(CNN) - A plume of thick smoke rose over a Louisiana chemical plant Thursday after an explosion and fire that one government agency said left at least 33 people injured and forced authorities to ask people as far as two miles away to stay inside to avoid exposure to potentially toxic fumes.
A dramatic image provided to CNN affiliate WAFB by a plant worker who did not want to be identified showed workers running from a towering orange column of flame ripping through part of the plant.
Firefighters and a hazardous materials team were evaluating the situation at the Williams Geismar plant, which appeared to be under control Thursday afternoon, Ascension Parish Sheriff Jeffrey Wiley told reporters.
"We think we have a stable situation," he said.
As Gov. Bobby Jindal traveled to the area to meet with emergency workers, authorities lifted the shelter-in-place order for nearby residents early Thursday afternoon. Four nearby chemical plans remained under a similar order, Ascension Parish spokesman Lester Kenyon told CNN.
While police provided no accounting of injuries, a spokesman for the Louisiana Department of Environmental Quality said 33 people had been hurt.
Three people were hospitalized in critical condition, according to information provided by hospitals who reported receiving patients from the blast -- Baton Rouge General Hospital, Our Lady of the Lake Regional Medical Center and St. Elizabeth Hospital.
Two people were in serious condition, seven were in fair condition, 11 were in good condition and four had not yet been evaluated, according to the hospitals.
While no fatalities had been reported, contractors with workers at the site were still accounting for their employees, authorities said.
About 600 people were at the plant when the explosion occurred, Louisiana State Trooper Jared Sandifer told CNN.
It was unclear what caused the blast, he said.
The plant produces about 1.3 billion pounds of ethylene and 90 million pounds of polymer-grade propylene each year, according to the company's website.
WAFB, citing state police, said two state routes had been closed near the plant, which is about 30 miles southeast of Baton Rouge.
The explosion in Louisiana comes two months after a deadly fertilizer plant explosion in West, Texas, on April 17. In that incident, 15 people died and a significant portion of the town was damaged by the explosion.