WASHINGTON (AP) — The IRS failed to do background checks on some private contractors who handled confidential taxpayer information, exposing more than a million taxpayers to an increased risk of fraud and identity theft, a government investigator said Thursday.

In one case, the IRS gave a printing contractor a computer disk with names, addresses and Social Security numbers of 1.4 million taxpayers, but didn’t require a background check for anyone who worked on the job, said a report by the Treasury inspector general for tax administration.