In the wake of shocking revelations of widespread sexual abuse of students, Chicago Public Schools is clinging tightly to plans to run new criminal background checks this summer on thousands of adults who work in schools, including teachers, security guards and vendors.

Depending on the results, some familiar faces might be missing when classes resume — even among the army of volunteers who help keep some schools functioning.

CPS officials announced the $2 million background check effort earlier this June. Officials have also removed principals, turned over some investigation authority to the CPS Inspector General Nicholas Schuler, and hired former federal prosecutor Maggie Hickey to conduct a top down review. Her report is due in August.

The background checks are one of several district measures announced this month amid fallout from a student abuse scandal spurred by a Chicago Tribune investigation.

Previously, the district reportedly failed to conduct proper background checks on adults who sexually abused or assaulted students inside school buildings. Some had prior criminal records, including  convictions and arrests for child sex crimes.

CPS Chief Safety and Security Officer Jadine Chou said, “we believe that we have one of the most rigorous background check processes for school districts in the country.” Yet there’s ample evidence some people might have passed checks when standards were less stringent, while others might have committed crimes after passing the checks or never been checked properly in the first place.

On Monday, CPS announced that a district audit of management practices at Simeon High School found systematic problems with how Simeon handles volunteer background checks. The audit, which focused particularly on the school’s past failures to put volunteer coaches through proper background checks, also revealed a new allegation of sexual abuse by a Simeon volunteer. The volunteer has been barred from the school pending an investigation, according to the district.

The new background checks are being conducted to catch those who have slipped through the cracks.

Here’s a closer look at what’s happening.

Who and what is CPS checking?

At least 45,000 employees, 5,000 vendors and 5,000 volunteers will have their fingerprints run through criminal databases held by Illinois State Police and the FBI. Authorities will search for their names among Illinois and federal sex offender registries, as well as the Illinois Crimes Against Youth Database. Names also will be checked against state child protection agency records for findings of child abuse, and the district will look through prior employment records, Chou explained.

“A combination of those sources help us to determine if any of these checks result in a finding, and if there is a finding on one of them then we take further investigation from there,” Chou said.  “When you do a background check, it’s not just a red light, green light – there’s a lot of nuance behind this information and we take the time and effort to look into what we’re seeing.”

The main thing CPS is looking for is criminal history, especially any of the “enumerated offenses” that automatically disqualify people from school district employment under the Illinois School Code.

The full list of disqualifying offenses includes first-degree murder, armed robbery, numerous classifications of sexual assault, abuse and exploitation, and crimes against children. As for drug possession, anyone caught in possession of more than 100 grams of marijuana (about 3.5 ounces) will be unable to work at schools; so is anyone convicted for growing marijuana or possessing more than 2.5 grams of the plant with intent to deliver. However, people who have completed special probation for first-time offenders would get the green light, according to the school code.

To determine whether someone is fit to be around children, Chou said CPS goes beyond the requirements of the school code and also looks for convictions that don’t rise to the level of a felony and aren’t included in the school code.

“We could look at things like battery and see if there are patterns,” she said. “Those are the type of things that require further investigation.”

An arrest in itself couldn’t be grounds for release. But that doesn’t mean CPS won’t look at arrests.

“If a person has a pattern of related arrests for something, let’s say repeated arrests for domestic battery, but every time the charges were dropped, through our investigation we are able to look into the circumstances behind those arrests so we can understand more around what really happened in those situations,” she said.

Chou said the district will flag anybody who it believes could pose a risk to children, and after further investigation will refer their case to the background check committee, which will recommend whether or not a person should be allowed to work or volunteer at schools.

Christine Geovanis, spokeswoman for the Chicago Teachers Union, said the union is watching the process closely to ensure that members flagged during in background checks receive due process and are only targeted with just cause for offenses that violate the school code or indicate they are a danger to a child.

She expressed particular concern for teachers with arrests tied to activism or protests against the board of education, and for collateral consequences to people of color, especially African-Americans, whose communities suffer disproportionate, sometimes discriminatory policing around drug law enforcement.

What about volunteers?

About 5,000 volunteers will need criminal background checks, according to CPS. That includes coaches, mentors, administrative and classroom assistants and others, as well as some parent volunteers. Among several types of volunteers, those classified as Level 1 have to get background checks.

CPS divides volunteers into two levels. Level I volunteers include the following: coaches; one-on-one tutors and mentors at schools; anybody who volunteers at their child’s school 10 or more hours a week or volunteers at least five hours at a school where they don’t have a kid; chaperones on overnight field trips; and volunteers in unsupervised settings.

Level II volunteers have less frequent contact with students and aren’t required to get background checks unless a principal requests it. They include those who volunteer fewer than 10 hours at their child’s school or fewer than five hours at a school where they don’t have a child, chaperones on field trips that don’t involve overnight stays, and adults who visit schools to speak to classes or to perform at assemblies.

Even before CPS tightened its background check policy, Level II volunteers had to get fingerprint-based criminal background checks and show a valid photo ID at the school they want to serve. Members of Local School Councils were supposed to undergo background checks.

Level II Volunteers didn’t have to get a background check, but still had to show photo ID. However, Chou explained, CPS principals still have the right to require that any volunteer regardless of tier undergo a background check.

“The volunteer criteria is the minimum, and principals have the discretion to go above and beyond that at their schools,” she said.

Jeanette Taylor, a CPS parent and education organizer on the South Side, said that CPS definitely should redo background checks before school starts but stressed that most of the perpetrators of sexual abuse and assault at schools identified in the Tribune investigation were school staff, vendors and coaches, not parent volunteers.

Taylor is also concerned that giving principals the discretion to require Level II volunteers to undergo background checks could be abused. She said that anybody who poses a risk to children shouldn’t be allowed to volunteer, but that the background checks bar many well-intentioned parents who want to invest time at their children’s schools, including undocumented parents and those whose past run-ins with the law have saddled them with collateral consequences long after they’ve served their sentences and paid their debt to society.

“It shouldn’t be because the principal decides they don’t like me,” she said.