Documents stolen from a Capitol employee Wednesday left one-third of the state Assembly and 74 of their aides potentially vulnerable to personal identity theft.

The Legislative Human Resources Office contacted the 109 affected individuals through an e-mail Thursday, explaining the theft of documents that included legislators' names, insurance information and social security numbers.

Among those contacted were Assembly Speaker Mike Huebsch, R-West Salem, and Rep. Marlin Schneider, D-Wisconsin Rapids — two of the Legislature's foremost advocates of privacy and personal information security.

"I was not happy," Schneider said, responding to the theft. "I don't know what [she was] doing; … [she] just shouldn't have taken it [from the Capitol]."

The 26-year-old human resources employee told Madison police she took the documents from her state office Jan. 31 to work at home. On her way home, the employee stopped at the Princeton Health Club on Madison's east side, where a thief broke into several gym lockers. The thief stole some of her belongings, including her car keys.

Police believe the thief used the stolen keys to break into her vehicle, where other belongings and a work bag were stolen. The state documents in the work bag listed people who were enrolled in a particular health insurance program.

No state senators or their aides were listed on the stolen documents, but they were notified of the incident by the Senate Chief Clerk's Office.

Responding to the theft, Schneider started collecting co-sponsors for a new legislation Friday that would prohibit insurance companies from using social security numbers as personal identifiers.

Parties may be able to use social security numbers to illegally access sensitive information, such as bank or credit card accounts.

Mark Browne, a University of Wisconsin business professor, said more insurance providers have abandoned using social security numbers in recent years because customers are increasingly more concerned with personal identity theft.

"I couldn't give you a reason — except cost — why some still do it," Browne said.

Student identification cards at UW once included social security numbers, but the university transitioned the system to random numbers for security purposes.

Schneider also plans to draft legislation that would prohibit state employees from accessing personal information electronically. He hopes to introduce the legislation as soon as possible.

In his e-mail notifying Assemblymen of the theft, Legislative Human Resources Manager Joel Warnick said the office notified the Federal Trade Commission and three major credit bureaus to place those affected on fraud alert.

Warnick also urged those affected to periodically monitor their accounts for suspicious activity and to immediately notify police and the FTC if any incident occurs.

Schneider had called on Gov. Jim Doyle Friday to issue an executive order prohibiting employees from removing documents from Capitol offices. Doyle spokesperson Carla Vigue said it would not be appropriate for the governor to issue such an order.

"Because it was a legislative aide and because it was a legislative branch, it's the legislative branch's [responsibility]." Vigue said. "It may be beyond Doyle's authority."