The Guatemalan migrant was found unresponsive during a welfare check, according to a tweet by US Customs and Border Protection (CBP). The cause of death is not known at this time.
CBP said that "a large number" of people in custody were found to have high fevers, in a statement on Tuesday. The agency is working to provide medical treatment to those affected.
Migrants who are apprehended in the area will be held at other locations until the situation is fixed, according to the CBP.
The CBP's processing center is a converted warehouse that holds hundreds of parents and children in large, fenced pens, according to WMCTV.