Mayor Nutter on Tuesday signed off on an expansion of a Philadelphia law that outlines when employers can ask potential hires about their criminal backgrounds. He also strengthened the city's rules on hiring former offenders.

Under the updated "ban-the-box" law, employers are not be permitted to complete a background check until they have made a conditional job offer, as opposed to after the first interview. The term comes from a box on application forms asking about a criminal record.

With the update, the law now will apply to businesses with one or more employees, as opposed to those with at least 10.

"For the thousands of Philadelphians and millions of Americans who may have made a bad decision at some point in their life but then served their time and are now back on the streets of our city and our nation, we must offer them a second chance," Nutter said at a signing ceremony in City Hall.

City Council passed the initial ban-the-box law - meant to assure applicants are considered on their qualifications, not their records - in 2011. One out of five adults in the city has a criminal record, according to city officials.

Nationally, ban-the-box laws have been adopted in 18 states and more than 100 cities and counties, according to the National Employment Law Project. Michelle Natividad Rodriguez, a senior staff attorney with the group, which advocates for workers' rights, said Philadelphia's new law is "a stronger policy than most."

"With a city like Philadelphia taking that kind of stand, I hope they can help other cities and counties see this is workable," she said.

The law, which was introduced by Councilman Curtis Jones Jr. and will take effect in 90 days, also bans employers from reviewing a person's criminal history going back more than seven years, excluding periods of incarceration.

If an employer decides not to hire an employee based on a background check, the employer must provide written notice of why the applicant is being rejected and a copy of the criminal history report. The employee will have 10 days to correct the report and 300 days to file a complaint with the city.

Nutter on Tuesday also signed an executive order regarding how the city considers applicants with criminal backgrounds.

Nutter said that the city hired nearly 400 such applicants during his first 33 months in office, when the city still had a question on applications regarding criminal history. He said checks are not completed until after a job offer has been made.

The order signed Tuesday will require that all city offices create a list of "qualified sensitive positions" and corresponding "barrier convictions" that might disqualify applicants.

For example, the child protective services law limits a person with an assault conviction from working with children, which would exclude some jobs at libraries or recreation centers. A person with a drug conviction would not be eligible for a job at the airport, due to Transportation Security Administration regulations.

Nutter said that list of positions and convictions will be made public.

"Our goal is to lead by example," Nutter said.

In a third related action Tuesday, Nutter signed a bill that will put a ballot question to voters asking whether the city should make permanent the Commission on African American Males. Nutter reestablished the commission, which was started under Mayor W. Wilson Goode Sr., in 2011.

Voters will weigh in on the ballot question in the April primary.

Editor's Note: This story was revised to reflect that the city hired 400 applicants with criminal backgrounds in Mayor Nutter's first 33 months in office, not during his full tenure.