Emergency management officials closed Airport-Fernwood Road early Wednesday after a tanker hauling hazardous materials sprang a leak.
The driver of a truck coming north from New Orleans marked as being owned by Southern Tank Leases and hauling corrosive chemicals pulled off Interstate 55 at the Airport-Fernwood Road exit around midnight and called 911 after noticing a malfunction with the tank, state troopers said.
Officials closed the ramps on both sides of the interstate and they remained closed Wednesday as thin white fumes could be observed billowing out the bottom of the tanker.
Wind blew the gases north-northeast across Gateway Road.
The air near the spill bore no particular odor.
Officers with the Mississippi Highway Patrol, Mississippi Department of Transportation and Mississippi Department of Environmental Quality responded to the scene and were still working Wednesday evening.
The hazardous materials indicator placard with the number UN 2920 was affixed to the back of the tanker, indicating that it was hauling dichlorobutene, a highly flammable substance that will decompose to form hydrogen chloride gas if exposed to water or moist air.
First responders kept a wide berth from the tanker as it released fumes from its underside. Exposure to the chemical is hazardous and inhalation of its gases can cause serious and irreversible effects. Dichlorobutene also is toxic to aquatic ecosystems.
When chlorinated hydrocarbons such as dichlorobutene are released into the atmosphere and combine with oxygen, explosive mixtures easily ignited by heat or sparks form. Those fires release toxic chlorine gases. Dicholorobutene is used widely for industrial purposes as an intermediary material in the production of neoprene, which is a material similar to vinyl and used to insulate piping used in fracking and to manufacture wetsuits, among other purposes.
In this situation, the release of fumes is a good thing, because pressure inside the tank is relieved, State Trooper David Blackwell said. When responders first arrived, they were worried mounting pressure inside the tank could cause a chemical fire.
“Once it dissipates in the air, we’re in a lot less dangerous of a situation,” Blackwell said. “I’m staying back, like it’s a downed power line.”