Using Identity Finder software, security researchers scanned IRS Form 990s filed by nonprofit organizations from tax years 2001 through 2006 for sensitive information such as social security numbers.

The researchers found that 132,362 charitable organizations published 472,866 social security numbers, of which 171,005 were unique. In all, 287,238 Form 990s contained at least one social security number, according to the Identity Finder report.

All Form 990s are open to public inspection and are published by the IRS and third parties. At least 35% of the numbers belonged to tax preparers who identified themselves by their social security number instead of their preparer tax identification number.

"Organizations and tax preparers must understand the risks of including social security numbers on public documents, such as the IRS 990 form. Unlike a credit card number, social security numbers cannot easily be revoked. Given the risks of identity theft, tax preparers should avoid including SSNs on 990 forms", advised Todd Feinman, chief executive officer of Identity Finder

