Work continues at the intersection of E. North Ave. and N. Oakland Ave. following a six-alarm fire that destroyed the building housing Pizza Man, Grecian Delight, Black and White Cafe, CUSH Lounge and 10 apartments.

The flames were extinguished earlier Tuesday afternoon, but firefighters are still working to smother smoldering piles of rubble to prevent further flareups.

Members of the Milwaukee Fire Department Arson Unit spent much of the afternoon investigating the blaze, the cause of which has not been determined. In addition to the local team, state and federal fire officials are also assisting with the investigation.

More than 150 firefighters and about 30 vehicles were called to the fire, which was reported at 3:33 a.m. and was declared to be under control around 9 a.m.

All of but one of the tenants living in 10 rental units above the businesses were accounted for and the last individual is believed to be out of the country.

Three firefighters were treated for minor injuries, according to Acting Fire Chief Michael Jones. They were treated and released from a nearby hospital.

Jones commended first responders for what he called a "gallant effort" in evacuating residents upon arriving on the scene.

Firefighters also battled problems with low-hanging power lines as well as low water pressure while battling the blaze.

The building, assessed at $1.235 million, is considered a total loss after portions of it collapsed.

A real estate listing for the building was found online, suggesting all or parts of it were available for lease, but Jean Lockwood of Bieck Management said that she had no knowledge of the listing, nor any availability in the building. Bieck's Web site apparently lists all its buildings as "commercial properties for lease."

"The building was not for sale," Lockwood said. "The whole building was fully leased."

When contacted by OnMilwaukee.com last week about the listing, a Pizza Man employee laughed and said the restaurant was not closing.

In the meantime, cleanup efforts continue to snarl traffic around the busy East Side intersection.

North Avenue remains closed between Farwell Avenue and Bartlett Avenue, while Oakland Avenue is closed between E. Windsor Place and E. Bradford Avenue.

The closures are disrupting two Milwaukee County Transit System lines. Detours have been put in place for both Rts. 15 and 21 and will remain until the intersection has been cleared.

"We will have signs posted for passengers," says Jackie Janz of MCTS. Riders can also get route and schedule information from the MCTS Web site or Twitter feed.

A number of area residents and businesses were without power during the day but We Energies spokesman Barry McNaulty says that service was restored around 4 p.m.

Crews remain on the scene though assisting with issues pertaining to power and natural gas lines.

John Hyland, Drew Olson and Bobby Tanzilo contributed to this report.