MIAMI (AP) — Private contractors that are supposed to guard against Medicare fraud paid claims submitted in the names of dead providers or for unnecessary medical treatments, which were among problems estimated to cost more than $1 billion in 2009, according to an inspector general report released Friday.

Federal health officials contract with private companies to process and pay Medicare claims and investigate fraud. The U.S. Department of Health and Human Services inspector general examined how effectively several types of fraud contractors are investigating an estimated annual $60 billion in Medicare fraud.

The report found 62 areas vulnerable to fraud during a 2009 investigation. The most common were related to billing and coding, such as paying a claim even though it had an incorrect code or a provider who billed for an excessive number of services. Another common issue included bills that used the identification numbers of dead providers.