HIALEAH, Fla. -- A dialysis patient went to a local clinic for treatment, but instead of getting better he got much sicker. His family said the clinic's contaminated water is to blame.

Noemy Estevez said that, for the past five years, her father, Tony, has been a healthy dialysis patient.

"He's been a healthy dialysis patient," Estevez said. "So far he's never had any serious issues."

However, things changed and he was taken to Mount Sinai Hospital in critical condition.

"I could automatically tell that there was something different," Estevez said. "He wasn't feeling well, he wasn't sleeping well and he wasn't eating well."

She said her father's health took a turn for the worse while recently undergoing dialysis treatment at the Fresenius Medical Care Center in Hialeah.

"I was repeatedly told that nothing out of the ordinary was going on at the clinic," Estevez said.

Something was wrong, and after some questioning, Estevez said the truth came out that the water at the clinic was contaminated.

"After my confronting them they did come forth and say there was something in the water," she said. "The water was not filtered properly, and as a result, several patients had received the non-filtered water with a chemical called chloramine in it."

Chloramine is safe for the public, but for dialysis patients like Tony Estevez, it kills red blood cells and can cause heart attacks. That's exactly what happened to him, doctors said.

The stress was too much for his wife of 40 years, who was admitted to the same hospital Wednesday night complaining of chest pains.

"Essentially these people received a chemical that they couldn't deal with," Noemy Estevez said. "Their bodies couldn't tolerate it. It's unacceptable. It's very, very disappointing."

The family hired an attorney. He said this is not the first time for problems with water at the clinic. He said health officials cited the medical center in 2004, and he said he believes this time, they were trying to cover the whole thing up.

"Fortunately, at this point, he is living," attorney Robert Boyers said. "God willing he will continue to live. But he suffered unnecessarily. He suffered a heart attack that likely could've been prevented."

The clinic said it noticed the water contamination on April 30. It released a statement on Thursday.

"The problem was corrected within 24 hours," the statement from the Fresenius Medical Care Center of Hialeah said. "After the water system was checked thoroughly and determined to be functioning properly, the facility began treating patients again on Thursday, May 1. A number of patients were admitted to the hospital, and many have since been released."

The Estevez family said its case is far from over.