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18-wheelers carrying hazardous materials through DFW could become a ‘giant bomb’

A truck on a freeway seen from behind
Yfat Yossifor
A truck carrying volatile chemicals on the I-635 Loop, which is part of a designated hazardous material route for Dallas.

Thousands of trucks loaded with hazardous materials rumble along Dallas-Fort Worth highways every day. Experts say they don't know exactly what they carry — or how much.

Toxic inhalants, flammable gases and explosive chemicals are just some of what rolls along Dallas-Fort Worth area highways every day. A simple road accident involving an 18-wheeler carrying hazardous materials could put dozens of people, if not whole neighborhoods, at risk.

Trucks carrying volatile chemicals rumble down highways that were designated as “hazmat routes” in 1985, when the population of DFW was half the size it is now. At the time, large portions passed through sparsely populated areas.

Almost 40 years later, empty space has been replaced by businesses, residential neighborhoods — even schools and churches.

The hazmat routes are designed to minimize the chances of a mass-casualty event. They rely on truckers using them. But not all the trucks stay on those routes.

No one really knows how much hazardous materials pass through North Texas.  And emergency personnel say they have virtually no way of knowing what’s being carried until an accident happens.

Trucks carrying hazardous materials are supposed to display placards that gives first responders some idea of what’s on board. But if a placard isn’t accurate — or has been obscured by fire or smoke – the threat may not be apparent.

And the threat is real. Trucks carrying hazardous materials have been involved in deadly accidents across the nation.

  • In 2019 a semi-truck carrying empty propane tanks crashed into multiple other cars on I-35 near Denton. The truck and vapors seeping out of the propane tanks caught on fire, as did other vehicles. Three people were killed in the crash and three others were injured, according to incident and media reports.
  • In 2020, a tanker truck carrying 8,500 gallons of fuel rear-ended a Volkswagen Passat that had stopped on a highway interchange in suburban Atlanta. The impact caused the tanker to rollover into four lanes of traffic and both vehicles caught fire. Both individuals died because of the crash, according to incident and media reports.
  • And less than six months later on Valentine’s Day 2023, a tractor-trailer carrying over 3,000 gallons of nitric acid crashed along I-10 near Tucson. Reddish-orange fumes could be seen rising from the wreckage as the area was evacuated. The driver of the truck was killed in the collision, according to Arizona Department of Public Safety. Nitric acid is toxic if inhaled.

    First responders and emergency planners say that errors in labeling hazmat materials – and truckers who fail to follow hazmat rules — can lead to a catastrophe. So can a shortage of people trained to handle hazmat emergencies.

    “From radioactive waste to the most toxic chemicals that you can imagine all travel by truck transport through all our cities in the metroplex,” Grand Prairie Fire Capt. John Stevenson said. “It’s an obvious concern.”

    ‘It was a bomb.’

    Grand Prairie Fire Department hazmat-trained firefighters respond to an overturned truck under highway 161 in Grand Prairie, Texas.
    John Stevenson / Grand Prairie Fire Department
    Grand Prairie Fire Department hazmat-trained firefighters respond to an overturned truck under State Highway 161 in Grand Prairie.

    Stevenson is the special operations captain for the Grand Prairie Fire Department. The city of almost 200,000 sits 14 miles west of downtown Dallas and has eight hazmat-designated arteries running through it.

    Stevenson recalls an accident involving a truck carrying hazardous materials about three years ago. A semi had rolled over while trying to make a tight turn under a freeway overpass.

    Firefighters at the scene called the department’s hazmat personnel only after they encountered a substance leaking out of the overturned tractor-trailer.

    “We got the shipping papers from the driver and identified the product as 85-percent phosphoric acid,” Stevenson said. “And he was carrying multiple 330-gallon totes in the back of his trailer.”

    The chemical is much heavier than water. Stevenson said the driver didn’t secure the load properly and the weight caused the truck to roll over.

    Hundreds of gallons of the corrosive leaked out onto the roadway. Firefighters on the scene tried to stop it from flowing into storm drains. Once hazmat personnel arrived they realized they had a much bigger problem than preventing the chemical from leaking into storm drains.

    “As we were walking up to the trailer, the explosive meters started going off,” Stevenson said.

    He says hazmat responders use what’s called a “5-Gas Monitor” that can detect different vapors and flammable build up in the air. The meters won’t tell you exactly what the substance is but will alert when the substance reaches an explosive limit.

    Stevenson said the alarms immediately sounded and “we couldn’t figure out why.”

    Stevenson said they had to reevaluate the situation. After some research they realized the volatile liquid had reacted with the wood and aluminum of the tractor-trailer.

    The meters had detected the byproduct of that chemical reaction. The truck had filled with hydrogen gas.

    “All you needed was a spark or a little bit more increase in heat, and it would have blown up that overpass of 161,” Stevenson said.

    “It was a bomb. A giant bomb.”

    Grand Prairie’s hazmat-trained personnel worked quickly to pump “positive pressure” into the trailer to ventilate it.

    “What we did was we changed the atmosphere inside the trailer,” Stevenson said.

    Stevenson says this is just one of many examples of emergencies involving hazmat transport.

    Dan Kessler is the assistant director of transportation for the North Central Texas Council of Governments (NCTCOG) and led the route study for the metroplex in 1985.

    He says that certain reports — called commodity flow surveys — can give a more detailed look into what kinds and how much hazmat moves through an area. National data suggests that 5,000 to 10,000 shipments of hazardous materials come through the area per day, according to Kessler.

    That said, there hasn’t been a flow study conducted in the DFW area in decades.

    “That’s the one area that I have the greatest amount of uncertainty, is that we have not collected that data over the last several decades to give you an amount of how much that’s changed,” Kessler said.

    ◆ ◆ ◆

    Population growth: Then and now

    (Large areas along what became Dallas County's designated hazmat route were sparsely populated in the mid-1980s. But that has changed dramatically. Move slider to change the image from an aerial view in 1984 to 2020.)

    ◆ ◆ ◆

    Growing demands

    The population of DFW is growing rapidly. Between 2010 and 2020 the region grew nearly 20% — adding around 1.3 million people.

    The outer loop highways — such as the Interstate 635 loop in Dallas and the Interstate 820 loop in Fort Worth — presented the best remedy 40 years ago for hazmat shipments to avoid moving through heavily populated areas.

    Kessler says the risk assessments included in the original route report did not factor in population growth.

    “Over the last 40 years the landscape has changed dramatically on those outer interstate loops,” Kessler said.

    He said his current work estimates the DFW area will be nearing 14 million people by 2050. Where hazmat moves around the region is “a challenge that is not going away,” he said.

    Stevenson said it’s rare for a fire department in North Texas to have a dedicated hazmat team. The NCTCOG member counties work together to share resources and equipment to mitigate hazmat disasters.

    Hazmat-trained firefighters in Dallas and Grand Prairie aren’t part of independent teams. They operate as regular firefighters on top of responding to hazmat emergencies. Each departments answer around other 500 hazmat calls a year. That includes calls related to materials stored in buildings, vehicle accidents and pipeline ruptures.

    “The things that will kill you that you never see, those are the things the hazmat team identifies and keeps the public safe from,” Dallas Fire Rescue Captain Ryan Thornton said.

    Dallas Fire Rescue has 10 hazmat trained responders on each shift — but sometimes that isn’t enough.

    Thornton has received advanced hazmat training. He says with the hazmat-trained firefighters the department has now can’t respond to the number of calls they get alone.

    “Currently we have to rely on surrounding suburb city fire departments to come into our city…to respond to our hazmat calls.” Thornton said. “…when you’re one of the biggest cities in the nation, that’s just not good enough. We should be able to take care of our calls.”

    Stevenson says that when Grand Prairie was smaller, responding to hazmat incidents was not part of the fire department’s responsibility. But that’s changed.

    “The explosive growth that we’ve had in the city of Grand Prairie has only occurred over about the last 10 years,” Stevenson said.

    And that’s when “we noticed the influx in industry and increase in transportation through here.”

    He said residential communities are “co-located” with the hazmat route, a byproduct of booming growth around decades-old hazmat routes.

    David Bierling is a program manager and senior research scientist at the Texas A&M Transportation Institute. He says as communities grow around hazmat paths, alternative routing options decrease.

    “The routes are either longer or populations have increased in the alternate locations as well,” Bierling said of hazmat routing options.

    ‘Not if, but when.’

    A truck seen from behind with hazmat signage on a road
    Emily Nava
    A tanker truck with hazmat signage makes its way along Interstate 30.

    Trucks carrying hazardous cargo are required to display placards indicating what materials they are hauling. Drivers have to change the placard manually depending on their load. Stevenson said first responders rely on the correct labeling to figure out how dangerous the cargo is.

    “If that driver fails to flip that placard from him hauling a corrosive to a toxin, that can really change the dynamic,” Stevenson said of a potential hazmat accident.

    In addition to designated hazmat routes that truckers are supposed to use, there are also “restricted” portions of highway that they are discouraged from using.

    In Dallas that includes portions of highway that are close to or in the downtown area. One section is the highway between I-35 and North Central Expressway that passes under Klyde Warren Park.

    Twenty years ago the Dallas Police Department had a dedicated truck enforcement unit. That unit has since been disbanded but officers still conduct truck stops and inspections as part of the department’s traffic unit — although they are not the main agency for truck enforcement.

    DPD has issued 10 citations for “improper placarding of a vehicle” containing hazmat since 2018. Thornton says he doesn’t know how many times he’s run across this, but unfortunately it happens.

    Numerous federal, state and regional agencies that regulate hazmat shipments. On top of two main federal agencies, the Texas Commission on Environmental Quality and the Texas Department of Public Safety have a hand in regulating hazmat in the state. The Dallas County Sheriffs Office has a dedicated unit to commercial vehicle enforcement.

    The Federal Motor Carrier Safety Administration (FMCSA) documents and publishes data on roadside inspections — which both federal and state agencies conduct in Texas.

    According to the data, the annual number of statewide inspections represents only a fraction of how many hazmat shipments experts say move through the DFW area alone.

    And of the trucks that were stopped, about one in eight received a violation.

    The uncertainty around what a vehicle might be carrying is why Dallas County Judge Clay Jenkins says Local Emergency Planning Committees (LEPC) play a crucial role in coordinating emergency response across a region.

    Jenkins is the Dallas County emergency response coordinator and says the LEPC is very active — specifically for this reason.

    “Emergency management is one of those things that people forget about until something happens,” Jenkins said.

    It’s not if a hazmat incident will happen, but when according to Jenkins. The LEPC holds monthly meetings with its members and tries to engage in making response plans known at a community level.

    “We believe that if you fail the plan, you’re planning to fail,” Jenkins said.

    Closer to home

    Restricted highways in downtown business center of Dallas.
    Texas Department of Transportation
    "Restricted" highways in or near the downtown business center of Dallas.

    One complication is that trucks carrying hazardous materials sometimes must make deliveries to locations throughout a city. And by necessity they have to leave the designated routes.

    “It’s nearly impossible to route all those carriers, because there are so many destinations that are now within our cities,” Kessler said.

    Hazardous materials are integral to everyday life and industry. Small businesses from dry cleaners to filling stations require the delivery of hazardous materials.

    Stevenson says it’s not always 18-wheeler trucks that carry the most dangerous cargo. Smaller vehicles making deliveries throughout the city are also a potential risk.

    “They're in sprinter vans and it’s in box trucks with miscellaneous packaging on it,” Stevenson said.

    He says that these vehicles carry multiple substances or materials that alone are not toxic but when mixed creates something volatile which the vehicles aren’t placarded for.

    Kessler says the bigger challenge with hazmat transport are “internal shipments” or deliveries within the city.

    He said one thing that might mitigate that risk is speed — or the lack of it. Trucks delivering hazardous materials using city streets aren’t likely to be going as fast as on the highway, nor is other traffic.

    If you take into consideration the sheer amount of hazmat cargo entering and exiting the region on a daily basis, the routing plan has worked out considerably well, according to Kessler. But he said there’s still room for improvement.

    First responders say they work extremely hard to protect the public when there’s an accident involving hazardous materials. And they hope that truck drivers follow federal and state regulations.

    Thornton says sometimes they don’t.

    “18-wheelers have been known to stop, swap out a placard so they can go through the city and not be stopped,” Thornton said.

    “On a highway, we have to accept the fact that people…break the law.”

    ‘Hazmat is a mystery’

    Dallas Fire Rescue is working on getting a new group of firefighters hazmat certified. They take time off and fly out to a specialized training facility in Colorado. Those who have already had hazmat training take time off for more instruction and to help train others.

    “This extra training requires a lot of out-of-service time,” Thornton said.

    While those firefighters are out, Thornton says “you can always count on a hazmat call to come in.”

    With two groups of trained firefighters, one can be on call while the other group is getting trained or recertified. Likewise, with the volume of calls the department gets — more personnel means the department is less dependent on surrounding cities when there’s multiple hazmat emergencies.

    As the region continues to grow, the hazmat routes and mitigation strategies need to evolve, according to experts and first responders.

    As the areas around the current loop highways becomes more populated, experts are looking for alternatives.

    That work could be decades into the future. Instead of thinking about revised routes, communities should be focusing more on response and mitigation to hazmat emergencies, according to Bierling.

    The Dallas County’s emergency planning committee discussed trying to get a commodity flow survey funded last year. But Jenkins did not know if that idea is going to move forward.

    First responders say educating local governments and the public about potential threats from hazardous materials is critical. And they want elected officials to keep that in mind when budget season comes around.

    “Hazmat is a mystery to a lot of people,” Thornton said.

    KERA News is made possible through the generosity of our members. If you find this reporting valuable, consider making a tax-deductible gifttoday. Thank you.

    Nathan Collins is the Dallas Accountability Reporter for KERA. Collins joined the station after receiving his master’s degree in Investigative Journalism from Arizona State University. Prior to becoming a journalist, he was a professional musician.