A report from the Environmental Working Group finds that the tap water of 218 million Americans contains levels of the cancer-causing chemical chromium-6 that the group considers dangerous.

New York state follows federal guidelines set by the EPA of 100 parts per billion. Adrienne Esposito, of Citizens Campaign for Environment, would rather New York embrace the standards set by California: 10 parts per billion. A map released by the group puts chromium-6 levels in Suffolk County at 5 and 7 parts per billion. 

"It is very hazardous to our health. It's associated with stomach cancer, lung cancer and reproductive disorders," says Esposito. "We cannot be so casual about finding these toxic chemicals and say 'it's OK.' It's not OK."

Suffolk County Water Authority CEO Jeff Szabo admits the potential of chromium-6 in drinking water can be scary, but Szabo said the company goes beyond EPA regulations to ensure the water is at a safe level.

"We meet all current health regulations of 100 ppb," says Szabo. "California presently has a standard of 10 ppb, and we are far below that."

Federal regulations on chromium-6 could be changing soon, according to the EPA. Officials say they've been reviewing chemical levels since 2010 and plan to release the findings within the year,