Mayor Tito Brown lead a conference for city officials and media Thursday morning with updates on the next steps for the Realty Building.

Three different structural engineers will be on site at the Realty building beginning Friday.

They will be working to determine whether it's safe for NTSB investigators to go inside and begin gathering evidence of what led to last week's deadly explosion.

"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 to have full access to the building alone."

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

21 News previously reported that the work that was being done at the time of the explosion was ordered by the city as a part of its "SMART 2" project to upgrade downtown roads.

Youngstown's board of control approved a payment to the building's owner, Greenheart properties, to do the work without any bidding process.

When further pressing the mayor on what sort of vetting the city did before awarding the contract to Greenheart, he refused to answer with any specifics, stating "We're a municipality, we don't just grab people off the street. There's a process that we use throughout our city, and we do it often."

When asked why the work was awarded to Greenheart without first taking bids, the city's director of public works also declined to answer, other than to say it was a matter of 'timing.'

"The work within the right of way conflicted with the basement vault top, so it had to be dealt with," Charles Shasho noted. "We'd been trying for months to try to reach a solution to that, and this was the fastest way possible to move the project forward."

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