PORTLAND, Ore. (KOIN) — The Oregon Department of Revenue confirmed to KOIN 6 that thousands of tax documents were sent to the wrong taxpayers due to a printing mistake.

Of the 600,000 taxpayers forms mailed, the state estimates 5,000 residents in Portland have received the incorrect state tax form 1099-G. The forms contain someone else’s partial Social Security number, name and address.

The issue was first reported by The Oregonian/OregonLive.

The state, which uses a third-party print and mail vendor, said the information on the forms did not match that of the taxpayer addressed on the outside of the form.

Once aware of the mistake, the revenue department said it ordered the vendor to send corrected forms to anyone that was possibly impacted. The state also said all affected taxpayers will receive a letter notifying them of the mistake and with a free one-year membership for a credit monitoring program.

Anyone that received the incorrect 1099-G form is urged to destroy it.

To avoid similar mistakes in the future, the Department of Revenue said it and the vendor are evaluating the printing processes.