Is a building damaged by an explosion safe enough to venture inside and can it be restored? Those are some of the questions engineers will try to answer when an inspection of Youngstown's Realty Building begins Friday.

Mayor Tito Brown announced on Thursday that three structural engineers will be at the site of the May 28 explosion that killed a Chase Bank employee, injured several others, and displaced apartment tenants.

The engineers will be working to determine whether it's safe for National Transportation Safety Board investigators to go inside and begin gathering evidence of what led to the blast.

"At the bottom of the structures -- and this is the engineer talk -- they want to look at the column, they want to look at the integrity," Mayor Brown said. "If and when the building is considered safe for accessibility, NTSB has made it clear they want full access to the building alone."

 There is no timeframe for how long the engineers may take to determine whether the building is structurally sound.

The NTSB is expected to issue a preliminary report within 30 days.