June 14, 2013 04:09

Department spokesman Juan Rodriguez said the cause of Thursday's blast at the plant in an industrial area of Geismar hasn't been determined yet.

GEISMAR, La. (AP) - The Labor Department's Occupational Safety and Health Administration is investigating an explosion at a south Louisiana chemical plant that killed one worker and injured dozens of others.

Department spokesman Juan Rodriguez said the cause of Thursday's blast at the plant in an industrial area of Geismar hasn't been determined yet.

Officials from the plant's owner, Williams Companies Inc., planned to hold a news conference Friday in Gonzales.

The company said one of its employees, 29-year-old Zachary Green, died in the explosion. Green was an operator at the plant and started working for Williams last October.

Louisiana's health department said 77 people were treated at hospitals and at least 51 of them had been released by Thursday evening.