Hazmat Teams Prevent Potential Boilover

Issue 3 and Volume 15.

What exactly is a boilover? It is one of the most dangerous flammable liquid fires that firefighters face. Full-surface crude oil fires can have catastrophic consequences if adequate resources, immediate actions, and proper techniques are not executed. Historically speaking, flammable liquid fires have some of the highest death counts. They are unique beasts you never want to fight underprepared!

Boilovers can occur in crude oil/mixed fuel storage tanks when a full-surface fire is not quickly extinguished. Left to burn, the heated surface layer will move downward through the tank’s product and eventually find a water pocket or water layer at the bottom of the tank. If the crude oil temperature is 212°F or higher when it finds a water layer, the water will expand to at least 1,700:1. This causes flaming crude oil to be forcefully pushed up and out of the storage tank onto responders and civilians. The hazard zone can reach as far as 10 tank diameters. Anyone in the area not in full personal protective equipment can be killed or severely burned. The radiant heat alone can be lethal.

Houston, Texas, is often referred to as the petrochemical capital of the world. Hazardous materials are a way of life for the thousands of industrial workers who work in the chemical industry. Although chemical fires are infrequent, they do occur. One volunteer fire department found itself facing a potential boilover, a crude oil full-surface fire.

The Incident

(Captain Kevin Okonski, Houston Fire Department Hazmat photo)

Shortly before midnight, the Houston Fire Department received a call for a mutual-aid hazmat incident at a shipyard along the Houston Ship Channel. A storage tank of crude oil was on fire, and several other crude oil tanks were exposed. The local volunteer fire department and a three-member local hazmat team attempted to extinguish the fire with a foam blanket. However, the foam blanket did not extinguish the fire, so Houston’s hazardous materials response team (HMRT) was requested.

On arrival at the command post, Houston’s HMRT quickly recognized the time-sensitive nature of the incident. Tank temperatures were approaching 200°F. The hazmat team knew a boilover was imminent unless an adequate Class B foam blanket could be applied. Fortunately, Houston’s Foam Engine 22 was on scene with 750 gallons of AR-AFFF foam. Unfortunately, there was no water supply to the shipping yard.

The on-scene incident commander quickly coordinated a water shuttle. Houston’s 10-member Hazmat Team, with a four-member regional hazmat team as backup, positioned themselves for an offensive attack. Approximately four minutes after Foam 22 implemented foam operations, the fire was extinguished.

Call Gone Well

As stated above, flammable liquid fires involving crude oil can be deadly. The Houston Hazmat Team, along with an excellent team of responders, won the battle and prevented a potential boilover. On the one hand, this call could be viewed as a near miss because all incidents of this magnitude are high-risk incidents. However, this call should be viewed as a “call gone well” because adequate resources, expertise, and techniques were executed promptly, resulting in no injuries or significant loss of property.

High-risk low-frequency incidents are difficult to prepare for. However, we can all learn from our brothers and sisters. Lessons learned can be anything from “Don’t do what I did!” to “Hey, we had a call like that, and this is what worked well for us.” You never know when an article, or a Near Miss Report, will have an impact on some future decision you make if you fail to read it in the first place.


Dana Brown is a 20-year veteran of the Houston Fire Department and is a captain on the Hazardous Materials Response Team. She has dual MBAs and is a Ph.D. candidate. She is an aviator and veteran of the United States Army and flew the AH-64D Apache Helicopter for the 1-149th Aviation Attack Battalion in Texas. She has a decade of experience in search and rescue and as a K9 handler. She is an international hazmat and WMD instructor for first responders. She also works for the IAFC’s Near Miss Program as a reviewer, sits on the IFSTA validation committee, and serves on NFPA 472.