Compressed natural gas (CNG) fuel tanks explode during truck fire

From time to time, hazards that we may have previously recognized as low-frequency encounters become something we are much more likely to face on a fire or other emergency response. Technology or culture evolves. A particular process or type of equipment becomes more prevalent in society. And we get to deal with that.

While the particular changes or improvements may be deemed to make life easier, cheaper, or otherwise more efficient or friendly for society — new hazards may manifest, leaving firefighters and other emergency personnel with dangers we must take into account when responding to an incident. If you have not already done so, I would add compressed natural gas (CNG) fueled vehicles to the list. While generally recognized as a safe fuel source, like anything we encounter, a fire situation may put us in danger if the equipment or safety features are compromised.

CNG
WTHR Channel 13 – Indianapolis

This week, firefighters in Indianapolis responded to a fire in a garbage truck. This particular truck was fueled by natural gas, compressed into carbon fiber tanks. During the response, the tanks failed resulting in an explosion that  reportedly shot debris up to a quarter-mile and damaged five businesses. One firefighter was hit in the head by debris but suffered only minor injuries.

WTHR Channel 13 reported the following:

INDIANAPOLIS – The Indianapolis Fire Department is investigating what caused a Republic trash truck carrying compressed natural gas cylinders to explode in the parking lot of Ace Hardware in the 8500 block of Westfield Boulevard Tuesday morning.
One of the tanks flew across Westfield Boulevard and hit a dry cleaning business in the strip mall, IFD spokesperson Rita Reith said. One firefighter was struck in the head by debris, but his injury was minor. The driver of the truck was not injured.
It happened just before 6:00 am. Five businesses were damaged, along with other vehicles.
Indianapolis firefighters had to dodge exploding gas cylinders when they arrived at the scene of the truck fire. According to the driver, he’d just picked up the trash at ACE Hardware when he noticed fire coming from the back of his truck. 
Although it’s protocol for the driver to drop the trash load during a fire, the driver was worried about nearby power lines and was unable to drop it so firefighters could put it out. The fire grew and additional crews were called in.
At that point, the first of five tanks that sit atop the truck exploded and firefighters ran for cover. Crews set up aerial operations. It took about an hour to get it under control.
 None of the affected businesses were open at time.
Marion County Public Health was called to the scene for run off and unidentified green substance which was later determined to be hydraulic fluid. The runoff was contained by fire crews.
The carbon fiber cylinders were holding 5 – 100 lb compressed natural gas. The impact of the explosion sent the tanks 50 feet to a quarter of a mile, with one landing in the front yard of Northview Middle School. No students were at school yet, and the school opened on time. One of the exploding tanks struck a nearby fence, while another landed in the parking lot of the Nora Shops. Debris struck the front window of a dry cleaners and also damaged a van in the Kroger parking lot. Debris also struck a firefighter in the helmet, knocking him into the bushes.
 Via Trash truck’s gas cylinders explode on city’s northeast side
 

These types of incidents are becoming increasingly common, especially as more and more companies and municipalities adopt the use of CNG fuel in their fleet vehicles.

The best thing you can do is familiarize yourself with these vehicles, particularly learning how to recognize them and understanding the dangers they present.

One of the most important keys is to recognize the CNG sticker or designation that should be evident on most of these vehicles. While the exact design may vary slightly, depending on locale and manufacturer, the message is the same.

 

A notable amount of information is available on these vehicles and the fueling systems. A quick internet search for “compressed natural gas vehicle safety” will lead you to a number of industry organizations and associations that provide additional information on their websites.

Additionally, NFPA 52 is the Vehicular Gaseous Fuel Systems Code, which provides technical guidance on equipment installation, operation, and maintenance.

 

4 Comments

  • Tony balm says:

    Interesting article on CNG. what are the hazards to the community from the carbon fibre particles that were involved in the explosion. I understand carbon fibre can be as dangerous to health as asbestos.
    Thanks

  • Brandon says:

    Interesting read, thanks!

  • Ernesto Martinez says:

    I’m a certified fire mechanic / vehicle specification writer with a large garbage truck fleet and from experience working on garbage trucks it is best to dump the load if possible. In this case an Ibox CNG vertically stacked mounted behind the cab could have prevented this from happening. Roof mounted CNG tanks on a garbage truck body is not a good idea. If longer range is needed a saddle mounted LNG tank is the better answer; as we all know heat rises. In this case the CNG tanks stayed slow cooking on the top of the body like a BBQ. We can learn and avoid mistakes through leveraging resources and collaboration between agencies municipal and private. Together we can build better vehicles and share better bid specs.

  • Roger Philips says:

    I think it’s likely the fire crew sprayed water on the tanks before they exploded. This would have cooled the pressure relief devices and prevented them from venting pressure from the tanks. These devices are temperature activated. Fire crews need better training for dealing with CNG fires.

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