MEMPHIS, Tenn.– Hundreds of people were forced to evacuate a Midtown apartment building after a carbon monoxide leak Tuesday afternoon.

The Memphis Fire Department said the carbon monoxide leak at the Venue Apartment at the corner of Lamar and Central was caused by work on a boiler.

“It was a carbon monoxide leak. It has been determined they were doing some work on the boiler earlier so that might be the cause,” said Qwanesha Ward, Public Information Officer with the Memphis Fire Department.

Around 250-300 residents were forced to evacuate the building. Some residents told us they were sent text messages telling them to immediately evacuate the building.

MFD said four civilians were treated at the scene. A firefighter was also treated for shortness of breath.

“The firefighters got inside and one of the firefighters started to feel ill with shortness of breath,” said Ward.

All of them are expected to be okay but MFD did say three dogs and one cat did not survive.

Buses were brought to help people warm while they waited outside for hours in the cold. Small groups were let in to retrieve essential items while praying for protection for themselves and their homes.

After several hours on edge, residents told us management at the complex alerted them that the fire department said they can return to the building. However, the firefighters kicked in many of the doors as they were checking the units. People will be allowed back inside once the building emergency response teams finish securing them.