HARRISBURG, Pa. —  State officials are hoping to contain any worries about identity theft after more than 1,200 mailings containing the Social Security numbers of state welfare recipients were sent to the wrong addresses.

The mix-up happened at a state printing plant, where a paper jam on a mail inserter threw off the operation and caused some recipients' paperwork to be stuffed into envelopes labeled with the addresses of other welfare recipients.

More than 2,800 packets were mailed Aug. 18 to the wrong addresses, including 1,284 that contained Social Security numbers. Recipients began calling county welfare offices several days later to report the mistake, a Department of Public Welfare official said.

"We take this very seriously and we are working with the machine manufacturer to determine the cause of the problem to ensure that this doesn't happen again," said Ed Myslewicz, spokesman for the Department of General Services, which runs a printing plant that serves numerous state agencies.

The state Department of Public Welfare wrote to the people whose Social Security numbers were mailed to the wrong addresses and put a 90-day fraud alert on their credit reports, department spokeswoman Stacey Witalec said.

She said the department has no evidence that any information in the erroneous mailings had been used inappropriately.

The packets are sent periodically to recipients of state welfare benefits _ such as cash assistance, food stamps and Medicaid _ and must be filled out and returned to ensure that the person still qualifies for benefits.

Copyright 2008 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.