A blaze inside a Louisiana refinery that turned the night sky a shade of orange and sent a large plume of smoke into the air over Baton Rouge has been extinguished, ExxonMobil officials say.

The fire erupted at the facility in Baton Rouge around 11:30 p.m. Tuesday, Baton Rouge Fire Department spokesman Curt Monte told reporters. No injuries were reported, he said.

�We�ve seen reports of people saying explosion. I can tell you there was no explosion,� Monte told reporters at an early morning news conference Wednesday.

�We want the people to know that there has not been any off-site impact and we�re going to continue to be out here as long as it takes to make sure that that doesn�t happen,� he added.

ExxonMobil has been working with the fire department�s hazardous materials unit to monitor air quality in the area, company spokeswoman Megan Manchester told reporters shortly after dawn Wednesday. Results so far have been �below detectable limits,� she said.

The fire was contained to the location where it started, Monte said. The glow of the fire could be seen from miles away, news outlets reported.

It wasn�t immediately clear what caused the fire.

�Once deemed safe, our teams will go in to conduct a thorough investigation to determine the root cause of this incident and how we can learn from it,� Manchester said.

�Our response teams did exactly what they�re highly trained to do. They responded, they responded very quickly, so we�re very thankful for that,� she added.

ExxonMobil is the largest manufacturing employer in Louisiana and its Baton Rouge refinery is the fifth largest in the country, WAFB-TV reported. It produces gasoline, jet fuel and more, as well as items such as paint and adhesives at the chemical plant.

The company said in a tweet that it was responding the situation, including monitoring air quality at the fence line. The air outside the plant �bore no particular odor,� The Advocate reported.

Baton Rouge, Louisiana�s state capital, is about 80 miles (129 kilometers) northwest of New Orleans.

(AP)