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The Dangers of Truck Fires

The Dangers of Truck FiresSemi-trucks are already dangerous vehicles. As they are large, heavy, and difficult to maneuver, trucks can present risky scenarios out on the road when around other drivers. But whether they’re moving or parked, these vehicles can still lead to hazardous situations. When you’re trying to not get hit by them on the highway, you may have to watch for fires as well.

According to Eletrek, a news website that covers stories about electric vehicles and transportation, Phoenix has been seeing several truck fires from the EV truck company Nikola, many of them happening over the past couple of months. While the company claims foul play on at least one of those fires, it seems that the more likely culprit has to do with defective batteries.

Electrek reports that “inside sources” indicate that the battery modules used in Nikola’s trucks, sourced from Romeo Power, had a problem with corroded cells and self-discharge. This issue could potentially cause thermal events in battery packs, increasing the risk of fires.

Despite knowledge of these problems, Electrek claims, both Romeo Power and Nikola continued production, and it’s possible some of these potentially damaged battery modules ended up in Nikola trucks. While it’s uncertain if these issues caused the fires at Nikola’s headquarters, punctured cells can lead to battery thermal events.

What are the main causes of truck fires?

Penske, a company you likely know from its rental trucks, says there are about 7,000 truck fires a year.  In their 2020 safety bulletin, they say The Technology & Maintenance Council of the American Truckers Association cites the four most common causes of truck fires as:

  • Brakes
  • Wheel bearings
  • Air leaks
  • Tires

Of course, there are other, less common causes such as electrical malfunctions in the cab, sleeper or engine due to overloaded circuits; cigarette smoking; leaking oil or fuel; or improperly installed or defective heaters in the cargo. Electric batteries, as we see, are also causing their fair share of fires.


When a semi-truck slams on its brakes hard, especially when it’s carrying a heavy load, the mechanisms can get excessively heated. This intense heat can make the brakes extremely hot, to the point where it can actually set parts of the truck on fire, like the grease around the bearings, and it might even spread to the tires. This is more likely to happen with certain types of brakes that are shaped like big metal drums – they can easily pass that heat onto the tires.

There’s also something called “dragging brakes.” This is when the brakes don’t let go completely, even when you’re not pushing the brake pedal. It often happens with the last trailer of a semi-truck because the air pressure in the brakes can get low and take a while to come back up, and that can create excessive heat for the brakes as well.

To avoid fire risks, it’s crucial to keep the brakes in good shape. If some parts aren’t lined up right or they get stuck, they can create a huge amount of friction and heat. Additionally, if the brakes on one side aren’t working as well as the other, it can make one set of brakes get way too hot and cause problems. Even the most minor leaks in the brake system can make a mist of brake fluid, and if that mist gets near something hot enough, it can catch fire in the blink of an eye.

Wheel bearings

It’s crucial for vehicle and tire technicians to stay vigilant when inspecting wheel bearings and brakes because drivers often don’t notice when their trucks’ axle ends get too hot. Well-installed and properly lubricated high-quality wheel bearings rarely fail on their own.

Fires related to wheel bearings typically happen due to a lack of lubrication, whether it’s because the seal fails or the oil gets contaminated with water or debris, which damages the seal and leads to a leak. This is why regularly checking the hub cap is essential.

Getting the wheel bearings installed correctly is equally important. Over-tightening them, orapplying too much preload (“Preload” means squeezing the bearings in a wheel hub to remove any extra space and make sure they’re tight and ready to handle the weight and stress of the cargo) can reduce the amount of lubrication, causing excess heat. Conversely, too much end-play (“wheel endplay” means how much the wheel and its bearings can move back and forth on the spindle) can harm the seal, leading to contamination and leaks.

Some fleets use grease for wheel bearing lubrication. While packing the cavity with grease might seem like a good idea, overfilling it can actually cause overheating because there’s no way for the excess heat to escape. Ideally, wheel bearings should run at temperatures between 160°F and 175°F. Problems start when they reach 250°F or higher.

Air leaks

Air leaks in trucks can potentially cause fires because they disrupt the proper functioning of the brakes and other systems. When brakes overheat due to air leaks, they can ignite nearby flammable materials or components like tires and grease. Additionally, air leaks can lead to hydraulic fluid or oil leaks, electrical system damage, and even fuel leaks, all of which can create ignition sources for fires in trucks. Regular maintenance and inspections are crucial to prevent air leaks and reduce the risk of fires on the road.

In fact, in 2020, the National Highway Traffic Safety Administration (NHTSA) began an investigation into a problem with air brake systems in trucks, specifically the Haldex Gold Seal GC3030LCW air brake chambers used in trucks made between 2015 and 2020. There have been reports of these brakes losing air, which has led to multiple vehicle fires. It’s estimated that around 500,000 trucks could be affected.

The issue here is that the power spring in these brakes can break, and when it does, it can puncture a part called the diaphragm, causing air to leak from the brake system. This, in turn, can make the brakes not work properly and even cause them to drag without the driver getting enough warning.

The NHTSA started looking into this after receiving complaints from truck owners who had brake chambers from Haldex fail suddenly, without any clear warning. In some cases, these failures led to fires, and one fire investigation even pinpointed the brake system as the source of the fire.

As a result of these complaints, Haldex has agreed to replace brake chambers on some affected vehicles. The NHTSA’s investigation might lead to a recall of these faulty brake chambers to prevent further problems and fires.


Tire fires on a truck happen when something outside the tire makes it really hot until it catches fire. As we have discussed, this can be caused by things like brakes not working right, problems with wheel bearings, or tires that don’t have enough air in them.

When this heat builds up on the tire because of these problems, the tire can reach a super high temperature of around 600 degrees Fahrenheit, and that’s when it can burst into flames. Sometimes, the tire only starts burning after the vehicle has stopped because the air flowing over it when the truck is moving helps cool it down.

Once a tire starts burning, it’s extremely difficult to put out, and regular fire extinguishers usually can’t handle it. The best way to deal with a burning tire is to have professional firefighters use a continuous stream of water to get it under control.

Truck fires can cause severe burns, not only causing catastrophic injuries, but lifelong complications. Any automobile accident that results in a fire is in danger of explosion, so it is important to get far away from your vehicle in the case of a vehicle fire.

If you have been injured by a truck or due to a truck fire, then you deserve compensation. A truck fire means that someone, somewhere was neglectful. It could have been the truck part manufacturing company who made a defective product, it could be the driver’s fault, it could be the truck company’s fault for neglecting their hiring duties or training responsibilities. More than likely, more than one party is liable for the injuries you sustained from the accident. At Plattner Verderame, we have extensive experience in handling all automotive accident cases, including truck accidents and fires. To set up a free consultation today at our offices in either Phoenix or Tempe, call us or use our contact page. Our fees are contingency based, meaning that we only get paid if we win your case. Your victory is ours as well.