Danger lurks in the waters of the Donna Reservoir.
"We are asking people not to go swim there because if they swallow the water, they can get this contamination throughout their system," Commissioner Joel Quintanilla said.
The Precinct One commissioner for Hidalgo County added that for years the lake has had large amounts of toxic chemicals floating around.
The fish that call the reservoir home are also just as hazardous to a person's health.
According to the Texas Health and Human Services Commission, environmental crews first spotted the chemicals, known as PCB TMs, in the mid 90's.
"If catch it you cook it and you deep fry it you kill the contaminants and it TMs safe to it, but this fish is not, Commissioner Quintanilla said about the attitudes from people living nearby. We want to make that real clear."
Quintanilla said the Environmental Protection Agency will return to the valley in May to begin a six month study to identify and trace the source of the contamination.
"The plan is to go ahead and clean up the system; do whatever it need be to reassure that we clean up and contaminants and remove the contaminants," he explained.
Warnings will remain in place for as long as it takes to clear out the toxins
The EPA said eating the contaminated fish could lead to several health problems, including nausea, vomiting, abdominal pain, skin rashes, acne, and even cancer in the long run.