CONVENT, La. (AP) -- One of three storage domes collapsed Wednesday at the Nucor Corp. iron plant near Convent.
Authorities said the dome suffered a structural failure, just weeks before the plant was to start production after more than two years of construction.
The incident did not result in fires, explosions, release of hazardous materials or injuries, authorities said.
Company officials are investigating the cause of the collapse of the storage dome, which is at Nucor's direct reduced iron plant, Katherine Miller, spokeswoman for the Charlotte, N.C., company, told The Advocate (http://bit.ly/18YgvTL ).
St. James Parish officials said they received a 911 call of "an explosion" at the plant at 3:15 p.m. Wednesday. Firefighters from Paulina and Convent and other emergency response agencies rushed to the scene but were recalled once officials realized a structural failure had occurred, according to Eric Deroche, parish director of homeland security and emergency preparedness.
Sheriff Willy Martin speculated the collapse may have sounded like an explosion, leading to the initial 911 call and early news accounts of an explosion.
The $750 million plant will use natural gas to convert iron ore pellets into direct reduced iron once in production. DRI is a basic building block used in Nucor's electric arc furnaces to make steel, according to state air permit requests.
"The impact the collapse of the storage dome may have on the startup date for the DRI plant will not be known until the extent of the damage can be assessed," Miller said in a statement.
The reduced iron plant is the first of several phases in a planned $3.4 billion steel complex that would employ 1,250 people.
Before the collapse Wednesday, the DRI plant was undergoing "hot commissioning," which is a series of trial runs ahead of the planned startup, company officials have said.
Plant manager Lester Hart said construction and hot commissioning continues despite the collapse.
"We are still continuing the construction, but we just don't know if or what impact this will have on our startup," he said.
The DRI plant, which officials broke ground on in March 2011, is the first of five phases that Nucor may build to create a $3.4 billion integrated steel mill in Convent.
Nucor officials said Wednesday, before the collapse, that after startup in "the next few weeks," production would ramp up during the fourth quarter of 2013 and that the DRI plant would be fully operational by the start of the year.
The company has already hired 140 people to work in the DRI plant and aimed to reach its planned 150-employee mark a year ahead of a 2015 goal, company officials said.