WASHINGTON — Parents with children in day care often assume workers have cleared background checks and the facility has passed unannounced inspections, but a review to be released Tuesday finds a large number of states don’t have such requirements.

The watchdog arm of the Department of Health and Human Services found that 21 states do not require an annual unannounced inspection of all licensed child care providers and that only 15 require background checks considered comprehensive by the agency’s Administration for Children and Families, according to a copy of the report obtained by The Associated Press.

About 1.6 million children use federal subsidies to attend day care programs at about 500,000 different centers and home-based providers.

Even when unannounced inspections are required by states, they aren’t always done, according to the report from HHS’s inspector general, which took a closer look at California, Florida, Illinois, Ohio and Texas as part of its review. When inspection visits were done, the deficiencies found included not enough staff to maintain required staff-to-child ratios, unscreened people living in family day care homes and broken playground equipment.

The states tended to have more stringent requirements for center-based day cares than those based in homes, the report found. For example, seven states don’t require a background check of family members living in the house of a licensed home-based child care provider. But even in centers, 18 states don’t require background checks of janitorial staff; eight don’t require it for drivers; and seven don’t require it for owners.

The Administration for Children and Families oversees the Child Care and Development Fund, which last year distributed more than $5 billion in child care subsidies to parents living in poverty who work or go to school. Participating parents pick a provider — as long as it meets state and local requirements. That means children who don’t participate in the program often attend day care with those who do.

The agency has expressed concern about whether states are ensuring that child cares are safe, even though some local governments do provide oversight. Agency official Linda Smith testified last year before a congressional committee that some states lack basic requirements for their child cares, and that far too often, this “lack of accountability leads to tragedy,” including deaths.

The IG report recommends that more rigorous standards be rolled out and enforced as a condition for states to participate in the program, including requiring all licensed providers to undergo comprehensive criminal background checks using fingerprints and annual unannounced inspections. The Administration for Children and Families, earlier this year, proposed regulation changes that would implement much of what the IG has recommended.