LightFieldStudios/iStockBy LUKE BARR, ABC News

(CHICAGO) — When Jonathan Zumkehr woke up Thursday morning with mild symptoms of COVID-19, he said he figured he should get tested for the virus.

Later that day he found out he was COVID-19 positive, he said, making him the 20th staff member to test positive at the United States Penitentiary Thomson just outside of Chicago, Illinois.

But Zumkehr, like his colleagues, did not get tested at work, or through the Federal Bureau of Prisons. Zumkehr said he had to find an independent testing site on his own.

“Testing for staff isn’t available at the prison but they test inmates for COVID-19 at the prison,” Zumkehr, who also serves as the institution’s union president, told ABC News.

“Staff also can’t get tested due to being forced to work double 16-hour shifts almost on a daily basis,” he said.

Zumkehr says the overtime combined with the lack of testing for staff on site at the prison means that staff regularly don’t get tested. Zumkehr contends that if the Bureau would mandate testing for staff or provide on-site testing, the number of positive cases would rise.

Meanwhile, according to the Bureau of Prisons, only three inmates have tested positive for the virus and they list no staff as having contracted the virus.

“We cannot require that staff members be tested for COVID-19. However, for those staff that are presenting with symptoms or have been identified as a close contact of a COVID-19 diagnosed individual, given the critical role our staff play with regard to public safety, we have developed a letter for staff who are in close contact of a COVID-19 positive individual to provide to the local Health Department, to ensure such persons receive priority COVID-19 testing,” the Bureau said in a statement to ABC News. They also said that the facility is following Center for Disease Control guidelines, just like all other BOP facilities.

The BOP has been under scrutiny for its response to the COVID-19 pandemic, so much so that Pennsylvania Republican Rep. Fred Keller introduced a bill to require Senate confirmation for the BOP director.

In a letter to the Warden dated Aug. 4 and obtained by ABC News, Council of Prison Locals President Shane Fausey wrote that Thomson is operating at 55% capacity — and calls this development “alarming.”

In addition, the facility as a whole is operating at just 67% capacity with 193 vacancies at the facility.

“Who is going to man the prison if everyone tests positive,” Zumkehr asked.

Union officials have long said that the BOP has a staffing crisis, but the COVID-19 pandemic has further strained the system, they say.

Fausey said that the Warden at USP Thomson and others have done an “outstanding job” trying to hire the staff required.

“The staffing crisis is not unique to USP Thomson, however, Thomson is one of the lowest staffed facilities in the agency,” Fausey said in a statement to ABC News. “The Correctional Officers and employees of Thomson are extremely hardworking and dedicated men and women. Their efforts are nothing short of heroic and selfless during the current staffing shortfalls and limited resources at that facility. Their drive and focused motivation is to protect the surrounding community and each other. “

“The staffing crisis at Thomson is more concerning for me because it is one of the highest security prisons in the world. Operating with inadequate staffing, relying on excessive and mandatory overtime, leads to fatigue and a potential for an increase in errors. Errors that in such a serious environment can have dire consequences,” he continued.

In his letter to the Warden, Fausey said multiple employees at the facility are suffering from “extremely low morale.”

“This is in no way the fault of the employees at Thomson. Immediate intervention to alleviate the staffing crisis is necessary to reduce the immediate dangers facing the employees,” Fausey writes.

The low staffing levels at USP Thomson have drawn the attention of members of Congress.

“We write to support the efforts of the correctional staff at the United States Penitentiary (USP) Thomson to recruit qualified staff to work at the facility,” Rep. Cheri Bustos, Senator Dick Durbin and Senator Tammy Duckworth, all Democrats from Illinois, wrote to the Director of the BOP.

The members quote a letter written by Warden Chris Rivers to the staff in June underscoring just how overworked employees at the facility are.

“You have handled more correctional services issues than most correctional staff across the Bureau deal with in a 20+ year career.”

The Bureau of Prisons told ABC News that they do not respond to Congressional letters in the media.

“Out of respect and deference to Members, we do not share our Congressional correspondence with media,” a BOP spokesman told ABC News.

Copyright © 2020, ABC Audio. All rights reserved.