A chemical storage refrigerator may have caused a fire on the fourth floor of Welch Hall’s west wing Thursday morning, officials said.

The fire started at about 4 a.m. and caused minimal damage. The UT Police Department and Austin Fire Department arrived at the scene where the investigators ruled the cause of the fire to be undetermined at the time, said Garland Waldrop, UT fire marshal. Fire officials are still investigating the exact source of the fire.

“There was a minimal amount of fire damage because the fire sprinklers in the lab contained the flames in the one room, but we had to remove the water from the sprinklers that ran down from the fourth floor to the basement,” Waldrop said.

The fourth floor of the west wing was closed off to students Thursday in order to repair the water damage, but will be accessible again on Friday. False alarm sirens alerted those in and around the building throughout the day, but did not signal danger.

Dennis Nolan, assistant director of biological and lab safety, said investigators do not know if it was the refrigerator that caused the fire or the chemicals inside it.

“From what I can tell, it doesn’t look like the refrigerator [alone] caused the fire, but it is still not conclusive,” Nolan said. “All labs in the building were notified of what the best practices are in order to prevent this from happening again.”