On June 14, 2024, a 52-year-old firefighter with 19 years of experience tragically lost his life while combating a fire on a front-end loader. The incident occurred when the loader’s left rear tire exploded, with the force of the explosion fatally injuring the firefighter. The fire heated the tire, causing flammable gases to build up and ignite. The Los Angeles County Fire Department (LACoFD) classified this event as a line-of-duty death under report LAC 24-203895.
Background: Littlerock Quarry Operations
Hi-Grade Materials Co operates the Littlerock Quarry in Los Angeles County, California. The quarry employs 13 miners and processes sand and gravel for the construction industry. The site operates one shift per day, five days a week. Key management officials include Brent Mize, Quarry Plant Manager, and Dan Alfrey, Plant Foreman. The Mine Safety and Health Administration (MSHA) last inspected the mine on February 2, 2024. The quarry’s 2023 incident rate was 3.46, significantly higher than the national average of 0.92 for similar operations.
Timeline of the Incident
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4:00 a.m.: Ruben Ramirez, Front-End Loader Operator, began his shift by inspecting the loader. Later, while loading materials, he noticed smoke and unsuccessfully tried to extinguish the fire before evacuating the area.
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1:30 p.m.: Brent Mize noticed the loader fire and instructed the water truck operator, Cameron Ferris, to spray water on it from a safe distance. After Ferris’s truck ran out of water, the right rear tire exploded.
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1:53 p.m.: Mize successfully dispatched the LACoFD after earlier failed attempts to contact 911.
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2:06 p.m.: LACoFD arrived. Despite warnings to stay clear of the tires, a firefighter approached within four feet of the left rear tire to extinguish the fire.
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2:08 p.m.: The tire exploded, killing the firefighter instantly.
Investigation and Findings
The Department of Labor National Contact Center (DOLNCC) and MSHA launched an investigation. MSHA inspectors secured the site and interviewed personnel. The loader’s left rear tire explosion released debris up to 350 feet. Only the rubber and steel cord components were expelled; the rim assembly remained intact. Pre-operational inspections noted regular oil leaks in the loader, but investigators could not determine their role in the fire. The firefighter had extensive experience. However, proximity to the heated tire during suppression efforts proved fatal.
Cause of the Explosion: Tire Pyrolysis
The explosion occurred due to the buildup of flammable gases caused by tire pyrolysis—a chemical breakdown from heat exposure. Key steps in the process include:
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Pressure Increase: Internal heat builds, causing pressure to rise.
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Gas Accumulation: Rubber degradation releases flammable gases.
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Ignition and Explosion: The gases ignite, leading to violent explosions with debris projection and blast waves exceeding 1,000 psi.
Studies on tire explosions in open-pit environments highlight the need for maintaining safe distances to minimize injury risks.
Safety Recommendations
The LACoFD’s report emphasizes risk management, including:
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Calculating explosive energy based on tire dimensions.
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Establishing safe zones to protect personnel from blast effects.
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Training first responders to recognize hazards associated with tire fires.
Lessons Learned
This tragic incident underscores the critical importance of adhering to safety protocols, particularly when dealing with tire fires. Implementing strict guidelines and improving firefighter awareness can help prevent similar occurrences in the future.