Baltimore apartment building partially evacuated after firefighters discover high levels of carbon monoxide

An East Baltimore apartment building had to be evacuated Friday morning due to an underground fire and elevated levels of carbon monoxide. 

Firefighters arrived at the Johnston Square Apartments on Greenmount Ave. shortly after 7:15 a.m. and found an active fire in an outdoor flowerbed. 

First responders suspected gas or electricity may be involved, and a hazmat team was called in, along with Baltimore Gas and Electric.

Crews also found high levels of carbon monoxide on the ground floor and in the basement, as well as lower levels on the upper floors. 

The first and second floor were fully evacuated, while the third and fourth were partially evacuated. More vulnerable residents on the upper floors were also removed from the building, fire officials said. 

A neighbor told WJZ the building houses seniors and people with disabilities. 

Roughly two hours later, officials reported the carbon monoxide levels were subsiding as the building was being ventilated. Officials said they would bring the levels back down to zero before everyone is allowed back inside. 

"Now, we're moving into the next phase, addressing the needs of residents here. We have a lot of support agencies to help with that," Baltimore City Fire Chief James Wallace said on the scene. 

Three people were evaluated on the scene, but did not require hospitalization. 

An MTA bus was brought in to help shelter the displaced residents, and the Red Cross is also on the scene to assist. 

"Right now, we're going to try to maintain those buses until we can determine if this building needs to be completely evacuated or if BGE will be able to reenergize this building today," said Joey Henderson, director of the Office of Emergency Management.

Greenmount Ave. remains closed between Preston and Biddle streets as the investigation continues.