwan sign trade deal over China’s opposition

WASHINGTON (AP) — The United States signed a trade agreement Thursday with Taiwan over opposition from China, which claims the self-ruled island democracy as part of its territory. The two governments say the U.S.-Taiwan Initiative on 21st Century Trade will strengthen commercial relations by improving customs, investment and other regulation. The measure was signed by […]

23 hours ago

Sponsored Articles

Internet Washington...

Major Internet Upgrade and Expansion Planned This Year in Washington State

Comcast is investing $280 million this year to offer multi-gigabit Internet speeds to more than four million locations.

Compassion International...

Brock Huard and Friends Rally Around The Fight for First Campaign

Professional athletes are teaming up to prevent infant mortality and empower women at risk in communities facing severe poverty.

Emergency Preparedness...

Prepare for the next disaster at the Emergency Preparedness Conference

Being prepared before the next emergency arrives is key to preserving businesses and organizations of many kinds.

SHIBA volunteer...

Volunteer to help people understand their Medicare options!

If you’re retired or getting ready to retire and looking for new ways to stay active, becoming a SHIBA volunteer could be for you!

safety from crime...

As crime increases, our safety measures must too

It's easy to be accused of fearmongering regarding crime, but Seattle residents might have good reason to be concerned for their safety.

Comcast Ready for Business Fund...

Ilona Lohrey | President and CEO, GSBA

GSBA is closing the disparity gap with Ready for Business Fund

GSBA, Comcast, and other partners are working to address disparities in access to financial resources with the Ready for Business fund.

Deadly chocolate factory blast highlights combustion risks