Robert Hanssen's espionage bust may have been one of the FBI's worst cases of spying, but his breach was just one of many for an agency riddled with security transgressions, the agency's security chief said Tuesday.

Nothing so far has been as serious as the crime for which Hanssen was arrested in February 2001, but some 700 FBI employee lie detector have found Hanssen's wasn't the only breach, Kenneth Senser, head of the agency's new security division, told a Senate committee.

Some of the failed tests have sent FBI employees to be disciplined by the FBI's Office of Professional Responsibility while it continues to work with "slightly more than 1 percent of the tested population to resolve anomalies," said Senser, who is leading the revamp of the bureau's security systems.

"The depth of Hanssen's betrayal is shocking, but equally shocking is the ease with which he was able to steal classified material," former FBI and CIA Director William Webster, who wrote a report detailing security failures at the Federal Bureau of Investigation, told the Senate Judiciary Committee.

"Internal security has often been a low priority at the bureau," Webster said. "Security training has been almost nonexistent."

Hanssen has pleaded guilty to selling secrets to the Soviet Union and Russia over two decades in exchange for $1.4 million.

"The report is another wake-up call for the FBI. I worry that when wake-up calls come, the institutional reflex has been to hit the snooze button. That has to change," said committee chairman Sen. Patrick Leahy, D-Vt.

Two other government workers arrested for espionage since last July are Brian Regan, a former Air Force officer assigned to the National Reconnaissance Office, and Ana Belen Montes, a Defense Intelligence Agency employee, Senser said.

Montes has pleaded guilty, while Regan could go to trial as early as next month.

But since Hanssen, the FBI has taken many steps to improve security, Webster said. He said intelligence agencies now share security data so that a lapse in one agency leads to increased security for all.

"The most important change that must take place is a dramatic adjustment in the security 'culture,'" Senser said. "Continuing security education, widespread security awareness and making security accepted as a normal part of everyday business is a long-term challenge."

Leahy and Sen. Charles Grassley, R-Iowa, have been pushing an FBI security reorganization bill. It would require people working with sensitive information to take lie detector tests, allow Justice Department investigators to look at the agency independently and establish whistle-blower protections.

It also would make clear that the Justice Department's inspector general has jurisdiction over the FBI, create an FBI internal security division and make additional reporting requirements to Congress.

Fox News' Carl Cameron and the Associated Press contributed to this report.