Some lending companies with access to a national database that contains confidential information on tens of millions of student borrowers have repeatedly searched it in ways that violate federal rules, raising alarms about data mining and abuse of privacy, government and university officials said.

The improper searching has grown so pervasive that officials said the Education Department is considering a temporary shutdown of the government-run database to review access policies and tighten security. Some worry that businesses are trolling for marketing data they can use to bombard students with mass mailings or other solicitations.

Students' Social Security numbers, e-mail addresses, phone numbers, birth dates and sensitive financial information such as loan balances are in the database, which contains 60 million student records and is covered by federal privacy laws. "We are just in shock that student data could be compromised like this," said Nancy Hoover, director of financial aid at Denison University in Ohio.

Education Department spokeswoman Katherine McLane said the agency has spent more than $650,000 since 2003 to safeguard the database. The department has blocked thousands of users that it deemed unqualified for access after security reviews, McLane said, and it has blocked 246 users from the student loan industry for inappropriately accessing the data.

In general, the department allows lenders to search records in the database only if they have a student's permission or a financial relationship with the student.

The department has been "vigilant in its monitoring for unauthorized uses" of the database, McLane said.

Concerns about possible abuses of the database are emerging as the student loan industry is under investigation by congressional Democrats and the New York attorney general. Critics say the $85 billion-a-year industry has cozied up to government and university officials who are in a position to help lenders.

This month, a previously obscure Education Department official named Matteo Fontana was suspended after the revelation that he owned more than $100,000 worth of stock in a student loan company while he worked in a unit that helped oversee the industry -- and the student loan database. The stock holding raised questions about a possible violation of conflict-of-interest rules.

The database, known as the National Student Loan Data System, was created in 1993 to help determine whether students are eligible for student aid and to assist in collecting loan payments. About 29,000 university financial aid administrators and 7,500 loan company employees have access to it.

In a recent meeting with university financial aid directors, Theresa S. Shaw, chief operating officer of the department's Office of Federal Student Aid, which manages the database, said lenders have been mining it for student data with increasing frequency, according to three participants at the meeting. In the department's hierarchy, Shaw ranks above Fontana.

"She said the data mining had gotten out of control, and they were trying to tone it down," said Eileen K. O'Leary, director of student aid and finance at Stonehill College in Massachusetts, who was at the Feb. 26 session. "They'd seen the mining for a few years, but now they felt it had grown exponentially."

The department first started noticing a problem in mid-2003 when loan consolidation became more popular, according to an agency official who spoke on condition of anonymity because of the sensitivity of the matter. As companies began to aggressively look for low-risk borrowers to target for consolidation plans, they turned to the database for prospective customers, the official said.