BOSTON — Families applying for federal student aid are facing extra hurdles this year after a potential data breach led federal officials to remove an online tool that smoothed the process.

The Education Department and the Internal Revenue Service said Thursday that an online service known as the Data Retrieval Tool will stay offline for the rest of this application season. In the past, families could use the tool to import their tax information automatically to the Free Application for Federal Student Aid.

Now families filing the form will have to fill out their tax information manually using old tax returns, an obstacle that some education experts fear will deter families from filing.

“It’s not impossible, but it it’s going to make it more difficult,” said Justin Draeger, president of the National Association of Student Financial Aid Administrators. “Not everybody has access to their prior year’s return.”

Officials unexpectedly removed the online tool in early March, at a time when many families across the U.S. were applying for aid. The IRS later said it shut it down because identity thieves may have used personal information “obtained outside the tax system” to access the online tool in an attempt to steal further data.