Two Massachusetts firefighters were taken to the hospital after battling a massive four-alarm blaze that destroyed two houses and displaced at least two dozen residents late Wednesday.

The fire broke out just before 7 p.m. at a triple-decker house in Lynn, and it was initially spotted by Lynn firefighters who were on their way back to the station after another call, The Daily Item reports. Flames quickly spread to a neighboring home, and crews worried they would reach a third building.

Despite facing water pressure issues, firefighters from Lynn and the surrounding area—including Chelsea, Boston, Malden and Melrose—were able to get the blaze under control by about 9:30 p.m. Parts of two homes had collapsed and were uninhabitable, while two nearby buildings suffered heat and water damage.

Two Lynn firefighters suffered minor injuries battling the blaze One injured a shoulder and the other had an injured knee, according to the Item.

The residents who were inside the building when it caught fire were able to escape without injury. The cause of the blaze is under investigation, the Item added.