Lakeshore Mental Health Institute stopped admitting patients in 2012, but some of the clients' records were still at the facility Tuesday.
Former Lakeshore employee Hilda Lindeman was walking through Lakeshore Park when she noticed old patients records were on the floor of an abandoned, easily accessible hospital building named Waterside.
She showed 10News how she found the records at the doorstep. The door to the building was wide open and its glass windows were broken.
"I knew instantly what it was from just working here," said Lindeman, who worked at Lakeshore for 28 years.
The records contained social security data, names, case numbers, even birth dates. Lindeman said she did not notice the papers when she walked by the facility last week.
"If an individual had unkindness in their heart, this would be a goldmine," she said.
Lindeman contacted 10News about the incident, which then reached out to the State Department of Mental Health and Substance Abuse Services.
Communications Director Michael Rabkin said the department was not sure if the documents were left in the building after it closed in June 2012 or if someone put them there after that.
Upon hearing of the find, Rabkin said the department immediately contacted workers in Knoxville to retrieve the documents as soon as possible.
"Since we've just been made aware of what the issue is there, we will definitely look into what the files are that are at this facility," he said.
It is not clear if anyone took any of the records out of the building prior to their discovery Tuesday.
Hundreds of names were on the record that date back at least as far as 1995.