LAWRENCE (CBS) — A fire ripped through an apartment building on the same day residents were allowed to return home following the Merrimack Valley explosions. Firefighters responded to the Diamond Street building around 10:30 a.m.

Fire crews respond to Diamond Street in Lawrence Sunday (WBZ-TV)

Preliminary investigations show that the fire is unrelated to Thursday’s gas fires. No word yet on the exact cause.

According to Lawrence Fire Chief, one firefighter suffered a minor injury. There were no other reported injuries.