Americans have been shocked and horrified by news reports that residents of Flint, Mich., were being poisoned by lead leaching from old lead pipes that brought drinking water into their homes and businesses. But Flint's tragedy isn't unique. This month, an investigation by USA Today Network found excessive lead in almost 2,000 water systems scattered across all 50 states.

The report found that 6 million people are at risk due to water systems which have lead levels that exceed EPA standards. About 350 of those systems provide drinking water to schools and daycares.

According to the EPA, lead levels above 20 parts per billion (ppb) are excessive. Yet water in one elementary school in Ithaca, N.Y., was found to have 5,000 ppb, a level the EPA labels as "hazardous waste."

Many customers of the contaminated water systems don't realize they are at risk, since at least half of the systems bypassed federal regulations that they notify their customers. But lead contamination is a huge problem, especially to children and pregnant women.

According to the World Health Organization, no amount of exposure to lead is safe, and excessive lead can have a drastic effect on a child's intelligence, causing lower intelligence quotient (IQ), shortened attention span, and increased antisocial behavior.

"Lead exposure also causes anemia, hypertension, renal impairment, immunotoxicity and toxicity to the reproductive organs," says the organization. "The neurological and behavioral effects of lead are believed to be irreversible."

Irreversible? Not so, say experts. Chelation therapy is approved by the FDA for treating lead poisoning as well as poisoning by other heavy metals, such as mercury, and can permanently remove them from the body.

Chelation therapy uses intravenous injections (also called infusions) of a chelating factor called EDTA (ethylene diamine tetraacetic acid), a synthetic amino acid which binds to toxic metals and minerals in the bloodstream. The toxins are excreted in the urine.

Some experts believe heavy metal contamination causes or contributes to cardiovascular disease, and that chelation rids the body of deposits that can lead to atherosclerosis, which causes coronary arteries to narrow and leads to heart attacks.

While the treatment for heavy metal toxins is recognized as effective by mainstream medicine, chelation for other conditions, such as heart disease, isn't widely accepted.

Attitudes, however, are changing.

The federal agency's National Center for Complementary and Integrative Health has awarded an $800,000 grant to Mount Sinai Medical Center of Florida and the Duke Clinical Research Institute to begin a follow-up study of chelation that could lead to its use as a standard treatment for cardiovascular disease.

Dr. Gervasio Lamas of the Columbia University Division of Cardiology at Mount Sinai, one of the researchers benefiting from the grant, was once a skeptic of chelation therapy and set out to prove it was a sham.

Dr. Lamas was shocked when his first study, which was published in the American Heart Journal, found that chelation slashed the risk of dying for some heart patients by half. The treatment was found to be especially beneficial to diabetics.

Dr. Lamas' study involved 1,708 heart patients at 134 clinics in the U.S. and Canada. All were above the age of 50, and all were heart attack survivors who were taking heart medications. A third of them were diabetics.

The patients were divided into four groups: The first group received chelation injections plus high-dose oral multivitamins; the second was given chelation with a placebo (in place of vitamins); the third group was administered placebo infusions (in place of chelation) with high-dose multivitamins; and the fourth group received placebo infusions with oral placebo.

The participants were followed for seven years to see which patients experienced a second heart attack, stroke, bypass surgery, other cardiovascular events, or died.

The results showed those who received chelation therapy plus vitamin supplements had a 26 percent lower risk of cardiac problems, compared with those given placebos.

But diabetic patients, the group that received the combination of chelation with vitamins, experienced a 49 percent lower risk of heart complications. Chelation (with or without vitamins) was also found to cut the risk of death among diabetics by half over the length of the study.

"There is nothing like this for diabetes care," Dr. Lamas told Newsmax Health. "There just isn't."

"When we started this research … we expected this would be a negative study that would be debunking chelation and this would prove it doesn’t work," he said.

"But in fact, we didn’t find that," Dr. Lamas said. "It was a complete turnaround from what we expected."