HARVEY, La. -- Officials are investigating what caused a two-alarm fire at a fourplex apartment building in the early morning hours Sunday.

Firefighters with Harvey Volunteer Fire Company #2 said they arrived around 12:30 a.m. to find the two-story building on West Chelsea Road heavily involved with heavy fire and smoke.

Officials said it took 20 firefighters about 3 hours to put out the flames.

Only one apartment was reportedly occupied and all of the residents were accounted for with no injuries.

One firefighter was brought to the hospital as a precaution when a ceiling collapsed on him, but officials did not provide his condition.

The building had 5 apartment units inside.