Washington ? The Transportation Department inspector general found airport security screeners on several dozen occasions failed to catch guns and simulated explosives, even after the September terrorist attacks, a person familiar with the report said Monday.

Inspector General Kenneth Mead’s report found screeners missed knives 70 percent of the time, guns 30 percent of the time and simulated explosives 60 percent of the time, said the source, speaking on condition of anonymity.

The story was first reported in USA Today.

Tests of the security system were conducted at 32 airports while the screening checkpoints were still primarily under the supervision of the airline industry, with some oversight by the Federal Aviation Administration. The new Transportation Security Administration took over responsibility for airline security Feb. 17.

Security administration spokesman Paul Turk said the White House requested the investigation. “The idea was to get a realistic assessment of potential needs,” he said.

The security agency is hiring 30,000 federal employees to take over passenger screening. On Monday, it began training the first 300 of 1,200 senior supervisors, who will run the airport checkpoints. The other 900 will be trained over the next three weeks. The supervisors all have law enforcement, security or military backgrounds, Turk said.

Following several well-publicized post-Sept. 11 incidents, Transportation Secretary Norman Y. Mineta in October ordered government officials to close airport concourses and rescreen passengers.

Security breaches caused the government to evacuate 59 airport concourses or terminals between Oct. 30 and March 7, forcing 2,456 flights to be delayed or canceled, the FAA says. Passengers on another 734 flights had to leave their seats and go through security a second time, the FAA said.

Former FAA security chief Billie Vincent said the report was not surprising, considering the checkpoints were staffed by the same low-paid, poorly trained screeners who were there before Sept. 11.

In addition, Vincent said, current equipment cannot detect explosives, nor can it detect many varieties of cutting tools.

“The technology at the screening points is not there,” Vincent said. “The current metal detectors won’t do the job. If you turn it high enough to detect that much metal, you will have an alarm on every person going through.”