"I saw the flames inside the apartment," she said. "I went upstairs and knocked on the doors trying to get people out."
Among the people she warned were Kenny and Stacey Shoemaker.
"We didn't hear the smoke alarm at all," Stacey Shoemaker said. "We had no idea. We just thought some nutty person was beeping our door. We get that all the time."
When they realized there was a fire in the building, Kenny Shoemaker said he tripped the fire alarm and made sure his family got out of the building as quickly as possible.
"I know it doesn't take long for fire to spread," he said.
Horn said firefighters brought the fire under control in about five minutes and prevented the fire from spreading to other parts of the building.
"We were more concerned about making sure everyone was out of the building," he said. "The neighbors did a good job on that, and the alarms."
Other than the apartment in which the fire started, the rest of the four-story building sustained only minor smoke damage, fire officials said.
Robin Ward, who returned home from work to find firefighters outside her building, said she was concerned smoke might damage her belongings.
"I live on the fourth floor and I hope my stuff will be untouched," she said. "I'm getting renter's insurance tomorrow."
Building owner Josef Grewe, who owns other rental properties in Hagerstown, said Wednesday's fire was the second fire at the Broadway location in the two decades he has owned it.
Grewe, 58, of 110 Greenwood Circle in Hagerstown, said the fire "could have been worse ... It's a big building."
The cause of the fire was under investigation.