IRS Principal Deputy Commissioner Daniel Werfel provided no details of what inappropriate criteria were on the lists, but said "there was a wide-ranging set of categories and cases that spanned a broad spectrum."
The practice of using so-called "Be On the Look Out" or BOLO criteria has been suspended in considering tax-exempt applications, Werfel told reporters in announcing his initial review of the agency he took over in May.
His report was the most substantive IRS response to date of the scandal uncovered by an inspector general's report that found conservative groups applying for tax-exempt status came under extra scrutiny because of labels such as "tea party" in their name.
Use of some lists of conservative labels for further screening stopped in May 2012 when IRS officials were first notified of the practice.
However, an IRS document obtained by CNN showed that other inappropriate lists continued to be used until as recently as this month by the unit that handles tax-exempt applications.
