5.2 Handling Leaks, Spills, and Overheated Tires

5.2 Handling Leaks, Spills, and Overheated Tires

Why This Topic Matters

Roadside leaks and tire fires are among the most common and dangerous hazardous materials incidents. Texas HME candidates must know how to distinguish between tasks they can perform safely and those that require professional intervention. Overheated tires can act as an intense ignition source, making proper inspection and immediate containment essential. A single mistake—such as trying to drive a smoking tire to a distant truck stop or attempting to sweep up chemical runoff—can cause devastating environmental damage or lead to a massive cargo fire.

Core Definitions

To safely manage leaks, spills, and tire friction, drivers must understand these critical operational concepts:

• Runaway tire fire: A fire originating in a tire due to underinflation, overloading, dragging brakes, or mechanical friction. It produces intense, deep-seated heat that can easily breach cargo linings.
• Spill containment: The act of diverting or blocking the flow of a spilled liquid or solid to prevent it from reaching sensitive areas, without directly touching, cleaning, or neutralizing the material.
• Hazardous runoff: Liquid containing dissolved or suspended hazardous materials that flows into water systems, storm sewers, or agricultural lands, creating secondary environmental emergencies.
• Emergency Response Guidebook (ERG): A joint guide published by the United States Department of Transportation (DOT), Transport Canada, and the Secretariat of Communications and Transportation of Mexico, used by first responders to identify specific hazards and protective actions.

Procedures for Handling Leaks and Spills

When a hazardous materials leak or spill occurs, the driver must act quickly to minimize the risk to the public and the environment. However, the driver's role is strictly limited to initial actions. Follow these regulatory and safety procedures:

• Maintain a Safe Distance: First priority is personal safety. Never walk through, touch, or inhale spilled material. Keep upwind and uphill of any fumes or liquid flow.
• Consult the ERG: Immediately consult the Emergency Response Guidebook to identify the product's primary hazards and safety distances.
• Attempt Safe Containment: If the leak is small and can be stopped safely, the driver may do so. For example, if a drum is leaking, turn it so the leak is on top. If a valve is leaking, try to close it if you can do so without skin contact or inhaling vapors.
• Protect Waterways: Use dirt, sand, or emergency spill kits to build dikes (barriers) or block storm drains. This prevents the spill from reaching streams, rivers, or storm sewers, which can lead to widespread environmental contamination and massive carrier liability.
• Avoid Improvised Cleanup: Drivers must never attempt to clean up, shovel, or neutralize hazardous materials. Chemical cleanup requires specialized training and personal protective equipment (PPE) mandated under hazardous waste operations standards.
• Leaks in Transit: If a vehicle starts leaking in a hazardous or populated area (such as a bridge, tunnel, or busy intersection), and the vehicle can still be driven safely, move it to a less populated or safer area before stopping. If the leak is severe or moving the vehicle increases the danger, stop immediately in the safest possible spot.
• Special Rules for Class 1 (Explosives): If a vehicle carrying explosives is involved in a crash or experiences a leak, do not move the vehicle. If a fire starts or is imminent, do not attempt to fight it; evacuate the area immediately.

Procedures for Handling Overheated Tires

Friction and heat are constant threats to commercial motor vehicles. Under the FMCSRs, you must check your tires at the beginning of each trip and every time the vehicle is parked. When a tire is hot to the touch or smoking, it represents a severe fire hazard. An overheated tire can smolder for hours and suddenly burst into flames.

• Stop Immediately: You must never drive on an overheated or flat tire when carrying hazardous materials. Park the vehicle in a safe, open area, away from buildings, other vehicles, and people.
• Wait for Cooling: Do not resume driving until the tire has cooled down completely.
• Monitor Close-Up: A hot tire must be monitored closely because it can catch fire.
• Understand Tire Fire Dynamics: Tire fires are notoriously difficult to extinguish. The heat is trapped inside the rubber. Even if you use a dry chemical fire extinguisher, the tire may reignite minutes later. Water is often the only effective way to cool the core of the tire. If water is not available, the tire must be monitored closely or, if safe, removed from the vehicle to prevent it from igniting the cargo.

Real-World Commercial Driving Scenarios and Traps

Scenario 1: The Acid Drip in Dallas A driver hauling a load of Class 8 (Corrosive) liquid in drums notices a wet trail behind the trailer. The driver pulls onto the shoulder and sees liquid pooling. Remembering they have a shovel, they begin throwing dirt on the liquid to cover it up, then sweep the dirt into a nearby ditch. The Trap: Covering a spill with dirt does not neutralize the chemical. Sweeping contaminated soil into a ditch is a serious federal violation, as it allows the corrosive to enter the watershed. The driver should have used the dirt to build a dike around the spill to contain it, then waited for a professional hazmat cleanup team to remove the contaminated soil.

Scenario 2: The Smoking Dual on Interstate 35 A driver hauling Class 3 Flammable Liquids notices a dual tire on the trailer is smoking. They are only five miles from a truck stop, so they decide to keep driving slowly. The Trap: The continuous rotation of the tire generates intense friction, causing the tire to ignite. The flames quickly spread to the trailer's floorboards and ignite the flammable cargo, resulting in a total loss of the vehicle and a major highway closure. The driver should have parked immediately on the shoulder and monitored the tire until it was cold.