Though most states require nursing homes to conduct criminal background checks for prospective hires, 92 percent employ at least one worker with a criminal conviction, according to a report released today by the inspector general for the Department of Health and Human Services.

About 5 percent of nursing home workers—or one out of every 20—had at least one conviction, according to the report, which took a random sample of 260 nursing homes certified by Medicare and ran FBI background checks on their workers.

State rules differ regarding background checks: 43 states require nursing homes to perform background checks against state records, ten of those require an additional FBI background check, and eight states don’t require background checks at all.

The rules also differ on what types of crimes disqualify workers. The report noted that of the workers with convictions, 44 percent had committed property crimes such as theft, vandalism or writing bad checks. Some 16 percent had drug-related crimes, and 13 percent had committed crimes against people, including sexual offenses.

Federal regulations prohibit nursing homes from employing workers convicted of “abusing, neglecting, or mistreating residents,” but because FBI data do not show whether the victims of the crimes were nursing home residents, it’s unclear whether these rules were violated.

The New York Times noted that the current system for background checks—which Wisconsin Democrat Sen. Herb Kohl criticized as “haphazard, inconsistent, and full of gaping holes—has allowed people convicted of crimes in one state simply find jobs at nursing homes in another state.

We’ve noted a similar lack of oversight in the nursing field, which allowed problem nurses to cross state lines in order to keep working and avoid consequences. A national database was created decades ago to prevent this from happening, but reporting failures at both the state and federal level have left the database riddled with gaps.

The inspector general recommended that the federal government’s Centers for Medicare and Medicaid Services, or CMS, work with the states to develop background check procedures, including lists of convictions that would disqualify a potential hire.

CMS oversees nursing homes eligible for funding under Medicare and Medicaid. In a written response to the report, the agency agreed with the recommendation. CMS also runs Nursing Home Compare, a searchable database with ratings on nursing homes.

For more, read the full report.