"Air cargo is vulnerable," says the report released Nov. 25 by Homeland Security Department Inspector General Richard Skinner.

The TSA "has not been effective" in making airlines and freight-handling companies comply with security rules for cargo, Skinner says. In the report, he cites instances where investigators were able to slip into “secure” warehouses where cargo is stored before being loaded onto airplanes and walk around unchallenged. Skinner also found some workers who handle the cargo had not received required background checks or training.

In a response attached to the report, TSA acting Administrator Gale Rossides said agency officials "are in agreement" that the problems must be addressed. The report's six recommendations, including improved employee training, "will provide additional benefit to TSA," Rossides said.

The report comes as the TSA and air cargo industry gear up for stricter rules for screening cargo carried on passenger planes that will take effect in August 2010. TSA is tasked with overseeing the airlines, freight handlers and manufacturers who pack and transport cargo and ensure its security.

But the oversight process "has not effectively ensured" that those companies comply with TSA regulations, the inspector general said. Indeed, the report noted that the TSA's own inspectors had found repeated violations of agency rules. And the report noted that "there are repeat patterns of violations" that the agency has been unable to resolve."