Texas Health Harris Methodist Hospital Fort Worth, a 726-bed full-service medical center, has notified patients of a privacy breach in which portions of their protected health information has been compromised and found in a park as well as other public locations.

According to the Fort Worth Star-Telegram, Wendell Watson—spokesman for Arlington-based Texas Health Resources, the hospital’s corporate parent—said the mammoth breach involves about 277,000 records on microfiche from 1980 to 1990.

On Texas Health Fort Worth’s website, the medical center explains how a portion of the microfiche that it had provided to Shred-it, its Toronto-based paper-shredding vendor, had been discovered in a park on May 11 by a local resident who immediately reported the incident to the Dallas Police Department and observed the microfiche until the police had arrived.

In addition, three sheets of microfiche were found during that general time frame in two other public areas. Texas Health Fort Worth recovered the microfiche and then began an investigation, determining that Shred-it had not destroyed the microfiche. Texas Health Fort Worth officials say they had arranged with Shred-it to destroy microfiche containing patient medical records.

The records on the microfiche may have included patient names, addresses, dates of birth, medical record numbers, clinical information, health insurance information, and in some instances, Social Security numbers. The medical center has no knowledge that any of the information included on the microfiche has been accessed or used inappropriately. Furthermore, microfiche is no longer commonly used, and specialized equipment is needed to read the information it contains.