At midnight on May 15, 2010 an estimated one-fifth to one-quarter of some 1.6 million charities, trade associations and membership groups will lose their tax exemptions, thanks to a provision buried in a 2006 federal bill aimed at pension reform.

It's going to be an unholy mess once these organizations realize what's happened to them.

The federal legislation passed in 2006 required all nonprofits to file tax forms the following year. Previously, only organizations with revenues of $25,000 or more - or the vast majority of nonprofit groups - had to file.

The new law, embedded in the 393 pages of the Pension Protection Act of 2006, also directed the Internal Revenue Service to revoke the tax exemptions of groups that failed to file for three consecutive years. Three years have passed, and thus the deadline looms.

The I.R.S. has long complained it lacks adequate data on nonprofit groups because so many of them did not file tax forms. Without basic facts about organizations, the agency has little chance of overseeing one of the most generous tax breaks the federal government offers.

Congress should had asked the I.R.S. to suspend, rather than revoke, the exemptions of nonprofits that miss the deadline.

Small organizations are the most likely to be hit. It is likely that many of them are inactive and were unaware of the requirement that they inform the I.R.S. 

What does this mean to you? If you give money to a non profit organization that has been revoked, your charitable contribution is disallowed.