A Customs and Border protection officer checks her phone in the terminal at Dulles International airport in Dulles, Virginia on March 17, 2020.
CNN  — 

A coronavirus outbreak has spread through a federal law enforcement training facility in South Carolina prompting the national employees union to call for a halt to training.

At least 23 students and faculty have tested positive at Federal Law Enforcement Training Center in Charleston, where Customs and Border Protection personnel were training, according to the National Treasury Employees Union.

On Friday, the union, which represents thousands of CBP employees, officially requested that the agency immediately send home any employees currently in training, as well as test employees for Covid-19 prior to the departure.

“The FLETC Charleston facility is no longer safe for trainees under the current circumstances,” said union National President Tony Reardon in a statement to CNN, adding that the union learned of the “alarming outbreak” earlier this week.

Shutting down training would allow for an evaluation and to avoid recurrence, said Reardon.

The outbreak comes amid increased concern about exposure for federal frontline employees and a spike in coronavirus cases in the southern United States. As of Thursday, 1,426 CBP employees have tested positive for Covid-19 and eight have died as a result of the virus, according to the agency.

The Charleston facility is one of three federal law enforcement residential training sites and is used for CBP, US Coast Guard, Immigration and Customs Enforcement and other federal law enforcement agencies.

The agencies, which conducted contact tracing, believe the outbreak may have been caused by a contractor infected with coronavirus visiting the facility’s bar, according to a letter from Reardon to local union chapter presidents. It was then transmitted to other students who were at the bar and then to additional students.

The union raised concerns that other factors contributed to the outbreak.

According to the union, there was a failure to question and take the temperature of all individuals who come and go on a daily basis. Additionally, social distancing and mask-wearing guidance was not followed or enforced.

“Most importantly, and this is a problem CBP-wide, the agency is still not conducting testing for its employees, including all students, contractors and instructors at the FLETC sites,” said Reardon.

Students are in classrooms with around 50 people with people wearing masks, according to a person at the training center who asked not to be identified because they weren’t authorized to speak for the center.

It’s “probably a breeding ground,” said the person at the training center, who added that outside of class the requirements for mask wearing and social distance are even more relaxed.

Neither DHS nor CBP responded to a request for comment. However, Federal Law Enforcement Training Center Director Thomas J. Walters said in a news release Friday that his department is working “to test, identify, isolate and contain the COVID-19 virus in order to keep and maintain safe training and working conditions.”

“In today’s world, zero risk is not attainable, but getting as close to that number as possible is my daily charge,” he said.

In March, the Federal Law Enforcement Training Center, which trains upwards of 67,000 law enforcement officers each year, temporarily halted on-site training. That pause resulted in a delay of newly trained law enforcement officers to the field, according to a spokesperson.

On June 17, the training center restarted training under the revamped protocols, such as social distancing, enhanced personal hygiene, and face coverings.