BROOKLYN - Flames tore through a Borough Park apartment building, just one day before the start of Passover, which many of the affected tenants will be observing. 

Fire officials say it started at around 10:30 a.m. Thursday on the second floor of 5120 19th Ave. Everyone was able to evacuate, and no serious injuries were reported. 

Firefighters shut off gas to the entire building, just as many of the ultra-Orthodox Jewish residents were cooking and preparing for the holiday. 

According to the chief on scene, the fire may have been electrical, and possibly the result of a dryer left running and unattended. However, the investigation is ongoing.