Lafayette fire officials say an overfilled railcar caused the chlorine leak on Walker Road last week.

Investigators say the excess liquids increased pressure in the car and caused its safety valve to activate.

As of 11 p.m. Sunday night, the chlorine was transferred to two separate railcars and the damaged safety valve was removed.

One Lafayette Utilities System employee was treated at the hospital with breathing issues and has since been released.

Axiall Corporation owns the railcar.