National Transportation Safety Board officials determined the crash was caused by a switch that was set to divert train traffic to the side track, but which should have been set to let traffic continue to the main line.
Graniteville residents were emotionally and economically shaken that January morning, and many have not yet fully recovered, city leaders say.
The train company settled a class-action lawsuit with 5,400 people who lived near the accident then settled with victims seriously injured by the chlorine release.
In an interview early this year, the Rev. James Abraham said tragedy has brought people closer.
"There has been a coalition between residents and church families no matter their color. I've seen the togetherness grow stronger even now," he said. "The economic situation is still tough, but we're still concerned about the healing process and healing the economic situation as well."