A spill of phosgene oxime, a synthetic and highly corrosive chemical classified as a warfare agent, shut down westbound Interstate 40 near Jennette, Arkansas overnight Thursday, triggering miles of bumper-to-bumper traffic before cleanup crews cleared the roadway. The closure came near mile marker 267.6, just west of West Memphis, and left commuters facing major delays through the overnight hours.
According to Action News 5, transit officials were alerted to the spill around 8:24 p.m. Thursday. The Arkansas Department of Transportation closed all westbound lanes near the mile marker as crews worked to contain the material, and the outlet's reporting, credited to Lydian Coombs, noted the closure caused significant overnight backups before all lanes reopened following the cleanup, per transportation officials.
Phosgene oxime, known by the military designation CX, is classified by the CDC as an urticant, or nettle agent, first synthesized in 1929. Unlike true blistering agents such as mustard gas, it causes immediate intense itching, redness, and hives without forming fluid-filled blisters. The same agency's medical management guidelines describe instant pain and severe tissue damage on contact, with no specific antidote available, leaving emergency crews reliant on rapid physical decontamination and supportive care.
Handling a Toxic Chemical
Phosgene oxime is a toxic substance that requires careful handling during transport.
Phosgene oxime is a manufactured chemical; the available material does not specify how long it persists in soil or water.
A Freight Corridor Under Repeated Strain
I-40 is a heavily traveled freight corridor, and roughly 26,500 trucks relied daily on the Hernando de Soto Bridge during its 2021 closure, according to metrics cited by Greer Injury Lawyers. Federal highway rules cap commercial truck gross vehicle weight at 80,000 pounds, more than 20 times the roughly 3,500-pound weight of an average passenger car, a disparity that can worsen crash severity when hazardous cargo is involved.
The Jennette exit near mile marker 267.6 has seen serious incidents before. In February 2024, a commercial semi-truck collided with an Arkansas Highway Police vehicle near the same interchange and caught fire, killing two people and causing four-mile backups, per CDLLife. A fatal crash involving a calcium-carbide spill onto I-40 was also reported, and westbound lanes were expected to be closed for several hours, according to NWA Law.
State Transportation Filings
The Arkansas State Legislature's website includes legislative filings related to transportation.
By the time the overnight spill was fully addressed, cleanup crews had cleared the scene and normal traffic flow resumed on all westbound lanes. It remains unclear from available reporting how the chemical warfare agent came to be on the roadway, including details about the vehicle's origin, destination, or hazmat placarding compliance. Available reporting does not establish whether this spill followed other recent I-40 incidents in the area.
