BALTIMORE — Maryland officials have taken a step toward building a new mental illness and substance abuse treatment center for nonviolent offenders in Baltimore. The Baltimore Sun reports that the Maryland Department of General Services has issued a request for proposal for a design and construction consultant.

The consultant would oversee various aspects of the planned Baltimore Treatment and Therapeutic Center. Officials say it is expected to take about 10 years and cost more than $450 million to complete. Plans call for the treatment center to be developed on the grounds of the former Baltimore City Detention Center, which was closed in 2015.