The latest issue of Banner Healths Smart & Healthy Magazine arrived to mailboxes over the weekend containing Social Security numbers of recipients on the address labels . We try so hard to protect our Social Security number and then to have it publicized , its very disturbing , Sun City West resident Janet Carlson said Monday . Ms. Carlson is one of 50,000 Medicare beneficiaries served by Banner Health in Maricopa County who received the magazine , according to hospital spokesman Bill Byron . Mr. Byron said staff is now looking at how this breach happened so that it is not repeated . We are very sorry and apologize that this has occurred , he said . We have mailed this magazine numerous times before and this has not been an issue . Banner Health has published six previous issues of the free magazine , which comes out twice a year . Mr. Byron said a letter of apology will be sent Wednesday morning to magazine recipients and that he hopes to find out in the next few days what went wrong . The likelihood of the sensitive data being exposed is very low , he said . He said the labels are automatically affixed to the magazines by machines and then sent to the U.S. Postal Service for mailing . Mr. Byron said Banner Health has received about a dozen phone calls from concerned residents , mostly from the Northwest and Southwest valleys . Sun City West resident Paul Seibert said both he and his wife each received a copy of the magazine Saturday and did not know anything was wrong until a neighbor informed them . There re probably several thousand people who have had their Social Security number compromised , he said . My wife seldom gives out the last four ( numbers ) of her 's period and here the whole number is running around now . ;