Fairfax County School Superintendent Robert R. Spillane, reacting to several embarrassing cases involving school employes during the past several months, has established an investigative unit in the school personnel department to perform better background checks on prospective employes.

The new personnel unit will help with background checks and investigations, "so that we'll professionalize this part of our function," Spillane said. The school system has not yet hired anyone to head the unit, he said.

Creating the unit is the latest change in the school system's personnel procedures since the case of former school psychologist Arthur S. Pomerantz came to light. Pomerantz was charged during the summer with several counts of child sexual abuse. Spillane also has promised more aggressive investigations of complaints against employes in the school system.

Pomerantz resigned from the school system last year after coworkers said they repeatedly complained about him, and Prince William County police said they showed Fairfax school officials incriminating photographs of Pomerantz.

Fairfax school officials have been criticized additionally for not providing better background checks in two other recent cases. In one, Clarence Harmon, a former Redskins running back, resigned his job as an aide at Langley High School after it was disclosed that school officials were unaware of his involvement in a well-publicized Texas drug case.

In the other incident, Edward D. Hall, a county school bus driver, was found to have a suspended D.C. driver's license after he was charged with reckless driving in a school bus accident last Tuesday.

Spillane obtained permission from the School Board Thursday night to create the investigative unit using existing job slots.

The board tentatively approved Spillane's proposal for what he called a "moderate reorganization" of the top-level school system bureacracy.

The reorganization will add a third deputy superintendent's job and realign responsibilities of the other two deputy superintendents. The third job will entail handling finances and probably will be filled by John P. Hess, now assistant superintendent for financial services.

Doris Torrice, a current deputy superintendent, will be in charge of school operations, to include matters such as personnel, area offices, special education, support services and facilities. The reorganization will make it easier for principals to deal with the central bureaucracy and will foster more decision making at the school level instead of at the main office, Spillane said.

The other deputy, Herman Howard, will remain in charge of curriculum and instruction.

Spillane said he believes that the reorganization will save money because some jobs can be combined. No one will be laid off in the reorganization, he said.