Preparation Pays Off At Thionyl Chloride Emergency

Seasoned responders are usually on the lookout for Murphy's Law at emergencies. What can go wrong quite often does go wrong and that is why we are called for help. But old Murphy took a day off at a hazardous material incident in northeastern Wisconsin.

Photo by Val Ihde
A tractor trailer carrying drums containing thionyl chloride, a corrosive chemical, was struck by a train. This view of the incident is from the southeast.

On Thursday, Dec. 7, 1995, a tractor-trailer carrying 55 drums of thionyl chloride was hit by a slow-moving train near the intersection of U.S. Highway 41 and Cleveland Avenue in Marinette, WI. The resulting collision left 26 drums on the ground; several of the drums were heavily damaged. Surprisingly, no drums leaked. No one was hurt in the accident but four civilians were treated and released at a local hospital.

Corrosive Product

The chemical in the drums, thionyl chloride, is classified as a corrosive by the U.S. Department of Transportation (DOT). It is a colorless to slightly yellow liquid with a suffocating odor that is used to manufacture other chemicals that help to make toilet paper biodegradable. Thionyl chloride is also used to make pesticides, plastics, chlorinating agents and catalysts. It decomposes into hydrogen chloride, which is highly irritating, and sulphur dioxide, especially on contact with water.

Symptoms from overexposure to thionyl chloride include irritated and burned skin and eye, nose, and respiratory irritation. Exposure to the decomposition gases are moderately toxic; however, acute doses may cause pulmonary edema, bronchial spasms and death.

How It Happened

The truck driver said he did not see the train when he turned the corner onto the road that crossed the tracks. When he heard the train's air horn, he stepped on the accelerator in an attempt to get across the tracks but his truck was hit.

The impact cut the trailer in half and spun the back end, emptying the 26 drums onto the intersection. The truck traveled 200 feet before stopping with the front half of the trailer still attached. The train, consisting of three engines and about 15 rail cars, stopped almost immediately, as it was moving at only 14 mph.

All of the 55-gallon drums had been placed over axles. With 26 drums over the two axles in the rear of the trailer, the others were loaded over the tractor's axles in the front of the trailer. The middle of the trailer, where the train hit, was empty. This greatly reduced the likelihood of drums rupturing. Of the 26 drums expelled from the rear half of the trailer, only eight landed on their sides; the rest were upright.

Photo by Val Ihde
Twenty-nine of the drums were loaded over the tractor's axles in the front of the trailer.

After the collision, the truck driver immediately ran to a nearby auto repair shop for help and to warn others to keep away. He called 911 and reported what happened and what was involved. The train engineer also went to the shop to warn people about the mishap and to evacuate the building. Three bystanders then instructed other people in the area to leave before themselves vacating the area.

About a half hour after these bystanders had left the scene, they began to experience upper respiratory discomfort. All three had apparently been exposed to chemical vapors at the scene and drove themselves to a hospital for treatment. The vapors were from residual chemical within the trailer and were not concentrated enough to cause a substantial exposure. The victims complained of nausea, burning noses and mouths, and funny tastes in their mouths. All were treated and released.

Law enforcement officials immediately shut off traffic from all directions, being careful to remain upwind and avoid exposure. (The wind was from the southwest at 7 mph; the temperature was 10 degrees Fahrenheit.) The Marinette Fire Department arrived and assisted with site control. The department's incident command system was immediately employed. Also, a command center was set up at the Marinette fire station.

Businesses and homes within 150 feet of the incident were evacuated by police and firefighters. Other people in buildings within 500 feet were protected in places with all windows and vents closed. This minimized needless chemical vapor exposures.

To further control the site and to minimize property exposure, the incident commander decided to remove the train engines from the site. He ordered the engineer to move the remaining engines very slowly from the intersection. It was feared the drums might rupture if the rumble of the engines was too harsh. Luckily, the movement was minimal and no product was released.

Emergency Response

The chemical involved in the incident was known from the start. The driver identified the chemical for dispatchers over the telephone; the dispatchers in turn spelled the chemical name and had it verified by the driver. Soon after the driver's call, the dispatchers called Marinette Emergency Government Director Charles Minerman and repeated the process.

Photo by Val Ihde
Employees of the cleanup contractor work in Level A suits and air lines while loading undamaged drums to be delivered to the chemical company.

These stainless steel drums were being transported to a nearby chemical company. On learning of the mishap, personnel from the company, SpecialtyChem Products Corp., responded with thionyl chloride Material Safety Data Sheets.

The Marinette Fire Department and its hazmat team also responded. This response team is a designated county unit composed of 21 hazmat technicians; 17 of them are also trained to the specialist level. The hazmat personnel inspected the site and found no visible leaks. Local ambulances stood by for assistance, and Superior Environmental Services (SES) arrived began the cleanup. SES personnel used Level A protection to check and upright the 750-pound drums. Two drums that were badly damaged were overpacked. All drums were delivered to SpecialtyChem.

The truck driver was cited for failure to stop at a railroad crossing. He apparently was concerned with finding the road to use to complete his delivery and was not aware of the rail crossing's activated red lights.

Textbook Case

The lessons learned were many. "It was a textbook example of preparation and teamwork," Minerman said. He complimented the Wisconsin Division of Emergency Government and the State Emergency Response Board for helping to equip and train the local responders. Other training came from Hazardous Material Transportation Act grant money.

Among other lessons learned:

  • Having an active Local Emergency Planning Committee (LEPC) leads to community and facility involvement, an invaluable resource in an emergency. SpecialtyChem is active in its LEPC and was involved from the start of the incident, providing chemical engineering and safety advice. It also hosts an annual plant tour for responders and planners.
  • A community Level B team is critical in areas such as Marinette with their transportation exposure. It was able to respond within minutes as opposed to the one to two hours it would have taken for a regional team to arrive.
  • Training grants played a large part in the success of this operation. All hazmat technicians and specialists involved had received refresher training within the prior three months.
  • No plan is any better than its most recent exercise. Mari-nette County had practiced a transportation accident scenario just two months prior to the real event.
  • The incident command system provided the framework for a safe and successful outcome.

The bottom line was no responders were injured and all personnel responded well in respect to their training and equipment limitations. Beating old Murphy is never easy but can be accomplished with plenty of preparation.

The author would like to credit Marinette Eagle Herald writers Penny Mullins and Christena T. O'Brien, Marinette Emergency Government Director Charles Minerman and photographer Val Ihde for their help with this article. Other assistance comes from "Marinette Dodges the Bullet," DEG Digest, Vol. 5, No. 1.

David F. Peterson is a career fire/medic with the city of Madison, WI, Fire Department. He also responds on the Hazardous Incident Team, a Level A Regional team that serves 11 counties in Wisconsin. Peterson conducts hazmat training for his department as well as area industry. He is also the founder and president of the Wisconsin Association of Hazardous Materials Responders Inc.