Fire rips into 5-story apartment building on Capitol Hill (PHOTOS)

SEATTLE -- A 5-story apartment building caught on fire around noon Thursday in the Capitol Hill neighborhood of Seattle.

The Seattle Fire Department said the fire was a two-alarm blaze at 12 p.m. There were no immediate reports of injuries, though a loud boom was heard when a propane tank on the roof vented when the tank heated up.

The fire appeared largely contained by 12:30 p.m., multiple Twitter users reported. Firefighters told Q13 FOX news photographers the fire was largely contained to the roof.

The fire caused $25,000 in damage to the roof and was caused by improperly discarded smoking materials, fire officials said.