PHILADELPHIA (CBS) — The fire department battled a blaze at an apartment building in the Spring Garden section of Philadelphia that has caused a high school to be evacuated.

Crews found heavy fire on the roof of the four-story apartment building at 15th and Mount Vernon Streets around 1:15 p.m.

Ben Franklin High School has been evacuated as a precaution.

No one was injured.

Authorities are trying to determine the cause of the fire.