When Bruce Patterson testifies tonight about diversity in the construction industry, he'll be talking about something that's neither white, nor black, but green.

Green, as in getting paid.

"It's a construction industry problem," said Patterson, the African American owner of Patterson Construction Co. in Philadelphia, who says businesses can sink in the time it takes them to get paid. "It's a small business problem."

The mayor's Advisory Commission on Construction Industry Diversity will hold its second hearing in City Hall today from 4 to 8 p.m.

Also expected to testify are Sandra Dungee-Glenn, chairwoman of the Philadelphia School Reform Commission, and Glenn Bryan, an official from the University of Pennsylvania's community relations office.

The school district and the university have programs to bring minorities into the building trades.

Patterson, who is the first person on tonight's agenda, is now a major contractor on the Progress Plaza project in North Philadelphia.

He said successful minority contractors may tend to hire more minority workers, so the success of the contractors will lead to success in diversifying the construction workforce.

On construction jobs, Patterson said, subcontractors like himself are the ones who do the actual work and carry the weekly payroll, including union benefits.

Subcontractors, which can be small or minority businesses, shoulder these expenses up front and then are paid 90 percent of their contract amount 45 to 90 days later. Developers or contractors often hold the remaining 10 percent - known as "retainage" - for a year or more as a guarantee on the work.

"That means the contractor has worked the project for $0 cash flow," he wrote in a printed version of his testimony distributed in advance.

"This is both a travesty and an injustice," he wrote.

Mayor Nutter created the commission in February after the standoff between union building trades and City Council over minority participation in the Convention Center expansion, now expected to cost nearly $800 million.

Contact staff writer Jane M. Von Bergen at 215-854-2769 or jvonbergen@phillynews.com.