Isobutene Leak on I-10 in Baton Rouge, Louisiana

Early this morning, a tanker truck full of the toxic chemical isobutene was damaged in an accident on Interstate 10 in Baton Rouge, Louisiana.

You may have noticed diamond-shaped signs, or placards, containing a number on the back of tanker trucks. These placards are required on all trucks carrying hazardous material in the U.S. The identification number on the placard makes it easy for emergency responders to quickly determine what chemical they are dealing with. For this morning’s accident, the placard read “1075,” indicating that the chemical is isobutene. Every chemical tanker truck is also required to carry Material Safety Data Sheets (MSDS) that describe the chemicals being transported.

The MSDS for isobutene indicates that it is a colorless gas that smells like gasoline or natural gas. It is highly flammable and may cause organ damage if inhaled or swallowed. Because isobutene boils at 12 degrees at normal air pressure, it is shipped under pressure to keep it in liquid form. If isobutene leaks from a tank, it very rapidly boils and forms a gas so cold that it may even cause frostbite in anyone who comes in contact with it. The resulting vapors are heavier than air and will flow out along the ground and tend to settle in low-lying areas.

Related Material:
Evacuations and the Isobutene Event in Baton Rouge, Louisiana
Multi-Modal Transportation Safety and Security


Author: Steve Stage, Atmospheric Physicist/Dispersion Modeler