SALEM — Oregon mailed thousands of tax forms with personal information to the wrong people last week, the second such mistake in as many years.

The state Department of Administrative Services said nearly 33,000 mailings last week were affected by a contractor’s error, which put some 1099-G tax forms from the Oregon Employment Department into envelopes that already contained another person’s form. Then both forms went to a single address.

The tax forms were for people who received unemployment insurance benefits last year.

Their tax forms, sent to other people by mistake, included their name and address, the last four digits of their Social Security number, the amount of unemployment benefits they received last year, and the amount of state and federal income taxes withheld from those payments.

That’s less information than would typically be exploited by identity thieves, though they could pair information from the tax forms with other information. The risk may be lower here than in other cases because the private information was mailed to individuals rather than posted online or stolen from a database by hackers.

Information about individual tax payments is supposed to be protected under state law, though.

People looking at someone else’s 1099-G tax form could tell that person received unemployment assistance and make informed estimates of their income based on their tax withholding.

The same tax form was the subject of a similar mistake last year, when 5,000 mailings from the state Department of Revenue went to the wrong people.

In both cases, state officials say it was a contractor’s error that caused the mistake. The contractor last year was R.R. Donnelley; this year it was Garten Services.

The Department of Administrative Services learned of Garten’s mistake last Wednesday, according to the agency, and ordered an immediate halt to the mailing. But thousands of forms had already gone out on Monday and Tuesday.

“This was an issue caused by a contractor but is ultimately the Department of Administrative Services’ responsibility. We take ownership of this error and are correcting this mistake immediately,” the agency said in a written statement.

The department said it will mail fresh tax forms and explanatory letters to those whose tax forms went to other people and to those who received someone else’s tax form in their mailing. People who don’t want to wait can obtain an online copy of their 1099-G through the employment department’s online claims system.

Because the mailings included only the last four digits of taxpayers’ Social Security numbers, the department said it doesn’t constitute a breach of the Oregon Consumer Information Protection Act.

The agency asks that people who receive someone else’s tax documents destroy that information immediately.

The state had agreed to pay Garten about $90,000 to put the tax forms in envelopes and mail them, including $72,000 for postage. The Department of Administrative Services said it is “reviewing its options” regarding whether it will pay the full amount of the original contract and whether it will seek to have Garten cover some or all of the cost of followup mailings.